KR102710151B1 - Formulation of organic functional materials - Google Patents

Abstract

The present invention relates to formulations containing at least one organic functional material and at least first and second organic solvents, and to electronic devices manufactured by using these formulations, wherein the first organic solvent is an adamantane derivative.

Description

Formulation of organic functional materials

The present invention relates to formulations containing at least one organic functional material and at least first and second organic solvents, and to electroluminescent devices manufactured by using these formulations, wherein the first organic solvent is an adamantane derivative.

Organic light emitting devices (OLEDs) have been fabricated by vacuum deposition processes for a long time. Other technologies, such as inkjet printing, have been investigated more recently due to their advantages such as cost savings and scale-up potential. One of the major challenges in multilayer printing is to identify relevant parameters to obtain a uniform deposition of ink on the substrate. In order to trigger these parameters, such as surface tension, viscosity or boiling point, some additives can be added to the formulation.

Many solvents have been proposed for inkjet printing in organic electronic devices. However, the number of important parameters that play a role during the deposition and drying processes makes the selection of the solvent very difficult. Therefore, formulations containing organic semiconductors used for deposition by inkjet printing still require improvement. One object of the present invention is to provide formulations of organic semiconductors which enable controlled deposition to form organic semiconductor layers having good layer properties and efficiency performance. A further object of the present invention is to provide formulations of organic semiconductors which, when used in inkjet printing processes, enable uniform application of ink droplets onto a substrate, thereby providing good layer properties and efficiency performance.

The above object of the present invention is solved by providing a formulation comprising at least one organic functional material and at least first and second organic solvents, wherein the first solvent is an adamantane derivative.

The present inventors surprisingly found that the use of an organic solvent, an adamantine derivative, as the first solvent enables complete control of the surface tension and induces effective ink deposition to form uniform and well-defined organic layers of functional materials with good layer properties and performance.

Figure 1 shows a typical layer structure of a device containing a substrate, an ITO anode, a hole injection layer (HIL), a hole transport layer (HTL), a green-emitting layer (G-EML), a hole blocking layer (HBL), an electron transport layer (ETL), and an Al cathode.
Figures 2 to 10 show the membrane profiles of Comparative Example 1 and Examples 1 to 8.

The present invention relates to a formulation comprising at least one organic functional material and at least first and second organic solvents, wherein the first organic solvent is an adamantane derivative.

Preferred embodiment

In a first preferred embodiment, the first organic solvent is an adamantane derivative according to general formula (I),

Here

X is CR or N, preferably CR;

R is in each case, identically or differently, H, D, F, CN, NO ₂ , N(R ¹ ) ₂ , Si(R ¹ ) ₃ , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 20 carbon atoms, a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 carbon atoms, a straight-chain alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkenyl or alkynyl group having 3 to 20 carbon atoms, wherein one or more non-adjacent CH ₂ groups may be replaced by -O-, -S-, -NR ¹ -, -CONR ¹ -, -S(O) ₂ -O-, -Si(R ¹ ) ₂ -, -CO-O-, -C=O-, -CR ¹ =CR ¹ - or -C≡C-, wherein one or more hydrogen atoms may be replaced by D, F, CN or NO ₂ ), or an aryl or heteroaryl group having 5 to 60 ring atoms, or an aryloxy or heteroaryloxy group having 5 to 40 ring atoms, or an arylalkyl or heteroarylalkyl group having 5 to 40 ring atoms (which may be substituted by one or more non-aromatic R ¹ radicals), and two substituents R on the same ring may in turn be taken together to form a monocyclic or polycyclic aliphatic, aromatic or heteroaromatic ring system, which may be substituted by a plurality of substituents R ¹ ; and

R ¹ is, in each case, identically or differently, a straight-chain alkyl or alkoxy group having 1 to 20 carbon atoms, or a branched or cyclic alkyl or alkoxy group having 3 to 20 carbon atoms, wherein one or more non-adjacent CH ₂ groups may be replaced by -O-, -S-, -CO-O-, -C=O-, -CH=CH- or -C≡C- and one or more hydrogen atoms may be replaced by F, or an aryl or heteroaryl group having 4 to 14 carbon atoms, which may be substituted by one or more non-aromatic R ¹ radicals.

In a first more preferred embodiment, the first organic solvent is an adamantane derivative according to general formula (I),

X is CR

Not only R but also R ¹ is as defined above.

In a second more preferred embodiment, the first organic solvent is an adamantane derivative according to general formula (I),

X is N, and

Not only R but also R ¹ is as defined above.

In a first most preferred embodiment, the first organic solvent is an adamantane derivative according to general formula (I),

Here

Not only R but also R ¹ is as defined above.

Preferably, in the general formula (II):

R is in each case, identically or differently, H, D, F, CN, NO ₂ , N(R ¹ ) ₂ , Si(R ¹ ) ₃ , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 20 carbon atoms, a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 carbon atoms, a straight-chain alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkenyl or alkynyl group having 3 to 20 carbon atoms, wherein one or more non-adjacent CH ₂ groups may be replaced by -O-, -S-, -NR ¹ -, -CONR ¹ -, -S(O) ₂ -O-, -Si(R ¹ ) ₂ -, -CO-O-, -C=O-, -CR ¹ =CR ¹ - or -C≡C-, One or more hydrogen atoms may be replaced by D, F, CN or NO ₂ , and

R ¹ is, in each case, identically or differently, a straight-chain alkyl or alkoxy group having 1 to 20 carbon atoms, or a branched or cyclic alkyl or alkoxy group having 3 to 20 carbon atoms, wherein one or more non-adjacent CH ₂ groups may be replaced by -O-, -S-, -CO-O-, -C=O-, -CH=CH- or -C≡C-, and one or more hydrogen atoms may be replaced by F.

Examples of desirable adamantane derivatives and their boiling points (BP) are shown in Table 1 below.

Table 1: Preferred adamantane derivatives and their boiling points (BP).

Preferably, the first organic solvent has a surface tension of ≥ 20 mN/m. More preferably, the surface tension of the first organic solvent is in the range of 25 to 40 mN/m, and most preferably in the range of 28 to 37.5 mN/m.

The content of the first organic solvent is preferably in the range of 0.1 to 30 wt%, more preferably in the range of 0.5 to 25 wt%, and most preferably in the range of 1 to 20 wt%, based on the total amount of solvent in the formulation.

As a result, the content of the second organic solvent is preferably in the range of 70 to 99.9 wt%, more preferably in the range of 75 to 99.5 wt%, and most preferably in the range of 88 to 99 wt%, based on the total amount of solvent in the formulation.

Preferably, the boiling point of the first organic solvent is in the range of 100 to 400°C, more preferably in the range of 150 to 350°C.

The formulation according to the present invention, in one preferred embodiment, comprises at least a second organic solvent, different from the first organic solvent. The second organic solvent is employed together with the first organic solvent.

In one embodiment, the second organic solvent may be an adamantane derivative different from the first organic solvent. Nonetheless, preferably, the second organic solvent is not an adamantane derivative.

Suitable second organic solvents are preferably organic solvents comprising, in particular, alcohols, aldehydes, ketones, ethers, esters, amides such as di-C _1-2 -alkylformamides, sulfur compounds, nitro compounds, hydrocarbons, halogenated hydrocarbons (e.g. chlorinated hydrocarbons), aromatic or heteroaromatic hydrocarbons, and halogenated aromatic or heteroaromatic hydrocarbons.

Preferably, the second organic solvent may be selected from one of the following groups: substituted and unsubstituted aromatic or linear esters, such as ethyl benzoate, butyl benzoate; substituted and unsubstituted aromatic or linear ethers, such as 3-phenoxytoluene or anisole; substituted or unsubstituted arene derivatives, such as xylene; indane derivatives, such as hexamethylindane; substituted and unsubstituted aromatic or linear ketones; substituted and unsubstituted heterocycles, such as pyrrolidinone, pyridine, pyrazine; other fluorinated or chlorinated aromatic hydrocarbons.

Particularly preferred second organic solvents are, for example, 1,2,3,4-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, 1,2,3-trimethylbenzene, 1,2,4,5-tetramethylbenzene, 1,2,4-trichlorobenzene, 1,2,4-trimethylbenzene, 1,2-dihydronaphthalene, 1,2-dimethylnaphthalene, 1,3-benzodioxolane, 1,3-diisopropylbenzene, 1,3-dimethylnaphthalene, 1,4-benzodioxane, 1,4-diisopropylbenzene, 1,4-dimethylnaphthalene, 1,5-dimethyltetraline, 1-benzothiophene, thianaphthalene, 1-bromonaphthalene, 1-chloromethylnaphthalene, 1-Ethylnaphthalene, 1-Methoxynaphthalene, 1-Methylnaphthalene, 1-Methylindole, 2,3-Benzofuran, 2,3-Dihydrobenzofuran, 2,3-Dimethylanisole, 2,4-Dimethylanisole, 2,5-Dimethylanisole, 2,6-Dimethylanisole, 2,6-Dimethylnaphthalene, 2-Bromo-3-bromomethylnaphthalene, 2-Bromomethylnaphthalene, 2-Bromonaphthalene, 2-Ethoxynaphthalene, 2-Ethylnaphthalene, 2-Isopropylanisole, 2-Methylanisole, 2-Methylindole, 3,4-Dimethylanisole, 3,5-Dimethylanisole, 3-Bromoquinoline, 3-Methylanisole, 4-Methylanisole, 5-Decanolide, 5-methoxyindane, 5-methoxyindole, 5-tert-butyl-m-xylene, 6-methylquinoline, 8-methylquinoline, acetophenone, anisole, benzonitrile, benzothiazole, benzyl acetate, bromobenzene, butyl benzoate, butyl phenyl ether, cyclohexylbenzene, decahydronaphthol, dimethoxytoluene, 3-phenoxytoluene, diphenyl ether, propiophenone, ethylbenzene, ethyl benzoate, hexylbenzene, indane, hexamethylindane, indene, isochromane, cumene, m-cymene, mesitylene, methyl benzoate, o-, m-, p-xylene, propyl benzoate, propylbenzene, o-dichlorobenzene, pentylbenzene, phenetole, Ethoxybenzene, phenyl acetate, p-cymene, propiophenone, sec-butylbenzene, t-butylbenzene, thiophene, toluene, veratrol, monochlorobenzene, o-dichlorobenzene, pyridine, pyrazine, pyrimidine, pyrrolidinone, morpholine, dimethylacetamide, dimethyl sulfoxide, decalin and/or mixtures of these compounds.

These solvents may be used individually or as mixtures of two, three or more solvents forming a second solvent.

Preferably, the boiling point of the second organic solvent is in the range of 100 to 400°C, more preferably in the range of 150 to 350°C.

At least one organic functional material has a solubility in the first and second organic solvents, preferably in the range of 1 to 250 g/l, and more preferably in the range of 1 to 50 g/l.

The content of at least one organic functional material in the formulation is in the range of 0.001 to 20 wt%, preferably in the range of 0.01 to 10 wt%, more preferably in the range of 0.1 to 5 wt%, and most preferably in the range of 0.3 to 5 wt%, based on the total weight of the formulation.

The formulation according to the present invention preferably has a surface tension in the range of 10 to 50 mN/m, more preferably in the range of 25 to 40 mN/m.

