JP2012009518A - Organic solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell module which uses an inexpensive resin substrate as a substrate and prevents deterioration of a transparent electrode.SOLUTION: The problem is solved by laminating a lower electrode, an organic semiconductor layer, a buffer layer, and an inorganic transparent electrode on a resin substrate in this order.

Description

  The present invention relates to a solar cell module, and more particularly to an organic thin film solar cell module using an organic thin film as a solar cell element.

  An organic solar cell is attracting attention as a solar cell suitable for mass production because an organic solar cell element can be formed by a coating method. Further, as an organic solar cell, a bottom incidence structure and a top incidence structure are known, and the top incidence structure is highly demanded as a practical structure because it can be coated and formed in air.

  As an organic solar cell having a top incidence structure, a solar cell described in FIG. In this solar cell, a glass substrate, an ITO electrode as a transparent electrode, a hole receiving layer p layer, a photovoltaic absorbing layer, an electron receiving layer n layer, and an electrode region En are laminated in this order from the sunlight receiving surface side. ing. A crystalline transparent conductive film such as an ITO electrode used as a transparent electrode has high transparency and conductivity, but has a large loss when light passes because of its high sheet resistance. Therefore, in order to reduce the sheet resistance of the crystalline transparent conductive film, it is necessary to form the film at a certain temperature, and a metal substrate having a high softening point such as a glass substrate is required. However, the metal substrate has poor surface smoothness, and it is necessary to provide a smoothing layer for practical use, which has been a problem in cost when manufacturing a solar cell having a large surface area.

  On the other hand, a resin substrate exists as a substrate having good smoothness, and the smoothing layer can be omitted by using the resin substrate. However, the resin substrate generally has a low softening point, and it has not been possible to form a crystalline transparent conductive film by raising the temperature of the substrate to some extent.

  On the other hand, in Patent Document 2, in a thin film solar cell including a photoelectric conversion layer having a thin film semiconductor containing silicon as a main component, a relatively low substrate temperature is used as a barrier layer between the photoelectric conversion layer and the back surface metal electrode layer. A thin film solar cell provided with a gallium-containing indium oxide film, which is a transparent conductive film that can be formed by the above method, is disclosed.

JP 2005-510065 Gazette JP 2010-10347 A

  In the present invention, an object is to provide a solar cell module using a resin substrate so that a smoothing layer required when using a metal substrate can be omitted (first problem), and earnest studies are repeated. It was. According to studies by the present inventors, the gallium-containing indium oxide film disclosed in Patent Document 2 is an amorphous transparent conductive film, and has been conceived to be usable as an electrode. And the solar cell was created using the non-crystalline transparent conductive film which can be formed at a relatively low substrate temperature with a resin substrate having good smoothness as the transparent electrode, but the transparent conductive film was heated by the process of manufacturing the solar cell. It turned out that it is easy to deteriorate. This invention makes it a subject to provide the solar cell module which can prevent deterioration of a transparent electrode, when manufacturing the solar cell using an amorphous transparent conductive film as a transparent electrode (2nd subject).

The inventors of the present invention have made extensive studies to solve the first problem and the second problem, and by providing a buffer layer between the organic semiconductor layer and the inorganic transparent electrode of the solar cell module, The inventors have conceived that deterioration can be prevented and completed the present invention. The present invention
A solar cell module comprising a solar cell element in which a lower electrode, an organic semiconductor layer, a buffer layer, and an inorganic transparent electrode are laminated in this order on a resin substrate.

  In addition, it is a preferable aspect that the inorganic transparent electrode is amorphous, an oxide of indium (In), tin (Sn), zinc (Zn), tungsten (W), gallium (Ga), or these It is a more preferred embodiment that it is a mixed oxide.

  In addition, the buffer layer is preferably a conductive polymer or a metal oxide, and is preferably a poly (3,4-ethylenedioxythiophene) or molybdenum trioxide. It is a preferred embodiment that the thickness of the buffer layer is 10 nm or more.

  Moreover, it is a preferable aspect that the glass transition point Tg of the said resin substrate is 130 degrees C or less.

  According to the present invention, a smoothing layer required when a metal substrate is used can be omitted, and an inexpensive solar cell module can be provided. In addition, it is possible to provide a solar cell module that can prevent deterioration of the inorganic transparent electrode and can form a film at a low temperature.

It is a conceptual diagram showing one Embodiment of the solar cell module of this invention. It is a conceptual diagram showing one Embodiment of the solar cell element used for this invention. It is a conceptual diagram showing one Embodiment of the solar cell element used for this invention.

