JP6137184B2 - Organic electroluminescence element, lighting device and display device - Google Patents

Description

The present invention relates to an organic electroluminescent device, related to the lighting device and a display device.

  Conventionally, there is an electroluminescence display (ELD) as a light-emitting electronic display device. As a constituent element of ELD, an inorganic electroluminescence element and an organic electroluminescence element (hereinafter also referred to as an organic EL element) can be given. Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  On the other hand, an organic EL element has a configuration in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer to recombine excitons. This is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts. Therefore, it has a wide viewing angle, high visibility, and since it is a thin-film type complete solid-state device, it is attracting attention from the viewpoints of space saving and portability.

  As development of an organic EL element for practical use, for example, Princeton University, M.M. A. Baldo et al. , Nature, 395, 151-154 (1998), an organic EL device using phosphorescence emission from an excited triplet has been reported. Since then, US Pat. No. 6,097,147 has been disclosed. , M.C. A. Baldo et al. , Nature, Vol. 403, No. 17, 750-753 (2000), and the like, studies on materials that exhibit phosphorescence at room temperature have become active.

  Organic EL elements that use phosphorescence emission can in principle achieve light emission efficiency about 4 times that of elements that use previous fluorescence emission. Research and development of electrodes and electrodes are conducted all over the world.

  As a material constituting the light-emitting element, many compounds have been studied focusing on heavy metal complexes such as iridium complexes. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001) describes that these metal complexes are used in a light emitting layer of an organic electroluminescence element (also referred to as an organic EL element).

  As described above, the phosphorescence emission method is a method having a very high potential, but in an organic EL device using phosphorescence emission, a method for controlling the position of the emission center, in particular, recombination inside the emission layer, How to stably emit light and how to improve the light emitting property of the phosphorescent material itself is an important technical issue from the viewpoint of the efficiency and life of the device.

  As luminescent materials for blue phosphorescence used in organic EL devices, iridium complexes having ligands such as phenylpyrazole, imidazophenanthridine, and phenylimidazole are known. It is very difficult to satisfy all of light emission and high durability at the same time.

  It is known that a simple iridium complex of phenylpyrazole does not emit light at room temperature, but only emits light when a group that reduces the band gap such as a benzene ring is introduced as a substituent (for example, (See Patent Document 1).

  Further, it is disclosed that a metal complex having imidazophenanthridine as a ligand is a light-emitting material having a short emission wavelength (see, for example, Patent Documents 2 and 3).

  Further, it is disclosed that a metal complex of phenylimidazole is a light emitting material having a relatively short emission wavelength (see, for example, Patent Documents 4, 5, 6, and 7).

  However, in the technique described in Patent Document 1, it is necessary to extend the π-conjugated system to increase the emission wavelength in order to improve the light emission property and the light emission lifetime at the same time. I can't meet. Further, in the techniques described in Patent Documents 2 and 3, the light emission efficiency is low, and it is impossible to simultaneously achieve reduction in power consumption and increase in light emission life. In addition, in the techniques described in Patent Documents 4, 5, 6, and 7, the light emission life cannot be sufficiently extended.

  On the other hand, a wet method (also referred to as a wet process or the like) has attracted attention as a method for producing an organic EL element from the viewpoint of increasing the area of the organic EL element, reducing costs, and increasing productivity. According to this wet method, film formation can be performed at a lower temperature than film formation by a vacuum process, so that damage to the organic layer located in the lower layer can be reduced, and luminous efficiency and device lifetime are improved. There is expected. However, the host material and the electron transport material of the organic EL element using blue phosphorescence are insufficient in solubility in a solvent and solution stability, and are difficult to manufacture by a wet method. Moreover, the organic EL element manufactured using the said host material and electron transport material also has a problem that a drive voltage is high.

International Publication No. 2004/085450 International Publication No. 2007/095118 International Publication No. 2008/156879 International Publication No. 2006/046980 US Patent Publication No. 2006/0251923 US Patent Publication No. 2011/0057559 Specification US Patent Publication No. 2011/02034333

  The present invention has been made in view of the above-mentioned problems and circumstances, and the problem to be solved is organic electroluminescence that has a low driving voltage, high light emission efficiency, excellent durability, and excellent dark spot and light emission unevenness prevention effects. It is to provide an element. Moreover, it is providing the illuminating device and display apparatus with which it was comprised.

  In order to solve the above-mentioned problems, the present inventor, for the cause of the above-mentioned problems, and the like, of the organometallic complex having phenylimidazole as a ligand, the effect of improving the luminous efficiency at the phenylimidazole moiety and the N-phenyl group of the imidazole ring Coordination represented by the general formula (1) or the general formula (2) as a result of intensive investigation of the chemical structure from the viewpoint of efficiently achieving the function of separating the carrier transfer effect from the bonded aryl group. It has been found that the above problems can be solved by an organic EL device containing a phosphorescent organic metal whose child is coordinated to a metal atom.

  That is, the said subject which concerns on this invention is solved by the following means.

  1. An organic electroluminescence device in which at least one organic layer including a light emitting layer is sandwiched between an anode and a cathode, wherein at least one of the organic layers is represented by the following general formula (1) or general formula (2): The organic electroluminescent element characterized by containing the phosphorescence-emitting organometallic complex in which the ligand represented by this coordinated to the metal atom.

［一般式（１）及び（２）中、環Ｂは、５員若しくは６員の芳香族炭化水素環又は芳香族複素環を表す。環Ｅは、炭素原子、ケイ素原子又は窒素原子を表すＧを介して環Ｄに結合している炭素数６〜３０の芳香族炭化水素環又は炭素数１〜３０の芳香族複素環を表す。

[In General Formulas (1) and (2), Ring B represents a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle. Ring E represents an aromatic hydrocarbon ring having 6 to 30 carbon atoms or an aromatic heterocyclic ring having 1 to 30 carbon atoms bonded to ring D through G representing a carbon atom, a silicon atom, or a nitrogen atom.

R ₁ and R ₂ are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-group It represents an aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. At least one of R ₁ and R ₂ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms. R ₃ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms.

Ra is selected from a hydrogen atom, a methyl group, an isopropyl group, an isobutyl group, a 3-pentyl group, a 4-heptyl group, and a 2-ethylbutyl group.
Rb, Rc, Rd and Re are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group Represents a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent.

  nb and nd represent an integer of 1 to 4, and na and nc represent 1 or 2. ne represents an integer of 1 to 20.

〔一般式（Ｌ１Ａ）〜（Ｌ１ＡＡ）及び一般式（Ｌ２Ａ）〜（Ｌ２Ｑ）において、環Ｂ、環Ｅ、Ｇ、Ｒ _１ 、Ｒ _２ 、Ｒ _３ 、Ｒａ、Ｒｂ、Ｒｃ、Ｒｄ、Ｒｅ、ｎａ、ｎｂ、ｎｃ、ｎｄ及びｎｅは、上記一般式（１）及び（２）の環Ｂ、環Ｅ、Ｇ、Ｒ _１ 、Ｒ _２ 、Ｒ _３ 、Ｒａ、Ｒｂ、Ｒｃ、Ｒｄ、Ｒｅ、ｎａ、ｎｂ、ｎｃ、ｎｄ及びｎｅと同義である。
Ｒａ _１ 〜Ｒａ _４ 、Ｒｃ _１ 〜Ｒｃ _２ 及びＲｄ _１ 〜Ｒｄ _４ は、それぞれ、置換基Ｒａ、Ｒｃ及びＲｄの位置違いを表す。
一般式（Ｌ１Ａ）〜（Ｌ１ＡＡ）及び一般式（Ｌ２Ａ）〜（Ｌ２Ｑ）において、Ｗ、Ｘ、Ｙ及びＺは、置換基を有しても良い炭素原子、置換基を有しても良い窒素原子、置換基を有するケイ素原子、酸素原子又は硫黄原子を表す。〕
２．前記一般式（１）又は一般式（２）で表される配位子が金属原子に配位したリン光発光性有機金属錯体が、下記一般式（３）又は一般式（４）で表されるリン光発光性有機金属錯体であることを特徴とする第１項に記載の有機エレクトロルミネッセンス素子。 Adjacent ring A and ring D, ring D and ring E may be bonded to each other at two points to form any condensed ring selected from dibenzofuran, dibenzothiophene, fluorene and carbazole . Further, ring A, ring D and ring E may form a condensed ring consisting of a series of five rings formed by combining two condensed rings selected from dibenzofuran, dibenzothiophene, fluorene and carbazole, or a triphenylene skeleton. good.
Here, the ligand represented by the general formula (1) is selected from the structures represented by the following general formulas (L1A) to (L1AA), and the ligand represented by the general formula (2) is: It is selected from the structures represented by the following general formulas (L2A) to (L2Q). ]

[In General Formulas (L1A) to (L1AA) and General Formulas (L2A) to (L2Q), Ring B, Ring E, G, R ₁ , R ₂ , R ₃ , Ra, Rb, Rc, Rd, Re, na , Nb, nc, nd and ne are the ring B, ring E, G, R ₁ , R ₂ , R ₃ , Ra, Rb, Rc, Rd, Re, na, in the general formulas (1) and (2) . It is synonymous with nb, nc, nd and ne.
_{Ra 1 ~Ra 4, Rc 1 ~Rc} 2 and _Rd 1 ~ Rd ₄ each represent the position difference of the substituents Ra, Rc and Rd.
In the general formulas (L1A) to (L1AA) and the general formulas (L2A) to (L2Q), W, X, Y, and Z are carbon atoms that may have a substituent, and nitrogen that may have a substituent. An atom, a silicon atom having a substituent, an oxygen atom or a sulfur atom is represented. ]
2. The phosphorescent organometallic complex in which the ligand represented by the general formula (1) or the general formula (2) is coordinated to a metal atom is represented by the following general formula (3) or the general formula (4). 2. The organic electroluminescence device according to item 1, which is a phosphorescent organic metal complex.

［一般式（３）及び（４）中、環Ｂは、５員若しくは６員の芳香族炭化水素環又は芳香族複素環を表す。環Ｅは、炭素原子、ケイ素原子又は窒素原子を表すＧを介して環Ｄに結合している炭素数６〜３０の芳香族炭化水素環又は炭素数１〜３０の芳香族複素環を表す。

[In General Formulas (3) and (4), Ring B represents a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle. Ring E represents an aromatic hydrocarbon ring having 6 to 30 carbon atoms or an aromatic heterocyclic ring having 1 to 30 carbon atoms bonded to ring D through G representing a carbon atom, a silicon atom, or a nitrogen atom.

R ₁ and R ₂ are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-group It represents an aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. At least one of R ₁ and R ₂ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms. R ₃ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms.

Ra is selected from a hydrogen atom, a methyl group, an isopropyl group, an isobutyl group, a 3-pentyl group, a 4-heptyl group, and a 2-ethylbutyl group.
Rb, Rc, Rd and Re are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group Represents a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent.

  nb and nd represent an integer of 1 to 4, and na and nc represent 1 or 2. ne represents an integer of 1 to 20.

Adjacent ring A and ring D, ring D and ring E may be bonded to each other at two points to form any condensed ring selected from dibenzofuran, dibenzothiophene, fluorene and carbazole . Further, ring A, ring D and ring E may form a condensed ring consisting of a series of five rings formed by combining two condensed rings selected from dibenzofuran, dibenzothiophene, fluorene and carbazole, or a triphenylene skeleton. good.

L represents one or more of monoanionic bidentate ligands coordinated to M. M represents an atomic number of 40 or more and a group 8-10 transition metal atom in the periodic table, and m represents an integer of 0-2. n is at least 1 and m + n is 2 or 3.
Here, the ligand represented by the general formula (1) is selected from the structures represented by the general formulas (L1A) to (L1AA), and is represented by the general formula (2). Is selected from the structures represented by the general formulas (L2A) to (L2Q). ]
3. The phosphorescent organometallic complex represented by the general formula (3) or (4) is a phosphorescent organometallic complex represented by the following general formula (5) or (6), The organic electroluminescent element according to item 2.

［一般式（５）及び（６）中、環Ｅは、炭素原子、ケイ素原子又は窒素原子を表すＧを介して環Ｄに結合している炭素数６〜３０の芳香族炭化水素環又は炭素数１〜３０の芳香族複素環を表す。

[In General Formulas (5) and (6), Ring E is an aromatic hydrocarbon ring having 6 to 30 carbon atoms or carbon bonded to Ring D via G representing a carbon atom, a silicon atom or a nitrogen atom. The aromatic heterocyclic ring of number 1-30 is represented.

R ₁ and R ₂ are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-group It represents an aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. At least one of R ₁ and R ₂ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms. R ₃ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms.

Ra is selected from a hydrogen atom, a methyl group, an isopropyl group, an isobutyl group, a 3-pentyl group, a 4-heptyl group, and a 2-ethylbutyl group.
Rb, Rc, Rd and Re are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group Represents a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent.

  nb and nd represent an integer of 1 to 4, and na and nc represent 1 or 2. ne represents an integer of 1 to 20.

Adjacent ring A and ring D, ring D and ring E may be bonded to each other at two points to form any condensed ring selected from dibenzofuran, dibenzothiophene, fluorene and carbazole . Further, ring A, ring D and ring E may form a condensed ring consisting of a series of five rings formed by combining two condensed rings selected from dibenzofuran, dibenzothiophene, fluorene and carbazole, or a triphenylene skeleton. good.