Furthermore, the formulation according to the present invention preferably has a viscosity in the range of 1 to 50 mPa ^. s, more preferably in the range of 2 to 40 mPa ^. s, and most preferably in the range of 2 to 20 mPa ^. s.

Preferably, the organic solvent blend comprises a surface tension in the range of 15 to 80 mN/m, more preferably in the range of 20 to 60 mN/m and most preferably in the range of 25 to 40 mN/m. The surface tension is The surface tension can be measured using a FTA (First Ten Angstrom) 1000 contact angle goniometer at 20°C. Details of the method are available in First Ten Angstrom, "Surface Tension Measurements Using the Drop Shape Method" by Roger P. Woodward, Ph.D. Preferably, the pendant drop method can be used to determine the surface tension. This measurement technique dispenses a drop from a needle in the bulk liquid or gas phase. The shape of the drop is obtained from the relationship between surface tension, gravity and density differences. When using the drop method, the surface tension is calculated from a shadow image of the drop using https://www.kruss.de/services/education-theory/glossary/drop-shape-analysis . A commonly used and commercially available high-precision drop shape analysis tool is the First Ten Angstrom. All surface tension measurements were performed using FTA1000 from Ngstrom. Surface tension is determined by software FTA1000. All measurements were performed at room temperature in the range of 20 °C to 22 °C. The standard operating procedure involves determining the surface tension of each formulation using a fresh disposable drop dispensing system (syringe and needle). Each drop is measured for 60 measurements over a period of 1 minute, which are then averaged. For each formulation, three drops are measured. The final value is averaged over the measurements. The instrument is regularly cross-checked against a variety of liquids with well-known surface tensions.

The viscosity of the formulations and solvents was measured using a TA Instruments ARG2 rheometer with 40 mm parallel plate geometry over a shear rate range from 10 to 1000 s ^-1 . The measurements were taken as an average from 200 to 800 s ^-1 , while temperature and shear rate were precisely controlled. Each solvent was measured in triplicate. The viscosity values stated are averaged over the measurements.

The formulation according to the present invention comprises at least one organic functional material that can be used in the manufacture of a functional layer of an electronic device. The functional material is typically an organic material introduced between the anode and the cathode of the electronic device.

The term organic functional material refers to, inter alia, organic conductors, organic semiconductors, organic fluorescent compounds, organic phosphorescent compounds, organic light absorbing compounds, organic photosensitizing compounds, organic photosensitizers and other organic photoactive compounds. Accordingly, the term organic functional material includes organometallic complexes of transition metals, rare earths, lanthanides and actinides.

The organic functional material is selected from the group consisting of a fluorescent emitter, a phosphorescent emitter, a host material, a matrix material, an exciton blocking material, an electron transport material, an electron injection material, a hole transport material, a hole injection material, an n-dopant, a p-dopant, a wide band gap material, an electron blocking material, and a hole blocking material.

Preferred embodiments of organic functional materials are disclosed in detail in WO 2011/076314 A1, the contents of which are incorporated herein by reference.

In a preferred embodiment, the organic functional material is an organic semiconductor selected from the group consisting of hole injecting, hole transporting, emissive, electron transporting and electron injecting materials.

More preferably, the organic functional material is an organic semiconductor selected from the group consisting of hole-injecting and hole-transporting materials.

The organic functional material can be a compound, a polymer, an oligomer or a dendrimer having low molecular weight, wherein the organic functional material can also be in the form of a mixture. Thus, the formulation according to the present invention may comprise two different compounds having low molecular weight, one compound having low molecular weight and one polymer or two polymers (blend).

Organic functional materials are often described by the properties of their frontier orbitals, which are explained in more detail below. Molecular orbitals, in particular also the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), their energy levels and the energies of the lowest triplet state T ₁ or of the lowest excited singlet state S ₁ of the material, are determined by quantum-chemical calculations. For the calculations of metal-free organic materials, a geometry optimization is first performed using the "Ground State/Semi-Empirical/Default Spin/AM1/Charge 0/Spin Singlet" method. Subsequently, an energy calculation is performed based on the optimized geometry. The "TD-SCF/DFT/Default Spin/B3PW91" method with the "6-31G(d)" basis set (charge 0, spin singlet) is used here. For metal-containing compounds, the geometry is optimized via the "ground state/Hartree-Fock/default spin/LanL2MB/charge 0/spin singlet" method. The energy calculations are performed similarly to the method described above for organic materials, except that the "LanL2DZ" base set is used for the metal atoms and the "6-31G(d)" base set is used for the ligands. The energy calculations provide the HOMO energy level HEh or the LUMO energy level LEh in Hartree units. The HOMO and LUMO energy levels in electron volts, calibrated with reference to cyclic voltammetry measurements, are determined therefrom as follows:

For the purposes of this application, these values will be considered as the HOMO and LUMO energy levels of the materials, respectively.

The lowest triplet state T ₁ is defined as the energy of the triplet state with the lowest energy resulting from the described quantum chemical calculations.

The lowest excited singlet state S ₁ is defined as the energy of the excited singlet state with the lowest energy resulting from the described quantum-chemical calculations.

The method described here is independent of the software package used and always gives the same results. Examples of programs frequently used for this purpose are "Gaussian09W" (Gaussian Inc.) and Q-Chem 4.1 (Q-Chem, Inc.).

Compounds having hole injection properties, also called hole injection materials herein, simplify or facilitate the transport of holes, i.e. positive charges, from the anode to the organic layer. Typically, the hole injection material has a HOMO level that is at or above the anode level, i.e. typically at least -5.3 eV.

Compounds having hole transport properties, also called hole transport materials herein, are capable of transporting holes, i.e. positive charges, which are generally injected from the anode or an adjacent layer, for example a hole injection layer. Hole transport materials generally preferably have a high HOMO level of at least -5.4 eV. Depending on the structure of the electronic device, hole transport materials can also be used as hole injection materials.

Preferred compounds having hole injection and/or hole transport properties include, for example, triarylamines, benzidines, tetraaryl-para-phenylenediamines, triarylphosphines, phenothiazines, phenoxazines, dihydrophenazines, thianthrenes, dibenzo-para-dioxines, phenoxathiines, carbazoles, azulenes, thiophenes, pyrrole and furan derivatives, and also additional O-, S- or N-containing heterocycles having a high HOMO (HOMO = highest occupied molecular orbital).

A compound having hole injection and/or hole transport properties, comprising: a phenylenediamine derivative (US 3615404), an arylamine derivative (US 3567450), an amino-substituted chalcone derivative (US 3526501), a styrylanthracene derivative (JP-A-56-46234), a polycyclic aromatic compound (EP 1009041), a polyarylalkane derivative (US 3615402), a fluorenone derivative (JP-A-54-110837), a hydrazone derivative (US 3717462), an acylhydrazone, a stilbene derivative (JP-A-61-210363), a silazane derivative (US 4950950), a polysilane (JP-A-2-204996), an aniline copolymer (JP-A-2-282263), a thiophene oligomer (JP Heisei 1 (1989) 211399), polythiophene, poly(N-vinylcarbazole) (PVK), polypyrrole, polyaniline and other electrically conductive macromolecules, porphyrin compounds (JP-A-63-2956965, US 4720432), aromatic dimethylidene type compounds, carbazole compounds, such as, for example, CDBP, CBP, mCP, aromatic tertiary amine and styrylamine compounds (US 4127412), such as, for example, triphenylamine of the benzidine type, triphenylamine of the styrylamine type and triphenylamine of the diamine type may be particularly mentioned. Furthermore, arylamine dendrimers (JP Heisei 8 (1996) 193191), monomeric triarylamines (US 3180730), triarylamines containing at least one functional group containing one or more vinyl radicals and/or active hydrogens (US 3567450 and US 3658520), or tetraaryldiamines (two tertiary amine units linked via an aryl group) may be used. Furthermore, more triarylamino groups may be present in the molecule. Also suitable are phthalocyanine derivatives, naphthalocyanine derivatives, butadiene derivatives and quinoline derivatives, for example dipyrazino[2,3-f:2',3'-h]quinoxalinehexacarbonitrile.

Aromatic tertiary amines containing at least two tertiary amine units (US 2008/0102311 A1, US 4720432 and US 5061569), for example NPD (α-NPD = 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl) (US 5061569), TPD 232 (= N,N'-bis-(N,N'-diphenyl-4-aminophenyl)-N,N-diphenyl-4,4'-diamino-1,1'-biphenyl) or MTDATA (MTDATA or m-MTDATA = 4,4',4"-tris[(3-methylphenyl)phenylamino]triphenylamine) (JP-A-4-308688), TBDB (= N,N,N',N'-tetra(4-biphenyl)diaminobiphenylene), TAPC (= 1,1-Bis(4-di-p-tolylaminophenyl)cyclohexane), TAPPP (= 1,1-bis(4-di-p-tolylaminophenyl)-3-phenylpropane), BDTAPVB (= 1,4-bis[2-[4-[N,N-di(p-tolyl)amino]phenyl]vinyl]benzene), TTB (= N,N,N',N'-tetra-p-tolyl-4,4'-diaminobiphenyl), TPD (= 4,4'-bis[N-3-methylphenyl]-N-phenylamino)biphenyl), N,N,N',N'-tetraphenyl-4,4"'-diamino-1,1',4',1",4",1"'-quaterphenyl, also tertiary amines containing carbazole units, for example TCTA (= Preferred are 4-(9H-carbazol-9-yl)-N,N-bis[4-(9H-carbazol-9-yl)phenyl]benzenamine). Likewise preferred are hexaazatriphenylene compounds and phthalocyanine derivatives (e.g. H ₂ Pc, CuPc (= copper phthalocyanine), CoPc, NiPc, ZnPc, PdPc, FePc, MnPc, ClAlPc, ClGaPc, ClInPc, ClSnPc, Cl ₂ SiPc, (HO)AlPc, (HO)GaPc, VOPc, TiOPc, MoOPc, GaPc-O-GaPc) according to US 2007/0092755 A1.

Particularly preferred are the following triarylamine compounds of the formulae (TA-1) to (TA-12), which are disclosed in EP 1162193 B1, EP 650 955 B1, Synth.Metals 1997 , 91(1-3), 209, DE 19646119 A1, WO 2006/122630 A1, EP 1 860 097 A1, EP 1834945 A1, JP 08053397 A, US 6251531 B1, US 2005/0221124, JP 08292586 A, US 7399537 B2 , US 2006/0061265 A1, EP 1 661 888 and WO 2009/041635. The compounds of formulae (TA-1) to (TA-12) may also be substituted:

Additional compounds which can be used as injecting materials are described in EP 0891121 A1 and EP 1029909 A1, and injecting layers generally in US 2004/0174116 A1.

These arylamines and heterocycles, which are generally used as hole-injecting and/or hole-transporting materials, preferably result in a HOMO in the polymer of greater than -5.8 eV (with respect to vacuum level), particularly preferably greater than -5.5 eV.

Compounds having electron injection and/or electron transport properties are, for example, pyridine, pyrimidine, pyridazine, pyrazine, oxadiazole, quinoline, quinoxaline, anthracene, benzanthracene, pyrene, perylene, benzimidazole, triazine, ketones, phosphine oxides and phenazine derivatives, as well as triarylboranes and additional O-, S- or N-containing heterocycles having a low LUMO (LUMO = lowest unoccupied molecular orbital).