  The solar cell module of the present invention includes a solar cell element in which a lower electrode, an organic semiconductor layer, a buffer layer, and an inorganic transparent electrode are stacked in that order on a resin substrate.

<Resin substrate>
The solar cell module of the present invention uses a resin substrate instead of a metal substrate that requires a smoothing layer. As the resin substrate, a widely used resin can be used. Specific types of resin include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), nylon, polyethersulfone (PES), polycarbonate (PC), polyethylene (PE), polypropylene (PP), urethane, fluorine-based Examples thereof include plastics such as resins. Among these, polyethylene terephthalate (PET) and polyethylene nanaphthalate (PEN) are preferable from the viewpoints of being inexpensive, excellent in strength, having both transparency and flexibility.

  The resin used for the resin substrate preferably has a glass transition point Tg of 130 ° C. or lower, and more preferably 120 ° C. or lower. Moreover, it is preferable that Tg of resin is 70 degreeC or more. When Tg is in the above-mentioned range, it has appropriate flexibility during heat treatment when it is integrated with a building material or the like to form a curved shape after manufacturing the solar cell module, and is excellent in workability. The glass transition point Tg is measured by DSC measurement.

The resin used for the resin substrate usually has a weight average molecular weight (Mw) of 10,000 or more. The upper limit is 70000 or less, and preferably 20000 or less. The weight average molecular weight in the present invention is determined by SEC (size exclusion chromatography) measurement. In SEC measurement, the elution time is shorter for higher molecular weight components and the elution time is longer for lower molecular weight components, but using the calibration curve calculated from the elution time of polystyrene (standard sample) with a known molecular weight, the elution time of the sample is changed to the molecular weight. The weight average molecular weight is calculated by conversion.

The film thickness of the resin substrate is preferably 50 μm or more. By setting the film thickness to 50 μm or more, the rigidity of the film-like substrate can be maintained, so that it becomes possible to handle various flexible functional elements in the manufacturing process and to curl the resin substrate. More preferably, it is 75 micrometers or more, More preferably, it is 100 micrometers or more.
Further, the film thickness of the resin substrate is preferably 250 μm or less, and more preferably 200 μm or less. By setting the film thickness within this range, the resin substrate can be reduced in weight, which is easy to handle and at the same time is preferable in terms of cost.

  The resin substrate is heated from 120 ° C. to 150 ° C. in the annealing process during the production of the solar cell module, but the dimensional change in the vertical direction (MD) and the horizontal direction (TD) of the resin substrate before and after the annealing step is Each is preferably 0.3% or less, more preferably 0.15% or less, and further preferably 0.1% or less. Further, the smaller the dimensional change, the better, but it is usually 0.01% or more. Because the dimensional change before and after the annealing process of the resin substrate is in this range, the dimensional change does not occur in the lamination process that repeats printing, drying, and heating when manufacturing a solar cell module, and printing misalignment is unlikely to occur. Become.

<Lower electrode>
The lower electrode which comprises the solar cell module of this invention is laminated | stacked between the resin substrate and the organic-semiconductor layer mentioned later, and has electroconductivity. The material may be any material as long as it has conductivity, such as metal such as gold, aluminum, and silver; metal oxide such as indium tin oxide, gallium-containing indium oxide, tungsten-containing indium oxide, and metal. Examples include alloys; inorganic salts such as lithium fluoride and cesium fluoride; vapor deposited films or sputtered films of metal oxides such as nickel oxide, aluminum oxide, lithium oxide, and cesium fluoride. Moreover, the layer manufactured with the said material can also be laminated | stacked.

  The manufacturing method of the lower electrode is not particularly limited, and can be performed according to a known method. For example, a printing method, vacuum deposition, sputtering, CVD, plasma CVD, etc. are mentioned. Two or more electrodes may be laminated, and characteristics (electric characteristics and wetting characteristics) may be improved by surface treatment. The film thickness of the lower electrode is usually 0.01 μm or more and preferably 0.1 μm or more. The upper limit is usually 1.0 μm or less, and preferably 0.2 μm or less.

<Organic semiconductor film>
The organic semiconductor constituting the solar cell module of the present invention is laminated between the lower electrode and a buffer layer described later.
Organic semiconductors are classified into p-type and n-type depending on semiconductor characteristics. The p-type and n-type indicate whether holes or electrons contribute to electrical conduction, and depend on the electronic state, doping state, and trap state of the material. Therefore, there are cases where p-type and n-type cannot always be clearly classified, and there are cases where the same substance exhibits both p-type and n-type characteristics.