L represents one or more of monoanionic bidentate ligands coordinated to M. M represents an atomic number of 40 or more and a group 8-10 transition metal atom in the periodic table, and m represents an integer of 0-2. n is at least 1 and m + n is 2 or 3.
Here, the ligand represented by the general formula (1) is selected from the structures represented by the general formulas (L1A) to (L1AA), and is represented by the general formula (2). Is selected from the structures represented by the general formulas (L2A) to (L2Q). However, in the general formulas (L1A) to (L1AA) and the general formulas (L2A) to (L2Q), the ring B represents a benzene ring. ]
4). Whether adjacent ring A and ring D, ring D and ring E of the organometallic complex are bonded to each other at two positions to form any condensed ring selected from dibenzofuran, dibenzothiophene, fluorene and carbazole Or ring A, ring D and ring E form a condensed ring consisting of a series of five rings formed by combining two condensed rings selected from dibenzofuran, dibenzothiophene, fluorene and carbazole, or a triphenylene skeleton . The organic electroluminescence device according to any one of items 1 to 3, wherein the organic electroluminescence device is characterized in that

  5. The organic electroluminescence device according to any one of items 2 to 4, wherein the transition metal atom of the atomic number 40 or more and the group 8 to 10 in the periodic table is iridium.

  6). A derivative having a ring structure in which at least one of the carbon atoms of the hydrocarbon ring constituting the light emitting layer is composed of a fluorene derivative, a dibenzofuran derivative, a dibenzothiophene derivative, a carbazole derivative, or a condensed ring compound derivative thereof. The organic electroluminescent element according to any one of items 1 to 5, which is contained.

  7). The organic electroluminescent device according to any one of items 1 to 6, wherein the organic layer containing the phosphorescent organometallic complex is a layer formed through a wet process. .

  8). 8. The organic electroluminescence element according to any one of items 1 to 7, wherein the emission color is white.

  9. A display device comprising the organic electroluminescence element according to any one of items 1 to 8.

  10. An organic electroluminescence element according to any one of items 1 to 8 is provided.

  By the above means of the present invention, there is provided an organic electroluminescence device having a low driving voltage, high luminous efficiency, excellent durability, and excellent dark spot and emission unevenness prevention effect, and an illumination device and a display device equipped with the organic electroluminescent device. it can.

  The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows. The D ring portion bonded to the N-phenyl group of the imidazole ring of the ligand represented by the general formula (1) or the general formula (2) protrudes to the m-position or the o-position with respect to the imidazole ring. Therefore, the interaction between the light-emitting dopants by the D ring part and the E ring part is not excessively strong, and the phenylimidazole part improves the light emission efficiency and is bonded to the N-phenyl group of the imidazole ring. It is considered that the function separation effect of carrier transfer is more strongly expressed in the ring portion and the E ring portion.

Schematic diagram showing an example of a display device composed of organic EL elements Schematic diagram of the display unit of the display device of FIG. Schematic diagram of the circuit of the display device of FIG. Schematic diagram of a passive matrix display device Schematic of lighting device Cross section of the lighting device

  The organic electroluminescence device of the present invention is an organic electroluminescence device in which at least one organic layer including a light emitting layer is sandwiched between an anode and a cathode, and at least one layer of the organic layer has the general formula The ligand represented by (1) or general formula (2) contains a phosphorescent organometallic complex coordinated to a metal atom. This feature is a technical feature common to the inventions according to claims 1 to 10.

  As an embodiment of the present invention, a phosphorescent organometallic complex in which the ligand represented by the general formula (1) or the general formula (2) is coordinated to a metal atom from the viewpoint of manifesting the effect of the present invention. However, it is preferable that it is a phosphorescence-emitting organometallic complex represented by General formula (3) or General formula (4). The phosphorescent organometallic complex represented by the general formula (3) or (4) is preferably a phosphorescent organometallic complex represented by the general formula (5) or (6).

Furthermore, in the present invention, adjacent ring A and ring D, ring D and ring E of the organometallic complex are bonded to each other at two positions, and any one selected from dibenzofuran, dibenzothiophene, fluorene and carbazole. These condensed rings may be formed. Further, ring A, ring D and ring E may form a condensed ring consisting of a series of five rings formed by combining two condensed rings selected from dibenzofuran, dibenzothiophene, fluorene and carbazole, or a triphenylene skeleton. good.

  Moreover, it is preferable that the transition metal atom of the atomic number 40 or more and 8-10 group in an element periodic table is iridium. Further, the light emitting layer has a ring structure in which at least one of carbon atoms of a hydrocarbon ring constituting a fluorene derivative, a dibenzofuran derivative, a dibenzothiophene derivative, a carbazole derivative or a condensed ring compound derivative thereof is substituted with a nitrogen atom. It is preferable to contain the derivative | guide_body which has.

  Moreover, it is preferable that the organic layer containing the phosphorescent organometallic complex is a layer formed through a wet process because a homogeneous film is easily obtained and pinholes are hardly generated.

  Furthermore, the emission color is preferably white.

  The organic electroluminescence element of the present invention can be suitably included in a display device and a lighting device.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

  Hereinafter, although the form for implementing this invention is demonstrated in detail, this invention is not limited to these.

<< Constituent layers of organic EL elements >>
In the present invention, the organic layer refers to a layer containing an organic substance. A hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection constituting organic electroluminescence (hereinafter also referred to as organic EL) provided between the anode and the cathode. Layers and the like are included in the organic layer.

  The constituent layers of the organic EL element of the present invention will be described. In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.

(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) Anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) Anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode (vi) anode // hole transport layer / anode buffer layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (vii) anode / anode Buffer layer / Hole transport layer / Light emitting layer / Electron transport layer / Cathode buffer layer / cathode When a plurality of light emitting layers are included, a non-light emitting intermediate layer may be provided between the light emitting layers. In addition, among the above layer structures, an organic compound layer including a light emitting layer excluding an anode and a cathode can be used as one light emitting unit, and a plurality of light emitting units can be stacked. The plurality of stacked light emitting units may have a non-light emitting intermediate layer between the light emitting units, and the intermediate layer may further include a charge generation layer.

  The organic EL element of the present invention is preferably a white light emitting layer, and is preferably a display device and a lighting device using these.

  Each layer which comprises the organic EL element of this invention is demonstrated.

<Light emitting layer>
The light emitting layer according to the present invention is a layer that emits light when excitons generated by recombination of electrons and holes injected from the cathode or the electron transport layer or the anode or the hole transport layer are deactivated. The portion to be formed may be in the light emitting layer or at the interface between the light emitting layer and the adjacent layer.

  The total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. Preferably, it is adjusted to the range of 2 nm to 5 μm, more preferably adjusted to the range of 2 to 200 nm, and particularly preferably adjusted to the range of 5 to 100 nm.

  For the production of the light emitting layer, a light emitting dopant or host compound described later is used, for example, a vacuum deposition method, a wet method (also referred to as a wet process, for example, a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, An ink-jet method, a printing method, a spray coating method, a curtain coating method, an LB method (a Langmuir-Blodgett method and the like can be used)) and the like can be formed. Preferably, the light emitting layer is a layer formed through a wet process. By forming the layer by a wet process, damage to the light emitting layer due to heat can be reduced as compared with the vacuum deposition method.

  The light emitting layer of the organic EL device of the present invention contains a light emitting dopant and a host compound, and at least one light emitting dopant is a ligand represented by the above general formula (1) or general formula (2). Is a phosphorescent organometallic complex coordinated to a metal atom, and is preferably a phosphorescent organometallic complex represented by any one of formulas (3) to (6).

  Moreover, you may use together the compound etc. which are described in the following patent gazettes in the light emitting layer which concerns on this invention.

  For example, International Publication No. 00/70655, JP 2002-280178, JP 2001-181616, JP 2002-280179, JP 2001-181617, JP 2002-280180, JP 2001-247859 A, JP 2002-299060 A, JP 2001-313178 A, JP 2002-302671 A, JP 2001-345183 A, JP 2002-324679 A, International Publication. No. 02/15645, JP 2002-332291 A, JP 2002-50484 A, JP 2002-332292 A, JP 2002-83684 A, JP 2002-540572 A, JP 2002-2002 A. No. 117978, Japanese Patent Application Laid-Open No. 2002-33858 JP, JP-A-2002-170684, JP-A-2002-352960, WO01 / 93642, JP-A-2002-50483, JP-A-2002-1000047, JP-A-2002-173684. JP-A-2002-359082, JP-A-2002-175484, JP-A-2002-363552, JP-A-2002-184582, JP-A-2003-7469, JP-A-2002-525808, JP 2003-7471, JP 2002-525833, JP 2003-31366, JP 2002-226495, JP 2002-234894, JP 2002-2335076, JP 2002 No. 2411751, JP 2001-319779 A. JP, 2001-319780, 2002-62824, 2002-100474, 2002-203679, 2002-343572, 2002-203678, etc. It is.

(1) Luminescent dopant A luminescent dopant is demonstrated.

  As the light-emitting dopant, a fluorescent dopant (also referred to as a fluorescent compound) or a phosphorescent dopant (also referred to as a phosphorescent light-emitting dopant, a phosphorescent compound, a phosphorescent compound, or the like) can be used.

  As a result of intensive studies to achieve the above-described object of the present invention, the present inventors have made phosphorescence emission in which a ligand represented by the general formula (1) or (2) is coordinated to a metal atom. The present inventors have found that by using a light-emitting organometallic complex as a phosphorescent dopant, high light emission luminance, low driving voltage, and longer light emission lifetime can be achieved at the same time. Moreover, it turned out that the organic electroluminescent element produced using the phosphorescence dopant of this invention is improved also at the point of temporal stability.

  As described in Patent Documents 6 and 7, it is already known that a metal complex coordinated with a ligand having an imidazole skeleton having a specific substituent is useful as a light-emitting dopant in an organic EL device. ing.

  These metal complexes have improved material efficiency due to the effect of improving luminous efficiency at the phenylimidazole part of the ligand and the function separation effect of carrier movement being carried out by the aryl group bonded to the N-phenyl group of the imidazole ring. However, since the interaction between the aryl groups bonded to the N-phenyl group becomes too strong, the decrease in light emission efficiency due to concentration quenching between the light emitting dopants cannot be overlooked, and the light emission lifetime The improvement was not enough.

  In the phosphorescent organometallic complex represented by any one of the general formulas (3) to (6) of the present invention, the N-- of the imidazole ring of the ligand represented by the general formula (1) or (2) Since the D ring portion bonded to the phenyl group protrudes to the m-position or the o-position with respect to the imidazole ring, the interaction between the light-emitting dopants due to the D ring portion and the E ring portion becomes too strong. In addition, the effect of improving the luminous efficiency in the phenylimidazole part and the function separation effect of carrier movement in the D ring part and E ring part bonded to the N-phenyl group of the imidazole ring are more strongly expressed, and the robustness of the material Further improved. In addition, since the shape of the light-emitting dopant molecules approaches a spherical shape, the dispersibility with respect to the host compound is improved, so that the carrier balance of the entire device can be optimized and the recombination of carriers at a more central portion of the light-emitting layer can be realized. Thus, it is considered that the light emission lifetime is improved and the uniformity of the light emitting layer is improved so that the occurrence of light emission unevenness is suppressed.

  In the phosphorescent organometallic complex in which the ligand represented by the general formula (1) or the general formula (2) according to the present invention is coordinated to a metal atom, M is preferably a transition metal atom. By changing the combination of the ligands coordinated to the transition metal atom M or introducing a substituent into the ligand, the emission wavelength of the phosphorescent organometallic complex can be controlled in the desired region. can do.

  By using such a metal complex as an organic EL device material, the initial driving voltage is low, the half-life is long, dark spots and light emission unevenness are not generated, external extraction quantum efficiency is high, and a desired emission wavelength is obtained. An organic electroluminescence element (organic EL element) capable of controlling light emission, and a lighting device and a display device including the organic electroluminescence element can be provided.

(1.1) Phosphorescent dopant The phosphorescent dopant according to the present invention will be described.

  The phosphorescent dopant according to the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescence at room temperature (25 ° C.), and a phosphorescence quantum yield is 25 ° C. The phosphorescence quantum yield is preferably 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. That's fine.

  There are two types of emission of phosphorescent dopants in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent dopant. It is an energy transfer type to obtain light emission from a phosphorescent dopant. The other is a carrier trap type in which a phosphorescent dopant serves as a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant is obtained. In any case, it is a condition that the excited state energy of the phosphorescent dopant is lower than the excited state energy of the host compound.

  As the phosphorescent dopant in the embodiment of the present invention, a phosphorescent organometallic complex in which a ligand represented by the general formula (1) or the general formula (2) described below is coordinated to a metal atom is described. Used. It is preferable to use a phosphorescent organometallic complex represented by any one of General Formula (3) to General Formula (6).

(1.1.1) A phosphorescent organometallic complex in which a ligand represented by the general formula (1) or the general formula (2) is coordinated

Here, the ligand represented by the general formula (1) is selected from the structures represented by the general formulas (L1A) to (L1AA), and is represented by the general formula (2). Is selected from the structures represented by the general formulas (L2A) to (L2Q).
In the general formula (1) and the general formula (2), examples of the 5-membered or 6-membered aromatic heterocycle represented by the ring B include a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, and a pyridazine. A ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an oxadiazole ring, a triazole ring, an imidazole ring, a pyrazole ring, a thiazole ring, and the like.

  Ring B is preferably a benzene ring.

  In the general formula (1) and the general formula (2), the ring E is an aromatic hydrocarbon ring having 6 to 30 carbon atoms bonded to the ring D through G representing a carbon atom, a silicon atom, or a nitrogen atom, or Represents an aromatic heterocycle having 1 to 30 carbon atoms.

  In the general formulas (1) and (2), examples of the aromatic hydrocarbon ring having 6 to 30 carbon atoms represented by ring E include, for example, a benzene ring, naphthalene ring, phenanthrene ring, benzophenanthrene ring, chrysene ring, benzochrysene Ring, triphenylene ring, picene ring, naphthochrysene ring, phenanthrochrysene ring and the like.