Compounds particularly suitable for the electron transport and electron injection layer are metal chelates of 8-hydroxyquinolines (e.g. LiQ, AlQ ₃ , GaQ ₃ , MgQ ₂ , ZnQ ₂ , InQ ₃ , ZrQ ₄ ), BAlQ, Ga oxinoid complexes, 4-azaphenanthren-5-ol-Be complexes (see US 5529853 A, formula ET-1), butadiene derivatives (US 4356429), heterocyclic optical brighteners (US 4539507), benzimidazole derivatives (US 2007/0273272 A1), such as for example TPBI (see US 5766779, formula ET-2), 1,3,5-triazines, for example spirobifluorenyltriazine derivatives (e.g. DE 102008064200), pyrene, anthracene, tetracene, fluorene, spirofluorene, dendrimers, tetracenes (e.g. rubrene derivatives), 1,10-phenanthroline derivatives (JP 2003-115387, JP 2004-311184, JP 2001-267080, WO 02/043449), silacyclopentadiene derivatives (EP 1480280, EP 1478032, EP 1469533), borane derivatives, such as for example Si-containing triarylborane derivatives (see US 2007/0087219 A1, formula ET-3), pyridine derivatives (JP 2004-200162), phenanthroline, in particular 1,10-phenanthroline Derivatives, such as for example BCP and Bphen, and also several phenanthrolines linked via biphenyl or other aromatic groups (US 2007-0252517 A1) or phenanthrolines linked to anthracene (see US 2007-0122656 A1, formulae ET-4 and ET-5).

Heterocyclic organic compounds, such as for example thiopyran dioxide, oxazoles, triazoles, imidazoles or oxadiazoles are likewise suitable. 5-membered rings containing N, such as for example oxazoles, preferably 1,3,4-oxadiazole, for example compounds of the formulae ET-6, ET-7, ET-8 and ET-9 as described in particular in US 2007/0273272 A1; examples of the use of thiazoles, oxadiazoles, thiadiazoles, triazoles are cf. inter alia in US 2008/0102311 A1 and in Y.A. Levin, M.S. Skorobogatova, Khimiya Geterotsiklicheskikh Soedinenii 1967 (2), 339-341 (preferably compounds of the formula ET-10, silacyclopentadiene derivatives). Preferred compounds are of the following formulae (ET-6) to (ET-10):

Additionally, derivatives of organic compounds such as fluorenone, fluorenylidenemethane, perylenetetracarboxylic acid, anthraquinonedimethane, diphenoquinone, anthrone and anthraquinonediethylenediamine can be used.

Preferred are 2,9,10-substituted anthracenes or molecules containing two anthracene units (with 1- or 2-naphthyl, and 4- or 3-biphenyl) (see US 2008/0193796 A1, formula ET-11). Also very advantageous are those in which the 9,10-substituted anthracene unit is linked to a benzimidazole derivative (see US 2006/147747 A and EP 1551206 A1, formulas ET-12 and ET-13).

The compound capable of generating electron injection and/or electron transport properties preferably results in a LUMO of less than -2.5 eV (with respect to vacuum level), particularly preferably less than -2.7 eV.

The formulation of the present invention may also comprise an emitter. The term emitter denotes a material which, after excitation, can undergo a radiative transition to the ground state with emission of light, which can occur by any type of energy transfer. In general, two classes of emitters are known, namely fluorescent and phosphorescent emitters. The term fluorescent emitter denotes a material or compound which undergoes a radiative transition from an excited singlet state to the ground state. The term phosphorescent emitter denotes a luminescent material or compound which preferably contains a transition metal.

An emitter is commonly referred to as a dopant when the dopant causes the properties described above in the system. In a system comprising a matrix material and a dopant, the dopant is taken to mean the component in the mixture having a smaller proportion. Correspondingly, in a system comprising a matrix material and a dopant, the matrix material is taken to mean the component in the mixture having a larger proportion. Thus, the term phosphorescent emitter can also be taken to mean, for example, a phosphorescent dopant.

Compounds capable of emitting light include, in particular, fluorescent emitters and phosphorescent emitters. These include, in particular, compounds containing stilbene, stilbenamine, styrylamine, coumarin, rubrene, rhodamine, thiazole, thiadiazole, cyanine, thiophene, paraphenylene, perylene, phthalocyanine, porphyrin, ketone, quinoline, imine, anthracene and/or pyrene structures. Particularly preferred are compounds which are capable of emitting light with high efficiency even from the triplet state at room temperature, i.e. which exhibit electrophosphorescence instead of electrofluorescence, which often leads to an increase in energy efficiency. Suitable for this purpose are first of all compounds containing heavy atoms having an atomic number greater than 36. Preference is given to compounds containing d- or f-transition metals which meet the conditions mentioned above. Here, corresponding compounds containing elements of groups 8 to 10 (Ru, Os, Rh, Ir, Pd, Pt) are particularly preferred. Suitable functional compounds here are various complexes, as described, for example, in WO 02/068435 A1, WO 02/081488 A1, EP 1239526 A2 and WO 2004/026886 A2.

Preferred compounds which can act as fluorescent emitters are described by way of example below. Preferred fluorescent emitters are selected from the classes of monostyrylamines, distyrylamines, tristyrylamines, tetrastyrylamines, styrylphosphines, styryl ethers and arylamines.

A monostyrylamine is understood to mean a compound containing one substituted or unsubstituted styryl group and at least one, preferably aromatic, amine. A distyrylamine is understood to mean a compound containing two substituted or unsubstituted styryl groups and at least one, preferably aromatic, amine. A tristyrylamine is understood to mean a compound containing three substituted or unsubstituted styryl groups and at least one, preferably aromatic, amine. A tetrastyrylamine is understood to mean a compound containing four substituted or unsubstituted styryl groups and at least one, preferably aromatic, amine. The styryl group is particularly preferably stilbene (which may also be additionally substituted). The corresponding phosphines and ethers are defined analogously to the amines. An arylamine or an aromatic amine in the sense of the present invention is understood to mean a compound containing three substituted or unsubstituted aromatic or heteroaromatic ring systems which are directly bonded to nitrogen. At least one of the above aromatic or heteroaromatic ring systems is preferably a fused ring system, preferably a fused ring system having at least 14 aromatic ring atoms. Preferred examples thereof are aromatic anthracenamines, aromatic anthracenediamines, aromatic pyrenamines, aromatic pyrenediamines, aromatic chrysenamines or aromatic chrysenediamines. An aromatic anthracenamine is understood to mean a compound in which one diarylamino group is directly bonded to an anthracene group, preferably in the 9-position. An aromatic anthracenediamine is understood to mean a compound in which two diarylamino groups are directly bonded to anthracene groups, preferably in the 2,6- or 9,10-positions. Aromatic pyrenamines, pyrenediamines, chrysenamines and chrysenediamines are defined similarly, wherein the diarylamino group is bonded to pyrene, preferably in the 1-position or the 1,6-position.

Additionally preferred fluorescent emitters are selected from indenofluorenamine or indenofluorenediamine, especially as described in WO 2006/122630; benzoindenofluorenamine or benzoindenofluorenediamine, especially as described in WO 2008/006449; and dibenzoindenofluorenamine or dibenzoindenofluorenediamine, especially as described in WO 2007/140847.

Examples of compounds from the class of styrylamines which can be used as fluorescent emitters are substituted or unsubstituted tristilbenamines or dopants as described in WO 2006/000388, WO 2006/058737, WO 2006/000389, WO 2007/065549 and WO 2007/115610. Distyrylbenzene and distyrylbiphenyl derivatives are described in US 5121029. Additional styrylamines can be found in US 2007/0122656 A1.

Particularly preferred styrylamine compounds are compounds of the formula EM-1 as described in US 7250532 B2 and compounds of the formula EM-2 as described in DE 10 2005 058557 A1:

Particularly preferred triarylamine compounds are compounds of the formulae EM-3 to EM-15, and derivatives thereof, disclosed in CN 1583691 A, JP 08/053397 A and US 6251531 B1, EP 1957606 A1, US 2008/0113101 A1, US 2006/210830 A, WO 2008/006449 and DE 102008035413:

Further preferred compounds which can be used as fluorescent emitters are naphthalene, anthracene, tetracene, benzanthracene, benzophenanthrene (DE 10 2009 005746), fluorene, fluoranthene, periflantene, indenoperylene, phenanthrene, perylene (US 2007/0252517 A1), pyrene, chrysene, decacyclene, coronene, tetraphenylcyclopentadiene, pentaphenylcyclopentadiene, fluorene, spirofluorene, rubrene, coumarin (US 4769292, US 6020078, US 2007/0252517 A1), pyran, oxazole, benzoxazole, benzothiazole, benzimidazole, pyrazine, cinnamic acid esters, diketopyrrolopyrrole, Selected from derivatives of acridone and quinacridone (US 2007/0252517 A1).

Among the anthracene compounds, 9,10-substituted anthracenes, such as, for example, 9,10-diphenylanthracene and 9,10-bis(phenylethynyl)anthracene, are particularly preferred. 1,4-Bis(9'-ethynylanthracenyl)benzene is also a preferred dopant.

Likewise preferred are derivatives of rubrene, coumarin, rhodamine, quinacridone, such as for example DMQA (= N,N'-dimethylquinacridone), dicyanomethylenepyrans, such as for example DCM (= 4-(dicyanoethylene)-6-(4-dimethylaminostyryl-2-methyl)-4H-pyran), thiopyran, polymethines, pyrylium and thiapyrylium salts, periflanthene and indenoperylene.

Blue fluorescent emitters are preferably polyaromatic compounds, such as for example 9,10-di(2-naphthylanthracene) and other anthracene derivatives, tetracenes, xanthenes, derivatives of perylenes, such as for example 2,5,8,11 -tetra- t-butylperylene, phenylenes, for example 4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-biphenyl, fluorene, fluoranthene, arylpyrene (US 2006/0222886 A1), arylenevinylene (US 5121029, US 5130603), bis(azinyl)imine-boron compounds (US 2007/0092753 A1), bis(azinyl)methene compounds and carbostyryl compounds.

Additional desirable blue fluorescent emitters are described in the literature, C.H. Chen et al.: "Recent developments in organic electroluminescent materials", Macromol. Symp. 125, (1997) 1-48, and "Recent progress of molecular organic electroluminescent materials and devices" Mat. Sci. and Eng. R, 39 (2002), 143-222.

Additional preferred blue fluorescent emitters are the hydrocarbons disclosed in DE 102008035413.

Preferred compounds which can act as fluorescent emitters are described, by way of example, below.

Examples of phosphorescent emitters are given by WO 00/70655, WO 01/41512, WO 02/02714, WO 02/15645, EP 1191613, EP 1191612, EP 1191614 and WO 2005/033244. In general, all phosphorescent complexes which are used according to the prior art for phosphorescent OLEDs and which are known to the person skilled in the art in the field of organic electroluminescence are suitable, and the person skilled in the art will be able to use additional phosphorescent complexes without the need for an inventive step.

