WO2011052572A1

WO2011052572A1 - Organic photoelectric conversion element

Info

Publication number: WO2011052572A1
Application number: PCT/JP2010/068946
Authority: WO
Inventors: 岳仁加藤; 大西　敏博
Original assignee: 住友化学株式会社
Priority date: 2009-10-30
Filing date: 2010-10-26
Publication date: 2011-05-05
Also published as: JP5608040B2; JP2011119684A

Abstract

Disclosed is an organic photoelectric conversion element having a long service life. Specifically disclosed is an organic photoelectric conversion element (100) comprising a first electrode (2), a second electrode (6), an active layer (4), and a gettering layer (7). The active layer (4) is provided between the first electrode (2) and the second electrode (6) and can generate an electrical charge upon the incidence of light. The gettering layer (7) is in contact with a surface (6U) of the second electrode (6) which is opposed to the first electrode (2) and can adsorb oxygen and water.

Description

Organic photoelectric conversion element

The present invention relates to an organic photoelectric conversion element.

The photoelectric conversion element is an element that can convert light energy into electric energy, and a solar cell is an example. A silicon solar cell is known as a typical solar cell. However, since the silicon solar cell prepares a high vacuum environment and a high pressure environment in the manufacturing process, the manufacturing cost is high. For this reason, the organic solar cell whose manufacturing cost is cheap compared with a silicon-type solar cell attracts attention.

However, since the organic solar cell uses an organic material, the organic material is easily deteriorated by oxygen, water, and the like, and the lifetime tends to be shorter than that of the silicon-based solar cell. Therefore, various technical developments have been made in order to extend the life of organic solar cells. For example, Patent Document 1 describes a configuration in which a getter agent made of a desiccant is provided in an organic photoelectric conversion element.

JP 2007-317565 A

If the organic photoelectric conversion element is provided with a getter agent made of a desiccant, the water in the organic photoelectric conversion element can be adsorbed by the getter agent, so that deterioration of the organic material in the organic photoelectric conversion element due to water is suppressed. The life of the organic photoelectric conversion element can be extended. However, the technique described in Patent Document 1 does not provide a long lifetime, and a technique for further extending the lifetime of the organic photoelectric conversion element has been desired.
The present invention has been made in view of the above problems, and provides a long-life organic photoelectric conversion element.

As a result of intensive studies in order to solve the above-mentioned problems, the present inventor has found that one of the major causes of the deterioration of the organic photoelectric conversion element is the deterioration of the electrode, and that oxygen and water are in direct contact with the electrode. It has been found that the electrode can be effectively prevented from being deteriorated by providing a getter layer capable of adsorbing and thus the present invention has been completed.

That is, the present invention is as follows.
[1] An organic photoelectric conversion element comprising a first electrode, a second electrode, an active layer, and a getter layer,
The active layer is a layer that is provided between the first electrode and the second electrode, and is capable of generating an electric charge upon incidence of light,
The getter layer is an organic photoelectric conversion element which is in contact with the surface of the second electrode opposite to the first electrode and can adsorb oxygen and water.
[2] The organic photoelectric conversion element according to [1], wherein the active layer includes a p-type semiconductor and an n-type semiconductor.
[3] The organic photoelectric conversion element according to [1] or [2], wherein the getter layer contains an alkoxide.
[4] The organic photoelectric conversion device according to [3], wherein the alkoxide is an alkoxide selected from the group consisting of aluminum-s-butoxide and titanium isopropoxide.
[5] The organic photoelectric conversion element according to [3] or [4], wherein the getter layer is formed through a step of applying a solution containing an alkoxide and an organic solvent.

FIG. 1 is a schematic cross-sectional view of an organic photoelectric conversion element according to an embodiment of the present invention.

DESCRIPTION OF SYMBOLS 1 Substrate 2 First electrode 3 Functional layer 4 Active layer 5 Functional layer 6 Second electrode 6U Upper surface of second electrode (surface opposite to first electrode 2)
7 Getter layer 8 Protective layer 9 Substrate 100 Organic photoelectric conversion element

Hereinafter, the present invention will be described in detail with reference to embodiments and examples, but the present invention is not limited to the embodiments and examples shown below, and may be arbitrarily changed without departing from the gist of the present invention. Can be implemented.

[1. Overview]
The organic photoelectric conversion element of the present invention includes a first electrode, a second electrode, an active layer, and a getter layer. The active layer is a layer that is provided between the first electrode and the second electrode and can generate an electric charge upon incidence of light. The getter layer is in contact with the surface of the second electrode opposite to the first electrode, and is a layer that can adsorb oxygen and water. Therefore, the arrangement order of the layers is the order of the first electrode, the active layer, the second electrode, and the getter layer. The getter layer adsorbs oxygen and water that have passed through the substrate, protective layer, sealing material layer, etc. and entered the organic photoelectric conversion element, or is organic in the active layer or the like constituting the organic photoelectric conversion element. Since residual oxygen and residual moisture mixed in the manufacturing process of the photoelectric conversion element can be adsorbed, it is possible to prevent the material in the organic photoelectric conversion element from being deteriorated by oxygen and water.
Furthermore, in the organic photoelectric conversion element of the present invention, since the getter layer is provided in contact with the second electrode, the distance from the first electrode and the second electrode to the getter layer is very short. Therefore, it is possible to effectively prevent electrode deterioration (particularly oxidation), which is a major cause of deterioration of the organic photoelectric conversion element. Oxidation of the electrode is often the biggest cause of deterioration of the organic photoelectric conversion element. However, the organic photoelectric conversion element of the present invention can effectively prevent oxidation of the electrode, so that the life can be extended more than before. It has become.

