WO2011158874A1 - Organic thin film solar cell - Google Patents

Abstract

Disclosed is an organic thin film solar cell which comprises: a gas barrier film substrate; an organic power generating laminate that contains at least, in the following order, a positive electrode, an organic photoelectric conversion layer, a metal oxide layer and a negative electrode that contains a metal nobler than iron; and a first gas barrier layer.

Description

Organic thin film solar cell

The present invention relates to an organic thin film solar cell having a resin film as a substrate, and more particularly to an organic thin film solar cell in which a photoelectric conversion part is sealed with a gas barrier film and a gas barrier layer as a substrate.

In recent years, photovoltaic power generation that converts sunlight into electricity has attracted attention as an effective means for solving energy problems. In general, a power generation module that performs solar power generation has a structure in which a portion that performs photoelectric conversion is disposed on a glass that is a substrate on which sunlight is incident, and is protected by sealing it with a gas barrier material. Have.

Various types of solar cells have been developed, and recently, organic thin-film solar cells that are expected to be low-cost, lightweight, and flexible are attracting attention. As a structure of the organic thin film solar cell, a structure in which a single layer or a plurality of layers of an organic thin film having a photoelectric conversion function is arranged between two different electrodes is common. This organic thin film solar cell has an advantage that it can be made light and flexible by using a plastic film as a substrate.
In order to meet the above expectations, studies have been made to use a plastic film, which is a resin material, as a substrate for a solar cell.

On the other hand, in general, organic optoelectronic devices are considered to have lower durability than inorganic optoelectronic devices. In particular, there is a problem of being easily deteriorated by corrosive gases such as oxygen and water vapor entering from the atmosphere. Under these circumstances, when a resin material is used instead of the conventionally used glass substrate, the plastic film cannot transmit water vapor, oxygen, or the like as much as the glass substrate. Deterioration is great and the durability of the solar cell is significantly reduced. For this reason, it has been impossible to mount a resin material while expecting a resin material as a substrate.

Organic thin-film solar cells have conventionally used a metal having a low work function, such as aluminum, as the negative electrode because of their high power generation efficiency. However, since a metal having a small work function generally has a large ionization tendency, it is easily corroded by oxygen or water vapor in the atmosphere and is inferior in durability.

The following technologies have been proposed from the viewpoint of preventing deterioration of the negative electrode. When configuring a battery structure in which an organic photoelectric conversion layer is arranged between a positive electrode and an aluminum negative electrode, a structure in which a titanium oxide layer is provided between the organic photoelectric conversion layer and the aluminum electrode, It is known to suppress degradation and improve conversion efficiency (for example, Advanced Material, 19 Volume, 19 Issue, 18, Air-Stable, Polymer, Electronic Device, p.2445-2449, K. Lee, J. Y, Kim, and S H. Park, S. H. Kim, S. Cho, A. J. Heeger.).

In addition, as another method for suppressing such deterioration of the negative electrode, a technique of sealing an organic optoelectronic device between gas barrier layers has been disclosed (for example, US Pat. No. 6,664,137). See the description).

On the other hand, durability can be improved by using a metal (eg, silver, copper) that has a smaller ionization tendency than aluminum and is less likely to corrode.

However, such a metal having a small ionization tendency has a problem that the work function becomes large, so that the open circuit voltage is lowered and the conversion efficiency is lowered. That is, a metal having a smaller ionization tendency such as silver or copper is more advantageous than aluminum in terms of improving durability, but it is significantly disadvantageous in terms of photoelectric conversion efficiency. Therefore, conventionally, it has been difficult to achieve both conflicting techniques such as suppressing the corrosion of the negative electrode and enhancing the durability while keeping the conversion efficiency high.

In addition, the above Advanced Materials: Volume 19, Issue 18, Air-Stable Polymer, Devices (p. 2445-2449), K. Lee, J. Y, Y Kim, S. H. Park, S. H. Kim, S. Cho , A. J. Heeger., In the case of a battery structure in which an organic photoelectric conversion layer is disposed between a positive electrode and a negative electrode made of aluminum, a titanium oxide layer between the organic photoelectric conversion layer and the aluminum electrode Although the deterioration of the negative electrode can be suppressed by adopting the structure provided with, the durability is still not sufficient.

Furthermore, as in the technique described in the above-mentioned US Pat. No. 6,664,137, the durability is insufficient only by the sealing method using the gas barrier material.

Therefore, if a metal that does not corrode easily is used as the negative electrode, the conversion efficiency decreases. Further, even if a structure in which an inorganic oxide layer such as titanium oxide is provided between aluminum and the organic photoelectric conversion layer, the durability is not sufficient. At present, the technology for improving the durability without reducing the conversion efficiency has not yet been established.

As described above, when considering the performance that is practically acceptable, the organic thin film solar cell provided with a plastic film as a substrate cannot be said to have sufficient durability even by various devices. There is a disadvantage that it cannot withstand long-term use.

The present invention has been made in view of the above, and aims to provide an organic thin-film solar cell that has high durability and can withstand long-term use, and that can maintain high photoelectric conversion efficiency while suppressing a decrease in efficiency. It is an object to achieve the object.

As a result of intensive studies by the present inventors based on the above problems, the substrate on which the organic thin-film solar cell is formed is a gas barrier film substrate, and only a gas barrier layer is provided outside the electrode on the side away from the gas barrier film substrate. In addition, the metal oxide layer is arranged between the negative electrode and the organic photoelectric conversion layer, and the negative electrode is made of a noble metal (less ionization tendency) than iron, so that the negative electrode is simply ionized. Acquired knowledge that reduction in conversion efficiency caused by using small metals can be suppressed, and that improvement effects are seen in preventing reduction in conversion efficiency and improving the life of organic thin-film solar cells, and achieved based on such knowledge It has been done.

Specifically, the above problem can be solved by the following means.
<1> a gas barrier film substrate, an organic power generation laminate including at least a positive electrode, an organic photoelectric conversion layer, a metal oxide layer, and a negative electrode containing a metal nobler than iron in this order; a first gas barrier layer; It is an organic thin-film solar cell provided with.
<2> The organic thin-film solar cell according to <1>, wherein the energy level of the conduction band of the metal oxide layer is higher than −4.5 eV.

<3> The organic thin-film solar cell according to <1> or <2>, wherein the negative electrode includes a metal or alloy having a smaller ionization tendency than hydrogen.
<4> The organic thin-film solar cell according to any one of <1> to <3>, wherein the negative electrode includes at least one of copper, silver, and an alloy including these.
<5> The organic thin film solar cell according to any one of <1> to <4>, wherein the metal oxide of the metal oxide layer includes at least one of titanium oxide and zinc oxide.

<6> The gas barrier film substrate includes a first resin film and a second gas barrier layer, and the second gas barrier layer is provided in contact with the first resin film. And the first inorganic layer provided on the first organic polymer layer. The organic thin-film solar cell according to any one of <1> to <5>.
<7> A second resin film is further provided on the side of the first gas barrier layer where the organic power generation laminate is not disposed, and the first gas barrier layer is in contact with the second resin film. The organic thin film solar according to any one of <1> to <6>, further comprising a second organic polymer layer provided and a second inorganic layer provided on the second organic polymer layer It is a battery.
<8>
The gas barrier film substrate includes a first resin film and a second gas barrier layer,
In the second gas barrier layer, at least two organic polymer layers and at least two inorganic layers are alternately laminated so that the organic polymer layers are in contact with the surface of the first resin film <1. The organic thin film solar cell according to any one of> to <5>.
<9>
A second resin film is further provided on the side of the first gas barrier layer where the organic power generation laminate is not disposed;
In the first gas barrier layer, at least two organic polymer layers and at least two inorganic layers are alternately laminated so that the organic polymer layers are in contact with the surface of the second resin film <1. >-<5> and <8> The organic thin-film solar cell according to any one of <8>.