The phosphorescent metal complex preferably contains Ir, Ru, Pd, Pt, Os or Re, more preferably Ir.

Preferred ligands are 2-phenylpyridine derivatives, 7,8-benzoquinoline derivatives, 2-(2-thienyl)pyridine derivatives, 2-(1-naphthyl)pyridine derivatives, 1-phenylisoquinoline derivatives, 3-phenylisoquinoline derivatives or 2-phenylquinoline derivatives. All of these compounds can be substituted with fluoro, cyano and/or trifluoromethyl substituents, for example for blue colour. The auxiliary ligand is preferably acetylacetonate or picolinic acid.

In particular, complexes of Pt or Pd having a tetradentate ligand of the chemical formula EM-16 are suitable.

Compounds of chemical formula EM-16 are described in more detail in US 2007/0087219 A1, which disclosure is incorporated herein by reference for the purpose of describing the substituents and indices in the above chemical formula. Also, Pt-porphyrin complexes (US 2009/0061681 A1) and Ir complexes having an extended ring system, for example, 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin-Pt(II), tetraphenyl-Pt(II) tetrabenzoporphyrin (US 2009/0061681 A1), cis-bis(2-phenylpyridinato-N,C ² ')Pt(II), cis-bis(2-(2'-thienyl)pyridinato-N,C ³ ')Pt(II), cis-bis(2-(2'-thienyl)quinolinato-N,C ⁵ ')Pt(II), (2-(4,6-difluorophenyl)-pyridinato-N,C ² ')Pt(II) (acetylacetonate), or tris(2-phenylpyridinato-N,C ² ')Ir(III) (= Ir(ppy) ₃ , green), bis(2-phenylpyridinato-N,C ² )Ir(III) (acetylacetonate) (= Ir(ppy) ₂ acetylacetonate, green, US 2001/0053462 A1, Baldo, Thompson et al. Nature 403, (2000), 750-753), bis(1-phenylisoquinolinato-N,C ^2' )(2-phenylpyridinato-N,C ^2' )iridium(III), bis(2-phenylpyridinato-N,C ^2' )(1-phenylisoquinolinato-N,C ^2' )iridium(III), bis(2-(2'-benzothienyl)pyridinato-N,C3 ^' )-iridium(III) (acetylacetonate), bis(2-(4',6'-difluorophenyl)pyridinato-N,C2 ^' )-iridium(III) (picolinate) (FIrpic, blue), bis(2-(4',6'-difluorophenyl)pyridinato-N,C2 ^' )Ir(III) (tetrakis(1-pyrazolyl)borate), tris(2-(biphenyl-3-yl)-4-tert-butylpyridine)iridium(III), (ppz) _2Ir (5phdpym) (US 2009/0061681 A1), (45ooppz) _2Ir (5phdpym) (US 2009/0061681 A1), derivatives of 2-phenylpyridine-Ir complexes, such as, for example, PQIr (= iridium(III) bis(2-phenylquinolyl-N,C ^2' )acetylacetonate), tris(2-phenylisoquinolinato-N,C)Ir(III) (red), bis(2-(2'-benzo[4,5-a]thienyl)pyridinato-N,C ³ )Ir (acetylacetonate) ([Btp ₂ Ir(acac)], red, Adachi et al. Appl. Phys. Lett. 78 (2001), 1622-1624).

Likewise suitable are complexes of trivalent lanthanides, such as, for example, Tb ³⁺ and Eu ³⁺ (J. Kido et al. Appl. Phys. Lett. 65 (1994), 2124, Kido et al. Chem. Lett. 657, 1990, US 2007/0252517 A1), or phosphorescent complexes of Pt(II), Ir(I), Rh(I) with maleonitrile dithiolate (Johnson et al., JACS 105, 1983, 1795), Re(I) tricarbonyl-diimine complexes (Wrighton, JACS 96, 1974, 998, inter alia), Os(II) complexes with cyano ligands and bipyridyl or phenanthroline ligands (Ma et al., Synth. Metals 94, 1998, 245) is suitable.

Additional phosphorescent emitters having tridentate ligands are described in US 6824895 and US 10/729238. Red emitting phosphorescent complexes are found in US 6835469 and US 6830828.

Particularly preferred compounds for use as phosphorescent dopants are, in particular, compounds of the formula EM-17 (described in particular in US 2001/0053462 A1 and Inorg. Chem. 2001, 40(7), 1704-1711, JACS 2001, 123(18), 4304-4312) and derivatives thereof.

Derivatives are described in US 7378162 B2, US 6835469 B2 and JP 2003/253145 A.

Furthermore, compounds of chemical formulae EM-18 to EM-21 (described in US 7238437 B2, US 2009/008607 A1 and EP 1348711) and their derivatives can be used as emitters.

Quantum dots can likewise be used as emitters, such materials being disclosed in detail in WO 2011/076314 A1.

In particular, compounds used as host materials, together with emitting compounds, include materials from various classes of substances.

The host material has a larger band gap between the HOMO and LUMO than the commonly used emitter materials. In addition, the preferred host material exhibits properties of a hole- or electron-transporting material. Furthermore, the host material may have both electron- and hole-transporting properties.

The host material is in some cases also called a matrix material, especially when the host material is used in combination with a phosphorescent emitter in an OLED.

Preferred host materials or co-host materials, in particular for use together with fluorescent dopants, are the class of oligoarylenes (e.g. 2,2',7,7'-tetraphenylspirobifluorene or dinaphthylanthracene according to EP 676461), in particular oligoarylenes containing condensed aromatic groups, such as for example anthracene, benzanthracene, benzophenanthrene (DE 10 2009 005746, WO 2009/069566), phenanthrene, tetracene, coronene, chrysene, fluorene, spirofluorene, perylene, phthaloperylene, naphthaloperylene, decacyclene, rubrene, oligoarylenevinylenes (e.g. DPVBi = according to EP 676461). 4,4'-bis(2,2-diphenylethenyl)-1,1'-biphenyl or spiro-DPVBi), polypodal metal complexes (for example according to WO 04/081017), in particular metal complexes of 8-hydroxyquinoline, for example AlQ ₃ (= aluminium(III) tris(8-hydroxyquinoline)) or bis(2-methyl-8-quinolinolato)-4-(phenylphenollinolato)aluminium, also imidazole chelates (US 2007/0092753 A1) and quinoline-metal complexes, aminoquinoline-metal complexes, benzoquinoline-metal complexes, hole-conducting compounds (for example according to WO 2004/058911), electron-conducting compounds, in particular ketones, phosphine oxides, sulfoxides etc. (for example according to WO 2004/058911 according to WO 2005/084081 and WO 2005/084082), atropisomers (for example according to WO 2006/048268), boronic acid derivatives (for example according to WO 2006/117052) or benzanthracenes (for example according to WO 2008/145239).

Particularly preferred compounds which can act as host materials or co-host materials are selected from the class of oligoarylenes, including anthracene, benzanthracene and/or pyrene, or atropisomers of such compounds. Oligoarylene in the sense of the present invention is taken to mean a compound in which at least three aryl or arylene groups are bonded to each other.

Preferred host materials are selected in particular from compounds of formula (H-1):

Ar ⁴ -(Ar ⁵ ) _p -Ar ⁶ (H-1)

wherein Ar ⁴ , Ar ⁵ , and Ar ⁶ are each, in their respective cases, identically or differently, an aryl or heteroaryl group having 5 to 30 aromatic ring atoms which may be optionally substituted, and p represents an integer in the range of 1 to 5; and the sum of π electrons in Ar ⁴ , Ar ⁵ and Ar ⁶ is at least 30 when p = 1, at least 36 when p = 2, and at least 42 when p = 3.

In the compound of the formula (H-1), the group Ar ⁵ particularly preferably represents anthracene, and the groups Ar ⁴ and Ar ⁶ are bonded in the 9- and 10-positions, wherein these groups may be optionally substituted. Very particularly preferably, at least one of the groups Ar ⁴ and/or Ar ⁶ is a condensed aryl group selected from 1- or 2-naphthyl, 2-, 3- or 9-phenanthrenyl, or 2-, 3-, 4-, 5-, 6- or 7-benzanthracenyl. Anthracene compounds are described in US 2007/0092753 A1 and US 2007/0252517 A1 and include, for example, 2-(4-methylphenyl)-9,10-di-(2-naphthyl)anthracene, 9-(2-naphthyl)-10-(1,1'-biphenyl)anthracene and 9,10-bis[4-(2,2-diphenylethenyl)phenyl]anthracene, 9,10-diphenylanthracene, 9,10-bis(phenylethynyl)anthracene and 1,4-bis(9'-ethynylanthracenyl)benzene. Preferred are compounds containing two anthracene units (US 2008/0193796 A1), for example 10,10'-bis[1,1',4',1"]terphenyl-2-yl-9,9'-bisanthracenyl.

Further preferred compounds are derivatives of arylamines, styrylamines, fluoresceins, diphenylbutadiene, tetraphenylbutadiene, cyclopentadiene, tetraphenylcyclopentadiene, pentaphenylcyclopentadiene, coumarins, oxadiazoles, bisbenzoxazolines, oxazoles, pyridines, pyrazines, imines, benzothiazoles, benzoxazoles, benzimidazoles (US 2007/0092753 A1), for example 2,2',2"-(1,3,5-phenylene)tris[1-phenyl-1H-benzimidazole], aldazines, stilbene, styrylarylene derivatives, for example 9,10-bis[4-(2,2-diphenylethenyl)phenyl]anthracene, and distyrylarylene derivatives (US 5121029), diphenylethylene, Vinylanthracene, diaminocarbazole, pyran, thiopyran, diketopyrrolopyrrole, polymethine, cinnamic acid ester and fluorescent dyes.

Derivatives of arylamines and styrylamines, for example TNB (= 4,4'-bis[N-(1-naphthyl)-N-(2-naphthyl)amino]biphenyl), are particularly preferred. Metal-oxinoid complexes, for example LiQ or AlQ _{3 ,} can be used as co-hosts.

Preferred compounds having oligoarylene as a matrix are described in US 2003/0027016 A1, US 7326371 B2, US 2006/043858 A, WO 2007/114358, WO 2008/145239, JP 3148176 B2, EP 1009044, US 2004/018383, WO 2005/061656 A1, EP 0681019B1, WO 2004/013073A1, US 5077142, WO 2007/065678 and DE 102009005746, wherein particularly preferred compounds are described by the formulae H-2 to H-8.

Furthermore, compounds that can be used as a host or matrix include materials used with phosphorescent emitters.