Examples of p-type semiconductors include porphyrin compounds such as tetrabenzoporphyrin, tetrabenzocopper porphyrin, tetrabenzozinc porphyrin; phthalocyanine compounds such as phthalocyanine, copper phthalocyanine, zinc phthalocyanine; naphthalocyanine compounds; polyacenes of tetracene and pentacene; Examples thereof include oligothiophene and derivatives containing these compounds as a skeleton. Furthermore, polymers such as polythiophene, polyfluorene, polyphenylene vinylene, polytriallylamine, polyacetylene, polyaniline, polypyrrole and the like including poly (3-alkylthiophene) are exemplified. When a polymer is used, its average molecular weight is not particularly limited, and those usually used for p-type semiconductors of solar cells can be used.

  Examples of n-type semiconductors include fullerenes (C60, C70, C76); octaazaporphyrins; perfluoro compounds of the above p-type semiconductors; naphthalenetetracarboxylic acid anhydrides, naphthalenetetracarboxylic acid diimides, perylenetetracarboxylic acid anhydrides, perylenes And aromatic carboxylic acid anhydrides such as tetracarboxylic acid diimide and imidized products thereof; and derivatives containing these compounds as a skeleton.

  The specific configuration of the organic semiconductor layer is arbitrary as long as at least a p-type semiconductor and an n-type semiconductor are contained. The organic semiconductor layer may be constituted only by a single layer film or may be constituted by two or more laminated films. For example, an n-type semiconductor and a p-type semiconductor may be contained in separate films, or an n-type semiconductor and a p-type semiconductor may be contained in the same film. In addition, each of the n-type semiconductor and the p-type semiconductor may be used alone or in combination of two or more in any combination and ratio.

  Specific examples of the structure of the organic semiconductor layer include a bulk heterojunction type having a layer (i layer) in which a p-type semiconductor and an n-type semiconductor are phase-separated in the layer, a layer containing a p-type semiconductor (p layer), and n, respectively. Examples include a stacked type (hetero pn junction type) in which a layer containing a p-type semiconductor (p layer) has an interface, a Schottky type, and a combination thereof. Among these, a bulk heterojunction type and a combination of a bulk heterojunction type and a stacked type (p-i-n junction type) are preferable because they exhibit high performance.

  The thicknesses of the p-layer, i-layer and n-layer of the organic semiconductor layer are usually 3 nm or more, preferably 10 nm or more, and usually 200 nm or less, preferably 100 nm or less. By setting the layer thickness within the above range, the uniformity of the film is increased, the transmittance is also improved, and the series resistance is lowered.

<Buffer layer>
The buffer layer which comprises the solar cell module of this invention is laminated | stacked between the said organic-semiconductor layer and the inorganic transparent electrode mentioned later. As described above, the present inventors have found that when an amorphous inorganic transparent electrode is used as the inorganic transparent electrode, the inorganic transparent electrode is easily deteriorated by heat. Then, it was conceived that the deterioration of the inorganic transparent electrode can be prevented by providing a buffer layer between the organic semiconductor layer and the inorganic transparent electrode of the solar cell module.
Although the mechanism by which the deterioration of the inorganic transparent electrode can be prevented by providing the buffer layer is not clear, the present inventors predict as follows.

  When the semiconductor layer is organic, the hydrophobicity is high, so that the wettability is poor and the adhesion is low at the interface between the organic semiconductor layer and the inorganic transparent electrode. However, adhesion between the organic semiconductor layer and the inorganic transparent electrode is achieved by providing a buffer layer such as a conductive polymer or metal oxide containing a polar functional group that improves wettability between the organic semiconductor layer and the inorganic transparent electrode. Is expected to improve the durability of the inorganic transparent electrode.

Examples of the buffer layer constituting the solar cell module of the present invention include conductive polymers and metal oxides. In addition, as a conductive polymer, a polar functional group containing conductive polymer is preferable. Examples of the polar functional group include a carboxyl group, a hydroxyl group, an epoxy group, and an amino group, and a hydroxyl group is preferable. As the polar functional group-containing conductive polymer, poly (3,4-ethylenedioxythiophene): poly (styrenesulfonic acid) (PEDOT: PSS), 2,9dimethyl-4,7-diphenyl-1,10-phenanthroline Examples of the metal oxide include molybdenum oxide and lithium fluoride. Preferable is poly (ethylenedioxythiophene): poly (styrenesulfonic acid) (PEDOT: PSS) or molybdenum trioxide.