<10> Hole collection including polyethylenedioxythiophene / polystyrenesulfonate (PEDOT-PSS; = Polystyrenesulfonate doped PEDOT) between the positive electrode and the organic photoelectric conversion layer The organic thin-film solar cell according to any one of <1> to <8>, further including a layer.
<11> The material according to any one of <1> to <9>, further including a hole collection layer containing at least one of molybdenum oxide and vanadium oxide between the positive electrode and the organic photoelectric conversion layer. This is an organic thin film solar cell.
<12> In at least one of the first gas barrier layer and the second gas barrier layer, at least two organic polymer layers and at least two inorganic layers are in contact with the organic polymer layer on the surface of the resin film. The organic thin film solar cell according to <6> or <7>, wherein the organic thin film solar cells are alternately stacked.

According to the present invention, it is possible to provide an organic thin-film solar cell that has high durability and can withstand long-term use, and that can maintain high photoelectric conversion efficiency while suppressing a decrease in efficiency. Furthermore, a flexible organic thin film solar cell can be provided as a solar cell.

It is a figure which shows the structural example of the organic thin film solar cell which concerns on the 1st aspect of this invention. It is a figure which shows the structural example of the organic thin film solar cell which concerns on the 2nd aspect of this invention. It is a figure which shows the structural example of the organic thin film solar cell which concerns on the 3rd aspect of this invention.

Hereinafter, the organic thin film solar cell of the present invention will be described in detail.
In the specification of the present application, “to” means that the numerical values described before and after are included as the lower limit value and the upper limit value. (Meth) acrylate is meant to include both acrylate and methacrylate.

In the organic thin film solar cell of the present invention, an organic power generation laminate including a gas barrier film substrate and at least a positive electrode, an organic photoelectric conversion layer, a metal oxide layer, and a negative electrode containing a metal nobler than iron in this order; The organic power generation laminate is shielded from the outside air by the gas barrier film substrate and the gas barrier layer.

Conventionally, a technique for sealing a battery by providing a gas barrier film substrate and a gas barrier layer is known. However, this alone is not sufficient to suppress the durability deterioration due to corrosion due to the influence of oxygen and water vapor entering from the atmosphere. Therefore, durability can be improved by substituting conventional general-purpose aluminum with metals that are more precious than iron such as silver, which is more difficult to corrode (metals with less ionization tendency). It will decline. Under such circumstances, in the present invention, in addition to sealing the inside by providing a gas barrier film substrate and a gas barrier layer, a metal noble (less ionized) than iron is used for the negative electrode, By adopting a structure in which a metal oxide layer is disposed between the organic photoelectric conversion layer, it is possible to effectively increase durability while not decreasing the release voltage of the element, that is, preventing a decrease in photoelectric conversion efficiency. It becomes possible.

The organic thin film solar cell of the present invention typically has, as a basic structure, a resin film / second gas barrier layer / positive electrode / organic layer / metal oxide layer / negative electrode / first gas barrier layer, or resin film / It has a configuration of second gas barrier layer / negative electrode / metal oxide layer / organic layer / positive electrode / first gas barrier layer. Further, the organic thin film solar cell of the present invention has a configuration using two gas barrier film substrates, that is, for example, resin film / second gas barrier layer / positive electrode / organic layer / metal oxide layer / negative electrode / protective layer / adhesive layer. The structure of / first gas barrier layer / resin film may be sufficient. In this case, a protective layer may be provided to protect the organic power generation laminate from the adhesive. Furthermore, in addition to the above configuration, another substrate or an arbitrary functional layer may be included.

The organic thin-film solar cell of the present invention has, for example, a conductive layer of a gas barrier film substrate provided with a light-transmitting conductive layer such as ITO (in particular, transparency with low sunlight absorption) as a positive electrode, and an organic layer thereon. It may be manufactured by sequentially installing a metal oxide layer, a negative electrode, and a gas barrier layer. Moreover, the conductive layer of the gas barrier film substrate provided with the conductive layer is used as a positive electrode, and an organic layer, a metal oxide layer, and a negative electrode are provided thereon to form a photoelectric conversion element, and the gas barrier film substrate is interposed therebetween through an adhesive layer. It may be manufactured by pasting together. Here, as the adhesive used for the adhesive layer, a thermosetting adhesive, an ultraviolet curable adhesive, or the like can be used. The curing conditions of the adhesive can be determined as appropriate according to the type of the adhesive. For example, the description of “Adhesive Data Book 2nd Edition, edited by the Japan Adhesive Society, Nikkan Kogyo Shimbun” can be referred to. it can.

A structural example of the organic thin film solar cell of the present invention is shown in FIGS. However, the organic thin-film solar cell of this invention is not limited to the structure shown by these.
In the 1st aspect of the organic thin-film solar cell of this invention, as FIG. 1 shows, the organic power generation laminated body 2 of laminated structure is formed on the gas barrier film board | substrate 1 with which the gas barrier layer 1b was provided in the base material 1a. A gas barrier layer 5 is provided so as to cover the power generation laminate.

In the 2nd aspect of the organic thin-film solar cell of this invention, as FIG. 2 shows, the organic electric power generation laminated body 2 is provided on the gas barrier film board | substrate 1 with which the gas barrier layer 1b was provided in the base material 1a, A gas barrier layer 5 is provided on the surface of the protective layer 3 provided so as to cover the power generation laminate.

In the 3rd aspect of the organic thin-film solar cell of this invention, as FIG. 3 shows, the organic electric power generation laminated body 2 is provided on the gas barrier film board | substrate 1 with which the gas barrier layer 1b was provided in the base material 1a, A gas barrier film substrate 10 is provided via an adhesive layer 4 on the surface of the protective layer 3 provided so as to cover the organic power generation laminate. The gas barrier film substrate 10 includes a base material 10a provided with a gas barrier layer 10b, and is bonded to the adhesive layer 4 on the surface of the gas barrier layer 10b.

(Gas barrier film substrate)
The organic thin film solar cell of the present invention includes a gas barrier film substrate having gas barrier properties that blocks permeation of oxygen, water vapor, and the like as a support substrate. The gas barrier film substrate may be composed of only a resin film (base material) depending on the film, but it is preferable to provide at least one gas barrier layer on the resin film. The gas barrier layer is preferably provided with at least one organic polymer layer and at least one inorganic layer.

-Resin film-
The following description regarding the resin film applies to all the resin films described in this specification.
The resin film used for the organic thin film solar cell of the present invention is not particularly limited in material, thickness, etc., as long as it is a resin film that can hold an organic polymer layer, an inorganic layer, etc. Can do. Specifically, as the resin film, polyester resin, methacrylic resin, methacrylic acid-maleic acid copolymer, polystyrene resin, transparent fluororesin, polyimide resin, fluorinated polyimide resin, polyamide resin, polyamideimide resin, polyetherimide Resin, cellulose acylate resin, polyurethane resin, polyetheretherketone resin, polycarbonate resin, alicyclic polyolefin resin, polyarylate resin, polyethersulfone resin, polysulfone resin, cycloolefin copolymer, fluorene ring-modified polycarbonate resin, alicyclic ring Examples include films formed using thermoplastic resins such as modified polycarbonate resins, fluorene ring-modified polyester resins, and acryloyl compounds.