Such compounds which can also be used as structural elements in polymers include CBP (N,N-biscarbazolylbiphenyl), carbazole derivatives (e.g. according to WO 2005/039246, US 2005/0069729, JP 2004/288381, EP 1205527 or WO 2008/086851), azacarbazoles (e.g. according to EP 1617710, EP 1617711, EP 1731584 or JP 2005/347160), ketones (e.g. according to WO 2004/093207 or DE 102008033943), phosphine oxides, sulfoxides and sulfones (e.g. according to WO 2005/003253), oligophenylenes, aromatic amines. (e.g. according to US 2005/0069729), bipolar matrix materials (e.g. according to WO 2007/137725), silanes (e.g. according to WO 2005/111172), 9,9-diarylfluorene derivatives (e.g. according to DE 102008017591), azaboroles or boronic esters (e.g. according to WO 2006/117052), triazine derivatives (e.g. according to DE 102008036982), indolocarbazole derivatives (e.g. according to WO 2007/063754 or WO 2008/056746), indenocarbazole derivatives (e.g. according to DE 102009023155 and DE 102009031021), Metal complexes of diazaphosphole derivatives (for example according to DE 102009022858), triazole derivatives, oxazoles and oxazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, distyrylpyrazine derivatives, thiopyran dioxide derivatives, phenylenediamine derivatives, tertiary aromatic amines, styrylamines, amino-substituted chalcone derivatives, indoles, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic dimethylidene compounds, carbodiimide derivatives, 8-hydroxyquinoline derivatives, such as for example AlQ ₃ (which may also contain triarylaminophenol ligands) (US 2007/0134514 A1), metal complexes/polysilane compounds, and thiophene, benzothiophene and dibenzothiophene derivatives.

Examples of preferred carbazole derivatives are mCP (= 1,3-N,N-dicarbazolylbenzene (= 9,9'-(1,3-phenylene)bis-9H-carbazole)) (formula H-9), CDBP (= 9,9'-(2,2'-dimethyl[1,1'-biphenyl]-4,4'-diyl)bis-9H-carbazole), 1,3-bis(N,N'-dicarbazolyl)benzene (= 1,3-bis(carbazol-9-yl)benzene), PVK (polyvinylcarbazole), 3,5-di(9H-carbazol-9-yl)biphenyl and CMTTP (formula H-10). Particularly preferred compounds are disclosed in US 2007/0128467 A1 and US 2005/0249976 A1 (formulae H-11 and H-13).

Preferred tetraaryl-Si compounds are disclosed, for example, in US 2004/0209115, US 2004/0209116, US 2007/0087219 A1 and in H. Gilman, E.A. Zuech, Chemistry & Industry (London, UK), 1960, 120.

Particularly preferred tetraaryl-Si compounds are described by the chemical formulae H-14 to H-21.

Particularly preferred compounds from group 4 for the production of matrices for phosphorescent dopants are disclosed, inter alia, in DE 102009022858, DE 102009023155, EP 652273 B1, WO 2007/063754 and WO 2008/056746, wherein particularly preferred compounds are described under the formulae H-22 to H-25.

As for the functional compound which can be used according to the present invention and which can act as a host material, a substance containing at least one nitrogen atom is particularly preferred. These preferably include aromatic amines, triazine derivatives and carbazole derivatives. Accordingly, carbazole derivatives exhibit particularly surprisingly high efficiency. Triazine derivatives unexpectedly prolong the life of electronic devices.

It may also be desirable to use a plurality of different matrix materials as a mixture, in particular at least one electron-conducting matrix material and at least one hole-conducting matrix material. It is likewise desirable to use a mixture of a charge-transporting matrix material and, if any, an electrically inactive matrix material which does not participate significantly in charge transport, as described in WO 2010/108579.

Furthermore, compounds may be used which improve the transition from the singlet state to the triplet state and which are used as supports for functional compounds having emitter properties and which improve the phosphorescent properties of these compounds. For this purpose, in particular carbazole and bridged carbazole dimer units (as described for example in WO 2004/070772 A2 and WO 2004/113468 A1) are suitable. Also suitable for this purpose are ketones, phosphine oxides, sulfoxides, sulfones, silane derivatives and similar compounds (as described for example in WO 2005/040302 A1).

In this paper, n-dopant is taken to mean a reducing agent, i.e. an electron donor. Preferred examples of n-dopants are W(hpp) ₄ and other electron-rich metal complexes (according to WO 2005/086251 A2), P=N compounds (e.g. WO 2012/175535 A1, WO 2012/175219 A1), naphthylenecarbodiimides (e.g. WO 2012/168358 A1), fluorenes (e.g. WO 2012/031735 A1), free radicals and diradicals (e.g. EP 1837926 A1, WO 2007/107306 A1), pyridines (e.g. EP 2452946 A1, EP 2463927 A1), N-heterocyclic compounds (e.g. WO 2009/000237 A1) and acridines, as well as Phenazines (e.g. US 2007/145355 A1).

Furthermore, the formulations may include a wide band gap material as the functional material. Wide band gap material is intended to mean a material within the meaning of the disclosure of US 7,294,849. These systems exhibit particularly advantageous performance data in electroluminescent devices.

A compound used as a wide band gap material can have a band gap of 2.5 eV or more, preferably 3.0 eV or more, particularly preferably 3.5 eV or more. The band gap can be calculated, in particular, using the energy levels of the highest unoccupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO).

Furthermore, the formulation may include a hole blocking material (HBM) as a functional material. A hole blocking material refers to a material that prevents or minimizes the transport of holes (positive charges) in a multilayer system, especially when such a material is arranged in the form of a layer adjacent to an emitting layer or a hole conducting layer. Typically, a hole blocking material has a lower HOMO level than a hole transport material in the adjacent layer. A hole blocking layer is often arranged between the emitting layer and the electron transport layer in an OLED.

Basically any known hole blocking material can be used. Besides the other hole blocking materials described elsewhere in the present application, advantageous hole blocking materials are metal complexes (US 2003/0068528), such as for example bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (BAlQ). For this purpose, Fac-tris(1-phenylpyrazolato-N,C2)iridium(III) (Ir(ppz) ₃ ) (US 2003/0175553 A1) is likewise used. Phenanthroline derivatives, such as for example BCP, or phthalimides, such as for example TMPP, can likewise be used.

Furthermore, advantageous hole blocking materials are described in WO 00/70655 A2, WO 01/41512 and WO 01/93642 A1.

Furthermore, the formulation may include an electron blocking material (EBM) as a functional material. An electron blocking material refers to a material that prevents or minimizes the transport of electrons in a multilayer system, especially when such a material is arranged in the form of a layer adjacent to an emitting layer or an electron conducting layer. Typically, an electron blocking material has a higher LUMO level than an electron transport material in the adjacent layer.

Basically any known hole blocking material can be used. In addition to other electron blocking materials described elsewhere in this application, advantageous electron blocking materials are transition-metal complexes, for example Ir(ppz) ₃ (US 2003/0175553).

The electron blocking material may preferably be selected from amines, triarylamines and derivatives thereof.

Furthermore, the functional compounds that can be used as organic functional materials in the formulation preferably have a molecular weight of ≤ 3,000 g/mol, more preferably ≤ 2,000 g/mol and most preferably ≤ 1,000 g/mol when they are low molecular weight compounds.

Furthermore, functional compounds which are distinguished by a high glass transition temperature are of particular importance. In this regard, particularly preferred functional compounds which can be used as organic functional materials in formulations are those which have a glass transition temperature of ≥ 70° C., preferably ≥ 100° C., more preferably ≥ 125° C., and most preferably ≥ 150° C., as determined according to DIN 51005.

The formulations can also contain polymers as organic functional materials. The compounds described above as organic functional materials, which often have relatively low molecular weights, can also be mixed with the polymer. Likewise, these compounds can be incorporated into the polymer by covalent bonding. This is possible, in particular, with compounds substituted by reactive leaving groups, such as bromine, iodine, chlorine, boronic acids or boronic esters, or by reactive polymerizable groups, such as olefins or oxetanes. These can be used as monomers for the production of corresponding oligomers, dendrimers or polymers. The oligomerization or polymerization here preferably takes place via halogen or boronic acid functions, or via polymerizable groups. It is also possible to crosslink the polymer via these types of groups. The compounds and polymers according to the invention can be used as crosslinked or non-crosslinked layers.

Polymers which can be used as organic functional materials often contain units or structural elements as described in the context of the compounds described above, in particular those disclosed and extensively listed in WO 02/077060 A1, WO 2005/014689 A2 and WO 2011/076314 A1, which are incorporated herein by reference. The functional materials can be derived, for example, from the following classes:

Group 1: Structural elements capable of generating hole injection and/or hole transport properties;

Group 2: Structural elements capable of producing electron injection and/or electron transport properties;

Group 3: Structural elements combining the characteristics described in relation to Groups 1 and 2;

Group 4: Structural elements having luminescent properties, in particular phosphorescent groups;

Group 5: Structural elements that improve the transition from the so-called singlet state to the triplet state;

Group 6: Structural elements which influence the morphology of the resulting polymer or also the emission colour;

Group 7: Structural elements typically used as backbones.

Here, the structural elements may also have various functions, so a clear designation is not necessarily advantageous. For example, the structural elements of group 1 may also act as a backbone.

A polymer having hole transport or hole injection properties, which is used as an organic functional material containing a structural element of group 1, may preferably contain a unit corresponding to the hole transport or hole injection material described above.

Further preferred structural elements of group 1 are, for example, triarylamines, benzidines, tetraaryl-para-phenylenediamines, carbazoles, azulenes, thiophenes, pyrrole and furan derivatives, and further O-, S- or N-containing heterocycles having a high HOMO. Such arylamines and heterocycles preferably have a HOMO greater than -5.8 eV (with respect to vacuum level), particularly preferably greater than -5.5 eV.

In particular, polymers having hole transport or hole injection properties containing at least one repeating unit of the following chemical formula HTP-1 are preferred:

Here the symbols have the following meanings:

Ar ¹ is, in each case, identically or differently for different repeating units, a single bond or a monocyclic or polycyclic aryl group, which may be optionally substituted;

Ar ² is, in each case, identically or differently for different repeating units, a monocyclic or polycyclic aryl group, which may be optionally substituted;

Ar ³ is, in each case, identical or different for the different repeating units, a monocyclic or polycyclic aryl group, which may be optionally substituted;

m is 1, 2, or 3.

Particularly preferred are repeating units of the formula HTP-1 selected from the group consisting of units of the formulae HTP-1A to HTP-1C:

Here the symbols have the following meanings:

R ^a is, in each case, identically or differently, H, a substituted or unsubstituted aromatic or heteroaromatic group, alkyl, cycloalkyl, alkoxy, aralkyl, aryloxy, arylthio, alkoxycarbonyl, silyl or carboxyl group, a halogen atom, a cyano group, a nitro group or a hydroxyl group;

r is 0, 1, 2, 3 or 4, and

s is 0, 1, 2, 3, 4, or 5.

In particular, polymers having hole transport or hole injection properties containing at least one of the following repeating units of the following chemical formula HTP-2 are preferred:

Here the symbols have the following meanings:

T ¹ and T ² are independently selected from thiophene, selenophene, thieno[2,3-b]thiophene, thieno[3,2-b]thiophene, dithienothiophene, pyrrole and aniline (wherein these groups may be substituted with one or more radicals R ^b );

R ^b is independently at each occurrence selected from halogen, -CN, -NC, -NCO, -NCS, -OCN, -SCN, -C(=O)NR ⁰ R ⁰⁰ , -C(=O)X, -C(=O)R ⁰ , -NH ₂ , -NR ⁰ R ⁰⁰ , -SH, -SR ⁰ , -SO ₃ H, -SO ₂ R ⁰ , -OH, -NO ₂ , -CF ₃ , -SF ₅ , an optionally substituted silyl, carbyl or hydrocarbyl group having 1 to 40 carbon atoms, which may be optionally substituted and which may optionally contain one or more heteroatoms;

R ⁰ and R ⁰⁰ are each independently H, or an optionally substituted carbyl or hydrocarbyl group having 1 to 40 carbon atoms, which may be optionally substituted and optionally contain one or more heteroatoms;

Ar ⁷ and Ar ⁸ independently represent a monocyclic or polycyclic aryl or heteroaryl group, which may be optionally substituted and optionally bonded to the 2,3-position of one or both of the adjacent thiophene or selenophene groups;

c and e are, independently of each other, 0, 1, 2, 3 or 4, where 1 < c + e ≤　6 and;

d and f are, independently of each other, 0, 1, 2, 3, or 4.