  When the buffer layer in the present invention is the above-exemplified buffer layer, in addition to the improvement of the wettability, it also has the effect of improving the electrical characteristics of the electrode interface facing the organic semiconductor layer.

  The layer thickness of the buffer layer in the present invention is usually 10 nm or more, preferably 15 nm or more, more preferably 20 nm or more. Moreover, it is 200 nm or less normally, Preferably it is 150 nm or less, More preferably, it is 100 nm or less. When the thickness of the buffer layer is in the above range, the film formability is improved and a uniform layer is easily formed. Further, the method for producing the buffer layer is not particularly limited. For example, when a material having sublimation properties is used, the buffer layer can be produced by a vacuum deposition method or the like. When a material soluble in a solvent is used, spin coating or ink jetting is used. It can be manufactured by a wet coating method such as.

<Inorganic transparent electrode>
The inorganic transparent electrode which comprises the solar cell module of this invention is an electrode which can permeate | transmit the light photoelectrically converted in an organic-semiconductor film. Examples of the material include Group 13 oxides, Group 14 oxides, Group 12 oxides, and Group 6 oxides. Specifically, indium (In), tin (Sn), and zinc (Zn). , Tungsten (W), gallium (Ga) oxide, or a mixed oxide thereof, preferably a mixture containing indium oxide as a main component. The main component is 90% by weight or more, preferably 95% by weight or more. Preferably it is 99% weight or less. More preferably, it is a mixture of indium oxide, tungsten oxide, and zinc oxide. The inorganic transparent electrode can include at least one selected from the group consisting of gallium, indium, tin, titanium, tungsten, molybdenum, and zirconium.
More preferably, the tungsten-containing indium oxide film has a tungsten content of 0.005 or more in terms of the W / In atomic ratio. On the other hand, the upper limit of the W / In atomic ratio is preferably 0.55, more preferably 0.1 or less, and still more preferably 0.01 or less.

The inorganic transparent electrode of the present invention is preferably amorphous. In the present invention, the term “amorphous” means a material in which X-ray diffraction is not observed in a state where the crystal structure is completely absent. By making it amorphous, the inorganic transparent electrode can be fired at a low temperature or normal temperature, and damage to the solar cell module can be minimized.
In the present invention, the term “transparent” means that the light transmittance at a wavelength of 380 to 780 nm is 50% or more, and preferably 80% or more. Moreover, it is 98% or less normally, Preferably it is 95% or less, More preferably, it is 90% or less.

  The film thickness of the inorganic transparent electrode of the present invention may be within the range in which the transparency can be ensured, but is preferably 100 nm or more, and more preferably 150 nm or more. Moreover, 500 nm or less is preferable normally, More preferably, it is 300 nm or less, More preferably, it is 200 nm or less. When the film thickness is in the above range, the conductivity of the electrode is improved, so that the area of the electrode can be increased. Moreover, moderate transparency can be provided to the electrode. The manufacturing method of an inorganic transparent electrode is not specifically limited, For example, it can also manufacture by dry processes, such as vacuum evaporation and a sputtering. It can also be manufactured by a wet process using conductive ink or the like. As the conductive ink, for example, a conductive polymer, a metal particle dispersion, or the like can be used.

Of these, the inorganic transparent electrode of the present invention is preferably produced by sputtering, and the temperature of the substrate is preferably 100 ° C. or less during production, more preferably at room temperature. Since the temperature of the substrate at the time of manufacture is moderate, the resin substrate is hardly deformed.
Further, two or more electrodes may be laminated, and surface treatment (such as electrical properties and wetting properties) can be improved by surface treatment.

<Second buffer layer>
In the solar cell module of the present invention, it is preferable to provide a second buffer layer between the lower electrode and the organic semiconductor layer. By providing the second buffer layer, the efficiency of extracting electrons to the electrode can be improved, and the electrical characteristics are improved.
The second buffer layer is not particularly limited as long as it is a material capable of improving the efficiency of extracting electrons to the electrode. Specifically, bathocuproine (BCP) or bathophenanthrene (Bphen) and a layer doped with an alkali metal or an alkaline earth metal can be given. It is also possible to use n-type semiconductor materials such as fullerenes or siloles. Several combinations can be used from the above bathocuproin (BCP) layer, bathophenanthrene (Bphen) layer, and a layer of bathocuproin (BCP) or bathophenanthrene (Bphen) doped with an alkali metal or an alkaline earth metal. Inorganic oxides and inorganic carbonates are also possible. For example, cesium carbonate, titanium oxide, zinc oxide, indium oxide, tin oxide and the like. Several of these can be combined.