The resin film is preferably formed using a material having heat resistance. Specifically, it is preferably formed using a transparent material having a glass transition temperature (Tg) of 100 ° C. or higher and / or a linear thermal expansion coefficient of 40 ppm / ° C. or lower and high heat resistance. Tg and a linear expansion coefficient can be adjusted with an additive. Examples of the thermoplastic resin which is such a material include polyethylene naphthalate (PEN: 120 ° C.), polycarbonate (PC: 140 ° C.), alicyclic polyolefin (for example, ZEONOR 1600 manufactured by Nippon Zeon Co., Ltd .: 160 ° C. ), Polyarylate (PAr: 210 ° C.), polyether sulfone (PES: 220 ° C.), polysulfone (PSF: 190 ° C.), cycloolefin copolymer (COC (for example, a compound described in JP-A No. 2001-150584): 162 ), Fluorene ring-modified polycarbonate (BCF-PC (for example, compound of JP 2000-227603 A): 225 ° C.), alicyclic modified polycarbonate (IP-PC (for example, compound of JP 2000-227603 A)): 205 ), An acryloyl compound (for example, JP-A-200) -80616 No. described in Japanese compound: 300 ° C. or higher), and polyimide, etc. The [The temperature in parentheses indicate the Tg].
Among the above, from the viewpoint of particularly obtaining transparency, it is preferable to use an alicyclic polyolefin.

The resin film used for the organic thin film solar cell of the present invention is usually required to have transparency, and the light transmittance is usually 80% or more, preferably 85% or more, more preferably 90. % Or more. The light transmittance is calculated by measuring the total light transmittance and the amount of scattered light using the method described in JIS-K7105, that is, an integrating sphere light transmittance measuring device, and subtracting the diffuse transmittance from the total light transmittance. Is the value to be

The thickness of the resin film is not particularly limited, but is typically 1 to 800 μm, preferably 10 to 200 μm. The resin film preferably has a gas barrier layer including a laminate having gas barrier properties. A laminate having a gas barrier property suitable for the present invention will be described later. Moreover, the resin film may have functional layers, such as a conductive layer and a primer layer.

Moreover, the organic thin film solar cell of the present invention includes a gas barrier film substrate using the resin film, but also when a resin film is provided on the side opposite to the side where the gas barrier film substrate is provided (particularly the outermost surface) A resin film similar to the above is preferably used.

-Gas barrier layer-
The gas barrier layer is a layer for preventing permeation of oxygen and water vapor in the atmosphere that adversely affects the organic thin film solar cell (hereinafter, this layer is also referred to as “second gas barrier layer”).

The type of the gas barrier layer is not particularly limited, and various organic layers and inorganic layers can be used. For example, at least one organic layer (hereinafter also referred to as “organic polymer layer”) and at least one. The form which provided the gas barrier layer which has the inorganic layer of a layer is mentioned. The gas barrier layer preferably has a water vapor transmission rate of 0.001 g / m ² / day or less. Specifically, such a gas barrier ability has a structure in which at least two organic polymer layers and at least two inorganic layers are alternately laminated like organic layer / inorganic layer / organic layer. It can be achieved by being formed. Among them, a gas barrier layer formed in an embodiment having an organic polymer layer in contact with the surface of the resin film described above and an inorganic layer provided on the organic polymer layer is preferable. Furthermore, at least two organic polymer layers and at least two inorganic layers are organic layers / inorganic layers / organic layers so that the organic polymer layers are in contact with the surface of the resin film described above. Thus, the gas barrier layer laminated | stacked alternately is preferable.
The description regarding the second gas barrier layer also applies to the first gas barrier layer described later.

(1) Organic polymer layer The following description regarding the organic polymer layer applies to all the organic polymer layers described in the present specification.
The organic polymer layer in the present invention includes, for example, polyester, acrylic resin, methacrylic resin, methacrylic acid-maleic acid copolymer, polystyrene, transparent fluororesin, polyimide, fluorinated polyimide, polyamide, polyamideimide, polyetherimide, cellulose acylate. Thermoplastic resins such as rate, polyurethane, polyether ether ketone, polycarbonate, alicyclic polyolefin, polyarylate, polyether sulfone, polysulfone, fluorene ring modified polycarbonate, alicyclic modified polycarbonate, fluorene ring modified polyester, or acryloyl compound, Or a layer using polysiloxane or other organic silicon compound (for example, silicon carbide or silicon oxide carbide produced by a CVD method using an organic silane gas as a raw material) That. The organic polymer layer may be formed of one kind of material or a mixture. Further, two or more organic polymer layers may be laminated. In this case, each layer may have the same composition or a different composition. Further, as described in U.S. Patent Publication No. 2004-46497, the organic polymer layer is a layer whose interface with the inorganic layer is not clear and whose composition changes continuously in the film thickness direction. Good.

The organic polymer layer is preferably a layer using a (meth) acrylate polymer. The (meth) acrylate polymer is a polymer obtained by polymerizing a polymerizable composition containing a (meth) acrylate monomer as a main component.

The “polymerizable composition containing a (meth) acrylate monomer as a main component” may include one (meth) acrylate monomer or a mixture of several (meth) acrylate monomers. Good. The molecular weight of the (meth) acrylate monomer is preferably 200 to 2000, and more preferably 400 to 1000.

  Hereinafter, specific examples of the (meth) acrylate monomer will be shown. However, the present invention is not limited to these.

 

 

 

 

 

 

 

 

 

 

[Acid monomer]
The polymerizable composition in the present invention may contain an acidic monomer. By including an acidic monomer, interlayer adhesion is improved. The acidic monomer refers to a monomer having an acidic group such as carboxylic acid, sulfonic acid, phosphoric acid, or phosphonic acid.
The acidic monomer used in the present invention is preferably a monomer containing a carboxylic acid group or a phosphoric acid group, more preferably a (meth) acrylate containing a carboxylic acid group or a phosphoric acid group, in terms of interlayer adhesion. (Meth) acrylate having an ester group is more preferred.

Hereinafter, specific examples of the acidic monomer suitable for the present invention will be shown. However, these are not limited in the present invention.

 

 

[Other polymerizable components / polymers]
The polymerizable composition containing the (meth) acrylate monomer as a main component includes a monomer other than (meth) acrylate (for example, a styrene derivative, a maleic anhydride derivative, an epoxy compound, and the like within the scope of the present invention). And oxetane derivatives) and various polymers (for example, polyester, methacrylic acid-maleic acid copolymer, polystyrene, transparent fluororesin, polyimide, fluorinated polyimide, polyamide, polyamideimide, polyetherimide, cellulose acylate, polyurethane) , Polyether ketone, polycarbonate, alicyclic polyolefin, polyarylate, polyethersulfone, polysulfone, fluorene ring-modified polycarbonate, alicyclic ring-modified polycarbonate, fluorene ring-modified polyester, etc.) .

[Polymerization initiator]
The “polymerizable composition containing a (meth) acrylate monomer as a main component” in the present invention may contain a polymerization initiator. When the photopolymerization initiator is contained, the content thereof is preferably 0.1 mol% or more, more preferably 0.5 to 2 mol%, based on the total amount of the polymerizable compounds. By setting it as such a composition, the polymerization reaction via an active component production | generation reaction can be controlled appropriately.

Examples of the photopolymerization initiator include Irgacure series (for example, Irgacure 651, Irgacure 754, Irgacure 184, Irgacure 2959, Irgacure 907, Irgacure 369, Irgacure 379, Irgacure, commercially available from Ciba Specialty Chemicals. 819), Darocure series (eg, Darocur TPO, Darocur 1173, etc.), Quantacure PDO, Ezacure series (eg, Ezacure TZM, Ezacure TZT, commercially available from Sartomer). ), And also the oligomer type Ezacure KIP series.

The thickness of the organic polymer layer is not particularly limited, but is usually 100 to 5000 nm, preferably 200 to 2000 nm per layer. Moreover, when it has two or more organic polymer layers, each organic polymer layer may be the same layer, or a different layer.

-Method for forming organic polymer layer-
Although there is no restriction | limiting in particular about the formation method of an organic polymer layer, For example, it can form by the solution coating method or the vacuum film-forming method. Examples of the solution coating method include a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, a slide coating method, or a hopper described in US Pat. No. 2,681,294. It can be applied by an extrusion coating method using-. Although there is no restriction | limiting in particular as a vacuum film-forming method, Film-forming methods, such as vapor deposition and plasma CVD, are preferable.
In the present invention, a polymer may be applied by solution, or a hybrid coating method containing an inorganic substance as described in JP-A Nos. 2000-323273 and 2004-25732 may be used. Good.