Preferred examples of polymers having hole transport or hole injection properties are described, inter alia, in WO 2007/131582 A1 and WO 2008/009343 A1.

A polymer having electron injecting and/or electron transporting properties, which is used as an organic functional material containing structural elements from group 2, may preferably contain units corresponding to the electron injecting and/or electron transporting material described above.

Further preferred structural elements of group 2 having electron injection and/or electron transport properties are derived, for example, from pyridine, pyrimidine, pyridazine, pyrazine, oxadiazole, quinoline, quinoxaline and phenazine groups as well as from triarylborane groups or further O-, S- or N-containing heterocycles having low LUMO levels. These structural elements of group 2 preferably have a LUMO of less than -2.7 eV (with respect to vacuum level), particularly preferably less than -2.8 eV.

The organic functional material may preferably be a polymer containing structural elements from group 3, in which structural elements which improve hole and electron mobility (i.e. structural elements from groups 1 and 2) are directly linked to each other. Some of these structural elements may serve as emitters herein, in which the emission color may be shifted, for example, to green, red or yellow. Their use is therefore advantageous, for example, for the generation of other emission colors or broadband emissions by polymers which originally emit blue.

A polymer having luminescent properties, which is used as an organic functional material containing structural elements from group 4, may preferably contain units corresponding to the emitter materials described above. Polymers containing phosphorescent groups, especially the above-described emitting metal complexes containing corresponding units containing elements of groups 8 to 10 (Ru, Os, Rh, Ir, Pd, Pt) are preferred.

A polymer used as an organic functional material containing a unit of group 5 which improves the transition from the so-called singlet state to the triplet state can be used to support a phosphorescent compound, preferably a polymer containing a structural element of group 4 described above. A polymeric triplet matrix can be used here.

For this purpose, in particular carbazole and linked carbazole dimer units (as described, for example, in DE 10304819 A1 and DE 10328627 A1) are suitable. For this purpose, ketones, phosphine oxides, sulfoxides, sulfones and silane derivatives and similar compounds (as described, for example, in DE 10349033 A1) are also suitable. Furthermore, preferred structural units can be derived from the compounds described above in connection with the matrix materials used together with the phosphorescent compounds.

The additional organic functional material is preferably a polymer containing units of group 6 which influence the morphology and/or the emission color of the polymer. These are, in addition to the polymers mentioned above, those which have at least one additional aromatic or another conjugated structure which is not considered among the groups mentioned above. Accordingly, these groups have little or no influence on the charge-carrier mobility, the non-organometallic complexation or the singlet-triplet transition.

These types of structural units can influence the morphology and/or emission color of the resulting polymer. Therefore, depending on the structural units, these polymers can also be used as emitters.

Therefore, for fluorescent OLEDs, aromatic structural elements having 6 to 40 C atoms or also tolan, stilbene or bisstyrylarylene derivative units are preferred, each of which may be substituted by one or more radicals. Particular preference is given here to using groups derived from 1,4-phenylene, 1,4-naphthylene, 1,4- or 9,10-anthrylene, 1,6-, 2,7- or 4,9-pyrenylene, 3,9- or 3,10-perylenylene, 4,4'-biphenylene, 4,4"-terphenylylene, 4,4'-bi-1,1'-naphthylylene, 4,4'-tolanylene, 4,4'-stilbenylene or 4,4"-bisstyrylarylene derivatives.

The polymer used as an organic functional material preferably contains a unit of group 7 containing an aromatic structure having 6 to 40 carbon atoms, which is commonly used as a backbone.

These include, in particular, 4,5-dihydropyrene derivatives, 4,5,9,10-tetrahydropyrene derivatives, fluorene derivatives (as described for example in US 5962631, WO 2006/052457 A2 and WO 2006/118345A1), 9,9-spirobifluorene derivatives (as disclosed for example in WO 2003/020790 A1), 9,10-phenanthrene derivatives (as disclosed for example in WO 2005/104264 A1), 9,10-dihydrophenanthrene derivatives (as disclosed for example in WO 2005/014689 A2), 5,7-dihydrodibenzoxepin derivatives, and cis- and trans-indenofluorene derivatives (as disclosed for example in WO 2004/041901 A1 and WO 2004/113412 A2), and binaphthylene derivatives (as described for example in WO 2006/063852 A1), and additional units (as disclosed for example in WO 2005/056633 A1, EP 1344788 A1, WO 2007/043495 A1, WO 2005/033174 A1, WO 2003/099901 A1 and DE 102006003710).

Particularly preferred are structural units of group 7 selected from fluorene derivatives (as disclosed for example in US 5,962,631, WO 2006/052457 A2 and WO 2006/118345 A1), spirobifluorene derivatives (as disclosed for example in WO 2003/020790 A1), benzofluorene, dibenzofluorene, benzothiophene and dibenzofluorene groups, and derivatives thereof (as disclosed for example in WO 2005/056633 A1, EP 1344788 A1 and WO 2007/043495 A1).

The structural elements of particularly preferred group 7 are represented by the general chemical formula PB-1:

Here, the symbols and indices have the following meanings:

A, B and B' are each, also for different repeating units, identically or differently, preferably a divalent group selected from -CR ^c R ^d -, -NR ^c -, -PR ^c -, -O-, -S-, -SO-, -SO ₂ -, -CO-, -CS-, -CSe-, -P(=O)R ^c -, -P(=S)R ^c - and -SiR ^c R ^d -;

R ^c and R ^d are each independently selected from H, halogen, -CN, -NC, -NCO, -NCS, -OCN, -SCN, -C(=O)NR ⁰ R ⁰⁰ , -C(=O)X, -C(=O)R ⁰ , -NH ₂ , -NR ⁰ R ⁰⁰ , -SH, -SR ⁰ , -SO ₃ H, -SO ₂ R ⁰ , -OH, -NO ₂ , -CF ₃ , -SF ₅ , an optionally substituted silyl, carbyl or hydrocarbyl group having 1 to 40 carbon atoms which may be optionally substituted and which may optionally contain one or more heteroatoms, wherein the groups R ^c and R ^d may optionally form a spiro group having a fluorene radical to which they are bonded;

X is a halogen;

R ⁰ and R ⁰⁰ are each, independently, H or an optionally substituted carbyl or hydrocarbyl group having 1 to 40 carbon atoms, which may be optionally substituted and optionally contain one or more heteroatoms;

g is, in each case, independently, 0 or 1, and h is, in each case, independently, 0 or 1, wherein the sum of g and h in the subunit is preferably 1;

m is an integer ≥ 1;

Ar ¹ and Ar ² independently represent a monocyclic or polycyclic aryl or heteroaryl group, which may be optionally substituted and may be optionally bonded to the 7,8-position or the 8,9-position of the indenofluorene group;

a and b, independently of each other, are 0 or 1.

When the groups R ^c and R ^d form a spiro group together with the fluorene group to which these groups are bonded, this group preferably represents spirobifluorene.

Particularly preferred is a repeating unit of the chemical formula PB-1 selected from the group consisting of units of the chemical formulas PB-1A to PB-1E:

Here, R ^c has the meaning described above for chemical formula PB-1, r is 0, 1, 2, 3 or 4, and R ^e has the same meaning as the radical R ^c .

R ^e is preferably -F, -Cl, -Br, -I, -CN, -NO ₂ , -NCO, -NCS, -OCN, -SCN, -C(=O)NR ⁰ R ⁰⁰ , -C(=O)X, -C(=O)R ⁰ , -NR ⁰ R ⁰⁰ , an optionally substituted silyl, aryl or heteroaryl group having 4 to 40, preferably 6 to 20, carbon atoms, or a straight-chain, branched or cyclic alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 20, preferably 1 to 12 carbon atoms, wherein one or more hydrogen atoms may be optionally replaced by F or Cl, and the groups R ⁰ , R ⁰⁰ and X have the meanings given above for formula PB-1.

Particularly preferred is a repeating unit of the chemical formula PB-1 selected from the group consisting of units of the chemical formulas PB-1F to PB-1I:

Here, the symbols have the following meanings:

L is H, halogen or an optionally fluorinated, linear or branched alkyl or alkoxy group having 1 to 12 C atoms, preferably H, F, methyl, i-propyl, t-butyl, n-pentoxy or trifluoromethyl; and

L' is an optionally fluorinated, linear or branched alkyl or alkoxy group having 1 to 12 carbon atoms, preferably n-octyl or n-octyloxy.

For carrying out the present invention, a polymer containing more than one of the structural elements of groups 1 to 7 described above is preferred. Furthermore, it may be provided that the polymer preferably contains more than one of the structural elements from one group described above, i.e. comprises a mixture of structural elements selected from one group.

In particular, polymers which, in addition to at least one structural element having luminescent properties (group 4), preferably at least one phosphorescent group, additionally contain at least one further structural element selected from groups 1 to 3, 5 or 6 as described above, preferably from groups 1 to 3, are particularly preferred.

When present in the polymer, the proportions of the various classes of groups can be within a wide range known to the skilled person. Surprising advantages can be achieved when the proportion of one class present in the polymer, selected in each case from the structural elements of groups 1 to 7 described above, is preferably in each case ≥ 5 mol-%, particularly preferably in each case ≥ 10 mol-%.

The production of white emitting copolymers is described in detail, in particular in DE 10343606 A1.

In order to improve the solubility, the polymer may also contain corresponding groups. Preferably, it may be provided that the polymer contains substituents such that on average at least 2 non-aromatic carbon atoms, particularly preferably at least 4 and particularly preferably at least 8 non-aromatic carbon atoms are present per repeat unit, wherein the average relates to the number average. Individual carbon atoms may be replaced here, for example, by O or S. However, it is possible that a certain proportion, optionally all of the repeat units, do not contain substituents containing non-aromatic carbon atoms. Short-chain substituents are preferred here, since long-chain substituents can have a detrimental effect on the layers obtainable using the organic functional material. The substituents preferably contain at most 12 carbon atoms, preferably at most 8 carbon atoms and particularly preferably at most 6 carbon atoms in the linear chain.

The polymer used according to the present invention as an organic functional material may be a random, alternating or regioregular copolymer, a block copolymer or a combination of these copolymer forms.

In a further embodiment, the polymer used as organic functional material can be a non-conjugated polymer having side chains, whereby such an embodiment is of particular importance for phosphorescent OLEDs based on the polymer. Typically, the phosphorescent polymer can be obtained by free-radical copolymerization of a vinyl compound, which vinyl compound contains at least one unit having a phosphorescent emitter and/or at least one charge transport unit, which is disclosed in particular in US 7250226 B2. Further phosphorescent polymers are described in particular in JP 2007/211243 A2, JP 2007/197574 A2, US 7250226 B2 and JP 2007/059939 A.