Moreover, the organic photoelectric conversion element of this invention may be provided with layers other than a 1st electrode, an active layer, a 2nd electrode, and a getter layer. Usually, the organic photoelectric conversion element of this invention is equipped with the protective layer which covers the surface of an organic photoelectric conversion element. For example, the organic photoelectric conversion element of the present invention may include a functional layer between the first electrode and the active layer, and may include a functional layer between the active layer and the second electrode. Also good.
Furthermore, the organic photoelectric conversion element of the present invention usually comprises a substrate, and each layer constituting the organic photoelectric conversion element of the present invention on the substrate (for example, a first electrode, an active layer, a second electrode, a getter layer, a protective layer) A layer and a functional layer).

[2. substrate]
A board | substrate is a member which functions as a support body of the organic photoelectric conversion element of this invention. As the substrate, a member that does not change chemically is usually used when an electrode is formed or an organic material layer is formed. Examples of the material for the substrate include glass, plastic, polymer film, and silicon. In addition, the material of a board | substrate may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
Usually, a transparent or translucent member is used as the substrate, but an opaque substrate can also be used. However, when an opaque substrate is used, the electrode opposite to the substrate (that is, the electrode farther from the opaque substrate among the first electrode and the second electrode) is transparent or translucent. It is preferable.

[3. First electrode and second electrode]
One of the first electrode and the second electrode is an anode, and the other is a cathode. In order for light to easily enter the active layer located between the first electrode and the second electrode, at least one of the first electrode and the second electrode is preferably transparent or translucent.

Examples of the transparent or translucent electrode include a conductive metal oxide film and a translucent metal thin film. Examples of the material of the transparent or translucent electrode include indium oxide, zinc oxide, tin oxide, and indium tin oxide (ITO), indium zinc oxide (IZO), NESA which are composites thereof. Examples thereof include a film manufactured using a conductive material such as gold, platinum, silver, and copper. Of these, ITO, indium / zinc / oxide, and tin oxide are preferable.
It is also possible to use an organic material as the material of the transparent or translucent electrode. Examples of organic materials that can be used as an electrode material include conductive polymers such as polyaniline and derivatives thereof, polythiophene and derivatives thereof.

Examples of the material for the opaque electrode include metals and conductive polymers. Specific examples include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and the like, Of the metals, two or more kinds of alloys, one or more kinds of the metals, and one or more kinds of metals selected from the group consisting of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, and tin Examples include alloys, graphite, graphite intercalation compounds, polyaniline and its derivatives, polythiophene and its derivatives. Specific examples of the alloy include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, calcium-aluminum alloy, etc. Is mentioned.
In addition, the material of an electrode may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The thicknesses of the first electrode and the second electrode are different depending on the type of electrode material, but are preferably 500 nm or less from the viewpoint of improving the light transmittance and reducing the electric resistance. Preferably it is 200 nm or less. In addition, although there is no restriction | limiting in a lower limit, Usually, it is 10 nm or more.

Examples of the method for forming the first electrode and the second electrode include a vacuum deposition method, a sputtering method, an ion plating method, a plating method, and the like. Further, when the first electrode and the second electrode are formed of, for example, a conductive polymer, they may be formed by a coating method.

[4. Active layer]
The active layer is a layer that can generate an electric charge upon incidence of light, and usually includes a p-type semiconductor that is an electron-donating compound and an n-type semiconductor that is an electron-accepting compound. The organic photoelectric conversion element of the present invention is referred to as an “organic” photoelectric conversion element because an organic compound is used as at least one of the p-type semiconductor and the n-type semiconductor, usually both. Note that the p-type semiconductor and the n-type semiconductor are relatively determined from the energy level of the energy level of the semiconductor.

It is considered that charges are generated in the active layer in the following manner. When light energy incident on the active layer is absorbed by one or both of the n-type semiconductor and the p-type semiconductor, excitons in which electrons and holes are combined are generated. When the generated excitons move and reach the heterojunction interface where the n-type semiconductor and the p-type semiconductor are adjacent, the respective HOMO (highest occupied orbit) energy and LUMO (lowest empty orbit) at the heterojunction interface. ) Electrons and holes are separated due to the difference in energy, and charges (electrons and holes) that can move independently are generated. The generated charges can be taken out as electric energy (current) to the outside of the organic photoelectric conversion element of the present invention by moving to the respective electrodes.

As long as it is a layer that can generate an electric charge upon incidence of light, the active layer may be a single-layered layer composed of only one layer or a layered structure including two or more layers. Examples of the layer structure of the active layer include the following examples. However, the layer configuration of the active layer is not limited to the following examples.
Layer structure (i) An active layer having a laminated structure including a layer containing a p-type semiconductor and a layer containing an n-type semiconductor.
Layer structure (ii) An active layer having a single-layer structure containing a p-type semiconductor and an n-type semiconductor.
Layer structure (iii) An active layer having a laminated structure including a layer containing a p-type semiconductor, a layer containing a p-type semiconductor and an n-type semiconductor, and a layer containing an n-type semiconductor.

Examples of p-type semiconductors include pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, oligothiophene and derivatives thereof, polyvinylcarbazole and derivatives thereof, polysilane and derivatives thereof, and aromatic amines in side chains or main chains. And polysiloxane derivatives, polyaniline and derivatives thereof, polythiophene and derivatives thereof, polypyrrole and derivatives thereof, polyphenylene vinylene and derivatives thereof, and polythienylene vinylene and derivatives thereof.

Furthermore, examples of suitable p-type semiconductors include organic polymer compounds having a structural unit represented by the following structural formula (1).

As the organic polymer compound, a copolymer of a compound having a structural unit represented by the structural formula (1) and a compound represented by the following structural formula (2) is more preferable.