  In the general formulas (1) and (2), examples of the aromatic heterocyclic ring having 1 to 30 carbon atoms represented by ring E include, for example, a furan ring, a thiophene ring, a pyrrole ring, a silole ring, a pyridine ring, a pyridazine ring, and a pyrimidine. Ring, pyrazine ring, triazine ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, oxazole ring, thiazole ring, benzofuran ring, benzothiophene ring, indole ring, indene ring, benzosilol ring, furofuran ring, thienothiophene ring , Furopyrrole ring, thienopyrrole ring, quinoline ring, isoquinoline ring, quinazoline ring, quinoxaline ring, naphthyridine ring, benzimidazole ring, indazole ring, benzotriazole ring, benzoxazole ring, benzothiazole ring, dibenzofuran ring, dibenzothiophene ring, Vazole ring, fluorene ring, dibenzosilole ring, benzodifuran ring, benzodithiophene ring, furindole ring, thienoindole ring, benzofuranobenzofuran ring, benzothienobenzothiophene ring, benzofurenoindole ring, benzothienoindole ring, indoloindole Ring, benzothienobenzofuran ring, benzofuranocarbazole ring, benzothienocarbazole ring, indolocarbazole ring, benzosilolocarbazole ring, acridine ring, benzoquinoline ring, phenazine ring, phenanthridine ring, phenanthroline ring, kindrin ring, quinindrin ring Benzofuroquinoline ring, benzothienoquinoline ring, triphenodithiazine ring, triphenodioxazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene Ring, Nafutojifuran ring, naphthodifuran thiophene ring, Antorafuran ring, anthradithiophene furan ring, anthracite thiophene ring, anthradithiophene ring, a thianthrene ring, a phenoxathiin ring, and the like.

  Ring E is preferably a benzene ring, dibenzofuran ring, dibenzothiophene ring, carbazole ring, or fluorene ring.

In the general formula (1), R ₁ and R ₂ are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group Represents a heteroaryl group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. At least one of R ₁ and R ₂ represents an alkyl group having 1 or more carbon atoms or a cycloalkyl group having 3 or more carbon atoms.

In the general formula (1), examples of the halogen atom represented by R ₁ and R ₂ include a fluorine atom, a chlorine atom, and a bromine atom.

In the general formula (1), examples of the alkyl group represented by R ₁ and R ₂ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, and dodecyl. Group, tridecyl group, tetradecyl group, pentadecyl group and the like.

In the general formula (1), examples of the alkenyl group represented by R ₁ and R ₂ include a vinyl group and an allyl group.

In the general formula (1), examples of the alkynyl group represented by R ₁ and R ₂ include an ethynyl group and a propargyl group.

In the general formula (1), examples of the alkoxy group represented by R ₁ and R ₂ include a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, and a dodecyloxy group. Can be mentioned.

In the general formula (1), examples of the amino group represented by R ₁ and R ₂ include an amino group, an ethylamino group, a dimethylamino group, a butylamino group, a cyclopentylamino group, a 2-ethylhexylamino group, and a dodecylamino group. Group, anilino group, naphthylamino group, 2-pyridylamino group and the like.

In the general formula (1), examples of the silyl group represented by R ₁ and R ₂ include a trimethylsilyl group, a triisopropylsilyl group, a triphenylsilyl group, and a phenyldiethylsilyl group.

In the general formula (1), examples of the arylalkyl group represented by R ₁ and R ₂ include a benzyl group, an α-methylbenzyl group, a cinnamyl group, an α-ethylbenzyl group, an α, α-dimethylbenzyl group, 4-methylbenzyl group, 4-ethylbenzyl group, 2-tert-butylbenzyl group, 4-n-octylbenzyl group, naphthylmethyl group, diphenylmethyl group and the like can be mentioned.

In the general formula (1), examples of the aryl group represented by R ₁ and R ₂ include a benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, Triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, And monovalent groups derived from a pyrene ring, a pyranthrene ring, an anthraanthrene ring, and the like.

In the general formula (1), examples of the heteroaryl group represented by R ₁ and R ₂ include a silole ring, a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, and a pyrazine ring. , Triazine ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, carbazole A ring, an azacarbazole ring (representing any one or more of the carbon atoms constituting the carbazole ring replaced by a nitrogen atom), a dibenzosilole ring, a dibenzofuran ring, a dibenzothiophene ring, a benzothiophene ring or a dibenzofuran ring Carbon source A ring in which one or more of the above are replaced by a nitrogen atom, a benzodifuran ring, a benzodithiophene ring, an acridine ring, a benzoquinoline ring, a phenazine ring, a phenanthridine ring, a phenanthroline ring, a cyclazine ring, a quindrine ring, a tepenidine ring, Ring, triphenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring, anthrathiophene And monovalent groups derived from a ring, an anthradithiophene ring, a thianthrene ring, a phenoxathiin ring, a dibenzocarbazole ring, an indolocarbazole ring, a dithienobenzene ring, and the like.

In the general formula (1), examples of the non-aromatic hydrocarbon ring group represented by R ₁ and R ₂ include a cycloalkane (eg, cyclopentane ring, cyclohexane ring, etc.), a cycloalkoxy group (eg, cyclopentyloxy). Group, cyclohexyloxy group, etc.), cycloalkylthio group (for example, cyclopentylthio group, cyclohexylthio group, etc.), cyclohexylaminosulfonyl group, tetrahydronaphthalene ring, 9,10-dihydroanthracene ring, biphenylene ring, etc. The group of is mentioned.

In the general formula (1), examples of the non-aromatic heterocyclic group represented by R ₁ and R ₂ include an epoxy ring, an aziridine ring, a thiirane ring, an oxetane ring, an azetidine ring, a thietane ring, a tetrahydrofuran ring, and a dioxolane ring. Pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, Morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring, thiomorpholine-1,1-dioxide ring, pyranose ring, diazabicyclo [2, 2,2] -Ok Down ring, phenoxazine ring, a phenothiazine ring, Okisantoren ring, thioxanthene ring, and a monovalent group derived from phenoxathiin ring.

Preferably, R ₁ and R ₂ are both an alkyl group having 1 or more carbon atoms or a cycloalkyl group having 3 or more carbon atoms, and at least one of R ₁ and R ₂ is a branched alkyl group having 3 or more carbon atoms. It is also preferable. More preferably, both R ₁ and R ₂ are branched alkyl groups having 3 or more carbon atoms.

In the general formula (2), R ₃ is an alkyl group having 1 or more carbon atoms or a cycloalkyl group having 3 or more carbon atoms.

Preferably, R ₃ is a branched alkyl group having 3 or more carbon atoms or a cycloalkyl group having 5 or more carbon atoms, and more preferably R ₃ is a branched alkyl group having 3 or more carbon atoms.

  In the general formulas (1) and (2), Ra, Rb, Rc and Rd are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, a silyl group, It represents an arylalkyl group, an aryl group, a heteroaryl group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent.

In the general formulas (1) and (2), the halogen atom, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group and arylalkyl group represented by Ra, Rb, Rc and Rd are In the formula (1), the same groups as those described as the halogen atom, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, and arylalkyl group represented by R ₁ and R ₂ are the same. Can be mentioned.

In the general formulas (1) and (2), the aryl group and heteroaryl group represented by Ra, Rb, Rc and Rd are the aryl group and heterocycle represented by R ₁ and R ₂ in the general formula (1). Examples thereof include the same groups as those exemplified as the aryl group.

In the general formula (1), the non-aromatic hydrocarbon ring group and non-aromatic heterocyclic group represented by Ra, Rb, Rc and Rd are represented by R ₁ and R ₂ in the general formula (1). Examples thereof include the same groups as those exemplified as the non-aromatic hydrocarbon ring group and the non-aromatic heterocyclic group.

  In general formula (1) and (2), nb and nd represent the integer of 1-4, na and nc represent 1 or 2. ne represents an integer of 1 to 20.

  Adjacent ring A and ring D, or ring D and ring E may be bonded to adjacent rings at two points to form a condensed ring. Furthermore, ring A, ring D, and ring E may form one condensed ring.

(1.1.2) A phosphorescent organometallic complex represented by general formula (3) or general formula (4)

The phosphorescent organometallic complex in which the ligand represented by the general formula (1) or the general formula (2) is coordinated to a metal atom is represented by the following general formula (3) or the general formula (4). It is preferably a phosphorescent organometallic complex.
In the general formulas (3) and (4), ring B, ring E, G, R ₁ , R ₂ , R ₃ , Ra, Rb, Rc, Rd, Re, na, nb, nc, nd and ne are the above Synonymous with ring B, ring E, G, R ₁ , R ₂ , R ₃ , Ra, Rb, Rc, Rd, Re, na, nb, nc, nd and ne in general formulas (1) and (2) .
Here, the ligand represented by the general formula (1) is selected from the structures represented by the general formulas (L1A) to (L1AA), and is represented by the general formula (2). Is selected from the structures represented by the general formulas (L2A) to (L2Q).

  In the general formulas (3) and (4), L represents one or more of monoanionic bidentate ligands coordinated to M. Specific examples of the monoanionic bidentate ligand represented by L include a ligand represented by the following formula.

  In the above formula, R ′, R ″ and R ″ ′ represent a hydrogen atom or a substituent. Examples of the substituent represented by R ′, R ″ and R ″ ″ include an alkyl group (for example, methyl Group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), alkenyl group (for example, vinyl group, allyl group, etc.) ), Alkynyl groups (for example, ethynyl group, propargyl group, etc.), non-aromatic hydrocarbon ring groups (for example, cycloalkyl groups (for example, cyclopentyl group, cyclohexyl groups, etc.)), cycloalkoxy groups (for example, cyclopentyloxy group, cyclohexyl) Oxy group, etc.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), teto Monovalent group derived from hydronaphthalene ring, 9,10-dihydroanthracene ring, biphenylene ring, etc.), non-aromatic heterocyclic group (for example, epoxy ring, aziridine ring, thiirane ring, oxetane ring, azetidine ring, thietane) Ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexa Hydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring, 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring, thiomorpholine-1,1-dioxide ring, Pila A monovalent group derived from a ring ring, a diazabicyclo [2,2,2] -octane ring, a phenoxazine ring, a phenothiazine ring, an oxanthrene ring, a thioxanthene ring, a phenoxathiin ring), an aromatic hydrocarbon group (For example, benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring , Monovalent groups derived from acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene ring, pyranthrene ring, anthraanthrene ring, etc.) , Aromatic heterocyclic groups (eg silole ring, furan ring, thiophene ring, oxazo Ring, pyrrole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benz Oxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, carbazole ring, azacarbazole ring (representing any one or more of the carbon atoms constituting the carbazole ring replaced by a nitrogen atom), dibenzosilole ring , Dibenzofuran ring, dibenzothiophene ring, benzothiophene ring or ring in which any one of carbon atoms constituting dibenzofuran ring is replaced by nitrogen atom, benzodifuran ring, benzodithiophene ring, acridine ring, benzoquinoline ring, phenazi Ring, phenanthridine ring, phenanthroline ring, cyclazine ring, quindrine ring, tepenidine ring, quinindrin ring, triphenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene Ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring, anthrathiophene ring, anthradithiophene ring, thianthrene ring, phenoxathiin ring, dibenzocarbazole ring, indolocarbazole ring, dithienobenzene ring, etc. Monovalent groups derived from the above), alkoxy groups (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), aryloxy groups (for example, phenoxy group) Xy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), Alkoxycarbonyl groups (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl groups (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.) ), Sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylamino) Sulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group) Cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy) Group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethyl Bonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc. ), Carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylamino) Carbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), urea Group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, Methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl Group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group Is a heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2- Ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (for example, fluorine atom, chlorine atom, bromine atom), fluorinated hydrocarbon group (for example, fluoromethyl group, trimethyl group) Fluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group) Etc.), phosphono groups Etc.

  In the general formula (3) and the general formula (4), M represents a transition metal atom having an atomic number of 40 or more and a group 8 to 10 in the periodic table, preferably Os, Ir, and Pt, more preferably Ir. It is.

  In General Formula (3) and General Formula (4), m represents an integer of 0 to 2, n is at least 1, and m + n represents 2 or 3.

(1.1.3) Phosphorescent organometallic complex represented by general formula (5) or general formula (6) Phosphorescent organometallic complex represented by general formula (3) or general formula (4) A preferred embodiment of the complex is a phosphorescent organometallic complex represented by the following general formula (5) or general formula (6).

In general formula (5) and general formula (6), ring E, G, R ₁ , R ₂ , R ₃ , Ra, Rb, Rc, Rd, Re, na, nb, nc, nd and ne It is synonymous with the rings E, G, R ₁ , R ₂ , R ₃ , Ra, Rb, Rc, Rd, Re, na, nb, nc, nd and ne in the formula (1) and the general formula (2).

Moreover, in General formula (5) and General formula (6), M, L, m, and n are synonymous with M, L, m, and n in General formula (3) and General formula (4).
Here, the ligand represented by the general formula (1) is selected from the structures represented by the general formulas (L1A) to (L1AA), and is represented by the general formula (2). Is selected from the structures represented by the general formulas (L2A) to (L2Q). However, in the general formulas (L1A) to (L1AA) and the general formulas (L2A) to (L2Q), the ring B represents a benzene ring.

  The ligand of the blue phosphorescent organometallic complex represented by the general formula (1) or the general formula (2) according to the present invention will be further described.

  In general formula (1) and general formula (2), adjacent ring A and ring D, ring D and ring E may be bonded to each other at two points to form a condensed ring, or ring A and ring D. And ring E may form one condensed ring.

  In the case of not forming a condensed ring and in the case of forming a condensed ring, the structure of the ligand is more specifically represented by the following general formulas (L1A) to (L1AA) and general formulas (L2A) to (L2Q).