In the present invention, a composition containing a polymerizable compound is usually cured by irradiation with light, and the irradiation light is usually ultraviolet light from a high-pressure mercury lamp or a low-pressure mercury lamp. The irradiation energy is preferably 0.1 J / cm ² or more, 0.5 J / cm ² or more is more preferable.
When a (meth) acrylate compound is used as the polymerizable compound, the polymerization is inhibited by oxygen in the air, so that it is preferable to reduce the oxygen concentration or oxygen partial pressure during polymerization. When the oxygen concentration during polymerization is lowered by the nitrogen substitution method, the oxygen concentration is preferably 2% or less, and more preferably 0.5% or less. When the oxygen partial pressure during polymerization is reduced by the decompression method, the total pressure is preferably 1000 Pa or less, and more preferably 100 Pa or less. Further, it is particularly preferable to perform ultraviolet polymerization by irradiating energy of 0.5 J / cm ² or more under a reduced pressure condition of 100 Pa or less.

(2) Inorganic layer The following description regarding the inorganic layer applies to all inorganic layers described in the present specification.
The inorganic layer in the present invention is not particularly limited as long as it is formed of an inorganic material and has a gas barrier property. Examples of inorganic substances generally include boron, magnesium, aluminum, silicon, titanium, zinc, tin oxides, nitrides, oxynitrides, carbides, and hydrides. These may be pure substances, a mixture containing a plurality of compositions, or a gradient material layer. Of these, aluminum oxide, nitride or oxynitride, or silicon oxide, nitride or oxynitride is preferable, and aluminum oxide or silicon oxide is particularly preferable.

As the method for forming the inorganic layer, any method can be applied as long as it can form a target thin film. For example, a sol-gel method, a sputtering method, a vacuum deposition method, an ion plating method, a plasma CVD method, and the like are suitable, and specifically, Japanese Patent No. 3434344, Japanese Patent Application Laid-Open No. 2002-322561, and Japanese Patent Application Laid-Open No. 2002. The method described in Japanese Patent No. -361774 can be applied. In particular, when a silicon compound is formed, it is preferable to employ either inductively coupled plasma CVD or PVD or CVD forming method using plasma applied with a microwave and a magnetic field set to electron cyclotron resonance conditions. It is most preferable to employ a formation method by inductively coupled plasma CVD. CVD (ECR-CVD) using inductively coupled plasma CVD or microwaves set to electron cyclotron resonance conditions and plasma applied with a magnetic field is described in, for example, Chemical Society of Japan, CVD Handbook, p. 284 (1991). It can be implemented by the method. PVD (ECR-PVD) using microwaves set to electron cyclotron resonance conditions and plasma applied with a magnetic field is, for example, Ono et al., Jpn. J. Appl. Phys. 23, No. 8, L534 ( 1984). As a raw material when using the CVD, a gas source such as silane or a liquid source such as hexamethyldisilazane can be used as a silicon supply source.

As the smoothness of the inorganic layer, the average roughness (Ra value) of 1 μm square is preferably less than 1 nm, and more preferably 0.5 nm or less. For this reason, it is preferable that the inorganic layer is formed in a clean room. The degree of cleanness is preferably class 10,000 or less, and more preferably class 1000 or less.
The Ra value is a value measured based on the DFM mode of the scanning probe microscope (SPM).

The thickness of the inorganic layer is not particularly limited, but is usually in the range of 5 to 500 nm, preferably 10 to 200 nm per layer. The inorganic layer may have a laminated structure including a plurality of sublayers. In this case, each sublayer may have the same composition or a different composition. Further, as described above, as described in US Publication No. 2004-46497, the inorganic layer has an unclear interface with the organic polymer layer, and the composition continuously changes in the film thickness direction. It may be a layer.

-Lamination of organic polymer layer and inorganic layer-
Lamination of the organic polymer layer and the inorganic layer can be carried out by successively and repeatedly forming the organic polymer layer and the inorganic layer in contact with each other according to the desired layer configuration. When the inorganic layer is formed by a vacuum film formation method such as a sputtering method, a vacuum vapor deposition method, an ion plating method, or a plasma CVD method, the organic polymer layer is also formed by a vacuum film formation method such as the flash vapor deposition method. Is preferred. During film formation of the gas barrier layer, it is particularly preferable to always laminate the organic polymer layer and the inorganic layer in a vacuum of 1000 Pa or less without returning to atmospheric pressure in the middle. The pressure is more preferably 100 Pa or less, still more preferably 50 Pa or less, and particularly preferably 20 Pa or less.
In particular, the present invention preferably has an aspect having a layer structure in which at least two organic polymer layers and at least two inorganic layers are alternately laminated. In this case, the alternately laminated structure is an organic polymer layer from the resin film side. The layers may be laminated in the order of / inorganic layer / organic polymer layer / inorganic layer, or in the order of inorganic layer / organic polymer layer / inorganic layer / organic polymer layer. Among these, from the viewpoint of improving the power generation efficiency when power is generated as a solar cell, at least two layers of organic polymer in the order of organic polymer layer / inorganic layer / organic polymer layer / inorganic layer from the resin film side. A mode in which layers and at least two inorganic layers are alternately laminated is most preferable.

(Organic power generation laminate)
An organic power generation laminate is provided in the organic thin film solar cell of the present invention.
The organic power generation laminate includes at least a pair of electrodes and an organic photoelectric conversion layer and a metal oxide layer provided between the pair of electrodes. Specifically, one of the paired electrodes is a positive electrode, and the other is a negative electrode. Between the positive electrode and the negative electrode, one or more organic photoelectric conversion layers and one or two layers are formed. A metal oxide layer equal to or more than one layer is provided.

It is preferable that at least one of the pair of electrodes forming part of the organic power generation laminate has transparency due to the nature of a solar cell. Here, having transparency means the property that sunlight passes through the battery to the extent that power generation can be performed when exposed to sunlight, and the amount of sunlight transmitted is preferably large, as will be described later. Preferably, the transmittance is 60% or more.

The organic photoelectric conversion layer provided between the electrodes has a function of absorbing light and generating electrons and holes. The simplest power generation laminate has a configuration of positive electrode / organic photoelectric conversion layer / metal oxide layer / negative electrode, and the organic photoelectric conversion layer is a mixed layer of a hole transport material and an electron transport material. In this configuration, the hole transport material and the electron transport material are preferably phase separated. The power generation laminate includes positive electrode / hole transport layer / electron transport layer / metal oxide layer / negative electrode structure, positive electrode / hole transport layer / mixed layer / electron transport layer / metal oxide layer / negative electrode. A configuration is also illustrated. The mixed layer is a mixed layer of a hole transport material and an electron transport material, and is preferably phase-separated.

Between the positive electrode and the hole transport layer, or between the negative electrode and the electron transport layer (specifically, between the negative electrode and the metal oxide layer), there are auxiliary layers such as a charge blocking layer and a charge injection layer. It may be. Each layer may be divided into a plurality of secondary layers. In addition, the organic thin film solar cell of the present invention may adopt a so-called tandem configuration having a plurality of pairs of a hole transport layer and an electron transport layer. An element configured in a tandem type is particularly preferable in terms of high open-circuit voltage and high conversion efficiency. At that time, a recombination layer is disposed as an intermediate layer. That is, as a typical example of the tandem element, a configuration of positive electrode / hole transport layer / electron transport layer / recombination layer / hole transport layer / electron transport layer / metal oxide layer / negative electrode is exemplified.

In the present invention, in addition to the above layers, other layers may be provided as necessary.
The other layers can be suitably formed by any of dry film forming methods such as vapor deposition and sputtering, transfer methods, and printing methods.