[In the formula (2), Ar ¹ and Ar ² are the same or different and each represents a trivalent heterocyclic group. X ¹ represents —O—, —S—, —C (═O) —, —S (═O) —, —SO ₂ —, —Si (R ³ ) (R ⁴ ) —, —N (R ⁵ )-, -B (R ⁶ )-, -P (R ⁷ )-or -P (= O) (R ⁸ )-. R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are the same or different and are a hydrogen atom, a halogen atom, an alkyl group, an alkyloxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, Arylalkyl group, arylalkyloxy group, arylalkylthio group, acyl group, acyloxy group, amide group, acid imide group, amino group, substituted amino group, substituted silyl group, substituted silyloxy group, substituted silylthio group, substituted silylamino group, 1 A valent heterocyclic group, heterocyclic oxy group, heterocyclic thio group, arylalkenyl group, arylalkynyl group, carboxyl group or cyano group is represented. R ⁵⁰ is a hydrogen atom, halogen atom, alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group, arylalkyl group, arylalkyloxy group, arylalkylthio group, acyl group, acyloxy group, amide Group, acid imide group, amino group, substituted amino group, substituted silyl group, substituted silyloxy group, substituted silylthio group, substituted silylamino group, monovalent heterocyclic group, heterocyclic oxy group, heterocyclic thio group, arylalkenyl group, An arylalkynyl group, a carboxyl group or a cyano group is represented. R ⁵¹ is an alkyl group having 6 or more carbon atoms, an alkyloxy group having 6 or more carbon atoms, an alkylthio group having 6 or more carbon atoms, an aryl group having 6 or more carbon atoms, an aryloxy group having 6 or more carbon atoms, or 6 or more carbon atoms. An arylthio group having 7 or more carbon atoms, an arylalkyloxy group having 7 or more carbon atoms, an arylalkylthio group having 7 or more carbon atoms, an acyl group having 6 or more carbon atoms, or an acyloxy group having 6 or more carbon atoms. X ¹ and Ar ² are bonded to the adjacent position of the heterocyclic ring contained in Ar ¹ , and C (R ⁵⁰ ) (R ⁵¹ ) and Ar ¹ are bonded to the adjacent position of the heterocyclic ring contained in Ar ² . . ]

Note that one type of p-type semiconductor may be used, or two or more types may be used in combination at any ratio.

Examples of the n-type semiconductor include oxadiazole derivatives, anthraquinodimethane and its derivatives, benzoquinone and its derivatives, naphthoquinone and its derivatives, anthraquinone and its derivatives, tetracyanoanthraquinodimethane and its derivatives, fluorenone derivatives, diphenyl dicyanoethylene and derivatives thereof, diphenoquinone derivatives, 8-hydroxyquinoline and metal complexes of derivatives thereof, polyquinoline and derivatives thereof, polyquinoxaline and derivatives thereof, polyfluorene and derivatives thereof, fullerenes and derivatives thereof such as C _60, such as bathocuproine Examples thereof include phenanthrene derivatives, metal oxides such as titanium dioxide, and carbon nanotubes. Among these, titanium dioxide, carbon nanotubes, fullerenes and fullerene derivatives are preferable, and fullerenes and fullerene derivatives are particularly preferable.

Examples of _{fullerene, C 60} _{fullerene, C 70} _{fullerene, C 76} _{fullerene, C 78} _fullerene, such as _{C 84} fullerene, and the like.
Examples of fullerene derivatives include derivatives such as C ₆₀ , C ₇₀ , C ₇₆ , C _78, and C ₈₄ . Specific examples of the fullerene derivative include compounds having the following structures.

Further, examples of another fullerene derivative [6,6] phenyl _{-C 61} butyric acid methyl ester _{(C60PCBM, [6,6] -Phenyl C} 61 butyric acid methyl ester), [6,6] phenyl _{-C 71} Butyric acid methyl ester (C70PCBM, [6,6] -Phenyl C ₇₁ butyric acid methyl ester), [6,6] Phenyl-C ₈₅ butyric acid methyl ester (C84PCBM, [6,6] -Phenyl C ₈₅ butyric acid methyl ester) , and the like [6,6] thienyl _{-C 61} butyric acid methyl ester _{([6,6] -Thienyl C 61 butyric} acid methyl ester).
Note that one type of n-type semiconductor may be used, or two or more types may be used in combination at any ratio.

The amount ratio of the p-type semiconductor and the n-type semiconductor in the active layer is arbitrary as long as the effect of the present invention is not impaired. For example, in the layer containing both the p-type semiconductor and the n-type semiconductor in the layer configurations (i) and (iii), the amount of the n-type semiconductor with respect to 100 parts by weight of the p-type semiconductor is preferably 10 parts by weight or more. More preferably, it is 20 parts by weight or more, preferably 1000 parts by weight or less, more preferably 500 parts by weight or less.

The thickness of the active layer is usually 1 nm or more, preferably 2 nm or more, more preferably 5 nm or more, particularly preferably 20 nm or more, and usually 100 μm or less, preferably 1000 nm or less, more preferably 500 nm or less, particularly preferably 200 nm or less. is there.

There is no limitation on the formation method of the active layer, and for example, a film deposition method from a liquid composition containing a material of the active layer (for example, one or both of a p-type semiconductor and an n-type semiconductor), a physical vapor deposition method such as a vacuum deposition method Examples thereof include a film formation method by a vapor deposition method such as (PVD method) and chemical vapor deposition (CVD method). Among these, a film forming method from a liquid composition is preferable because formation is easy and cost can be reduced.