  The method for producing the second buffer layer is not particularly limited. For example, when a material having sublimation properties is used, the second buffer layer can be produced by a vacuum deposition method or the like. Further, for example, when a material soluble in a solvent is used, it can be produced by a wet coating method such as spin coating or inkjet. The film thickness of the second buffer layer is preferably 0.1 nm or more, and preferably 20 nm or less.

<Solar cell module>
The solar cell module of the present invention includes a surface protection sheet, a sealing layer, a back surface protection sheet, and the like in addition to a solar cell element in which a lower electrode, an organic semiconductor layer, a buffer layer, and an inorganic transparent electrode are laminated in that order on a resin substrate. . Hereinafter, the solar cell module of the present invention will be described in detail with reference to the drawings. In addition, the aspect represented with drawing is one of the embodiments of this invention, and it cannot be overemphasized that it is not limited to this.

FIG. 1 shows the configuration of the solar cell module of the present invention.
A surface protection sheet 2 is provided on the light-receiving surface of sunlight 1 of the solar cell module, and the surface protection sheet 2 protects the solar cell element 4 (the light-receiving surface side of the solar cell element 4) from temperature change, humidity change, and wind and rain. It is a sheet-like member for doing. Accordingly, the surface protective sheet 2 has performances suitable as a surface coating material such as weather resistance, heat resistance, transparency, water repellency, stain resistance, and mechanical strength, and the performance is maintained for a long time in outdoor exposure. It is preferable to have the property.

The surface protection sheet 2 should just be what can protect the solar cell element 4 in some form. Therefore, as the surface protection sheet 2, for example, glass such as soda lime glass, white plate glass, alkali-free glass, and tempered glass thereof; acrylic resin such as polymethyl methacrylate and crosslinked acrylate; aromatic polycarbonate resin such as bisphenol A polycarbonate Polyester resin such as polyethylene terephthalate and polyethylene naphthalate; amorphous polyolefin resin such as polycycloolefin; epoxy resin; styrene resin such as polystyrene; polysulfone resin such as polyethersulfone; polyetherimide resin; -Is it a synthetic resin such as fluororesin such as perchloroalkoxy copolymer (PFA), 2-ethylene-4-fluoroethylene copolymer (ETFE), poly-3-fluoroethylene chloride (PCTFE)? Made things can be adopted. However, from the viewpoint of weather resistance, it is preferable to use glass or a fluororesin as the surface protective sheet 2.

  The glass used as the constituent material of the surface protective sheet 2 is preferably white plate glass or non-alkali glass because of its high light transmittance, and white plate tempered glass having excellent impact strength is desirable. Moreover, the fluororesin used as a constituent material of the surface protection sheet 2 is preferably ETFE because of its high light transmittance. Moreover, ETFE is preferable from the viewpoint of weight reduction of the solar cell module. In addition, the surface protection sheet 2 may be formed with 1 type of material, and may be formed with 2 or more types of materials. The surface protective sheet 2 may be formed of a single layer film, but may be a laminated film including two or more layers.

  Further, the surface protective sheet 2 is preferably one that transmits sunlight in order to obtain a larger amount of power generation. Therefore, as the surface protective sheet 2, the solar transmittance calculated from the wavelength range of 300 to 2100 nm by the method described in JIS R3106 is usually 75% or more, preferably 80% or more, more preferably 85% or more, and still more preferably. What should be 90% or more should be adopted.

  Furthermore, since the solar cell module is exposed to sunlight, the surface protective sheet 2 preferably has heat resistance. Therefore, the constituent material of the surface protection sheet 2 has a melting point of usually 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 130 ° C. or higher, and usually 350 ° C. or lower, preferably 320 ° C. or lower. Preferably a material below 300 ° C. should be used.

The thickness of the surface protective sheet 2 is not particularly specified, but in the case of a resin material, it is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less. It is. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility.
In the case of a glass material, from the balance of mechanical strength and weight, it is usually at least 0.8 mm, preferably at least 1.0 mm, more preferably at least 1.5 mm, and usually at most 5 mm, preferably at most 4 mm. is there.

  The surface protective sheet 2 may be laminated with a surface treatment such as corona treatment, UV ozone treatment, or plasma treatment, or a primer layer in order to improve adhesion with other layers in contact therewith.