In general formulas (L1A) to (L1AA) and general formulas (L2A) to (L2Q), ring B, ring E, G, R ₁ , R ₂ , R ₃ , Ra, Rb, Rc, Rd, Re, na, nb, nc, nd and ne are the ring B, ring E, G, R ₁ , R ₂ , R ₃ , Ra, Rb, Rc, Rd, Re, na, nb of the above general formulas (1) and (2). , Nc, nd and ne.

Ra _{1 to} Ra ₄ , Rc ₁ to Rc _2, and Rd _{1 to} Rd ₄ represent positional differences of the substituents Ra, Rc, and Rd, respectively.

  In the general formulas (L1A) to (L1AA) and the general formulas (L2A) to (L2Q), W, X, Y, and Z are carbon atoms that may have a substituent, and nitrogen that may have a substituent. An atom, a silicon atom having a substituent, an oxygen atom or a sulfur atom is represented.

  Preferably, W, X, Y and Z are a nitrogen atom, an oxygen atom or a sulfur atom which may have a substituent. More preferably, W, X, Y and Z are an oxygen atom or a sulfur atom.

(1.1.4) Specific Examples The following are general formulas (L1A) to (L1AA) and general formulas (L2A) to (L2Q), and general formulas (L1A) to (L1AA) and general formulas (L2A) to ( Specific examples of the ligand represented by L2Q) are described, but the present invention is not limited thereto.

  In addition, when a plurality of substituents can be substituted as in the columns of Ra, Rb, Rc, and Rd, “H” indicates that all are substituted with hydrogen atoms, and when a specific substituent is described. In addition to the substituents, the hydrogen atom is substituted.

Specific examples of phosphorescent organometallic complexes (phosphorescent dopants) represented by any one of the general formulas (3) to (6) are shown in Tables 1-1 to 1-6 below. The invention is not limited to these. In Table 1-1 to Table 1-6, the phosphorescent organometallic complex represented by any one of the general formulas (3) to (6) is represented by the general formula: (L) _n -M- ( AL) Each configuration is represented by _m . That is, in the general formula, L represents a ligand represented by the general formula (1) or (2) according to the present invention, and AL represents a conventionally known monoanionic bidentate ligand. , N represents the number of L coordinated to M, and m represents the number of AL coordinated to M.

Specifically, for example, DP-1 in the table can be represented as “(L1A-4) ₃ Ir”, and DP-459 in the table is represented by “(L2M-21) ₂ Ir (AL-11)”. "It can be expressed as. The structural formulas of DP-1 and DP-459 are shown below.

  Conventionally known ligands AL-1 to AL15 in Table 1-1 to Table 1-6 are the compounds shown below.

  Specific examples (DP-1 to DP) of phosphorescent organic metal complexes (phosphorescent dopants) represented by any one of the general formulas (3) to (6) are shown in Tables 1-1 to 1-6 below. -543).

  These metal complexes are described in, for example, Organic Letter, vol. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), Organic Letter, vol. 3, pages 415 to 418 (2006), and further by applying methods such as references described in these documents.

  Below, the synthesis example of a typical compound is shown.

[Synthesis of Complex DP-1]
(Synthesis of Ligand L1A-4)
1. Synthesis of Intermediate A-1 According to the following reaction scheme, Intermediate A-1 was synthesized from m-bromoaniline by a known method in a two-step reaction. The isolated yields after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) were 72% (Suzuki coupling) and 84% (bromination), respectively.

2. Synthesis of Intermediate C-1 According to the following reaction scheme, 3 equivalents of isopropenylboronic acid pinacol ester and 1 equivalent of Intermediate A-1, 3 equivalents of potassium phosphate, 2% palladium acetate, 4% Intermediate S-1 was obtained from S-Phos (2-dicyclohexylphosphino-2 ', 6'-dimethoxybiphenyl) in toluene-water (9: 1) at the reflux temperature for 12 hours. The isolated yield after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) was 68%. Next, intermediate B-1 was hydrogenated in ethyl acetate-ethanol at room temperature in the presence of 10% palladium carbon catalyst to obtain intermediate C-1. The isolated yield after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) was 87%.

3. Synthesis of Ligand L1A-4 According to the following reaction scheme, 1 equivalent of intermediate C-1 and 1.1 equivalents of benzoic acid chloride, 1.1 equivalents of triethylamine in toluene at reflux temperature for 2 hours By reacting, intermediate C-1 was converted to benzamide. The benzamide was then reacted with 1.1 equivalents of phosphorus oxychloride in toluene at reflux temperature for 2 hours to convert to imino chloride. The imino chloride was then reacted with 4 equivalents of aminoacetal, 10 equivalents of triethylamine in acetonitrile at room temperature for 3 hours to convert to benzimidazole. Finally, this benzimidamide was reacted with 5 equivalents of phosphoric acid in toluene at reflux temperature for 2 hours to obtain ligand L1A-4. The isolated yield after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) was 48% (4step).

4). Synthesis of complex DP-1

  Under a nitrogen atmosphere, 1.14 g (2.50 mmol) of ligand L1A-4 and 0.25 g (0.50 mmol) of trisacetylacetonatoiridium were suspended in 30 ml of ethylene glycol. The reaction was performed at reflux temperature for 48 hours under a nitrogen atmosphere. The reaction solution was cooled, 30 ml of methanol was added, and the precipitated crystals were collected by filtration. The obtained crystals were further washed with methanol, and dried to obtain 510 mg (65% yield) of a crude product. This crude product was purified by column gel chromatography (hexane-tetrahydrofuran = 10: 1 to 4: 1) to obtain 330 mg (42% yield) of complex DP-1.

It was confirmed by MASS and ¹ H-NMR that the purified compound was the target product.

  The PL emission maximum wavelength in a solution of Exemplified Compound DP-25 measured using Hitachi F-4500 was 466 nm (T = 77 K, in 2-methyltetrahydrofuran) and 475 nm (room temperature, in methylene chloride).

[Synthesis of Complex DP-404]
(Synthesis of Ligand L2G-13)
1. Synthesis of Intermediate A-2 Intermediate A-2 was synthesized in a two-step reaction from 1-nitro-8-phenyldibenzothiophene synthesized by a known method according to the following reaction scheme. The isolated yields after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) were 85% (hydrogenation) and 78% (bromination), respectively.

2. Synthesis of Intermediate C-2 According to the following reaction scheme, 3 equivalents of 2-penten-3-ylboronic acid pinacol ester and 1 equivalent of Intermediate A-2, 3 equivalents of potassium phosphate, 2% acetic acid Intermediate B-2 was obtained from palladium, 4% S-Phos in toluene-water (9: 1) in 12 hours reaction at reflux temperature. The isolated yield after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) was 72%. Next, intermediate B-2 was subjected to a hydrogenation reaction in ethyl acetate-ethanol at room temperature in the presence of 10% palladium carbon catalyst to obtain intermediate C-2. The isolated yield after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) was 88%.

3. Synthesis of Ligand L2G-13 According to the following reaction scheme, 1 equivalent of intermediate C-2 and 1.1 equivalents of benzoic acid chloride, 1.1 equivalents of triethylamine in toluene at reflux temperature for 2 hours By reacting, intermediate C-2 was converted to benzamide. The benzamide was then reacted with 1.1 equivalents of phosphorus oxychloride in toluene at reflux temperature for 2 hours to convert to imino chloride. The imino chloride was then reacted with 4 equivalents of aminoacetal, 10 equivalents of triethylamine in acetonitrile at room temperature for 3 hours to convert to benzimidazole. Finally, this benzimidamide was reacted with 5 equivalents of phosphoric acid in toluene at reflux temperature for 2 hours to give ligand L2G-13. The isolated yield after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) was 45% (4 steps).

4). Synthesis of Complex A According to the following reaction scheme, 350 mg (1.0 mmol) of 1 equivalent of iridium trichloride trihydrate and 620 mg of 2.5 equivalents of diphenylpyrazole derivative were mixed with ethoxyethanol-water (3: 1). In 20 ml, the mixture was reacted in a nitrogen atmosphere at reflux temperature for 6 hours to obtain Complex A. The reaction solution was cooled, 30 ml of methanol was added, and the precipitated crystals were collected by filtration. The obtained crystals were further washed with methanol and dried to obtain 520 mg (yield 72%) of complex A after drying.

5. Synthesis of complex DP-404

  Under a nitrogen atmosphere, 815 mg (1.5 mmol) of ligand L2G-13, 430 mg (0.30 mmol) of complex A and 200 mg (0.90 mmol) of silver trifluoroacetate were added into 30 ml of phenyl acetate. The reaction was carried out at 180 degrees for 4 hours in a nitrogen atmosphere. The reaction solution was filtered to remove insoluble matters. The filtrate was concentrated under reduced pressure, and phenyl acetate was distilled off, followed by cooling. 30 ml of methanol was added, and the precipitated crystals were collected by filtration. The obtained crystals were further washed with methanol, and after drying, a crude product having a yield of 695 mg (yield 76%) was obtained. The crude product was purified by column gel chromatography (hexane-tetrahydrofuran = 10: 1 to 4: 1) to obtain 440 mg (yield 48%) of complex DP-404.

It was confirmed by MASS and ¹ H-NMR that the purified compound was the target product.

  The PL emission maximum wavelength in the solution of Exemplified Compound DP-404 measured using Hitachi F-4500 was 460 nm (T = 77K in 2-methyltetrahydrofuran) and 471 nm (room temperature in methylene chloride).

[Synthesis of Complex DP-459]
(Synthesis of Ligand L2M-21)
1. Synthesis of Intermediate B-3 Intermediate B-3 was synthesized in a two-step reaction from commercially available dibenzofuran according to the following reaction scheme. The isolated yields after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) were 85% (bromination) and 65% (boronic acid pinacolation), respectively.

2. Synthesis of 2-bromo-6-isopropylaniline According to the following reaction scheme, commercially available 2-isopropylaniline and 1.1 equivalents of N-bromosuccinimide were reacted in methylene chloride at 0 ° C. for 3 hours. 2-Bromo-6-isopropylaniline was obtained. The isolated yield after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) was 86%.

3. Synthesis of Intermediate C-3 According to the following reaction scheme, 1.2 equivalents of Intermediate B-3 and 1 equivalent of 2-bromo-6-isopropylaniline, 3 equivalents of potassium phosphate, 2% palladium acetate Intermediate C-3 was obtained from 4% S-Phos in toluene-water (9: 1) in 10 hours of reaction at reflux temperature. The isolated yield after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) was 64%.

4). Synthesis of Ligands L2M-21 According to the following reaction scheme, 1 equivalent of Intermediate C-3 and 1.1 equivalents of 4-fluorobenzoic acid chloride, 1.1 equivalents of triethylamine were refluxed in toluene. The reaction was carried out at temperature for 2 hours, and intermediate C-3 was converted to benzamide. The benzamide was then reacted with 1.1 equivalents of phosphorus oxychloride in toluene at reflux temperature for 2 hours to convert to imino chloride. The imino chloride was then reacted with 4 equivalents of aminoacetal, 10 equivalents of triethylamine in acetonitrile at room temperature for 3 hours to convert to benzimidazole. Finally, this benzimidamide was reacted with 5 equivalents of phosphoric acid in toluene at reflux temperature for 2 hours to give ligand L2G-13. The isolated yield after purification by silica gel chromatography (hexane: ethyl acetate = 10: 1 to 2: 1) was 43% (4step).

5. Synthesis of Complex B According to the following reaction scheme, 350 mg (1.0 mmol) of 1 equivalent of iridium trichloride trihydrate and 360 mg of 2.5 equivalents of phenylpyrazole were added to 20 ml of ethoxyethanol-water (3: 1). The mixture was reacted in a nitrogen atmosphere at reflux temperature for 6 hours to obtain complex B. The reaction solution was cooled, 30 ml of methanol was added, and the precipitated crystals were collected by filtration. The obtained crystals were further washed with methanol and dried to obtain 370 mg (yield 72%) of complex B after drying.

6). Synthesis of Complex DP-459

  Under a nitrogen atmosphere, 670 mg (1.5 mmol) of ligand L2M-21, 310 mg (0.30 mmol) of complex B and 200 mg (0.90 mmol) of silver trifluoroacetate were added into 30 ml of phenyl acetate. The reaction was carried out at 180 degrees for 4 hours in a nitrogen atmosphere. The reaction solution was filtered to remove insoluble matters. The filtrate was concentrated under reduced pressure, and phenyl acetate was distilled off, followed by cooling. 30 ml of methanol was added, and the precipitated crystals were collected by filtration. The obtained crystals were further washed with methanol, and after drying, a yield of 405 mg (yield 73%) was obtained as a crude product. The crude product was purified by column gel chromatography (hexane-tetrahydrofuran = 10: 1 to 4: 1) to obtain 250 mg (yield 45%) of complex DP-459.

It was confirmed by MASS and ¹ H-NMR that the purified compound was the target product.

  The PL emission maximum wavelength in the solution of Exemplified Compound DP-1 measured using Hitachi F-4500 was 458 nm (T = 77K in 2-methyltetrahydrofuran) and 468 nm (room temperature in methylene chloride).

  Other compounds of the present invention can also be synthesized with good yield by using appropriate raw materials and reactions as in the above synthesis examples.

(1.2) Fluorescent dopants Fluorescent dopants (also referred to as fluorescent compounds) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamines. And dyes having a high fluorescence quantum yield such as laser dyes and the like, and dyes based on dyes, pyrylium dyes, perylene dyes, stilbene dyes, polythiophene dyes, rare earth complex phosphors, and the like.

(1.3) Combined use with conventionally known light-emitting dopants The light-emitting dopant according to the present invention may be used in combination with a plurality of types of compounds, a combination of phosphorescent dopants having different structures, a phosphorescent dopant and A combination of fluorescent dopants may also be used. Known phosphorescent dopants and fluorescent dopants can be used.