In the film-forming method from a liquid composition, an active layer is formed by preparing a liquid composition and depositing the liquid composition at a desired position.
The liquid composition usually contains an active layer material and a solvent. When the solvent is included, the liquid composition may be a dispersion in which the material of the active layer is dispersed in the solvent, but is preferably a solution in which the material of the active layer is dissolved in the solvent. Therefore, it is preferable to use a solvent that can dissolve the material of the active layer. Examples of solvents include toluene, xylene, mesitylene, tetralin, decalin, bicyclohexyl, unsaturated hydrocarbon solvents such as n-butylbenzene, sec-butylbenzene, tert-butylbenzene, carbon tetrachloride, chloroform, dichloromethane , Halogenated saturated hydrocarbon solvents such as dichloroethane, chlorobutane, bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane, bromocyclohexane, and halogenated unsaturated hydrocarbons such as chlorobenzene, dichlorobenzene, and trichlorobenzene Examples of the solvent include ether solvents such as tetrahydrofuran and tetrahydropyran. In addition, a solvent may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.

The concentration of each of the p-type semiconductor and the n-type semiconductor in the liquid composition is usually 0.1% by weight or more based on the solvent.

Examples of the liquid composition film forming method include spin coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, and screen. Examples of the printing method include gravure printing method, flexographic printing method, offset printing method, inkjet printing method, dispenser printing method, nozzle coating method, capillary coating method and the like. Of these, spin coating, flexographic printing, gravure printing, ink jet printing, and dispenser printing are preferred.

After film formation of the liquid composition, an active layer is obtained by performing a process such as removing the solvent from the formed film by drying as necessary.
In addition, when the active layer has a laminated structure of two or more layers, the respective layers constituting the active layer may be sequentially laminated by, for example, the method described above.

[5. Getter layer]
The getter layer is a layer that can adsorb oxygen and water. The getter layer adsorbs oxygen and water to reduce the amount of oxygen and water present in the organic photoelectric conversion element of the present invention, and the materials in the organic photoelectric conversion element of the present invention are deteriorated by oxygen and water. Can be prevented. Furthermore, in the organic photoelectric conversion element of the present invention, the getter layer is in contact with at least a part, preferably the whole, of the surface of the second electrode opposite to the first electrode. Therefore, since the getter layer is close to the electrode, it is possible to effectively prevent the oxidation of the electrode. Particularly, since the getter layer is in contact with the second electrode, the oxidation of the second electrode can be strongly prevented. Oxidation of the electrode is considered to be one of the main causes of deterioration of the organic photoelectric conversion element. Therefore, by effectively preventing the oxidation of the electrode, the organic photoelectric conversion element of the present invention has a longer photoelectric conversion efficiency than before. It becomes a long-life organic photoelectric conversion element capable of maintaining the above.

In order to realize the function of adsorbing oxygen and water, the getter layer includes a getter agent that is a material capable of adsorbing oxygen and water. Examples of the getter agent include alkoxides such as aluminum-S-butoxide, sodium methoxide, sodium ethoxide, potassium t-butoxide, potassium t-butoxide, and the like. Among them, the alkoxide is capable of forming a getter layer by a coating method, has high affinity with the second electrode, can effectively prevent oxidation of the second electrode, and has high stability of the getter agent itself. Is preferred. Among the alkoxides, alkoxides selected from the group consisting of aluminum-s-butoxide and titanium isopropoxide are particularly preferable because they are particularly excellent in water absorption.
In addition, a getter agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The getter layer may contain other components in addition to the getter agent as long as the effects of the present invention are not significantly impaired. When the example of another component is given, the binder for hold | maintaining a getter agent will be mentioned. Examples of the binder include a resin, and specific examples thereof include polyethylene trifluoride, poly (trifluoroethylene chloride) (PCTFE), polyimide, polycarbonate, polyethylene terephthalate, alicyclic polyolefin, and ethylene-vinyl alcohol copolymer. Etc.
Moreover, as other components, additives, such as a filler and antioxidant, are also mentioned, for example.
In addition, the other component may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
However, the proportion of the getter agent in the getter layer is preferably 80% by volume or more and 100% by volume or less, more preferably 90% by volume or more and 100% by volume or less, particularly preferably from the viewpoint of effectively adsorbing oxygen and water. It is 95 volume% or more and 100 volume% or less.

The thickness of the getter layer is usually 5 μm or more, preferably 10 μm or more, more preferably 100 μm or more, and usually 500 μm or less, preferably 300 μm or less. If the getter layer is too thin, oxygen and water may not be sufficiently adsorbed, and if it is too thick, the organic photoelectric conversion element may be excessively thick.

The getter layer can be formed by any method depending on the type of getter agent. For example, the getter layer material (getter agent or the like) is formed by a vapor deposition method such as a physical vapor deposition method (PVD method) such as a sputtering method or a vacuum vapor deposition method and a chemical vapor deposition method (CVD method). do it. However, since the getter layer can be easily formed and the cost can be reduced, the getter layer is preferably formed by a coating method. In particular, a coating method is suitable when an alkoxide is used as a getter agent. Hereinafter, a method for forming a getter layer by a coating method when an alkoxide is used as a getter agent will be described.

When an alkoxide is used as a getter agent, the getter layer is preferably formed through a step of preparing a getter layer forming solution containing an alkoxide and an organic solvent and applying the getter layer forming solution.

Examples of the organic solvent contained in the solution for forming the getter layer include the same solvents as those contained in the liquid composition for forming the active layer. In addition, an organic solvent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. In addition, when the getter layer contains a component other than the alkoxide, the component is usually included in the solution for forming the getter layer.

The amount of the organic solvent in the solution for forming the getter layer is usually 1000 parts by weight or more, preferably 5000 parts by weight or more, more preferably 10,000 parts by weight or more, and usually 20000 parts by weight with respect to 100 parts by weight of the alkoxide as the getter agent. It is 1 part by weight or less, preferably 15000 parts by weight or less, more preferably 12000 parts by weight or less.

After preparing a solution for forming a getter layer, the solution is applied to a predetermined position where a getter layer is to be formed. In the organic photoelectric conversion element of the present invention, since the getter layer is in contact with the second electrode, a solution for forming a getter layer is usually applied on the second electrode. Examples of the application method of the solution for forming the getter layer include the same application method as the application method of the liquid composition for forming the active layer.