  In addition, the surface protective sheet 2 is provided with functions such as ultraviolet ray blocking, heat ray blocking, antifouling property, antifogging property, abrasion resistance, conductivity, antireflection, antiglare property, light diffusion, light scattering, gas barrier property and the like. May be. In particular, from the viewpoint that the solar cell module is exposed to strong ultraviolet rays from sunlight, it is preferable that the surface protection sheet 2 has an ultraviolet blocking function. The surface protection sheet 2 having an ultraviolet blocking function can be obtained by laminating a layer having an ultraviolet blocking function on the surface protective sheet 2 by coating film formation or the like, and dissolving / dispersing a material that exhibits the ultraviolet blocking function. It can carry out by making it contain in the surface protection sheet 2, for example.

  The solar cell module according to the present invention shown in FIG. 1 is laminated between the surface protection sheet 2 and the solar cell element 4 so as to reinforce the solar cell module and protect the solar cell element 4. Can be provided. Moreover, the sealing layer 3b can be provided on the opposite side of the solar cell element 4 from the sealing layer 3a.

As a constituent material of the sealing layers 3a and 3b, any material can be used as long as it can reinforce the solar cell module or can protect the solar cell element 4 in some form. For example, an ethylene-vinyl acetate copolymer (EVA) film, a polyolefin film such as a propylene / ethylene / α-olefin copolymer, or the like can be used as a constituent material of the sealing layer 3. Note that the sealing layer 3 may be formed of one kind of material or may be formed of two or more kinds of materials. The sealing layer 3 may be formed of a laminated film, but may be composed of two or more layers.

  As the sealing layer 3a provided on the light receiving surface side of the solar cell element 4, in order to prevent the power generation amount from being lowered, one having a high light transmittance should be adopted. Specifically, as the sealing layer 3a, a layer having a solar transmittance of usually 75% or more, preferably 80% or more, more preferably 85% or more, and further preferably 90% or more should be adopted. is there. Naturally, the sealing layer 3b provided on the side opposite to the light receiving surface of the solar cell element 4 does not need to transmit light, and may be opaque.

  Furthermore, since the solar cell module is often heated by receiving light, the sealing layer 13 preferably has heat resistance. Accordingly, the constituent material of the sealing layer 3 has a melting point of 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 130 ° C. or higher, and usually 350 ° C. or lower, preferably 320 ° C. or lower, more preferably. Should be adopted that is 300 ° C. or lower.

  The thickness of the sealing layer 3 is not particularly limited, but is usually 100 μm or more, preferably 150 μm or more, more preferably 200 μm or more, and usually 1000 μm or less, preferably 800 μm or less, more preferably 600 μm or less. When the thickness is increased, the strength of the entire solar cell module is increased. However, when the thickness is excessively increased, flexibility is decreased.

  Further, the sealing layer 3 may be provided with functions such as ultraviolet ray blocking, heat ray blocking, conductivity, easy adhesion, antiglare property, light reflection, light diffusion, light scattering, and gas barrier properties. In addition, since a solar cell module is exposed to the strong ultraviolet rays from sunlight, it is preferable to give the sealing layer 3 (especially sealing layer 3a) the ultraviolet blocking function. In addition, the UV blocking function is imparted to the sealing layer 3 by laminating a layer having an UV blocking function on the sealing layer 3 by coating film formation or the like, and dissolving / dispersing a material that exhibits the UV blocking function. It can carry out by making it contain in the sealing layer 3, for example.

  FIG. 2 shows the configuration of the solar cell element 4 shown in FIG. 1 in more detail. As already explained, in the solar cell element 4 constituting the solar cell module of the present invention, the lower electrode 14, the organic semiconductor layer 13, the buffer layer 12, and the inorganic transparent electrode 11 are laminated in this order on the resin substrate 15. In addition, as shown in FIG. 3, it is preferable that a second buffer layer 16 is provided between the lower electrode 14 and the organic semiconductor layer 13.

  As the back surface protective sheet 5, various resin films and sheets having excellent strength, weather resistance, heat resistance, water resistance, and light resistance can be used. For example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, fluorine Resins, poly (meth) acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate or polyethylene naphthalate, polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyarylphthalate resins Sheet of various resins such as silicone resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyurethane resin, acetal resin, cellulose resin, etc. It can be used as a surface protective sheet 5.