(2) Host Compound In the present invention, the host compound is a phosphorescent quantum that emits phosphorescence at room temperature (25 ° C.) and has a mass ratio of 20% or more in the light-emitting layer. A yield is defined as a compound of less than 0.1. The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the mass ratio in the layer is 20% or more among the compounds contained in a light emitting layer.

  There is no restriction | limiting in particular as a host compound which can be used for this invention, The compound conventionally used with an organic EL element can be used. Typically, a carbazole derivative, a triarylamine derivative, an aromatic derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, an oligoarylene compound or the like having a basic skeleton, or a carboline derivative or a diazacarbazole derivative (here And the diazacarbazole derivative represents one in which at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom.

  As the known host compound that can be used in the present invention, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable.

  Moreover, in this invention, a conventionally well-known host compound may be used independently, and may be used in combination of multiple types. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of the metal complex of this invention used as the said phosphorescence dopant, and / or a conventionally well-known compound, and, thereby, arbitrary luminescent colors can be obtained.

  The host compound used in the present invention may be a low molecular compound, a high molecular compound having a repeating unit, or a low molecular compound (polymerizable host compound) having a polymerizable group such as a vinyl group or an epoxy group. Of course, one or more of such compounds may be used.

  Specific examples of known host compounds include compounds described in the following documents.

  JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  Hereinafter, although the specific example used as a host compound of the light emitting layer of the organic EL element of this invention is given, this invention is not limited to these.

  Furthermore, a compound represented by the following general formula (B) or general formula (E) is particularly preferable as the host compound of the light emitting layer of the organic EL device of the present invention.

  In general formula (B) and general formula (E), Xa represents an oxygen atom or a sulfur atom. Xb, Xc, Xd and Xe each represent a hydrogen atom, a substituent or a group represented by the following general formula (C). At least one of Xb, Xc, Xd and Xe represents a group represented by the following general formula (C), and at least one of the groups represented by the following general formula (C) represents Ar as a carbazolyl group. .

General formula (C)
Ar- _(L 4) n- *
In General Formula (C), L ₄ represents a divalent linking group derived from an aromatic hydrocarbon ring or an aromatic heterocyclic ring. n represents an integer of 0 to 3, and when n is 2 or more, the plurality of L ₄ may be the same or different. * Represents a linking site with the general formula (B) or the general formula (E). Ar represents a group represented by the following general formula (D).

In general formula (D), Xf represents N (R ″), an oxygen atom or a sulfur atom, E _{1 to} E ₈ represent C (R ″ ₁ ) or N, R ″ and R ″ ₁ are hydrogen atoms, It represents a substituent or a linking site with L ₄ in formula (C). * Represents a linking site with L ₄ in the general formula (C).

  In the compound represented by the general formula (B), preferably at least two of Xb, Xc, Xd and Xe are represented by the general formula (C), and more preferably Xc is represented by the general formula (C). And Ar in the general formula (C) represents a carbazolyl group which may have a substituent.

  Moreover, the compound represented by the following general formula (B ′) is also particularly preferably used as the host compound of the light emitting layer of the organic EL device of the present invention.

  In General Formula (B ′), Xa represents an oxygen atom or a sulfur atom, and Xb and Xc each represents a substituent or a group represented by General Formula (C). At least one of Xb and Xc represents a group represented by the above general formula (C), and at least one of the groups represented by the general formula (C) represents Ar as a carbazolyl group.

In the compound represented by the general formula (B ′), preferably, Ar in the general formula (C) represents a carbazolyl group which may have a substituent, and more preferably, in the general formula (C). Ar may have a substituent, and represents a carbazolyl group linked to L ₄ in formula (C) at the N-position.

  Next, an injection layer, a blocking layer, an electron transport layer, and the like that are preferably used as the constituent layers of the organic EL element of the present invention will be described.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer, and between the cathode and the light emitting layer or the electron transport layer. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Representative phthalocyanine buffer layer, oxide buffer layer typified by vanadium oxide, amorphous carbon buffer layer, polymer buffer layer using conductive polymer such as polyaniline (emeraldine) or polythiophene, tris (2-phenylpyridine) ) Orthometalated complex layers represented by iridium complexes and the like. Further, azatriphenylene derivatives such as those described in JP-T-2003-519432 and JP-A-2006-135145 can also be used as the hole injection material.

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

<Blocking layer: hole blocking layer, electron blocking layer>
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking.

  Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed.

  The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

  The hole blocking layer contains the carbazole derivative, carboline derivative, or diazacarbazole derivative (shown in which any one of the carbon atoms constituting the carboline ring of the carboline derivative is replaced by a nitrogen atom). It is preferable to contain.

  In the present invention, when a plurality of light emitting layers having different light emission colors are provided, the light emitting layer having the shortest wavelength of light emission is preferably closest to the anode among all the light emitting layers. In this case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the anode. Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.3 eV or more larger than the host compound of the shortest wave emitting layer.

  The ionization potential is defined by the energy required to emit an electron at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level, and can be obtained by the following method, for example.

  (1) Using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), a molecular orbital calculation software manufactured by Gaussian, USA The ionization potential can be obtained as a value obtained by rounding off the second decimal place of the value (eV unit converted value) calculated by performing structural optimization using B3LYP / 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.

  (2) The ionization potential can also be obtained by a method of directly measuring by photoelectron spectroscopy. For example, a method known as ultraviolet photoelectron spectroscopy can be suitably used by using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved.

  Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers. Further, azatriphenylene derivatives as described in JP-T-2003-519432 and JP-A-2006-135145 can also be used as the hole transport material.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and also two of those described in US Pat. No. 5,061,569. Having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8 are linked in a starburst type ( MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material. In addition, cyclometalated complexes and orthometalated complexes represented by copper phthalocyanine, tris (2-phenylpyridine) iridium complex, and the like can also be used as the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, these materials are preferably used because a light-emitting element with higher efficiency can be obtained.

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it exists in the range of 5 nm-200 nm. This hole transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  Conventionally, when a single electron transport layer and a plurality of layers are used, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the cathode side with respect to the light emitting layer is injected from the cathode. As long as it has a function of transmitting the generated electrons to the light emitting layer, any material can be selected from conventionally known compounds and used alone or in combination. Fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like can be mentioned.

  Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  Also, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum, Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg, Cu Metal complexes replaced with Ca, Sn, Ga, or Pb can also be used as electron transport materials.

  In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transport material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and the hole transport layer. Can also be used as an electron transporting material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

  Further, an electron transport layer having a high n property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be manufactured.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode substances include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO.

Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. The anode may be formed by depositing a thin film of these electrode materials by vapor deposition or sputtering, and a pattern having a desired shape may be formed by photolithography, or when pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.

  Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

  The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the emission luminance is advantageously improved.

  Moreover, after producing the said metal with the film thickness in the range of 1-20 nm in a cathode, producing a transparent or semi-transparent cathode by producing the electroconductive transparent material quoted by description of the anode on it. By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

《Support substrate》
The support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention is not particularly limited in the type of glass, plastic, etc., and is transparent. May be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones, Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned.

An inorganic film, an organic film, or a hybrid film of both may be formed on the surface of the resin film, and the water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , Relative humidity (90 ± 2)% RH) is preferably 0.01 g / (m ² · 24 h) or less, and further, oxygen measured by a method according to JIS K 7126-1987. A high barrier film having a permeability of 10 ⁻³ ml / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less is preferable.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

  Examples of the opaque support substrate include metal plates such as aluminum and stainless steel, films, opaque resin substrates, and ceramic substrates.

  The external extraction efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more.

  Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

  In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

<Sealing>
As a sealing means used for this invention, the method of adhere | attaching a sealing member, an electrode, and a support substrate with an adhesive agent can be mentioned, for example.

  As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and concave plate shape or flat plate shape may be sufficient. Further, transparency and electrical insulation are not particularly limited.

  Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

  In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned.

Furthermore, the polymer film has an oxygen permeability of 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less measured by a method according to JIS K 7126-1987, and a method according to JIS K 7129-1992. It is preferable that the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured in (1) is 1 × 10 ⁻³ g / (m ² · 24 h) or less.

  For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.

  Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

  In addition, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive.

  Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. . In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster-ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil can be injected in the gas phase and liquid phase. preferable. A vacuum is also possible. Moreover, a hygroscopic compound can also be enclosed inside.

  Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide etc.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate, and the like), and anhydrous salts are preferably used in sulfates, metal halides, and perchloric acids.

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction》
The organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1) and can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

  As a method for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (US Pat. No. 4,774,435), A method of improving efficiency by providing a light collecting property to a substrate (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an element (Japanese Patent Laid-Open No. 1-220394), and light emission from a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the bodies (Japanese Patent Laid-Open No. 62-172691), a flat having a lower refractive index between the substrate and the light emitter than the substrate A method of introducing a layer (Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any one of a substrate, a transparent electrode layer and a light emitting layer (including between the substrate and the outside) (Japanese Patent Laid-Open No. 11-283951) Gazette).

  In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used.

  In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

  When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower.

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.

  The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface that causes total reflection or in any medium has a feature that the effect of improving the light extraction efficiency is high. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction and second-order diffraction. Of these, light that cannot go out due to total reflection between layers, etc. is diffracted by introducing a diffraction grating into any layer or medium (inside a transparent substrate or transparent electrode). I want to take it out.

  It is desirable that the diffraction grating to be introduced has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. Therefore, the light extraction efficiency does not increase so much.

  However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and the light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any one of the layers or in the medium (in the transparent substrate or the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated.

  At this time, the period of the diffraction grating is preferably in the range of about 1/2 to 3 times the wavelength of light in the medium.

  The arrangement of the diffraction grating is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

《Condensing sheet》
The organic EL element of the present invention can be processed on a light extraction side of a substrate, for example, by providing a microlens array-like structure, or combined with a so-called condensing sheet, for example in a specific direction, for example, with respect to the element light emitting surface. By condensing in the front direction, the luminance in a specific direction can be increased.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably within a range of 10 to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

  Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode will be described.

  First, a desired electrode material, for example, a thin film made of an anode material is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm. Make it.

  Next, organic compound thin films such as a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, and an electron transport layer, which are organic EL element materials, are formed thereon.

  As a method for forming each of these layers, there are a vapor deposition method, a wet process (spin coating method, casting method, ink jet method, printing method) and the like as described above, but it is easy to obtain a homogeneous film and it is difficult to generate pinholes. In view of the above, film formation by a coating method such as a spin coating method, an ink jet method, or a printing method is preferable in the present invention. In particular, the organic layer containing the phosphorescent organometallic complex according to the present invention is preferably formed through a wet process for the above reason.

  Examples of the liquid medium for dissolving or dispersing the organic EL material according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, and mesitylene. Aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as DMF and DMSO can be used. Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

  After these layers are formed, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a thickness of 1 μm or less, preferably in the range of 50 to 200 nm. By providing, a desired organic EL element can be obtained.

  Further, it is also possible to reverse the production order and produce the cathode, the electron transport layer, the hole blocking layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order. When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

<Application>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. For example, lighting devices (home lighting, interior lighting), clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, light Although the light source of a sensor etc. are mentioned, It is not limited to this, Especially, it can use effectively for the use as a backlight of a liquid crystal display device, and a light source for illumination.

  In the organic EL element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like as needed during film formation. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire layer of the element may be patterned. In the fabrication of the element, a conventionally known method is used. Can do.

  The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with a total CS-1000 (manufactured by Konica Minolta Optics) is applied to the CIE chromaticity coordinates.

When the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE1931 color system at 1000 cd / m ² is X when the 2 ° viewing angle front luminance is measured by the above method. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

<Display device>
The display device of the present invention will be described. The display device of the present invention has the organic EL element.

  The display device of the present invention may be single color or multicolor, but here, the multicolor display device will be described.

  In the case of a multicolor display device, a shadow mask is provided only at the time of forming a light emitting layer, and a film can be formed on one surface by vapor deposition, casting, spin coating, ink jet, printing, or the like.

  When patterning is performed only on the light-emitting layer, the method is not limited, but a vapor deposition method, an inkjet method, and a printing method are preferable. In the case of using a vapor deposition method, patterning using a shadow mask is preferable.

  Moreover, it is also possible to reverse the production order to produce the cathode, the electron transport layer, the hole blocking layer, the light emitting layer, the hole transport layer, and the anode in this order.

  When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed when a voltage of about 2 V to 40 V is applied with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

  The multicolor display device can be used as a display device, a display, and various light emission sources. In a display device or display, full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.

  Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in an automobile. In particular, it may be used as a display device for reproducing still images and moving images, and the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.

  Light emitting sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. However, it is not limited to this.

  Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view showing an example of a display device composed of organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

  The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like. The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of a plurality of pixels based on image information from the outside, and the pixels for each scanning line respond to the image data signal by the scanning signal. The image information is sequentially emitted to scan the image and display the image information on the display unit A.

  FIG. 2 is a schematic diagram of the display unit A.

  The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below. FIG. 2 shows a case where the light L emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

  The scanning line 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at the orthogonal positions (details are illustrated). Not)

  When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data.

  Full-color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region on the same substrate.

  Next, the light emission process of the pixel will be described.

  FIG. 3 is a schematic diagram of the circuit.

  The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full color display can be performed by using red, green, and blue light emitting organic EL elements as the organic EL elements 10 in a plurality of pixels, and juxtaposing them on the same substrate.

  In FIG. 3, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

  By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10. The power supply line 7 connects the organic EL element 10 to the potential of the image data signal applied to the gate. Current is supplied.

  When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, since the capacitor 13 holds the charged potential of the image data signal even when the driving of the switching transistor 11 is turned off, the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues. When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.

  That is, the organic EL element 10 emits light by the switching transistor 11 and the drive transistor 12 that are active elements for the organic EL elements 10 of the plurality of pixels, and the organic EL elements 10 of the plurality of pixels 3 emit light. It is carried out. Such a light emitting method is called an active matrix method.