A film containing an alkoxide as a getter agent is formed by applying a solution for forming a getter layer. Therefore, after application of the solution for forming the getter layer, a getter layer containing an alkoxide can be obtained by performing a process such as drying the formed film and removing the organic solvent, if necessary.

[6. Protective layer]
The organic photoelectric conversion element of the present invention usually includes a protective layer. A protective layer is a layer which protects the organic photoelectric conversion element of this invention from oxygen, water, etc., for example, hits a layer called a gas barrier layer, a gas barrier property film, etc. Usually, a protective layer is provided so as to cover the first electrode, the second electrode, the active layer, and the getter layer. Therefore, usually, the first electrode, the second electrode, the active layer, and the getter layer are located in a space surrounded by the protective layer and the substrate.

The protective layer is preferably formed of a material having a property of blocking water vapor (water vapor barrier property) or a property of blocking oxygen (oxygen barrier property). Examples of suitable materials for the protective layer include trifluorinated polyethylene, polytrifluoroethylene chloride (PCTFE), polyimide, polycarbonate, polyethylene terephthalate, alicyclic polyolefin, and ethylene-vinyl alcohol copolymer. Examples thereof include organic materials such as resins, inorganic materials such as silicon oxide, silicon nitride, aluminum oxide, and diamond-like carbon. In addition, the material of a protective layer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

An additive may be included in the protective layer as necessary. When the example of a preferable additive is given, the said getter agent will be mentioned. When the protective layer contains a getter agent, the protective layer itself can function in the same manner as the getter layer, so that the amount of oxygen and water that enter the organic light source conversion element of the present invention can be further reduced. Thereby, it can prevent more effectively that the material in the organic photoelectric conversion element of this invention deteriorates with oxygen and water, and can implement | achieve the lifetime improvement of an organic photoelectric conversion element further.
In addition, the additive contained in a protective layer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The amount of the getter agent in the protective layer is usually 3% by volume or more, preferably 5% by volume or more, more preferably 10% by volume or more, and usually 50% by volume or less, preferably 30% by volume or less, more preferably 25%. % By volume or less. If the amount of the getter agent is too small, the effect of the getter agent may not be sufficiently exhibited, and if it is too large, oxygen and water may not be sufficiently blocked.

The thickness of the protective layer depends on the type of material of the protective layer, but is usually 5 μm or more, preferably 10 μm or more, and usually 300 μm or less, preferably 100 μm or less, from the viewpoint of protection performance by the protective layer and production cost. is there.
In the protective layer, the active layer may be a single-layer structure including only one layer, or may be a layered structure including two or more layers.

The protective layer can be formed by an arbitrary method depending on the type of material of the protective layer, and examples thereof include a vapor deposition method. Further, for example, the protective layer may be formed by applying a liquid composition containing a material for the protective layer by a coating method such as a spin coating method, a dip method, or a spray method. Furthermore, for example, a film-shaped molded product formed in advance may be formed by sticking with an adhesive or the like.

[7. Functional layer]
The organic photoelectric conversion element of the present invention may include a functional layer between the first electrode and the active layer and between the second electrode and the active layer. The functional layer is a layer that can transport the charge generated in the active layer to the electrode, and the functional layer between the first electrode and the active layer can transport the charge generated in the active layer to the first electrode. A functional layer between the second electrode and the active layer can transport charges generated in the active layer to the second electrode. The functional layer may be provided on one or both of the first electrode and the active layer and between the second electrode and the active layer.

The functional layer provided between the active layer and the anode can transport holes generated in the active layer to the anode, and is sometimes called a hole transport layer or an electron blocking layer. On the other hand, the functional layer provided between the active layer and the cathode can transport electrons generated in the active layer to the cathode, and is sometimes referred to as an electron transport layer or a hole blocking layer. By providing the functional layer, the effective photoelectric conversion element of the present invention can increase the efficiency of extracting holes generated in the active layer at the anode, increase the efficiency of extracting electrons generated in the active layer at the cathode, It is possible to prevent holes generated in the layer from moving to the cathode and to prevent electrons generated in the active layer from moving to the anode, and to improve photoelectric conversion efficiency.

The material of the functional layer may be any material that has the ability to transport charges generated in the active layer. In particular, the functional layer between the active layer and the anode preferably contains a material that has the ability to transport holes and can prevent electrons from moving to the functional layer. The functional layer between the active layer and the cathode preferably contains a material that has the ability to transport electrons and can prevent holes from moving to the functional layer.

Examples of functional layer materials include alkali metal or alkaline earth metal halides and oxides such as lithium fluoride, inorganic semiconductors such as titanium dioxide, bathocuproine, bathophenanthroline and derivatives thereof, triazole compounds, tris ( 8-hydroxyquinolinate) aluminum complex, bis (4-methyl-8-quinolinato) aluminum complex, oxadiazole compound, distyrylarylene derivative, silole compound, 2,2 ′, 2 ″-(1,3,5 -Benzenetolyl) tris- [1-phenyl-1H-benzimidazole] (TPBI) phthalocyanine derivative, naphthalocyanine derivative, porphyrin derivative, N, N'-bis (3-methylphenyl)-(1,1'-biphenyl) -4,4'-diamine (TPD), 4,4'-bi Aromatic diamine compounds such as [N- (naphthyl) -N-phenyl-amino] biphenyl (α-NPD), oxazole, oxadiazole, triazole, imidazole, imidazolone, stilbene derivative, pyrazoline derivative, tetrahydroimidazole, polyarylalkane , Butadiene, 4,4 ′, 4 ″ -tris (N- (3-methylphenyl) N-phenylamino) triphenylamine (m-MTDATA), polyvinylcarbazole, polysilane, poly-3,4-ethylenedioxide thiophene (PEDOT). In addition, the said material may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The functional layer may contain other components in addition to the materials described above as long as the effects of the present invention are not significantly impaired.
In addition, the other component may be used individually by 1 type, and may use 2 or more types together by arbitrary ratios.