Hereinafter, a positive electrode, a negative electrode, an organic photoelectric conversion layer (an organic layer such as a hole transport layer and an electron transport layer) forming a part of the organic photoelectric conversion layer, and other layers will be described.

(1) Positive electrode The positive electrode should just have a function as an electrode which receives a hole, and can be suitably selected from well-known electrode materials.
Suitable examples of the material for the positive electrode include metals, alloys, metal oxides, conductive compounds, and mixtures thereof. Specific examples of the positive electrode material include conductive metal oxides such as tin oxide doped with antimony or fluorine (ATO, FTO), tin oxide, indium oxide, indium tin oxide (ITO), zinc indium oxide (IZO), Metals such as gold, silver, chromium and nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene and polypyrrole And a laminate of these and a conductive metal oxide.

When the positive electrode requires transparency, the positive electrode is preferably a conductive metal oxide. In particular, from the viewpoints of productivity, high conductivity, transparency, and the like, it is preferable to use ITO, ATO, FTO, IZO, and a composite thereof.

The positive electrode preferably has a hole collection layer on the organic photoelectric conversion layer side. Specific examples of the hole collection layer include PEDOT-PSS, molybdenum oxide, tungsten oxide, and vanadium oxide. PEDOT-PSS is preferable in terms of hole mobility and valence band energy levels. , Molybdenum oxide, and vanadium oxide are preferred.

In addition, the energy level of the valence body of the hole collection layer is preferably larger than the work function of the positive electrode and smaller than the level of the valence band of the hole transport material of the photoelectric conversion layer. When the positive electrode includes up to the hole collecting electrode layer, the positive electrode preferably has a higher work function than the negative electrode described later. Specifically, the work function of the main component of the material to be the positive electrode is 4. Preferably it is greater than 6 eV.

The positive electrode is, for example, a wet method such as a printing method or a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as a CVD method or a plasma CVD method. It can form on the said gas barrier film board | substrate according to the method selected suitably in consideration of the suitability with the material to form.

In the organic thin film solar cell of the present invention, the position where the positive electrode is formed is not particularly limited and can be appropriately selected according to the use of the solar cell. In this case, the positive electrode may be formed on the entire one surface of the substrate, or may be formed in part by patterning. The patterning for forming the positive electrode may be performed by chemical etching such as photolithography, or may be performed by physical etching such as a laser, or vacuum deposition or sputtering with a mask overlapped. It may be performed by a lift-off method or a printing method.

The thickness of the positive electrode can be appropriately selected depending on the material forming the positive electrode and cannot be generally specified, but is usually about 10 nm to 50 μm, and preferably 50 nm to 20 μm.

The resistance value of the positive electrode is preferably 100Ω / □ or less, and more preferably 20Ω / □ or less. When the positive electrode has transparency, it may be colorless and transparent or colored and transparent. In order to capture light from the transparent positive electrode side, the transmittance is preferably 60% or more, and more preferably 70% or more.
The transparent positive electrode is described in detail in “New Development of Transparent Electrode Film” (supervised by Yutaka Sawada, published by CMC, 1999), and the matters described here can also be applied to the present invention.

(2) Negative electrode The negative electrode is roughly classified into a metal case and a combination of an oxide and a metal as a work function adjusting function. The negative electrode in the present invention contains a metal nobler than iron so that the metal is less susceptible to deterioration due to corrosion. A “metal more precious than iron” is a metal in which the redox potential between the metal and its hydrated ion is greater than that of iron. Specifically, the standard redox potential is higher than that of a standard hydrogen electrode. This is a metal larger than -0.5V. The standard oxidation-reduction potential is preferably greater than 0V and more preferably greater than 0.5V from the viewpoint of corrosion resistance.
The standard oxidation-reduction potential is determined by using the standard hydrogen electrode for the cathode reaction and the oxidation-reduction reaction for which the electrode potential is desired for the anodic reaction, respectively. The activity (or partial pressure) of the substances involved is 1).

Examples of metals preferable from the viewpoint of corrosion resistance include indium, cobalt, nickel, tin, copper, silver, and gold. On the other hand, since the negative electrode is required to have a function of accepting electrons from the organic layer or the metal oxide layer, the work function is preferably small. In this sense, examples of the metal or alloy used for the negative electrode in the present invention include silver (work function: 4.31 eV), copper (work function: 4.65 eV), indium (work function: 4.12 eV), or these An alloy containing is more preferable, and silver, copper, or an alloy containing these is particularly preferable. Similarly, an alloy of silver and indium can be mentioned as a particularly preferable example.

A combination of oxide and metal as a work function adjusting function may be used as the negative electrode. In this case, for example, a negative electrode in which a conductive oxide such as zinc oxide whose conductivity is improved by doping with zinc oxide, titanium oxide, boron, or aluminum, and a metal nobler than iron is used.

The method for forming the negative electrode is not particularly limited and can be performed according to a known method. The negative electrode is formed, for example, from a printing method, a wet method such as a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, and a chemical method such as CVD or plasma CVD method. It can be carried out according to a method appropriately selected in consideration of suitability with the material forming the negative electrode. For example, it can be formed by performing sputtering or the like on one or more metals used as a negative electrode material simultaneously or sequentially. The same method as that for the positive electrode can be used for patterning when forming the negative electrode.

In the present invention, the position where the negative electrode is formed is not particularly limited, and it may be formed on the entire organic compound layer or a part thereof. Further, a dielectric layer made of an alkali metal or alkaline earth metal fluoride or oxide may be inserted between the negative electrode and the organic compound layer with a thickness of 0.1 to 5 nm. This dielectric layer can also be regarded as a kind of electron injection layer. The dielectric layer can be formed by, for example, vacuum deposition, sputtering, or ion plating. The thickness of the negative electrode can be appropriately selected depending on the material for forming the negative electrode and cannot be generally defined, but is usually about 10 nm to 5 μm, and preferably 50 nm to 1 μm.

(3) Organic photoelectric conversion layer The organic photoelectric conversion layer is a mixed layer having a hole transport material and an electron transport material, and is a so-called bulk hetero layer. The organic photoelectric conversion layer may have a structure of (positive electrode) hole transport layer / electron transport layer (negative electrode) or a structure of (positive electrode) hole transport layer / mixed organic layer / electron transport layer (negative electrode). Here, the mixed organic layer is the same as the mixed layer, and details will be described later.

An auxiliary layer such as a charge blocking layer, a charge injection layer, or an exciton diffusion preventing layer may be provided between the positive electrode and the hole transport layer or between the negative electrode and the electron transport layer. Each layer may be divided into a plurality of secondary layers. In addition, the organic thin film solar cell of the present invention may adopt a so-called tandem configuration having a plurality of pairs of a hole transport layer and an electron transport layer. A tandem element is usually a serial connection type, and is particularly preferable in that it has a high open-circuit voltage and high conversion efficiency. At that time, a recombination layer is disposed as an intermediate layer. That is, as a typical tandem type device, the structure is positive electrode / mixed organic layer / recombination layer / mixed organic layer / negative electrode, or positive electrode / hole transport layer / electron transport layer / recombination layer / hole transport layer / electron transport. The structure which is a layer / negative electrode can be illustrated. A tandem element connected in parallel is also possible.

You may provide another layer in the organic photoelectric converting layer in this invention as needed.
In addition, in this specification, a layer using an organic compound such as a mixed organic layer, a hole transport layer, an electron transport layer, a charge blocking layer, a charge injection layer, and an exciton diffusion preventing layer is generally referred to as an “organic photoelectric conversion layer”. Called.

Each layer can be suitably formed by any of a dry film forming method such as a vapor deposition method and a sputtering method, a transfer method, and a printing method.

(4) Hole transport layer The hole transport layer is a layer having a function of receiving and transporting holes to the positive electrode or the positive electrode side.
The hole transport layer may be a single layer or a laminate of a plurality of layers. It is preferable that at least one layer of the hole transport layer has a charge generating ability to absorb light and generate electrons and holes. The hole transport layer can be formed using one or more hole transport materials.