In a further preferred embodiment, the non-conjugated polymer contains backbone units which are connected to each other by spacer units. Examples of such triplet emitters based on non-conjugated polymers based on backbone units are disclosed, for example, in DE 102009023154.

In a further preferred embodiment, the non-conjugated polymer can be designed as a fluorescent emitter. Preferred fluorescent emitters based on non-conjugated polymers having side chains contain anthracene or benzanthracene groups, or derivatives of these groups, in the side chains, such polymers are disclosed, for example, in JP 2005/108556, JP 2005/285661 and JP 2003/338375.

These polymers can often be used as electron- or hole-transporting materials, wherein these polymers are preferably designed as non-conjugated polymers.

Furthermore, the functional compound used as an organic functional material in the formulation preferably has a molecular weight M _w of ≥ 10,000 g/mol, particularly preferably ≥ 20,000 g/mol and especially preferably ≥ 50,000 g/mol in the case of a polymeric compound.

Here, the molecular weight M _w of the polymer is preferably in the range from 10,000 to 2,000,000 g/mol, particularly preferably in the range from 20,000 to 1,000,000 g/mol and very particularly preferably in the range from 50,000 to 300,000 g/mol. The molecular weight M _w is measured by means of GPC (= gel permeation chromatography) relative to an internal polystyrene standard.

The above-cited references for descriptions of functional compounds are incorporated herein by reference for the purposes of disclosure.

The formulation according to the present invention may comprise all organic functional materials necessary for the production of each functional layer of the electronic device. For example, if the hole transport, hole injection, electron transport or electron injection layer is constructed from exactly one functional compound, the formulation comprises exactly this compound as the organic functional material. If the emitting layer comprises, for example, an emitter in combination with a matrix or host material, the formulation comprises, as the organic functional material, precisely a mixture of the matrix or host material and the emitter, as described in more detail elsewhere in the present application.

In addition to the above components, the formulations according to the invention may also contain further additives and processing aids. These include, in particular, surface-active substances (surfactants), lubricants and greases, viscosity-modifying additives, conductivity-increasing additives, dispersants, hydrophobic agents, adhesion promoters, flow improvers, defoamers, deaerators, diluents which may be reactive or non-reactive, fillers, auxiliaries, processing aids, dyes, pigments, stabilizers, sensitizers, nanoparticles and inhibitors.

The present invention further relates to a method for producing a formulation according to the present invention, wherein at least a first organic solvent, a 1,1-diphenylethylene derivative, and at least one organic functional material that can be used for producing a functional layer of an electronic device are mixed.

The formulations according to the present invention can be used for the production of layered or multilayered structures, in which the organic functional material is present in the layers, as required for the production of desirable electronic or optoelectronic components, such as OLEDs.

The formulation of the present invention can preferably be used for the formation of a functional layer on a substrate or on one of the layers applied to the substrate. The substrate may or may not have a bank structure.

The present invention likewise relates to a method for manufacturing an electronic device, wherein a formulation according to the present invention is applied to a substrate and dried.

The functional layer can be produced on the substrate or on one of the layers applied to the substrate, for example by flood coating, dip coating, spray coating, spin coating, screen printing, relief printing, gravure printing, rotary printing, roller coating, flexographic printing, offset printing or nozzle printing, preferably inkjet printing.

After applying the formulation according to the invention to a substrate or to an already applied functional layer, a drying step can be carried out in order to remove the solvent from the continuous phase described above. The drying can preferably be carried out at a relatively low temperature and over a relatively long period of time in order to prevent bubble formation and to obtain a uniform coating. The drying can preferably be carried out at a temperature in the range of 80 to 300° C., more preferably in the range of 150 to 250° C., and most preferably in the range of 160 to 200° C. The drying here can preferably be carried out at a pressure in the range of 10 ^-6 mbar to 2 bar, more preferably in the range of 10 ^-2 mbar to 1 bar, and most preferably in the range of 10 ^-1 mbar to 100 mbar. During the drying process, the temperature of the substrate can vary between -15° C. and 250° C. The duration of drying will vary depending on the degree of dryness desired to be achieved, whereby small amounts of water can be removed, optionally at relatively high temperatures, and preferably in combination with sintering.

Furthermore, it may be provided that the process is repeated several times, with the formation of different or identical functional layers. Here, crosslinking of the formed functional layer can occur, as disclosed for example in EP 0 637 899 A1, thereby preventing its dissolution.

The present invention also relates to an electronic device obtainable by a method for manufacturing an electronic device.

The present invention further relates to an electronic device having at least one functional layer comprising at least one organic functional material obtainable by the method for manufacturing an electronic device mentioned above.

An electronic device is understood to mean a device comprising an anode, a cathode and at least one functional layer therebetween, wherein the functional layer comprises at least one organic or organometallic compound.

The organic electronic device is preferably an organic electroluminescent device (OLED), a polymeric electroluminescent device (PLED), an organic integrated circuit (O-IC), an organic field-effect transistor (O-FET), an organic thin-film transistor (O-TFT), an organic light-emitting transistor (O-LET), an organic solar cell (O-SC), an organic photovoltaic (OPV) cell, an organic photodetector, an organic photoreceptor, an organic field-quenching device (O-FQD), an organic electrical sensor, a light-emitting electrochemical cell (LEC) or an organic laser diode (O-laser), more preferably an organic electroluminescent device (OLED) or a polymeric electroluminescent device (PLED).

The active component is generally an organic or inorganic material introduced between the anode and the cathode (wherein this active component affects, maintains and/or improves the properties of the electronic device, for example its performance and/or its lifetime), for example a charge injection, charge transport or charge blocking material, in particular an emissive material and a matrix material. Accordingly, the organic functional material which can be used for the production of the functional layer of the electronic device preferably comprises an active component of the electronic device.

An organic electroluminescent device is a preferred embodiment of the present invention. The organic electroluminescent device comprises a cathode, an anode and at least one emitting layer.

It is also desirable to use a mixture of two or more triplet emitters together with a matrix, wherein the triplet emitter having a shorter emission spectrum serves here as a co-matrix for the triplet emitter having a longer emission spectrum.

In such cases, the proportion of the matrix material in the emission layer is preferably 50 to 99.9 vol%, more preferably 80 to 99.5 vol%, and most preferably 92 to 99.5 vol% for the fluorescent emission layer, and 85 to 97 vol% for the phosphorescent emission layer.

Therefore, the proportion of the dopant is preferably 0.1 to 50 vol%, more preferably 0.5 to 20 vol%, and most preferably 0.5 to 8 vol% in the fluorescent emitting layer, and 3 to 15 vol% in the phosphorescent emitting layer.

The emissive layer of the organic electroluminescent device may also comprise a system comprising a plurality of matrix materials (mixed-matrix systems) and/or a plurality of dopants. In both cases, too, the dopants are generally the lesser-proportioned material in the system, and the matrix materials are the greater-proportioned material in the system. However, in individual cases, the proportion of the individual matrix materials in the system may be smaller than the proportion of the individual dopants.

The mixed-matrix system preferably comprises two or three different matrix materials, more preferably two different matrix materials, whereby one of the two materials is preferably a material having hole-transport properties and the other material is a material having electron-transport properties. However, the desired electron-transport and hole-transport properties of the mixed-matrix components can also be combined primarily or entirely in a single mixed-matrix component, whereby the further mixed-matrix component(s) perform other functions. The two different matrix materials may be present in a ratio of from 1:50 to 1:1, preferably from 1:20 to 1:1, more preferably from 1:10 to 1:1 and most preferably from 1:4 to 1:1. Mixed-matrix systems are preferably employed in phosphorescent organic electroluminescent devices. Further details on mixed-matrix systems can be found, for example, in WO 2010/108579.

In addition to these layers, the organic electroluminescent device may also comprise additional layers, for example in each case one or more hole injection layers, hole transport layers, hole blocking layers, electron transport layers, electron injection layers, exciton blocking layers, electron blocking layers, charge generation layers (IDMC 2003, Taiwan; Session 21 OLED (5), T. Matsumoto, T. Nakada, J. Endo, K. Mori, N. Kawamura, A. Yokoi, J. Kido, Multiphoton Organic EL Device Having Charge Generation Layer) and/or organic or inorganic p/n junctions. Here, one or more of the hole transport layers can be p-doped, for example with a metal oxide, such as MoO ₃ or WO ₃ , or with a (per)fluorinated electron-deficient aromatic compound, and/or one or more of the electron transport layers can be n-doped. Likewise, an intermediate layer, for example having an exciton blocking function and/or controlling the charge balance in the electroluminescent device, can be introduced between the two emitting layers. However, it should be pointed out that each of these layers need not necessarily be present. These layers may likewise be present when using the formulation according to the present invention, as defined above.

In a further embodiment of the present invention, the device comprises a plurality of layers. Here, the formulation according to the present invention can preferably be used for the production of hole transport, hole injection, electron transport, electron injection and/or emissive layers.

Therefore, the present invention also relates to an electronic device comprising at least three layers, but in a preferred embodiment all said layers from a hole injection, hole transport, emitting, electron transport, electron injection, charge blocking and/or charge generating layer, wherein at least one layer is obtained by a formulation used according to the present invention. The thickness of the layers, for example the hole transport and/or hole injection layers, can preferably be in the range from 1 to 500 nm, more preferably in the range from 2 to 200 nm.

In addition, the device may comprise layers constructed of additional low molecular weight compounds or polymers not used in the formulation according to the present invention. These may also be prepared by evaporation of low molecular weight compounds in high vacuum.

It may also be desirable to use the compounds not as pure substances, but instead as mixtures (blends) with any desired type of additional polymeric, oligomeric, resinous or low molecular weight materials, which may, for example, enhance the electronic properties or may themselves be emitting.

In a preferred embodiment of the invention, the formulation according to the invention comprises an organic functional material which is used as a host material or matrix material in the emitting layer. Here, in addition to the host material or matrix material, the formulation may also comprise an emitter as described above. Here, the organic electroluminescent device may comprise one or more emitting layers. If several emitting layers are present, these preferably have several emission maxima between 380 nm and 750 nm, so that an overall white emission is obtained, i.e. various emitting compounds which are capable of causing fluorescence or phosphorescence are used in the emitting layers. Very particular preference is given to a three-layer system, the three layers of which exhibit blue, green and orange or red emission (for the basic structure, see, for example, WO 2005/011013). White-emitting devices are suitable, for example, as backlighting of LCD displays or for general lighting applications.

Additionally, multiple OLEDs can be arranged one on top of the other, which allows further increases in efficiency with respect to light yield to be achieved.

To improve the coupling-out of light, the final organic layer on the light exit side in OLEDs can be, for example, in the form of nanofoam, which results in a decrease in the ratio of total reflection.

Furthermore, an organic electroluminescent device is preferred, wherein one or more layers are applied by a sublimation process, wherein the material is applied by deposition in a vacuum sublimation apparatus at a pressure of less than 10 ^-5 mbar, preferably less than 10 ^-6 mbar, more preferably less than 10 ^-7 mbar.