The thickness of the functional layer is usually 0.01 nm or more, preferably 0.1 nm or more, more preferably 1 nm or more, and usually 1000 nm or less, preferably 500 nm or less, more preferably 100 nm or less. If the functional layer is too thin, the function of the functional layer described above may not be sufficiently exhibited, and if it is too thick, the organic photoelectric conversion element may be excessively thick.

The functional layer may be formed by, for example, a vapor deposition method, but is easy to form and can be manufactured at a low cost. Therefore, the functional layer is formed through a step of applying a liquid composition containing the functional layer material to a predetermined position. It is preferable. Hereinafter, the method for forming the functional layer from the liquid composition will be described.

The liquid composition for forming the functional layer usually contains a functional layer material and a solvent. When the solvent is included, the liquid composition may be a dispersion in which the functional layer material is dispersed in the solvent, or may be a solution in which the functional layer material is dissolved in the solvent.

Examples of the solvent contained in the liquid composition for forming a functional layer include the same solvents as those contained in the liquid composition for forming an active layer. In addition, a solvent may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
The amount of the solvent in the liquid composition is usually 100 parts by weight or more, preferably 1000 parts by weight or more, more preferably 10,000 parts by weight or more, and usually 1000000 parts by weight or less, preferably 100 parts by weight of the functional layer material. Is less than 100,000 parts by weight.

After preparing the liquid composition for forming the functional layer, the liquid composition is applied to a predetermined position where the functional layer is to be formed. Usually, the liquid composition is applied onto a layer (usually a first electrode, a second electrode, or an active layer) that comes into contact with the functional layer in the organic photoelectric conversion device of the present invention. As an example of the coating method of a liquid composition, the coating method similar to the coating method of the liquid composition for active layer formation is mentioned.

The film containing the functional layer material is formed by applying the liquid composition for forming the functional layer. Therefore, after applying the liquid composition, the functional layer can be obtained by performing a process such as drying the formed film and removing the solvent, if necessary.

[8. Other layers]
The organic photoelectric conversion device of the present invention includes layers other than the substrate, the first electrode, the second electrode, the active layer, the getter layer, the protective layer, and the functional layer, as long as the effects of the present invention are not significantly impaired. May be.
For example, the photoelectric conversion element of the present invention may include a sealing material layer. A sealing material layer is a layer which protects the organic photoelectric conversion element of this invention from external air, dust, etc. Usually, the sealing material layer is formed as a sealing material layer covering the first electrode, the second electrode, the active layer, the getter layer, the protective layer, and the functional layer. Therefore, usually, the first electrode, the second electrode, the active layer, the getter layer, the protective layer, and the functional layer are located in the space formed by the sealant layer and the substrate.

As the sealing material, an inorganic sealing material or an organic sealing material may be used. Examples of inorganic sealing materials include silicon compounds such as silicon oxide, silicon nitride, silicon oxynitride and silicon carbide, aluminum compounds such as aluminum oxide, aluminum nitride and aluminum silicate, zirconium oxide, tantalum oxide and titanium oxide. And metal oxides such as titanium nitride, diamond-like carbon, and the like. Examples of the organic sealing material include a photocurable resin and a thermosetting resin, and preferable examples include a silicone resin, an epoxy resin, a fluorine resin, and a wax.
In addition, a sealing material may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The thickness of the sealing material layer depends on the type of the sealing material, but is usually 1 μm or more, preferably 10 μm or more, and usually 100 μm or less from the viewpoints of the protection performance by the sealing material layer and the manufacturing cost.
As a method for forming the sealing material layer, for example, in the case of a sealing material layer using an inorganic sealing material, a vapor-phase film-forming method may be mentioned. For example, in the case of a sealing material layer using an organic sealing material, spin Examples thereof include a coating method, a dip method, a coating method such as a spray method, and a method of attaching a previously formed film-like molded product.

Incidentally, an additive may be included in the sealing material layer as necessary. Examples of preferred additives include getter agents, wavelength conversion agents, and ultraviolet absorbers. In addition, an additive may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.

[9. Embodiment]
Hereinafter, preferred embodiments of the organic photoelectric conversion element of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an organic photoelectric conversion device according to an embodiment of the present invention. In the following embodiments, a state in which the substrate of the organic photoelectric conversion element is placed horizontally will be described.

An organic photoelectric conversion element 100 shown in FIG. 1 includes a first electrode 2 that functions as an anode, a functional layer 3 that functions as a hole transport layer, and an active layer 4 that can generate an electric charge upon incidence of visible light. A functional layer 5 functioning as an electron transporting layer, a second electrode 6 functioning as a cathode, and a getter layer 7 capable of adsorbing oxygen and water. A terminal (not shown) is connected to the first electrode 2 and the second electrode 6 so that electricity can be taken out to the outside. The first electrode 2, the functional layer 3, the active layer 4, the functional layer 5, the second electrode 6 and the getter layer 7 are sealed by covering portions other than the terminals with the protective layer 8. A substrate 9 is provided on the protective layer 8. Therefore, the organic photoelectric conversion element 100 is provided between the first electrode 2 and the second electrode 6 via the first electrode 2, the second electrode 6, and the functional layer 3 and the functional layer 5. An active layer 4 and a getter layer 7 are provided. In addition, the getter layer 7 is in contact with the entire surface of the upper surface (surface opposite to the first electrode 2) 6U of the second electrode 6.