Examples of the hole transport material include carbazole derivatives, polyarylalkane derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic compounds. Examples include tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, porphyrin compounds, phthalocyanine compounds, polythiophene derivatives, polypyrrole derivatives, and polyparaphenylene vinylene derivatives.

Examples of the hole transport material include compounds described as “Hole Transport Material” in Chem. Rev. 2007, 107, 953-1010, and specific examples include the following.

 

 

 

 

Examples of the material of the hole transport layer having charge generation ability include porphyrin compounds, phthalocyanine compounds, polythiophene derivatives, polypyrrole derivatives, and polyparaphenylene vinylene derivatives, and examples thereof include Chem. Rev. 1993, 93, 449-406.

Examples of the method for forming the hole transport layer include a solvent coating method and a vacuum deposition method. Examples of the solvent coating method include spin coating, spray coating, bar coating, and die coating.

The thickness of the hole transport layer is preferably 1 nm to 500 nm, more preferably 2 nm to 200 nm, and even more preferably 5 nm to 100 nm. The hole transport layer may have a single-layer structure including one or more of the materials described above, or may have a multilayer structure including a plurality of layers having the same composition or different compositions.

(5) Electron transport layer The electron transport layer is a layer having a function of transporting electrons to the negative electrode or the negative electrode side.
The electron transport layer may be a single layer or a laminate of a plurality of layers. It is preferable that at least one of the electron transport layers has a charge generation capability of absorbing light and generating a charge. The electron transport layer can be formed using one kind or two or more kinds of electron transport materials.

Examples of the electron transport material include fullerene derivatives, paraphenylene vinylene derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, phenanthroline derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiols. Pyrandoxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, aromatic tetracarboxylic anhydrides such as naphthalene or perylene, and imides and heterocycles derived therefrom, 8-quinolinol derivatives Examples thereof include metal complexes, various metal complexes represented by metal complexes having benzoxazole or benzothiazole as a ligand, and organic silane derivatives.
Examples of the material for the electron transport layer having charge generation ability include fullerenes, polyparaphenylene vinylene derivatives, and imides and heterocycles derived from perylenetetracarboxylic anhydride. Examples thereof include those described as Electron Transport Materials in Chem. Rev. 2007, 107, 953-1010, and specific examples include the following.

 

 

 

 

 

 

Furthermore, specific examples of the phenanthroline derivative are described in JP-T-2008-522413.

Examples of the method for forming the electron transport layer include a solvent coating method and a vacuum deposition method. Specific examples of the solvent coating method are as described above.

The thickness of the electron transport layer is preferably 1 nm to 500 nm, more preferably 2 nm to 200 nm, and further preferably 5 nm to 100 nm. The electron transport layer may have a single layer structure including one or more of the above-described materials, or may have a multilayer structure including a plurality of layers having the same composition or different compositions.

(6) Mixed organic layer A mixed organic layer containing both a hole transporting material and an electron transporting material can be disposed between the hole transporting layer and the electron transporting layer. This is preferable in terms of improving efficiency. The mixing ratio is adjusted so as to increase the conversion efficiency, but is usually selected from the range of 20:80 to 80:20 in terms of mass ratio (hole transport material: electron transport material).
The details of the hole transport material and the electron transport material are as described above.

As a method for forming such a mixed organic layer, for example, a co-evaporation method by vacuum deposition can be applied. Or it is also possible to produce by carrying out solvent application | coating using the solvent in which both organic materials melt | dissolve. Specific examples of the solvent coating method are as described above.

(7) Recombination layer In the case of the tandem element as described above, a recombination layer is provided to connect a plurality of individual photoelectric conversion layers in series. As the recombination layer, a thin layer of a conductive material can be used. A metal is suitable as the conductive material, and examples of preferable metals include gold, silver, aluminum, platinum, and ruthenium oxide. Of these, silver is preferred.

The film thickness of the recombination layer is usually 0.01 to 5 nm, preferably 0.1 to 1 nm, and particularly preferably 0.2 to 0.6 nm. There is no restriction | limiting in particular about the formation method of a recombination layer, For example, it can form by a vacuum evaporation method, sputtering method, or an ion plating method.

The organic thin film solar cell of the present invention may be annealed by various methods for the purpose of crystallization of the organic layer and promotion of phase separation of the organic mixed layer. Examples of the annealing method include a method of heating the substrate temperature during vapor deposition to 50 ° C. to 150 ° C., a method of setting the drying temperature after coating to 50 ° C. to 150 ° C., and the like. Alternatively, annealing may be performed by heating to 50 ° C. to 150 ° C. after the electrode formation is completed.

(8) Metal Oxide Layer In the organic thin film solar cell of the present invention, a metal oxide layer is disposed between the organic photoelectric conversion layer and the negative electrode as a layer forming the organic power generation laminate.
The metal oxide layer in the present invention is located between the organic photoelectric conversion layer and the negative electrode and has a function of passing electrons generated in the organic photoelectric conversion layer to the negative electrode. Here, the energy level of the conduction band of the metal oxide is lower than the LUMO of the electron transport material in the organic photoelectric conversion layer, and the energy level of the negative electrode is preferably lower than the conduction band of the metal oxide. . As the metal oxide, a conventionally known metal oxide can be used. However, a metal oxide having a conduction band energy level higher than −4.5 eV in terms of excellent conversion efficiency when photoelectrically converted. Further, titanium oxide (conduction band level: -4.2 eV) and zinc oxide (conduction band level: -4.1 eV) are more preferable.
In this invention, since this metal oxide layer is arrange | positioned between an organic photoelectric converting layer and a negative electrode, it was able to prevent the fall of Voc of a cell, As a result, preventing the fall of photoelectric conversion efficiency. Further, it is possible to use a metal that is not easily corroded other than aluminum for the negative electrode, and it is possible to use a noble metal.

The energy level of the conduction band is measured by obtaining the valence band (VB) of the semiconductor using an ultraviolet photoelectron spectrometer (UPS), and separately from the absorption edge of the diffuse reflection ultraviolet-visible absorption spectrum. ), The energy level of the conduction band (CB) can be calculated from the difference.

(9) Protective layer The organic power generation laminate in the present invention may be protected by a protective layer.
The material contained in the protective _{layer, MgO, SiO, SiO 2,} Al 2 O 3, Y 2 O 3, and metal oxides such as TiO _2, metal nitrides such as SiN _x, such as _SiN x _{O y} metal Examples thereof include metal fluorides such as nitride oxide, MgF ₂ , LiF, AlF ₃ , and CaF ₂ , and polymers such as polyethylene, polypropylene, polyvinylidene fluoride, and polyparaxylylene. Of these, metal oxides, nitrides, and nitride oxides are preferable, and silicon, aluminum oxides, nitrides, and nitride oxides are particularly preferable. The protective layer may be a single layer or a multilayer structure.

The method for forming the protective layer is not particularly limited, and for example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency) Excited ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, vacuum ultraviolet CVD method, coating method, printing method, and transfer method can be applied. In the present invention, a protective layer may be used as the conductive layer.

(Gas barrier layer)
The organic thin film solar cell of the present invention includes a gas barrier layer (also referred to as a first gas barrier layer in the present specification) as a barrier layer for providing a gas barrier function. This gas barrier layer can be formed in the same manner as the second gas barrier layer that forms the gas barrier film substrate described above. Specifically, the first gas barrier layer can be suitably formed by providing at least one organic polymer layer and at least one inorganic layer.

Among them, like the second gas barrier layer in the gas barrier film substrate described above, at least two organic polymer layers and at least two inorganic layers are alternately formed as inorganic layer / organic layer / inorganic layer. It is a gas barrier layer which has the laminated structure laminated | stacked on.