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or by turning on / off a predetermined light emission amount by a binary image data signal. Good. The potential of the capacitor 13 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

  In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

  FIG. 4 is a schematic diagram of a passive matrix display device. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal.

  In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

《Lighting device》
The lighting device of the present invention will be described. The illuminating device of this invention has the said organic EL element.

  The organic EL element of the present invention may be used as a kind of lamp such as an illumination or exposure light source, a projection device that projects an image, or a display device that directly recognizes a still image or a moving image ( It may be used as a display.

  The driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, it is possible to produce a full-color display device by using two or more organic EL elements of the present invention having different emission colors.

  The organic EL material of the present invention can be applied as an illumination device to an organic EL element that emits substantially white light. A plurality of light emitting colors are simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing. The combination of a plurality of emission colors may include three emission maximum wavelengths of the three primary colors of blue, green, and blue, or two using the relationship of complementary colors such as blue and yellow, blue green and orange, etc. The thing containing the light emission maximum wavelength may be used.

  In addition, a combination of light emitting materials for obtaining a plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials, a light emitting material that emits fluorescence or phosphorescence, and light from the light emitting material as excitation light. Any of those combined with a dye material that emits light may be used, but in the white organic EL device according to the present invention, only a combination of a plurality of light-emitting dopants may be mixed.

  It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, or the like, and simply arrange them separately by coating with the mask. Since other layers are common, patterning such as a mask is unnecessary, In addition, for example, an electrode film can be formed by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like, and productivity is also improved. According to this method, unlike a white organic EL device in which light emitting elements of a plurality of colors are arranged in parallel in an array, the elements themselves are luminescent white.

  There is no restriction | limiting in particular as a luminescent material used for a light emitting layer, For example, if it is a backlight in a liquid crystal display element, the metal complex which concerns on this invention so that it may suit the wavelength range corresponding to CF (color filter) characteristic, Any one of known luminescent materials may be selected and combined to whiten.

  As described above, the white light emitting organic EL element according to the present invention is used as a kind of lamp such as household illumination, interior lighting, and exposure light source as various light emitting light sources and lighting devices in addition to the display device and display. It is also useful for display devices such as backlights for liquid crystal display devices.

  Others such as backlights for watches, signboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. There are a wide range of uses such as household appliances.

<< One Embodiment of Lighting Device of the Present Invention >>
One aspect of the lighting device of the present invention that includes the organic EL element of the present invention will be described.

  The non-light emitting surface of the organic EL device of the present invention is covered with a glass case, a 300 μm thick glass substrate is used as a sealing substrate, and an epoxy photocurable adhesive (LUX The track LC0629B) is applied, and this is overlaid on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured, sealed, and illuminated as shown in FIGS. A device can be formed.

  FIG. 5 shows a schematic diagram of the illumination device. As shown in FIG. 5, the organic EL element 101 is covered with a glass cover 102.

  The sealing operation with the glass cover 102 is preferably performed in a glove box (in an atmosphere of high purity nitrogen gas having a purity of 99.999% or more) in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere.

  FIG. 6 shows a cross-sectional view of the lighting device. As shown in FIG. 6, the lighting device mainly includes a cathode 105, an organic EL layer 106, and a glass substrate 107 with a transparent electrode, and these members are covered with a glass cover 102. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

  The structures of the compounds used in the examples are shown below.

[Example 1]
<Vapor deposition type blue light emitting organic EL element>
<< Preparation of Blue Light-Emitting Organic EL Element 1-1 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  This transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of the hole injection material 1 is put into a molybdenum resistance heating boat, and 200 mg of the hole transport material 1 is put into another molybdenum resistance heating boat, 200 mg of the host compound (OC-11) is put into another resistance heating boat made of molybdenum, 100 mg of the luminescent dopant (Comparative Compound 1) is put into another resistance heating boat made of molybdenum, and the electron transport material 1 is put into another resistance heating boat made of molybdenum. And 200 mg of the electron transport material 2 was put in another molybdenum resistance heating boat, and attached to a vacuum deposition apparatus.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing the hole injecting material 1 is energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second. A 20 nm hole injection layer was provided.

Furthermore, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing the hole transport material 1 was heated by heating, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second. A 20 nm thick hole transport layer was provided.

  Furthermore, the hole-transporting layer is heated at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively, by heating the heating boat containing the host compound (OC-11) and the light-emitting dopant (Comparative Compound 1). A 40 nm-thick luminescent layer was provided by co-evaporation. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Further, the heating boat containing the electron transport material 1 was energized and heated, and deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm thick hole blocking layer.

  In addition, the heating boat containing the electron transport material 2 is further energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to further form an electron transport layer having a thickness of 20 nm. Was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited, the cathode was formed, and the organic EL element 1-1 was produced. In the following table, the organic EL element is abbreviated as EL, and for example, the organic EL element 1-1 is denoted as EL1-1.

<< Production of Organic EL Elements 1-2 to 1-161 >>
In the production of the organic EL element 1-1, except that the hole injection material, the hole transport material, the host compound, and the light emitting dopant were replaced with the compounds shown in Table 2-1 to Table 2-6, Similarly, organic EL elements 1-2 to 1-161 were produced.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL elements 1-1 to 1-161, the non-light-emitting surface of each organic EL element after production was covered with a glass case, and a glass substrate having a thickness of 300 μm was used as a sealing substrate. An epoxy photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied as a sealant around the periphery, and this is placed on the cathode so as to be in close contact with the transparent support substrate and irradiated with UV light from the glass substrate side. Then, it was cured and sealed, and an illumination device as shown in FIGS. 5 and 6 was formed and evaluated.

  FIG. 5 shows a schematic view of the illumination device. The organic EL element 101 is covered with a glass cover 102 (in addition, the sealing operation with the glass cover 102 is a glove box (purity of 99.999% or more in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere). In a high-purity nitrogen gas atmosphere).

  FIG. 6 shows a cross-sectional view of the lighting device. Inside the lighting device, a glass substrate 107 with a transparent electrode as an anode, an organic EL layer 106 and a cathode 105 are laminated in this order. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

(1) taking out at room temperature the quantum efficiency organic EL elements (25 ° C.), the initial luminance 2000 cd / ^{m 2,} and 4000 cd / ^{m 2} at a current giving by constant current driving, the lighting start immediately after the drive current [mA] to By measuring, external extraction quantum efficiency (η) was calculated as an evaluation scale of luminous efficiency. Here, CS-1000 (manufactured by Konica Minolta Optics) was used for measurement of light emission luminance.

The external extraction quantum yields were all expressed as relative values with the organic EL element 1-1 at an initial luminance of 2000 cd / m ² as a reference (100).

(2) RT driving voltage the organic EL element (about 23 to 25 ° C.), the initial luminance 2000 cd / ^{m 2,} and 4000 cd / ^{m 2} at a current giving by constant current driving, immediately after the lighting start drive current [mA] The drive voltage was measured by measuring Here, CS-1000 (manufactured by Konica Minolta Optics) was used for measurement of light emission luminance.

All the driving voltages are shown as relative values with the organic EL element 1-1 at an initial luminance of 2000 cd / m ² as a reference (100).

Drive voltage = {(drive voltage of each element / drive voltage of the organic EL element 1-1 (initial luminance 2000 cd / m ² ))} × 100
A smaller value indicates a lower drive voltage for comparison.

(3) Driving voltage increase rate When driving at a constant current of 10 mA / cm ² , the initial voltage and the voltage after 200 hours were measured. The increase in voltage after 200 hours with respect to the initial voltage was displayed as a percentage and used as the drive voltage increase rate.

Driving voltage increase rate (%) = {[(driving voltage after driving 200 hours of each organic EL element / V) − (initial driving voltage / V of each organic EL element)] / (initial driving voltage of each organic EL element) / V)} × 100
(4) Half light emission lifetime (25 ° C)
The half-light emission lifetime was evaluated according to the measurement method shown below.

Each organic EL element is driven at a constant current in a constant temperature bath at 25 ° C. and 70 ° C. with a current that gives an initial luminance of 2000 cd / m ² , and a time that is ½ of the initial luminance (1000 cd / m ² ) is obtained. This was taken as a measure of half-life.

  The half-light emission lifetime was expressed as a relative value that sets the half-light emission lifetime of the organic EL device 1-1 obtained at 25 ° C. as a reference (100).

(5) Initial degradation Initial degradation was evaluated according to the measurement method shown below.

At the time of measuring the half light emission lifetime at 25 ° C., the time required for the emission luminance of each organic EL element to reach 90% (1800 cd / m ² ) of the initial luminance was measured, and this was used as a measure of initial deterioration.

  The initial deterioration was expressed as a relative value that sets the half-light emission lifetime of the organic EL element 1-1 as a reference (100).

  The initial deterioration was calculated based on the following formula.

Initial degradation = {(90% arrival time of luminance of organic EL element 1-1 (hr)) / (90% arrival time of each organic EL element (hr))} × 100
That is, the smaller the initial deterioration value is, the smaller the initial deterioration is.

(6) Luminous unevenness during continuous driving In constant current driving at an initial luminance of 2000 cd / m ² , the luminous luminance after 150 hours was measured using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Optics). 20 arbitrary points on the light emitting surface were measured, and from the measured value at this time, light emission unevenness = in-plane minimum luminance / maximum luminance was calculated, and three-level rank evaluation was performed as follows. The case where the light emission unevenness was 0.90 or more was indicated by “◯”, the case where the light emission unevenness was 0.86 or more and less than 0.90 was indicated by “Δ”, and the case where the light emission unevenness was less than 0.86 was indicated by “x”.

(7) Dark Spot The light emitting surface when each organic EL element was continuously lit by driving at constant current with a current giving an initial luminance of 2000 cd / m ² at room temperature was visually evaluated.

  By visual evaluation by 10 people extracted at random, each element after 10 hours of continuous lighting time was evaluated according to the following scale.

× When the number of confirmed dark spots is 5 or more △ When the number of confirmed dark spots is 14 ○ When the number of confirmed dark spots is 0 The above evaluation results are shown in Table 2-1 to Table 2- 6 shows.

  From Table 2-1 to Table 2-6, compared with the comparative organic EL elements 1-1 to 1-4, the organic EL elements 1-5 to 1-161 of the present invention have high external extraction quantum efficiency, and It can be seen that there is little deterioration in luminance at the initial stage, and accordingly, the lifetime is long at both room temperature and high temperature.

  Furthermore, it turns out that the organic EL elements 1-5 to 1-161 of the present invention also suppress the generation of light emission unevenness and dark spots and the increase in driving voltage.

  From these results, it can be seen that it is useful to use the phosphorescent organometallic complex according to the present invention as a luminescent dopant in at least improving luminous efficiency, reducing driving voltage, and improving luminous lifetime.

[Example 2]
<Wet process type blue light emitting element>
<< Preparation of Blue Light-Emitting Organic EL Element 2-1 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After the film formation by spin coating, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  This substrate was transferred to a nitrogen atmosphere, and a solution obtained by dissolving 50 mg of the hole transport material 2 in 10 ml of toluene was formed on the first hole transport layer by spin coating at 1000 rpm for 30 seconds. . Furthermore, after irradiating with ultraviolet light for 180 seconds to perform photopolymerization / crosslinking, vacuum drying was performed at 60 ° C. for 1 hour to obtain a second hole transport layer.

  On this second hole transport layer, using a solution in which 100 mg of the host compound (host material 1) and 15 mg of the luminescent dopant (comparative compound 1) are dissolved in 10 ml of butyl acetate, under the condition of 600 rpm for 30 seconds, A thin film was formed by spin coating. Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer with a film thickness of about 70 nm.

  Next, a thin film was formed on the light emitting layer by spin coating under a condition of 1000 rpm and 30 seconds using a solution in which 50 mg of the electron transport material 3 was dissolved in 10 ml of hexafluoroisopropanol (HFIP). Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the electron carrying layer with a film thickness of about 30 nm.

Subsequently, this substrate is fixed to a substrate holder of a vacuum deposition apparatus, and after the vacuum chamber is depressurized to 4 × 10 ⁻⁴ Pa, 0.4 nm of potassium fluoride is deposited as a cathode buffer layer, and further, 110 nm of aluminum is deposited. Thus, a cathode was formed, and an organic EL element 2-1 was produced.

<< Production of Organic EL Elements 2-2 to 2-161 >>
In the production of the organic EL element 2-1, the organic EL element 2-2 is the same as the organic EL element 2-1, except that the host compound and the light-emitting dopant are replaced with the compounds shown in Tables 3-1 to 3-6. 2-161 was prepared.

<< Evaluation of organic EL elements >>
About the obtained organic EL elements 2-1 to 2-161, the performance of the organic EL elements was evaluated in the same manner as in Example 1.

  In this example, in each evaluation of (1) external extraction quantum efficiency, (2) driving voltage, (4) half-light emission lifetime, and (5) initial deterioration, the example is based on the organic EL element 2-1. The relative value was determined in the same manner as in 1.

  The evaluation results are shown in Tables 3-1 to 3-6.

  From Table 3-1 to Table 3-6, compared with the comparative organic EL elements 2-1 to 2-4, the organic EL elements 2-5 to 2-161 of the present invention have high external extraction quantum efficiency, and It can be seen that there is little deterioration in luminance at the initial stage, and accordingly, the lifetime is long at both room temperature and high temperature.

  Further, it can be seen that the organic EL elements 2-5 to 2-161 of the present invention also suppress the generation of light emission unevenness and dark spots and the increase in driving voltage.

  From these results, even when the light emitting layer is formed by a wet process using a spin coating method, the phosphorescent organic material according to the present invention is used as a light emitting dopant in order to improve the light emitting efficiency, reduce the driving voltage, and improve the light emitting lifetime. It can be seen that it is useful to use a metal complex.