  Among these resin sheets, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), fluororesin such as tetrafluoroethylene and ethylene or propylene copolymer (ETFE), polyethylene, etc. It is preferable to use a sheet of a resin, a polypropylene resin, a polyvinyl chloride resin, a polycarbonate resin, a poly (meth) acrylic resin, a polyamide resin, or a polyester resin. In addition, these may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  As the back surface protection sheet 5, a sheet made of a metal material can also be used. For example, an aluminum foil and a plate, a stainless steel thin film, a rigid plate, and the like can be given. Such a metal material is preferably subjected to corrosion prevention. In addition, the said metal may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, a sheet made of a composite material of resin and metal can be used as the back surface protection sheet 5. For example, a highly waterproof sheet in which a fluorine resin film is bonded to an aluminum foil can be used as the back surface protection sheet 5. Examples of the fluorine-based resin include ethylene monofluoride (trade name: Tedlar, manufactured by DuPont), polytetrafluoroethylene (PTFE), a copolymer of tetrafluoroethylene and ethylene or propylene (ETFE), and a vinylidene fluoride resin. (PVDF), vinyl fluoride resin (PVF) and the like. In addition, 1 type may be used for fluororesin and it may use 2 or more types together by arbitrary combinations and a ratio.

  The thin film of the back surface protective sheet 5 is usually 50 μm or more, preferably 100 μm or more. Moreover, it is 5 cm or less normally, Preferably it is 3 cm or less, More preferably, it is 1 cm or less, More preferably, it is 500 micrometers or less. If it is thinner than the above range, the solar cell module may not have sufficient strength or moisture resistance, and if it is thick, the weight of the solar cell module will increase. Therefore, it may be necessary to strengthen the fixing method at the time of installation. Because there is.

  In addition, the back protective sheet 5 has functions such as ultraviolet ray blocking, heat ray blocking, antifouling properties, abrasion resistance, easy adhesion, conductivity, light reflection, antiglare properties, light diffusion, light scattering, weather resistance, gas barrier properties, etc. It may be given. In particular, from the viewpoint of moisture resistance, the back protective sheet 5 is preferably provided with gas barrier performance.

  From the viewpoint of increasing the amount of power generation, the solar cell module of the present invention preferably has a solar transmittance from the surface protective sheet 2 to the solar cell element 4 of 80% or more, more preferably 83% or more, It is more preferably 86% or more, and particularly preferably 90% or more. Although ideally 100%, it is usually 99% or less in consideration of reflection on the surface of the solar cell module.

  Moreover, although the heat-resistant temperature of the solar cell module of this invention is represented by the mechanical continuous use temperature of a resin substrate, it is preferable that it is 80 degreeC or more, it is more preferable that it is 90 degreeC or more, and it is 100 degreeC or more. More preferably it is. When polyethylene naphthalate is used for the resin substrate, the temperature is 130 ° C., and when polyethylene terephthalate is used for the resin substrate, the temperature is 105 ° C.

Moreover, since the solar cell module of the present invention has a top incidence structure, it can be manufactured in the atmosphere. And it can be used without using a film having a barrier property against moisture and oxygen.
The tensile strength of the solar cell module of the present invention is preferably 230 MPa or more and more preferably 280 MPa in the method described in JIS K7133.

  Hereinafter, although the solar cell module of this invention is demonstrated still in detail using an Example, it cannot be overemphasized that this invention is not limited only to the form of an Example.

<Example 1>
Silver is deposited at a thickness of 100 nm on a polyethylene naphthalate (PEN) substrate having a side of 40 mm, and further IWZO (tungsten-containing indium oxide: WO ₃ is 1.0 Wt%, ZnO is 0.5 wt. % Of indium oxide) was formed into a pattern by sputtering so as to have a thickness of 140 nm at room temperature to manufacture a lower electrode.
Next, a solution in which cesium carbonate was dissolved in ethoxyethanol was prepared, and the solution was applied on the lower electrode using a spin coater. After the coating, it was immediately moved to an oven and heated at 160 ° C. for 15 minutes to form a second buffer layer having a thickness of about 1 nm on the lower electrode.
In the atmosphere, a solution in which P3HT (poly (3-hexylthiophene)) and PCBM (phenyl C ₆₁ butyric acid methyl ester) were dissolved in monochlorobenzene at a ratio of 3: 5 was prepared, and the solution was spun onto the second buffer layer. The solution was applied using a coater. After the application, the film was immediately moved to an oven and heated at 50 ° C. for 15 minutes to form an organic semiconductor layer having a thickness of 200 nm on the second buffer layer.
Next, molybdenum trioxide was vapor-deposited with a thickness of 20 nm on the organic semiconductor layer using a vapor deposition apparatus, and a buffer layer was formed.
And on the buffer layer, IWZO made by Sumitomo Metal Mining Co., Ltd. was formed into a pattern by sputtering so as to have a thickness of 140 nm at room temperature, thereby producing an inorganic transparent electrode. And it heated at 140 degreeC for 10 minute (s) under nitrogen atmosphere, and manufactured the solar cell module.