(Functional layer)
The organic thin film solar cell of the present invention may have various functional layers on the laminated structure including the gas barrier film substrate / organic power generation laminate / gas barrier layer or at other positions, in addition to the above layers. The functional layer is described in detail in paragraph numbers [0036] to [0038] of JP-A-2006-289627. Examples of functional layers include matting agent layers, protective layers, solvent-resistant layers, antistatic layers, smoothing layers, adhesion improving layers, light shielding layers, antireflection layers, hard coat layers, stress relaxation layers, antifogging layers, Examples thereof include an antifouling layer, a printing layer, and an easy adhesion layer.

The thickness of the organic thin film solar cell of the present invention is preferably 50 μm to 1 mm, and more preferably 100 μm to 500 μm.

The production of the organic thin film solar cell of the present invention can be carried out with reference to the description of “solar power generation, latest technology and system” (written by Yasuhiro Kajikawa, CMC Co., Ltd.) and the like.

Hereinafter, the present invention will be described more specifically with reference to examples. The materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific examples shown below.

<Production of gas barrier film substrate>
-Production of gas barrier film substrate (G-1)-
On a polyethylene naphthalate (PEN) film (manufactured by Teijin DuPont, Teonex Q65FA, thickness 100 μm), 14 parts by mass of the following three polymerizable compounds in total amount and a polymerization initiator (IRGACURE, Ciba Specialty) (Manufactured by Chemicals Co., Ltd.) A composition containing 907 parts by mass and 185 parts by mass of 2-butanone was applied with a wire bar, and cured by irradiation with an ultraviolet ray irradiation amount of 0.5 J / cm ² in an atmosphere of 100 ppm nitrogen. An organic polymer layer was formed. The thickness of the formed organic polymer layer was 400 nm.

<Composition of polymerizable compound>
Compound A: EB-3702 (manufactured by Daicel Cytec Co., Ltd.) ... 60% by mass
Compound B: EB-150 (manufactured by Daicel Cytec Corporation) 35% by mass
Compound C: KAYARAD PM-21 (manufactured by Nippon Kayaku Co., Ltd .; the following compound)
... 5% by mass

 

 

Next, an Al ₂ O ₃ film (inorganic layer) was formed on the surface of the organic polymer layer by depositing Al ₂ O ₃ by vacuum sputtering (reactive sputtering) so as to have a film thickness of 35 nm.
As described above, a gas barrier film substrate (G-1) having a gas barrier layer on a PEN film was produced.

-Production of gas barrier film substrate (G-2)-
On the gas barrier layer on the PEN film of the gas barrier film substrate (G-1), one organic polymer layer and one inorganic layer (Al ₂ O ₃ film) were further formed by the same method as described above.
In this way, a gas barrier film substrate (G-2) in which two organic polymer layers and two inorganic layers were alternately laminated was produced.

-Production of gas barrier film substrate (G-3)-
On the gas barrier layer on the PEN film of the gas barrier film substrate (G-2), one organic polymer layer and one inorganic layer (Al ₂ O ₃ film) were further formed by the same method as described above.
In this way, a gas barrier film substrate (G-3) in which three organic polymer layers and three inorganic layers were alternately laminated was produced.

-Production of gas barrier film substrate (G-4)-
In the production of the gas barrier film substrate (G-3), the gas barrier film substrate (G-3) was prepared in the same manner as in the production of the gas barrier film substrate (G-3) except that the Al ₂ O ₃ film as the inorganic layer was replaced with a SiO ₂ film. A film substrate (G-4) was produced.

-Production of inorganic gas barrier film substrate (GX)-
One inorganic layer (Al ₂ O ₃ film) was formed in the same manner as the gas barrier film substrate (G-1) except that the organic polymer layer was not applied in the production of the gas barrier film substrate (G-1). An inorganic gas barrier film substrate (GX) having only the same was produced.

-Measurement of water vapor transmission rate-
About each of the gas barrier film board | substrate obtained above, barrier performance (water-vapor-permeation rate) was measured and evaluated by the following method.
[Barrier performance]
The water vapor permeability (g / m ² / day) was measured using the method described in G. NISATO, PCPBOUTEN, PJSLIKKERVEER et al. SID Conference Record of the International Display Research Conference, pages 1435-1438 (so-called calcium method). At this time, the temperature was 40 ° C. and the relative humidity was 90%.

 

 

As is clear from Table 1, the gas barrier film substrates (G-1) to (G-4) showed better gas barrier ability than the gas barrier film substrate (GX). In particular, it can be seen that the gas barrier film substrates (G-2) to (G-4) have a water vapor permeation ability of 0.001 or less and show extremely high gas barrier ability.

<Preparation of transparent conductive film>
An ITO film is sputtered on the surface of the inorganic layer (Al ₂ O ₃ film or SiO ₂ film) on the outermost surface of the gas barrier film substrate (G-1 to G-4, GX) so as to have a thickness of 100 nm. A film substrate with a patterned ITO film was obtained.
Hereinafter, this film substrate is referred to as an ITO-attached film substrate (G-1 to G-4 or GX).

In order to form a hole collection layer on each of the obtained film substrates with ITO, an aqueous dispersion of polyethylene dioxythiophene / polystyrene sulfonic acid (abbreviation: PEDOT-PSS) (manufactured by HC Starck Co., Ltd.) Crevius P) was applied.

Next, the coated film substrate is dried by heating at 130 ° C. for 10 minutes to form a conductive polymer layer, a transparent conductive film substrate (T-1 to T-4), and a transparent conductive film having no organic polymer layer. A film substrate (TX) was produced.

-Measurement of surface resistivity-
When the surface resistivity of each conductive polymer layer of these transparent conductive film substrates was measured according to JIS 7194 using a low resistivity meter Lorester GP / ASP probe manufactured by Mitsubishi Chemical Corporation, all of them were 10Ω / It was below sq.

Example 1
Using the transparent conductive film substrate (T-1 to T-4 or TX) obtained above, an organic thin-film solar cell having the configuration shown in FIG. 3 was produced according to the following procedure.

-Production of organic thin-film solar cells (S-1 to S-4, SX)-
First, 200 mg of poly-3-hexylthiophene (P3HT) and 140 mg of [6,6] phenyl-C ₆₁ -methyl butyrate (PCBM) are mixed with 10 ml of chlorobenzene, and shaken on a shaker for 15 hours to completely dissolve. A coating liquid for photoelectric conversion layer was prepared.

Next, 9.6 g of tetraisopropyl orthotitanate was dissolved in 51.8 g of 2-methoxyethanol, and 5.1 g of 2-aminoethanol was added thereto. The resulting mixture was heated at 80 ° C. for 2 hours and then refluxed at 120 ° C. for 1 hour. After allowing to cool, the mixed solution was diluted 10-fold with 2-propanol to prepare a coating solution for a titanium oxide layer.

The transparent conductive film substrates (T-1 to T-4) prepared above and the comparative transparent conductive film substrate (TX) for comparison were thoroughly blown with a nitrogen gun, and then the conductive polymer layer surface of each film substrate was subjected to the above process. A 0.13 ml coating solution for photoelectric conversion layer was dropped using an Eppendorf pipette and rotated at 2000 rpm for 120 seconds to form a photoelectric conversion layer. The film thickness of the photoelectric conversion layer after drying was 90 nm.

Subsequently, 0.20 ml of the above-described coating solution for titanium oxide layer was dropped onto the surface of the photoelectric conversion layer formed on each film substrate using an Eppendorf pipette and rotated at 2000 rpm for 120 seconds. Then, this was heated for 10 minutes at 80 degreeC using the hotplate, and the titanium oxide layer (electron transport layer) was formed as a metal oxide layer. The thickness of the titanium oxide layer after drying was 30 nm, and the energy level of the conductor of the titanium oxide layer was -4.2 eV.