Example 3
<Vapor deposition type white light emitting element-1>
<< Production of White Light-Emitting Organic EL Element 3-1 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  This transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of the hole injection material 1 is put into a molybdenum resistance heating boat, and 200 mg of the hole transport material 1 is put into another molybdenum resistance heating boat, 200 mg of the host compound (OC-11) is placed in another molybdenum resistance heating boat, 100 mg of the luminescent dopant (Comparative Compound 1) is placed in another resistance heating boat made of molybdenum, and the luminescent dopant (D -6) was put in 100 mg, 200 mg of the electron transport material 1 was put in another resistance heating boat made of molybdenum, and 200 mg of the electron transport material 2 was put in another resistance heating boat made of molybdenum, and attached to the vacuum deposition apparatus.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing the hole injecting material 1 is energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second. A 20 nm hole injection layer was provided.

Furthermore, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing the hole transport material 1 was heated by heating, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second. A 20 nm thick hole transport layer was provided.

  Further, the heating boat containing the host compound (OC-11), the luminescent dopant (Comparative Compound 1), and the luminescent dopant (D-6) was energized and heated, and the deposition rates were 0.2 nm / second and 0.020 nm, respectively. A light emitting layer having a film thickness of 40 nm was provided by co-evaporation on the hole transport layer at a rate of 0.0010 nm / second. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Further, the heating boat containing the electron transport material 1 was energized and heated, and deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm thick hole blocking layer.

  In addition, the heating boat containing the electron transport material 2 is further energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to further form an electron transport layer having a thickness of 20 nm. Was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited to form a cathode, and an organic EL element 3-1 was produced.

<< Production of Organic EL Elements 3-2 to 3-161 >>
In the production of the organic EL device 3-1, the hole injecting material, the hole transporting material, the host compound, and the light emitting dopant (only the comparative compound 1) were replaced with the compounds shown in Tables 4-1 to 4-6. Organic EL elements 3-2 to 3-161 were produced in the same manner as EL element 3-1.

<< Evaluation of organic EL elements >>
About the obtained organic EL elements 3-1 to 3-161, the performance of the organic EL elements was evaluated in the same manner as in Example 1.

  In this example, in each evaluation of (1) external extraction quantum efficiency, (2) driving voltage, (4) half light emission lifetime, and (5) initial deterioration, the example is based on the organic EL element 3-1. The relative value was determined in the same manner as in 1.

  The evaluation results are shown in Tables 4-1 to 4-6.

The organic EL element according to the present invention was measured with a spectral radiance meter CS-1000 (manufactured by Konica Minolta Optics). As a result of measuring the 2-degree viewing angle front luminance at 1000 cd / m ² , CIE chromaticity coordinates (CIE1931) were obtained. It was confirmed that the chromaticity in the color system was in the region of X = 0.33 ± 0.07, Y = 0.33 ± 0.1 and emitted white light.

  From Table 4-1 to Table 4-6, the organic EL elements 3-5 to 3-161 of the present invention have higher external extraction quantum efficiency than the comparative organic EL elements 3-1 to 3-4, and It can be seen that there is little deterioration in luminance at the initial stage, and accordingly, the lifetime is long at both room temperature and high temperature.

  Furthermore, it turns out that the organic EL elements 3-5 to 3-161 of the present invention also suppress the generation of light emission unevenness and dark spots and the increase in driving voltage.

  From these results, even in the case where a single light emitting layer is formed with two kinds of light emitting dopants to emit white light, the invention relates to the present invention as a light emitting dopant in order to improve light emission efficiency, drive voltage, and light emission life. It can be seen that it is useful to use a phosphorescent organometallic complex.

Example 4
<Vapor deposition type white light emitting element-2>
<< Preparation of white light emitting element 4-1 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  This transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of the hole injection material 1 is put into a molybdenum resistance heating boat, and 200 mg of the hole transport material 1 is put into another molybdenum resistance heating boat, 200 mg of the host compound (OC-11) is placed in another molybdenum resistance heating boat, 100 mg of the luminescent dopant (Comparative Compound 1) is placed in another resistance heating boat made of molybdenum, and the luminescent dopant (D -3) 100 mg, 100 mg of the luminescent dopant (D-6) in another molybdenum resistance heating boat, 200 mg of the electron transport material 1 in another molybdenum resistance heating boat, and another molybdenum resistance heating boat 200 mg of the electron transport material 2 was put in and attached to a vacuum deposition apparatus.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing the hole injecting material 1 is energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second. A 20 nm hole injection layer was provided.

Furthermore, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing the hole transport material 1 was heated by heating, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second. A 20 nm thick hole transport layer was provided.

  Further, the hole-transporting layer is heated at a deposition rate of 0.2 nm / second and 0.020 nm / second, respectively, by heating the heating boat containing the host compound (OC-11) and the light-emitting dopant (Comparative Compound 1). A blue light emitting layer having a thickness of 20 nm was provided by co-evaporation. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Further, the heating boat containing the host compound (OC-11), the luminescent dopant (D-3), and the luminescent dopant (D-6) was energized and heated, and the deposition rates were 0.2 nm / second and 0.010 nm, respectively. A yellow light emitting layer having a thickness of 20 nm was provided by co-evaporation on the hole transport layer at a rate of 0.0010 nm / sec. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Further, the heating boat containing the electron transport material 1 was energized and heated, and deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm thick hole blocking layer.

  In addition, the heating boat containing the electron transport material 2 is further energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to further form an electron transport layer having a thickness of 20 nm. Was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited to form a cathode, and an organic EL element 4-1 was produced.

<< Production of Organic EL Elements 4-2 to 4-161 >>
In the production of the organic EL element 4-1, the hole injection material, the hole transport material, the host compound, and the light emitting dopant (only the comparative compound 1) were replaced with the compounds shown in Tables 5-1 to 5-6. Organic EL elements 4-2 to 4-161 were produced in the same manner as EL element 4-1.

<< Evaluation of organic EL elements >>
About the obtained organic EL elements 4-1 to 4-161, the performance of the organic EL elements was evaluated in the same manner as in Example 1.

  In this example, in each evaluation of (1) external extraction quantum efficiency, (2) driving voltage, (4) half-light emission lifetime, and (5) initial deterioration, the example is based on the organic EL element 4-1. The relative value was determined in the same manner as in 1.

  The evaluation results are shown in Tables 5-1 to 5-6.

The organic EL device according to the present invention was measured with a spectral radiance meter CS-1000 (manufactured by Konica Minolta Optics). As a result of measuring the 2-degree viewing angle front luminance at 1000 cd / m ² , CIE chromaticity coordinates (CIE1931) were obtained. It was confirmed that the chromaticity in the color system was in the region of X = 0.33 ± 0.07, Y = 0.33 ± 0.1 and emitted white light.

  From Tables 5-1 to 5-6, the organic EL elements 4-5 to 4-161 of the present invention have higher external extraction quantum efficiency than the comparative organic EL elements 4-1 to 4-4, and It can be seen that there is little deterioration in luminance at the initial stage, and accordingly, the lifetime is long at both room temperature and high temperature.

  Furthermore, it turns out that the organic EL elements 4-5 to 4-161 of the present invention also suppress the generation of light emission unevenness and dark spots and the increase in driving voltage.

  From these results, even when two layers of light emitting layers are formed with the same host compound and three types of light emitting dopants to emit white light, it is necessary to improve the light emission efficiency, drive voltage, and light emission life. It can be seen that it is useful to use the phosphorescent organometallic complex according to the present invention as a dopant.

Example 5
<Vapor deposition type white light emitting element-3>
<< Preparation of white light emitting element 5-1 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  This transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of the hole injection material 1 is put into a molybdenum resistance heating boat, and 200 mg of the hole transport material 1 is put into another molybdenum resistance heating boat, 200 mg of host compound 1 (OC-11) is put into another resistance heating boat made of molybdenum, 200 mg of host compound 2 (OC-6) is put into another resistance heating boat made of molybdenum, and the luminescent dopant is put into another resistance heating boat made of molybdenum. 100 mg of (Comparative Compound 1), 100 mg of the luminescent dopant (D-3) is put in another molybdenum resistance heating boat, 100 mg of the luminescent dopant (D-6) is put in another resistance heating boat made of molybdenum, and another molybdenum 200 mg of electron transport material 1 is put into a resistance heating boat, and another molybdenum resistance heating boat The electron transport material 2 placed 200mg, was attached to a vacuum vapor deposition apparatus.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing the hole injecting material 1 is energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second. A 20 nm hole injection layer was provided.

Furthermore, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing the hole transport material 1 was heated by heating, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second. A 20 nm thick hole transport layer was provided.

  Further, the hole-transporting layer is heated at a deposition rate of 0.2 nm / second and 0.020 nm / second, respectively, by heating the heating boat containing the host compound (OC-11) and the light-emitting dopant (Comparative Compound 1). A blue light emitting layer having a thickness of 20 nm was provided by co-evaporation. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Further, the heating boat containing the host compound (OC-6), the luminescent dopant (D-3), and the luminescent dopant (D-6) was energized and heated, and the deposition rate was 0.2 nm / second and 0.010 nm, respectively. A yellow light emitting layer having a thickness of 20 nm was provided by co-evaporation on the hole transport layer at a rate of 0.0010 nm / sec. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Further, the heating boat containing the electron transport material 1 was energized and heated, and deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm thick hole blocking layer.

  In addition, the heating boat containing the electron transport material 2 is further energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to further form an electron transport layer having a thickness of 20 nm. Was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of lithium fluoride and 110 nm of aluminum were deposited to form a cathode, and an organic EL element 5-1 was produced.

<< Production of Organic EL Elements 5-2 to 5-161 >>
In the production of the organic EL element 5-1, the hole injection material, the hole transport material, the host compound 1, the host compound 2, and the light emitting dopant (only the comparative compound 1) are converted into the compounds shown in Tables 6-1 to 6-6. Organic EL elements 5-2 to 5-161 were produced in the same manner as the organic EL element 5-1, except that the replacement was performed.

<< Evaluation of organic EL elements >>
About the obtained organic EL elements 5-1 to 5-161, the performance of the organic EL elements was evaluated in the same manner as in Example 1.

  In this example, in each evaluation of (1) external extraction quantum efficiency, (2) driving voltage, (4) half-light emission lifetime, and (5) initial deterioration, the example is based on the organic EL element 5-1. The relative value was determined in the same manner as in 1.

  The evaluation results are shown in Tables 6-1 to 6-6.

The organic EL device according to the present invention was measured with a spectral radiance meter CS-1000 (manufactured by Konica Minolta Optics). As a result of measuring the 2-degree viewing angle front luminance at 1000 cd / m ² , CIE chromaticity coordinates (CIE1931) were obtained. It was confirmed that the chromaticity in the color system was in the region of X = 0.33 ± 0.07, Y = 0.33 ± 0.1 and emitted white light.

  From Table 6-1 to Table 6-6, compared with the comparative organic EL elements 5-1 to 5-4, the organic EL elements 5-5 to 5-161 of the present invention have high external extraction quantum efficiency, and It can be seen that there is little deterioration in luminance at the initial stage, and accordingly, the lifetime is long at both room temperature and high temperature.

  Furthermore, it can be seen that the organic EL elements 5-5 to 5-161 of the present invention also suppress the generation of light emission unevenness and dark spots and the drive voltage.

  From these results, even when two light emitting layers are formed with two different host compounds and three light emitting dopants to emit white light, the light emission efficiency is improved, the driving voltage is reduced, and the light emission life is improved. Then, it turns out that it is useful to use the phosphorescence-emitting organometallic complex which concerns on this invention as a light emission dopant.

Example 6
<Wet process type white light emitting element-1>
<< Preparation of White Light-Emitting Organic EL Element 6-1 >>
After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After the film formation by spin coating, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  This substrate was transferred to a nitrogen atmosphere, and a solution in which 50 mg of the hole transport material 3 was dissolved in 10 ml of toluene was formed on the first hole transport layer by spin coating at 1000 rpm for 30 seconds. After irradiating with ultraviolet light for 180 seconds to carry out photopolymerization / crosslinking, vacuum drying was performed at 60 ° C. for 1 hour to form a second hole transport layer.

  On this second hole transport layer, 100 mg of the host compound (OC-11), 10 mg of the luminescent dopant (Comparative Compound 1), 1 mg of the luminescent dopant (D-13) and 0.5 mg of the luminescent dopant (D-6). ) Was dissolved in 10 ml of toluene using a spin coating method at 1000 rpm for 30 seconds to form a light emitting layer. Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer with a film thickness of about 70 nm.

  Next, a thin film was formed on the light emitting layer by spin coating under a condition of 1000 rpm and 30 seconds using a solution in which 50 mg of the electron transport material 3 was dissolved in 10 ml of hexafluoroisopropanol (HFIP). Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the electron carrying layer with a film thickness of about 30 nm.

Subsequently, this substrate is fixed to a substrate holder of a vacuum deposition apparatus, and after the vacuum chamber is depressurized to 4 × 10 ⁻⁴ Pa, 0.4 nm of potassium fluoride is deposited as a cathode buffer layer, and further, 110 nm of aluminum is deposited. Then, a cathode was formed, and an organic EL element 6-1 was produced.

  In addition, the substrate temperature at the time of vapor deposition was room temperature.

<< Production of Organic EL Elements 6-2 to 6-161 >>
In the production of the organic EL element 6-1, the same procedure as in the organic EL element 6-1 was conducted except that the host compound and the light-emitting dopant (only comparative compound 1) were replaced with the compounds shown in Tables 7-1 to 7-6. Organic EL elements 6-2 to 6-161 were produced.

<< Evaluation of organic EL elements >>
About the obtained organic EL element 6-1 to 6-161, the performance of the organic EL element was evaluated in the same manner as in Example 1.