Furthermore, it may be provided that one or more layers of the electronic device according to the present invention are applied by an OVPD (organic vapor deposition) process or with the aid of carrier-gas sublimation, wherein the material is applied at a pressure of 10 ^-5 mbar to 1 bar.

Furthermore, it may be provided that one or more layers of the electronic device according to the invention are produced from a solution, for example by spin coating, or by any desired printing process, for example screen printing, flexographic printing or offset printing, but particularly preferably LITI (light-induced thermal imaging, thermal transfer printing) or inkjet printing.

These layers can also be applied by a method that does not use compounds of formulae (I) or (II). An orthogonal solvent can preferably be used here, although it does not dissolve the functional material of the layer to be applied, but rather the layer to which the functional material is applied.

The device typically comprises a cathode and an anode (electrodes). The electrodes (cathode, anode) are selected so that their band energies correspond as closely as possible to the band energies of the adjacent organic layers to ensure highly efficient electron or hole injection for the purposes of the present invention.

The cathode preferably comprises a metal complex, a metal having a low work function, a metal alloy or a multilayer structure (including various metals such as, for example, alkaline earth metals, alkali metals, main group metals or lanthanoids (e.g. Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.). In the case of multilayer structures, in addition to the above metals, further metals having a relatively high work function, such as, for example, Ag and Ag nanowires (Ag NWs), can also be used, in which case combinations of metals, such as, for example, Ca/Ag or Ba/Ag, are typically used. It may also be desirable to introduce a thin intermediate layer of a material having a high dielectric constant between the metal cathode and the organic semiconductor. Alkali metal or alkaline earth metal fluorides as well as the corresponding oxides (e.g. LiF, Li ₂ O, BaF ₂ , MgO, NaF, etc.) are suitable for this purpose. The layer thickness of such layers is preferably 0.1 to 10 nm, more preferably 0.2 to 8 nm, and most preferably 0.5 to 5 nm.

The anode preferably comprises materials having a high work function. The anode preferably has a potential of more than 4.5 eV with respect to vacuum. On the one hand, metals having a high redox potential, such as for example Ag, Pt or Au, are suitable for this purpose. On the other hand, metal/metal oxide electrodes (e.g. Al/Ni/NiO _x , Al/PtO _x ) may also be preferred. For some applications, at least one of the electrodes should be transparent to enable irradiation of the organic material (O-SC) or coupling out of light (OLED/PLED, O-laser). A preferred structure uses a transparent anode. Preferred anode materials are conductive, mixed metal oxides here. ITO (indium tin oxide) or IZO (indium zinc oxide) are particularly preferred. Furthermore, conductively doped organic materials, in particular conductively doped polymers, such as for example poly(ethylenedioxythiophene) (PEDOT) and polyaniline (PANI), or derivatives of these polymers, are preferred. Furthermore, it is preferred, if a p-doped hole-transporting material is applied to the anode as a hole injection layer, suitable p-dopants being metal oxides, for example MoO ₃ or WO ₃ , or (per)fluorinated electron-deficient aromatic compounds. Further suitable p-dopants are the compounds NPD9 or HAT-CN (hexacyanohexaazatriphenylene) from Novaled. Layers of this type simplify hole injection in materials with a low HOMO, i.e. a HOMO with a large value.

In general, any material used in a layer according to prior art may be used in an additional layer, and a person skilled in the art will be able to combine each of these materials with the material according to the present invention in an electronic device without any advances.

Since the life of such devices is dramatically shortened in the presence of water and/or air, the devices are structured, provided with contacts and finally hermetically sealed in a manner known per se, depending on the application.

The formulation according to the present invention and the electronic devices, in particular organic electroluminescent devices, obtainable therefrom are distinguished from the prior art by one or more of the following surprising advantages:

1. The electronic device obtainable using the formulation according to the present invention exhibits very high stability and very long lifespan compared to electronic devices obtained using conventional methods.

2. The formulation according to the present invention can be processed using conventional methods, whereby cost advantages can also be achieved.

3. The organic functional material used in the formulation according to the present invention is not subject to any special restrictions, so that the process of the present invention can be comprehensively utilized.

4. Coatings obtainable using the formulation of the present invention exhibit excellent quality, particularly with respect to uniformity of the coating.

These advantages mentioned above do not entail any degradation of other electronic properties.

It should be pointed out that variations of the embodiments described in the present invention are within the scope of the present invention. Each feature disclosed in the present invention may be replaced by an alternative feature that can be used for the same, equivalent or similar purpose, unless explicitly excluded. Accordingly, each feature disclosed in the present invention is to be regarded as an example of a comprehensive series or as an equivalent or similar feature, unless otherwise stated.

All features of the invention may be combined in any way with one another, provided that the specific features and/or steps are not mutually exclusive. This applies in particular to the preferred features of the invention. Equally, features of non-essential combinations may be used individually (not combined).

Furthermore, it should be noted that many features, and especially features of preferred embodiments of the present invention, are in themselves inventive and should not be regarded as merely part of the embodiments of the present invention. For these features, independent protection may be sought as an alternative to or in addition to the individual inventions explicitly claimed.

The teachings of the technical operations disclosed in the present invention can be extracted and combined with other examples.

The present invention is described in more detail below with reference to working examples, but is not limited thereto.

A person skilled in the art will be able to use the detailed description, without the need for advance capabilities, to manufacture additional electronic devices according to the present invention, and thus practice the invention to the fullest extent claimed.

Work example

Formation of a barrier

Nine inks were prepared for the hole injection layer (HIL) as shown in Table 2. The inks were inkjet printed and the film profiles were measured after drying. The results are shown in FIGS. 2 to 10 . The solvent 3-phenoxy toluene was selected as a reference solvent (Comparative Example) and shows a uniform film profile. By adding adamantane derivatives (adamantane-1-sulfonic acid methyl ester and ethyl adamantane-1-carboxylate), the film profile shows a slightly more uniform organic layer than the Comparative Example. Another main solvent, butyl benzoate, is selected to further prove the working concept. Addition of 10% of adamantane derivative to butyl benzoate results in a flatter film profile compared to this reference solvent.

The film profiles were measured using a KLA-Tencor Corporation Alpha-Step D120 profiler with a 2 μm stylus. The flatness factor is calculated by the following formula and used to determine flatness:

Here

is the height of the pixel edge, and

is the height at the center of the pixel.

A membrane is considered flat when the flatness factor is less than 10%.

Claims (22)

A formulation comprising at least one organic functional material and at least first and second organic solvents,
The above first organic solvent is an adamantane derivative according to the general chemical formula (I),

Here
X is CR;
R is in each case, identically or differently, H, D, F, CN, NO ₂ , N(R ¹ ) ₂ , Si(R ¹ ) ₃ , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 20 carbon atoms, a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 20 carbon atoms, a straight-chain alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkenyl or alkynyl group having 3 to 20 carbon atoms, wherein one or more non-adjacent CH ₂ groups may be replaced by -O-, -S-, -NR ¹ -, -CONR ¹ -, -S(O) ₂ -O-, -Si(R ¹ ) ₂ -, -CO-O-, -C=O-, -CR ¹ =CR ¹ - or -C≡C-, one or more hydrogen atoms may be replaced by D, F, CN or NO ₂ ), or an aryl or heteroaryl group having 5 to 60 ring atoms, or an aryloxy or heteroaryloxy group having 5 to 40 ring atoms, or an arylalkyl or heteroarylalkyl group having 5 to 40 ring atoms (which may be substituted by one or more non-aromatic R ¹ radicals), and two substituents R on the same ring may in turn be taken together to form a monocyclic or polycyclic aliphatic, aromatic or heteroaromatic ring system, which may be substituted by a plurality of substituents R ¹ ); and
R ¹ is, in each case, identically or differently, a straight-chain alkyl or alkoxy group having 1 to 20 carbon atoms, or a branched or cyclic alkyl or alkoxy group having 3 to 20 carbon atoms, wherein one or more non-adjacent CH ₂ groups may be replaced by -O-, -S-, -CO-O-, -C=O-, -CH=CH- or -C≡C- and one or more hydrogen atoms may be replaced by F, or an aryl or heteroaryl group having 4 to 14 carbon atoms, which may be substituted by one or more non-aromatic R ¹ radicals,
The formulation comprises at least one second organic solvent different from the first organic solvent,
The content of the first organic solvent is in the range of 0.5 to 25 wt% based on the total amount of solvent in the formulation,
A formulation wherein the content of the second organic solvent is in the range of 75 to 99.5 wt% based on the total amount of solvent in the formulation. delete delete delete In paragraph 1,
The above first organic solvent is an adamantane derivative according to the general chemical formula (II),

wherein R and R ¹ are formulations as defined in claim 1. In the first paragraph,
A formulation wherein the first organic solvent has a surface tension of ≥ 20 mN/m. delete In the first paragraph,
The formulation wherein the first organic solvent has a boiling point in the range of 100 to 400°C. delete In the first paragraph,
The formulation wherein the second organic solvent has a boiling point in the range of 100 to 400°C. In the first paragraph,
A formulation wherein said at least one organic functional material has a solubility in the first organic solvent as well as in the second organic solvent of from 1 to 250 g/l. In paragraph 1,
The above formulation is a formulation having a surface tension in the range of 10 to 50 mN/m. In paragraph 1,
The above formulation is a formulation having a viscosity in the range of 1 to 50 mPa ^. s. In paragraph 1,
A formulation wherein the content of at least one organic functional material in the formulation is in the range of 0.001 to 20 wt% based on the total weight of the formulation. In paragraph 1,
A formulation wherein said at least one organic functional material is selected from the group consisting of organic conductors, organic semiconductors, organic fluorescent compounds, organic phosphorescent compounds, organic photoabsorbing compounds, organic photosensitizing compounds, organic photosensitisation agents, and other organic photoactive compounds, such as organometallic complexes of transition metals, rare earths, lanthanides and actinides. In Article 15,
A formulation wherein said at least one organic functional material is selected from the group consisting of fluorescent emitters, phosphorescent emitters, host materials, matrix materials, exciton blocking materials, electron transport materials, electron injection materials, hole transport materials, hole injection materials, n-dopants, p-dopants, wide band gap materials, electron blocking materials and hole blocking materials. In Article 15,
A formulation wherein said at least one organic functional material is an organic semiconductor selected from the group consisting of hole injecting, hole transporting, emissive, electron transporting and electron injecting materials. In Article 17,
A formulation wherein said at least one organic semiconductor is selected from the group consisting of hole injecting and hole transporting materials. In Article 18,
The above hole-injecting and hole-transporting material is a formulation which is a polymeric compound or a blend of a polymeric compound and a non-polymeric compound. A method for producing a formulation according to any one of claims 1, 5, 6, 8 and 10 to 19,
A method for preparing a formulation, wherein at least one organic functional material and at least first and second organic solvents are mixed. A method for manufacturing an electroluminescent device,
A method for producing an electroluminescent device, wherein at least one layer of the electroluminescent device is produced in such a way that a formulation according to any one of claims 1, 5, 6, 8 and 10 to 19 is deposited or printed on a surface and subsequently dried. An electroluminescent device, wherein at least one layer is manufactured by depositing or printing a formulation according to any one of claims 1, 5, 6, 8 and 10 to 19 onto a surface and subsequently drying.