Since the organic photoelectric conversion element 100 is configured as described above, when irradiated with light, the irradiated light enters the active layer 4 and charges are generated in the active layer 4. As for the electric charges generated in the active layer 4, holes are transported from the functional layer 3 to the first electrode 2, and electrons are transported from the functional layer 5 to the second electrode 6, and are taken out through the terminals.
In addition, since the organic photoelectric conversion element 100 includes the protective layer 8, it is difficult for oxygen and water to enter the space surrounded by the substrate 1 and the protective layer 8. Further, even if oxygen and moisture penetrate through the protective layer 8 and enter the space, the penetrated oxygen and moisture can be adsorbed by the getter layer 7. Further, even if oxygen and moisture remaining in the device during the manufacturing process of the organic photoelectric conversion device 100 exist, the remaining oxygen and moisture can be adsorbed by the getter layer 7.

Therefore, according to the organic photoelectric conversion element 100 of the present embodiment, the first electrode 2, the functional layer 3, the active layer 4, the functional layer 5, and the second electrode 6 can be hardly deteriorated by oxygen and moisture. In particular, since the second electrode 6 is in direct contact with the getter layer 7, deterioration (particularly oxidation) of the second electrode 6 due to oxygen and water can be effectively prevented. For this reason, the organic photoelectric conversion element 100 is a long-life organic photoelectric conversion element that can maintain photoelectric conversion efficiency over a long period of time as compared with a conventional organic photoelectric conversion element.
In addition, in the organic photoelectric conversion element 100 according to the present embodiment, the example in which the far side to the getter layer 7 is an anode and the near side is a cathode is shown. Conversely, the far side to the getter layer 7 is a cathode and the near side is an anode. The same effect can be obtained.

[10. Applications of organic photoelectric conversion elements]
A photovoltaic force is generated between the electrodes of the organic photoelectric conversion element of the present invention by irradiation with light such as sunlight in the manner described above. The organic photoelectric conversion element of this invention can be used as a solar cell, for example using the said photovoltaic power. When used as a solar battery, the organic photoelectric conversion element of the present invention is usually used as a solar battery cell of an organic thin film solar battery. Further, a plurality of solar cells may be integrated into a solar cell module (organic thin film solar cell module) and used in the form of a solar cell module. Since the organic photoelectric conversion element of the present invention has a long lifetime as described above, a solar cell including the organic photoelectric conversion element of the present invention can be expected to have a long lifetime.

Also, the organic photoelectric conversion element of the present invention can be used as an organic photosensor. For example, when light is applied to the organic photoelectric conversion element of the present invention with voltage applied between the electrodes or without application, charges are generated. Therefore, if the charges are detected as photocurrents, The organic photoelectric conversion element can be operated as an organic light sensor. Furthermore, it can also be used as an organic image sensor by integrating a plurality of organic optical sensors.

[11. Solar cell module]
When the solar cell module is configured using the organic photoelectric conversion element of the present invention as a solar cell, the solar cell module can basically have the same module structure as a conventional solar cell module. A solar cell module generally has a configuration in which solar cells are provided on a support substrate such as metal or ceramic, and the solar cell is covered with a filling resin, protective glass, or the like. Light can be captured through the opposite surface. In addition, the solar cell module has a configuration in which a transparent material such as tempered glass is used as a support substrate and solar cells are provided on the support substrate, and light can be taken in through the transparent support substrate. It may be.

As the configuration of the solar cell module, for example, a super straight type, a substrate type, a potting type or the like module structure, a substrate integrated module structure used in an amorphous silicon solar cell, or the like is known. For the solar cell module using the organic photoelectric conversion element of the present invention, an appropriate module structure may be appropriately selected according to the purpose of use, the place of use, the environment, and the like.

For example, a super straight type and substrate type solar cell module, which is a typical module structure, has a structure in which solar cells are arranged at regular intervals between a pair of support substrates. One or both of the support substrates are transparent and are usually subjected to antireflection treatment. Adjacent solar cells are electrically connected to each other by wiring such as metal leads and flexible wiring, and an integrated electrode is disposed on the outer edge portion of the solar cell module so that power generated in the solar cells can be taken out to the outside. It has become.
Between the support substrate and the solar cells, a layer of a filling material such as a plastic material such as ethylene vinyl acetate (EVA) may be provided as necessary for protecting the solar cells and improving the current collection efficiency. . The filling material may be attached after being formed into a film shape in advance, or may be cured after filling a resin at a desired position.

In addition, when the solar cell module is used in a place where it is not necessary to cover the surface with a hard material, for example, a place where there is little impact from the outside, one support substrate may not be provided. However, a surface protective layer is provided on the surface of the solar cell module on which the support substrate is not provided, for example, by covering with a transparent plastic film or by curing the resin after coating with a filling resin, thereby providing a protective function. It is preferable.
Further, usually, the periphery of the support substrate is fixed by sandwiching the solar cell module with a metal frame in order to ensure the internal sealing and the rigidity of the solar cell module. Further, a hermetic seal is usually applied between the support substrate and the frame with a sealing material.

Since the organic photoelectric conversion element of the present invention, which is a photoelectric conversion element using an organic material, is provided, the solar cell module can be used in a mode that takes advantage of the organic photoelectric conversion element. For example, since an organic photoelectric conversion element can be configured as a flexible element, a solar cell module can be provided on a curved surface by using a flexible material as a support substrate, a filling material, a sealing material, and the like.

Moreover, since an organic photoelectric conversion element can be manufactured at low cost using a coating method, a solar cell module can also be manufactured using a coating method. For example, when manufacturing a solar cell module using a flexible support such as a polymer film as a support substrate, solar cells are sequentially formed using a coating method or the like while feeding a roll-shaped flexible support, After cutting to a desired size, the solar cell module main body can be manufactured by sealing the periphery of the cut piece with a flexible and moisture-proof material. Furthermore, for example, a solar cell module having a module structure called “SCAF” described in Solar Energy Materials and Solar Cells, 48, p383-391 can be obtained.
Moreover, the solar cell module using a flexible support can be used by being bonded and fixed to curved glass or the like.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples, and can be arbitrarily modified without departing from the gist of the present invention.