Silver was vapor-deposited on the formed titanium oxide layer (electron transport layer) to a thickness of 100 nm with a vacuum evaporator, and heated at 150 ° C. for 10 minutes using a hot plate to obtain a negative electrode.
In this way, the organic thin film solar cell element substrate (D-1 to D-4) provided with the transparent conductive film substrate (T-1 to T-4) and the transparent conductive film substrate (TX) for comparison. An organic thin film solar cell element substrate (DX) provided with

Next, by using a thermosetting adhesive (Epotec 310 manufactured by Daizonichi Mori Co., Ltd.), the organic thin film solar cell element substrate (D-1 to D-4 or DX) prepared above, and separately from this The prepared gas barrier film substrates (G-1 to G-4 or GX) are arranged and bonded so that the gas barrier layer side of each gas barrier film substrate faces the organic thin-film solar cell element substrate, and at 65 ° C. The adhesive was cured by heating for 3 hours.
In this way, organic thin-film solar cells (S-1 to S-4, SX) sealed using two gas barrier film substrates were produced.
The produced organic thin-film solar cell has an effective area of 2 mm square and an effective area of 0.04 cm ² .

-Fabrication of organic thin film solar cell (S-5)-
In the production of the organic thin film solar cell (S-3), an organic thin film solar cell (S-3) was prepared in the same manner as the organic thin film solar cell (S-3) except that Ag used for forming the negative electrode was replaced with Sn. −5) was produced.

-Fabrication of organic thin film solar cell (S-6)-
In the production of the organic thin film solar cell (S-1), the organic thin film solar cell (S-1) is the same as the organic thin film solar cell (S-1) except that 5 nm of molybdenum oxide is evaporated instead of applying the aqueous dispersion of PEDOT-PSS. Similarly, an organic thin film solar cell (S-6) was produced.

(Comparative Example 1)
In the production of the organic thin film solar cell (S-1) of Example 1, the organic thin film solar cell was the same as the organic thin film solar cell (S-1) except that Al used for forming the negative electrode was replaced with Al. A battery (SA) was produced.

(Comparative Example 2)
In the production of the organic thin film solar cell (S-1) of Example 1, two gas barrier film substrates (G-1) were made of polyethylene naphthalate (PEN) film (Teijin DuPont, Teonex Q65FA, thickness 100 μm). The organic thin film solar cell is the same as the organic thin film solar cell (S-1) except that a transparent conductive PEN film substrate having no gas barrier capability is formed by forming an ITO film having a thickness of 100 nm by sputtering. (SB) was prepared.

(Comparative Example 3)
In the production of the organic thin film solar cell (SB) of Comparative Example 2, an organic thin film solar cell was obtained in the same manner as the organic thin film solar cell (SB), except that Al used for forming the negative electrode was replaced with Al. A battery (SC) was produced.

(Comparative Example 4)
The organic thin film solar cell (S-B) and the organic thin film solar cell (SC) of Comparative Example 3 were manufactured except that the metal oxide layer was not provided in the production of the organic thin film solar cell (SB) of Comparative Example 2. Organic thin film solar cells (SD) and organic thin film solar cells (SE) were produced in the same manner as in B) or (SC).

 

 

(Evaluation)
The following evaluation was performed about each organic thin film solar cell obtained above. The evaluation results are shown in Table 3 below.

-1. Initial photoelectric conversion efficiency
About the organic thin film solar cell immediately after preparation produced above, each organic thin film solar cell is irradiated with simulated sunlight with an air mass of 1.5 and 100 mW / cm ² using an L12 type solar simulator (manufactured by Pexel Technologies). However, the current value was measured in a voltage range from −0.1 V to +0.7 V with a source measure unit (SMU 2400 type, manufactured by KEITHLEY).
The current-voltage characteristics obtained by the measurement were evaluated using an IV curve analyzer (manufactured by Pexel Technologies), and the conversion efficiency was calculated. The calculated conversion efficiency is shown in Table 3 below as the initial photoelectric conversion efficiency of each organic thin film solar cell.
Here, the value of the conversion efficiency of each organic thin film solar cell was expressed as a relative value obtained by normalizing the conversion efficiency of the organic thin film solar cell (S-1) to 1.

-2. Durability-
Each organic thin-film solar cell was allowed to stand in a high-temperature and high-humidity chamber at 65 ° C. and a relative humidity of 90% for 200 hours, and then air mass of 1.5, 100 mW / cm ² as in “1. Initial photoelectric conversion efficiency”. Current-voltage characteristics were measured while irradiating simulated sunlight, and the conversion efficiency maintenance rate [%] relative to the initial photoelectric conversion efficiency before standing was calculated by the following formula.
Conversion efficiency maintenance rate [%] = (conversion efficiency after high temperature and high humidity) / (initial photoelectric conversion efficiency immediately after device fabrication) × 100

 

 

As shown in Table 3, the organic thin film solar cell of the present invention showed a high conversion efficiency maintenance ratio after high-temperature and high-humidity aging with respect to the organic thin-film solar cell of the comparative example, and showed excellent durability performance. In particular, the organic thin film solar cells S-2 to S-4 and S-5 formed by laminating two or more organic polymer layers and inorganic layers were excellent in durability performance.
As described above, it was confirmed that the organic thin film solar cell of the present invention has high durability.

Since the organic thin-film solar cell of the present invention has high temporal stability, it is useful in fields and applications that are expected to be used for a long period of time, particularly in environments with severe temperature and humidity conditions such as outdoors.
The disclosure of Japanese application 2010-136429 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Claims (11)

A gas barrier film substrate;
An organic power generation laminate including at least a positive electrode, an organic photoelectric conversion layer, a metal oxide layer, and a negative electrode including a metal nobler than iron in this order;
A first gas barrier layer;
Organic thin-film solar cell with The organic thin-film solar cell according to claim 1, wherein the energy level of the conduction band of the metal oxide layer is higher than -4.5 eV. The organic thin-film solar cell according to claim 1 or 2, wherein the negative electrode contains a metal or alloy having a smaller ionization tendency than hydrogen. The organic thin film solar cell according to any one of claims 1 to 3, wherein the negative electrode contains at least one of copper, silver, and an alloy containing these. 5. The organic thin film solar cell according to claim 1, wherein the metal oxide of the metal oxide layer contains at least one of titanium oxide and zinc oxide. The gas barrier film substrate includes a first resin film and a second gas barrier layer,
The said 2nd gas barrier layer contains the 1st organic polymer layer provided in contact with the said 1st resin film, and the 1st inorganic layer provided on this 1st organic polymer layer. The organic thin film solar cell according to any one of claims 5 to 6. A second resin film is further provided on the side of the first gas barrier layer where the organic power generation laminate is not disposed;
The first gas barrier layer includes a second organic polymer layer provided in contact with the second resin film and a second inorganic layer provided on the second organic polymer layer. The organic thin film solar cell according to any one of claims 6 to 6. The gas barrier film substrate includes a first resin film and a second gas barrier layer,
The second gas barrier layer is formed by alternately laminating at least two organic polymer layers and at least two inorganic layers so that the organic polymer layers are in contact with the surface of the first resin film. The organic thin film solar cell according to any one of claims 1 to 5. A second resin film is further provided on the side of the first gas barrier layer where the organic power generation laminate is not disposed;
The first gas barrier layer is formed by alternately laminating at least two organic polymer layers and at least two inorganic layers so that the organic polymer layers are in contact with the surface of the second resin film. The organic thin-film solar cell according to any one of claims 1 to 5 and claim 8. 9. The hole collection layer comprising polyethylene dioxythiophene / polystyrene sulfonic acid (PEDOT-PSS) between the positive electrode and the organic photoelectric conversion layer. Organic thin film solar cell. 10. The organic thin-film solar cell according to claim 1, further comprising a hole collection layer containing at least one of molybdenum oxide and vanadium oxide between the positive electrode and the organic photoelectric conversion layer. .

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