  In this example, in each evaluation of (1) external extraction quantum efficiency, (2) drive voltage, (4) half-light emission lifetime, and (5) initial deterioration, the example is based on the organic EL element 6-1. The relative value was determined in the same manner as in 1.

  The evaluation results are shown in Tables 7-1 to 7-6.

The organic EL device according to the present invention was measured with a spectral radiance meter CS-1000 (manufactured by Konica Minolta Optics). As a result of measuring the 2-degree viewing angle front luminance at 1000 cd / m ² , CIE chromaticity coordinates (CIE1931) were obtained. It was confirmed that the chromaticity in the color system was in the region of X = 0.33 ± 0.07, Y = 0.33 ± 0.1 and emitted white light.

  From Table 7-1 to Table 7-6, compared with the comparative organic EL elements 6-1 to 6-4, the organic EL elements 6-5 to 6-161 of the present invention have high external extraction quantum efficiency, and It can be seen that there is little deterioration in luminance at the initial stage, and accordingly, the lifetime is long at both room temperature and high temperature.

  Further, it can be seen that the organic EL elements 6-5 to 6-161 of the present invention also suppress the generation of light emission unevenness and dark spots and the increase in driving voltage.

  From these results, even when a light emitting layer is formed by a wet process using a spin coating method using three kinds of light emitting dopants to emit white light, in order to improve light emission efficiency, drive voltage, and light emission life, It can be seen that it is useful to use the phosphorescent organometallic complex according to the present invention as a dopant.

Example 7
<Wet process type white light emitting element-2>
<< Preparation of White Light-Emitting Organic EL Element 7-1 >>
After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After the film formation by spin coating, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  This substrate was transferred to a nitrogen atmosphere, and a solution in which 50 mg of the hole transport material 3 was dissolved in 10 ml of toluene was formed on the first hole transport layer by spin coating at 1000 rpm for 30 seconds. After irradiating with ultraviolet light for 180 seconds to carry out photopolymerization / crosslinking, vacuum drying was performed at 60 ° C. for 1 hour to form a second hole transport layer.

  On this second hole transport layer, 100 mg of the host compound (host material 1), 10 mg of the luminescent dopant (Comparative Compound 1), 1 mg of the luminescent dopant (D-33), and 0.5 mg of the luminescent dopant (Ir-14). ) Was dissolved in 10 ml of butyl acetate using a spin coating method at 1000 rpm for 30 seconds to form a light emitting layer. Ultraviolet light was irradiated for 15 seconds to cause photopolymerization / crosslinking, and further vacuum drying at 60 ° C. for 1 hour to obtain a light emitting layer having a film thickness of about 70 nm.

  Next, a thin film was formed on the light emitting layer by spin coating under a condition of 1000 rpm and 30 seconds using a solution of 50 mg of the electron transport material 4 dissolved in 10 ml of methanol. After irradiating with ultraviolet light for 60 seconds to perform photopolymerization / crosslinking, it was further vacuum-dried at 60 ° C. for 1 hour to obtain an electron transport layer having a film thickness of about 30 nm.

Subsequently, this substrate is fixed to a substrate holder of a vacuum deposition apparatus, and after the vacuum chamber is depressurized to 4 × 10 ⁻⁴ Pa, 0.4 nm of potassium fluoride is deposited as a cathode buffer layer, and further, 110 nm of aluminum is deposited. Then, a cathode was formed, and an organic EL element 7-1 was produced.

  In addition, the substrate temperature at the time of vapor deposition was room temperature.

<< Production of Organic EL Elements 7-2 to 7-161 >>
In the production of the organic EL device 7-1, the same procedure as in the organic EL device 7-1 was conducted except that the host compound and the light-emitting dopant (only comparative compound 1) were replaced with the compounds shown in Tables 8-1 to 8-6. Organic EL elements 7-2 to 7-161 were produced.

<< Evaluation of organic EL elements >>
About the obtained organic EL elements 7-1 to 7-161, the performance of the organic EL elements was evaluated in the same manner as in Example 1.

  In this example, in the evaluations of (1) external extraction quantum efficiency, (2) drive voltage, (4) half-emission lifetime, and (5) initial deterioration, the example is based on the organic EL element 7-1. The relative value was determined in the same manner as in 1.

  The evaluation results are shown in Tables 8-1 to 8-6.

The organic EL device according to the present invention was measured with a spectral radiance meter CS-1000 (manufactured by Konica Minolta Optics). As a result of measuring the 2-degree viewing angle front luminance at 1000 cd / m ² , CIE chromaticity coordinates (CIE1931) were obtained. It was confirmed that the chromaticity in the color system was in the region of X = 0.33 ± 0.07, Y = 0.33 ± 0.1 and emitted white light.

  From Table 8-1 to Table 8-6, the organic EL elements 7-5 to 7-161 of the present invention have higher external extraction quantum efficiency than the comparative organic EL elements 7-1 to 7-4, and It can be seen that there is little deterioration in luminance at the initial stage, and accordingly, the lifetime is long at both room temperature and high temperature.

  Furthermore, it turns out that the organic EL elements 7-5 to 7-161 of the present invention also suppress the generation of light emission unevenness and dark spots and the increase in driving voltage.

  From these results, even when a light emitting layer is formed by a wet process using a spin coating method using three kinds of light emitting dopants to emit white light, in order to improve light emission efficiency, drive voltage, and light emission life, It can be seen that it is useful to use the phosphorescent organometallic complex according to the present invention as a dopant.

  The organic electroluminescence element of the present invention has a low driving voltage, high light emission efficiency, excellent durability, excellent dark spot and uneven emission prevention effects, and can be suitably used for lighting devices and display devices.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power supply line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate 108 with a transparent electrode Nitrogen gas 109 Water capturing Agent A Display part B Control part L Light

Claims (10)

An organic electroluminescence device in which at least one organic layer including a light emitting layer is sandwiched between an anode and a cathode, wherein at least one of the organic layers is represented by the following general formula (1) or general formula (2): The organic electroluminescent element characterized by containing the phosphorescence-emitting organometallic complex in which the ligand represented by this coordinated to the metal atom.

[In General Formulas (1) and (2), Ring B represents a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle. Ring E represents an aromatic hydrocarbon ring having 6 to 30 carbon atoms or an aromatic heterocyclic ring having 1 to 30 carbon atoms bonded to ring D through G representing a carbon atom, a silicon atom, or a nitrogen atom.
R ₁ and R ₂ are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-group It represents an aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. At least one of R ₁ and R ₂ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms. R ₃ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms.
Ra is selected from a hydrogen atom, a methyl group, an isopropyl group, an isobutyl group, a 3-pentyl group, a 4-heptyl group, and a 2-ethylbutyl group.
Rb, Rc, Rd and Re are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group Represents a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent.
nb and nd represent an integer of 1 to 4, and na and nc represent 1 or 2. ne represents an integer of 1 to 20.
Adjacent ring A and ring D, ring D and ring E may be bonded to each other at two points to form any condensed ring selected from dibenzofuran, dibenzothiophene, fluorene and carbazole . Further, ring A, ring D and ring E may form a condensed ring consisting of a series of five rings formed by combining two condensed rings selected from dibenzofuran, dibenzothiophene, fluorene and carbazole, or a triphenylene skeleton. good.
Here, the ligand represented by the general formula (1) is selected from the structures represented by the following general formulas (L1A) to (L1AA), and the ligand represented by the general formula (2) is: It is selected from the structures represented by the following general formulas (L2A) to (L2Q). ]

[In General Formulas (L1A) to (L1AA) and General Formulas (L2A) to (L2Q), Ring B, Ring E, G, R ₁ , R ₂ , R ₃ , Ra, Rb, Rc, Rd, Re, na , Nb, nc, nd and ne are the ring B, ring E, G, R ₁ , R ₂ , R ₃ , Ra, Rb, Rc, Rd, Re, na, in the general formulas (1) and (2) . It is synonymous with nb, nc, nd and ne.
_{Ra 1 ~Ra 4, Rc 1 ~Rc} 2 and _Rd 1 ~ Rd ₄ each represent the position difference of the substituents Ra, Rc and Rd.
In the general formulas (L1A) to (L1AA) and the general formulas (L2A) to (L2Q), W, X, Y, and Z are carbon atoms that may have a substituent, and nitrogen that may have a substituent. An atom, a silicon atom having a substituent, an oxygen atom or a sulfur atom is represented. ] The phosphorescent organometallic complex in which the ligand represented by the general formula (1) or the general formula (2) is coordinated to a metal atom is represented by the following general formula (3) or the general formula (4). The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device is a phosphorescent organic metal complex.

[In General Formulas (3) and (4), Ring B represents a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocycle. Ring E represents an aromatic hydrocarbon ring having 6 to 30 carbon atoms or an aromatic heterocyclic ring having 1 to 30 carbon atoms bonded to ring D through G representing a carbon atom, a silicon atom, or a nitrogen atom.
R ₁ and R ₂ are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-group It represents an aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. At least one of R ₁ and R ₂ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms. R ₃ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms.
Ra is selected from a hydrogen atom, a methyl group, an isopropyl group, an isobutyl group, a 3-pentyl group, a 4-heptyl group, and a 2-ethylbutyl group.
Rb, Rc, Rd and Re are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group Represents a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent.
nb and nd represent an integer of 1 to 4, and na and nc represent 1 or 2. ne represents an integer of 1 to 20.
Adjacent ring A and ring D, ring D and ring E may be bonded to each other at two points to form any condensed ring selected from dibenzofuran, dibenzothiophene, fluorene and carbazole . Further, ring A, ring D and ring E may form a condensed ring consisting of a series of five rings formed by combining two condensed rings selected from dibenzofuran, dibenzothiophene, fluorene and carbazole, or a triphenylene skeleton. good.
L represents one or more of monoanionic bidentate ligands coordinated to M. M represents an atomic number of 40 or more and a group 8-10 transition metal atom in the periodic table, and m represents an integer of 0-2. n is at least 1 and m + n is 2 or 3.
Here, the ligand represented by the general formula (1) is selected from the structures represented by the general formulas (L1A) to (L1AA), and is represented by the general formula (2). Is selected from the structures represented by the general formulas (L2A) to (L2Q). ] The phosphorescent organometallic complex represented by the general formula (3) or (4) is a phosphorescent organometallic complex represented by the following general formula (5) or (6), The organic electroluminescent element according to claim 2.

[In General Formulas (5) and (6), Ring E is an aromatic hydrocarbon ring having 6 to 30 carbon atoms or carbon bonded to Ring D via G representing a carbon atom, a silicon atom or a nitrogen atom. The aromatic heterocyclic ring of number 1-30 is represented.
R ₁ and R ₂ are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group, non-group It represents an aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. At least one of R ₁ and R ₂ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms. R ₃ represents a linear alkyl group having 1 or more carbon atoms or a branched alkyl group or cycloalkyl group having 3 or more carbon atoms.
Ra is selected from a hydrogen atom, a methyl group, an isopropyl group, an isobutyl group, a 3-pentyl group, a 4-heptyl group, and a 2-ethylbutyl group.
Rb, Rc, Rd and Re are each independently a hydrogen atom, halogen atom, cyano group, alkyl group, alkenyl group, alkynyl group, alkoxy group, amino group, silyl group, arylalkyl group, aryl group, heteroaryl group Represents a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent.
nb and nd represent an integer of 1 to 4, and na and nc represent 1 or 2. ne represents an integer of 1 to 20.
Adjacent ring A and ring D, ring D and ring E may be bonded to each other at two points to form any condensed ring selected from dibenzofuran, dibenzothiophene, fluorene and carbazole . Further, ring A, ring D and ring E may form a condensed ring consisting of a series of five rings formed by combining two condensed rings selected from dibenzofuran, dibenzothiophene, fluorene and carbazole, or a triphenylene skeleton. good.
L represents one or more of monoanionic bidentate ligands coordinated to M. M represents an atomic number of 40 or more and a group 8-10 transition metal atom in the periodic table, and m represents an integer of 0-2. n is at least 1 and m + n is 2 or 3.
Here, the ligand represented by the general formula (1) is selected from the structures represented by the general formulas (L1A) to (L1AA), and is represented by the general formula (2). Is selected from the structures represented by the general formulas (L2A) to (L2Q). However, in the general formulas (L1A) to (L1AA) and the general formulas (L2A) to (L2Q), the ring B represents a benzene ring. ] Whether adjacent ring A and ring D, ring D and ring E of the organometallic complex are bonded to each other at two positions to form any condensed ring selected from dibenzofuran, dibenzothiophene, fluorene and carbazole Or ring A, ring D and ring E form a condensed ring consisting of a series of five rings formed by combining two condensed rings selected from dibenzofuran, dibenzothiophene, fluorene and carbazole, or a triphenylene skeleton . The organic electroluminescent element according to any one of claims 1 to 3, wherein   The organic electroluminescent element according to any one of claims 2 to 4, wherein the transition metal atom of the atomic number of 40 or more and 8-10 group in the periodic table is iridium.   A derivative having a ring structure in which at least one of the carbon atoms of the hydrocarbon ring constituting the light emitting layer is composed of a fluorene derivative, a dibenzofuran derivative, a dibenzothiophene derivative, a carbazole derivative, or a condensed ring compound derivative thereof. It contains, The organic electroluminescent element as described in any one of Claim 1-5 characterized by the above-mentioned.   The organic electroluminescent element according to any one of claims 1 to 6, wherein the organic layer containing the phosphorescent organometallic complex is a layer formed through a wet process.   The organic electroluminescence element according to any one of claims 1 to 7, wherein the emission color is white.   A display device comprising the organic electroluminescence element according to any one of claims 1 to 8.   An illuminating device comprising the organic electroluminescence element according to any one of claims 1 to 8.

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