[Evaluation methods]
In Examples and Comparative Examples described below, 2 mm × 2 mm regular square organic photoelectric conversion elements were manufactured. The produced organic photoelectric conversion element is irradiated with a certain amount of light using a solar simulator (trade name: CEP-2000 type, irradiance: 100 mW / cm ² ) manufactured by Spectrometer, and the generated current and voltage are measured. The photoelectric conversion efficiency is evaluated.

[Example 1]
A glass substrate on which an ITO film having a thickness of about 150 nm was patterned as a first electrode by sputtering was prepared. The prepared glass substrate was washed with an organic solvent, an alkaline detergent, and ultrapure water, dried, and then subjected to ultraviolet-ozone treatment (UV-O ₃ treatment) using a UV-O ₃ apparatus.

A suspension of poly (3,4) ethylenedioxythiophene / polystyrene sulfonic acid (manufactured by HC Starck B-Tech, Bytron P TP AI 4083) was prepared and filtered through a filter having a pore size of 0.5 micron. The filtered suspension was spin-coated on the surface of the glass substrate on which the ITO film was formed to form a film with a thickness of 70 nm. Thereafter, the film was dried on the hot plate at 200 ° C. for 10 minutes in the atmosphere to form a functional layer.

Next, polymer compound A, which is an alternating polymer of the monomer represented by formula (3) and the monomer represented by formula (4), and [6,6] -phenyl C ₆₁ butyric An orthodichlorobenzene solution containing acid methyl ester (hereinafter abbreviated as “[6,6] -PCBM” as appropriate) at a weight ratio of 1: 3 was prepared. The polymer compound A was 1% by weight with respect to orthodichlorobenzene. The prepared solution was stirred and mixed and subjected to ultrasonic treatment. The solution subjected to ultrasonic treatment was spin-coated on the functional layer, and then dried in an N ₂ atmosphere. As a result, an active layer having a thickness of 100 nm was obtained. The polymer compound A had a polystyrene equivalent weight average molecular weight of 17,000 and a polystyrene equivalent number average molecular weight of 5,000. Furthermore, the light absorption edge wavelength of the polymer compound A was 925 nm.

Further, on the active layer, a functional layer is formed by forming a LiF film with a thickness of about 2.3 nm in a resistance heating vapor deposition apparatus, and subsequently forming a second electrode with a film of Al having a thickness of about 70 nm. Formed.
A solution in which 5% by weight of titanium isopropoxide was dropped into acetone and mixed by stirring was prepared. The prepared solution was spin-coated on the second electrode and dried under reduced pressure to form a getter layer having a thickness of about 100 μm.
Furthermore, sealing treatment was performed by adhering a glass substrate with an epoxy resin (rapid curing type araldite) as a sealing material from above the getter layer to obtain an organic photoelectric conversion element.

[Example 2]
An organic photoelectric conversion device was produced in the same manner as in Example 1 except that aluminum-S-butoxide was used instead of titanium isopropoxide used in Example 1.

[Example 3]
An organic photoelectric conversion element was obtained in the same manner as in Example 1 except that the active layer was formed as described below.
The active layer was formed as follows. First, an orthodichlorobenzene solution containing poly (3-hexylthiophene) (hereinafter abbreviated as “P3HT” as appropriate) and [6,6] -PCBM at a weight ratio of 1: 0.8 was prepared. P3HT was 1% by weight with respect to orthodichlorobenzene. The prepared solution was stirred and mixed and subjected to ultrasonic treatment. The solution subjected to ultrasonic treatment was spin-coated on the functional layer, and then dried in an N ₂ atmosphere. As a result, an active layer having a thickness of 150 nm was obtained.

[Comparative Example 1]
An organic photoelectric conversion element was obtained in the same manner as in Example 1 except that the getter layer was not formed.

[Comparative Example 2]
An organic photoelectric conversion element was obtained in the same manner as in Example 3 except that the getter layer was not formed.

[Evaluation results]
For each of Examples 1 to 3 and Comparative Examples 1 and 2, the conversion efficiency immediately after the production of the organic photoelectric conversion element and the conversion efficiency after 24 hours from the production of the organic photoelectric conversion element were obtained, and the conversion after 24 hours from the production. The maintenance factor was calculated by dividing the efficiency by the conversion efficiency immediately after fabrication. The results are shown in the table below. Compared with the organic photoelectric conversion elements manufactured in Comparative Examples 1 and 2, the organic photoelectric conversion elements manufactured in Examples 1, 2, and 3 were able to maintain the photoelectric conversion efficiency over a long period of time. That is, the organic photoelectric conversion elements of Examples 1 to 3 had a longer lifetime than the organic photoelectric conversion elements of Comparative Examples 1 and 2.

The organic photoelectric conversion element of the present invention can be used for, for example, a solar cell, an optical sensor and the like.

Claims

An organic photoelectric conversion element comprising a first electrode, a second electrode, an active layer, and a getter layer,
The active layer is a layer that is provided between the first electrode and the second electrode, and is capable of generating an electric charge upon incidence of light,
The getter layer is an organic photoelectric conversion element which is in contact with the surface of the second electrode opposite to the first electrode and can adsorb oxygen and water.
The organic photoelectric conversion element according to claim 1, wherein the active layer includes a p-type semiconductor and an n-type semiconductor.
The organic photoelectric conversion element according to claim 1, wherein the getter layer contains an alkoxide.
The organic photoelectric conversion device according to claim 3, wherein the alkoxide is an alkoxide selected from the group consisting of aluminum-s-butoxide and titanium isopropoxide.
The organic photoelectric conversion element according to claim 3, wherein the getter layer is formed through a step of applying a solution containing an alkoxide and an organic solvent.