The manufactured solar cell module was irradiated with light having an intensity of 100 mW / cm ² using a solar simulator (AM1.5G). When the current-voltage characteristic between the lower electrode and the inorganic transparent electrode was measured with a source meter (Keisley, Model 2400) and the photoelectric conversion efficiency was calculated, it was 0.65% (Voc: 0.51 V Jsc). : 4.84 mA / cm ² FF: 0.25). The area of the solar cell element is 7 mm × 7 mm.

<Comparative Example 1>
A solar cell module was manufactured in the same manner as in Example 1 except that the buffer layer (molybdenum oxide) was not provided. When the photoelectric conversion efficiency was calculated in the same manner as in Example 1, it was 0%, and no power was generated.

<Reference Example>
Silver was vapor-deposited with a thickness of 100 nm on a glass substrate (Corning 1737) to produce a lower electrode.
Next, a solution in which polyethylene glycol was dissolved in methanol was prepared, and the solution was applied onto the lower electrode using a spin coater, and a second buffer layer having a thickness of 5 nm or less was formed on the lower electrode.
In the atmosphere, a solution in which P3HT (poly (3-hexylthiophene)) and PCBM (phenyl C ₆₁ butyric acid methyl ester) are dissolved in monochlorobenzene at a ratio of 1: 1 is prepared, and spin on the second buffer layer. The solution was applied using a coater and heated at 160 ° C. for 10 minutes to form an organic semiconductor layer having a thickness of 200 nm on the second buffer layer.
Next, on the organic semiconductor layer, molybdenum trioxide was vapor-deposited with a thickness of 15 nm using a vapor deposition apparatus to form a buffer layer.
And on the buffer layer, IWZO manufactured by Sumitomo Metal Mining Co., Ltd. was formed into a pattern by sputtering so as to have a thickness of 140 nm, thereby producing an inorganic transparent electrode. And it heated at 110 degreeC for 10 minute (s) under nitrogen atmosphere, and manufactured the solar cell module.

The manufactured solar cell module was heated from 100 ° C. to 10 ° C., left at each temperature for 10 minutes, and the solar cell module was observed.
The observation was confirmed by visual observation using an optical microscope (magnification 100 times). As a result, in the solar cell module having the buffer layer, the inorganic transparent electrode was not deteriorated even when the temperature was raised to 180 ° C.

<Reference Comparative Example>
A solar cell module was manufactured in the same manner as in the reference example except that the buffer layer (molybdenum oxide) was not provided. When the temperature was raised in the same manner as in the reference example and the solar cell module was observed, in the solar cell module having no buffer layer, the inorganic transparent electrode was cracked and deteriorated when observed at 130 ° C.

  The solar cell module of the present invention can be manufactured by a low temperature process using a resin substrate, and is industrially useful as an inexpensive solar cell module.

DESCRIPTION OF SYMBOLS 1 Sunlight 2 Surface protection sheet 3a Sealing layer 3b Sealing layer 4 Solar cell element 5 Back surface protection sheet 11 Inorganic transparent electrode 12 Buffer layer 13 Organic-semiconductor layer 14 Lower electrode 15 Resin substrate 16 2nd buffer layer

Claims (7)

  A solar cell module comprising a solar cell element in which a lower electrode, an organic semiconductor layer, a buffer layer, and an inorganic transparent electrode are laminated in that order on a resin substrate.   The solar cell module according to claim 1, wherein the inorganic transparent electrode is an amorphous inorganic transparent electrode.   The inorganic transparent electrode includes an oxide of indium (In), tin (Sn), zinc (Zn), tungsten (W), gallium (Ga), or a mixed oxide thereof. Or the solar cell module of 2.   The solar cell module according to any one of claims 1 to 3, wherein the buffer layer is a conductive polymer or a metal oxide.   The solar cell module according to any one of claims 1 to 4, wherein the buffer layer is poly (3,4-ethylenedioxythiophene) or molybdenum trioxide.   The solar cell module according to claim 1, wherein the buffer layer has a thickness of 10 nm or more.   The solar cell module according to claim 1, wherein the resin substrate has a Tg of 130 ° C. or less.

Images