JP5310838B2 - Organic photoelectric conversion element, solar cell, and optical sensor array - Google Patents

Abstract

Provided are an organic photoelectric conversion element, which can achieve high conversion efficiency and has a high durability, a solar cell, and an optical sensor array. The organic photoelectric conversion element at least has, between a counter electrode and a transparent electrode, a photoelectric conversion layer having a p-i-n configuration wherein a p-layer composed of only a p-type organic semiconductor material, an i-layer composed of a layer having a p-type organic semiconductor material and an n-type organic semiconductor material mixed therein, and an n-layer composed of only an n-type organic semiconductor material are laminated. The carrier mobility of the p-layer on the light incoming side or that of the organic semiconductor material used for the n-layer is lower than the carrier mobility of the same kind of organic semiconductor material as the organic semiconductor material on the light incoming side which is used for the i-layer.

Description

  The present invention relates to an organic photoelectric conversion element, a solar cell, and an optical sensor array, and more particularly to a bulk heterojunction type organic photoelectric conversion element, a solar cell using the organic photoelectric conversion element, and an optical array sensor.

  Due to the recent rise in fossil energy, a system that can generate electric power directly from natural energy has been demanded. Si-based solar cells using various single-crystal / polycrystalline / amorphous Si, compound-based solar cells such as CIGS, or Dye-sensitized photoelectric conversion elements (Gretzel cells) have been proposed and put into practical use.

  However, the cost of generating electricity with these solar cells is still higher than the price of electricity generated and transmitted using fossil fuels, which has hindered widespread use. In addition, since heavy glass must be used for the substrate, reinforcement work is required at the time of installation, which is one of the causes that increase the power generation cost.

  In such a situation, as a solar cell that can achieve a power generation cost lower than that of fossil fuel, an electron donor layer (p-type semiconductor layer) and an electron acceptor are provided between the transparent electrode and the counter electrode. An organic photoelectric conversion element having a bulk heterojunction layer mixed with a layer (n-type semiconductor layer) has been proposed (see, for example, Non-Patent Document 1).

  Organic thin-film solar cells composed of organic photoelectric conversion elements can be formed on inexpensive and lightweight plastic substrates, and can be formed by coating methods. Therefore, they attract attention as solar cells suitable for mass production, and are popular in many research institutions. Has been studied. Organic thin-film solar cells have improved charge separation efficiency, which has been a problem, by a so-called bulk heterojunction structure in which an electron donor material and an electron acceptor material are mixed (see, for example, Non-Patent Document 1). In recent years, the photoelectric conversion efficiency has improved to the 5-6% range, and it can be said that this is a field where research for practical use has become more active. However, in organic photoelectric conversion elements for practical use in the future, it is desired to develop organic photoelectric conversion elements that generate power with higher efficiency and have longer durability.

The operation principle of the organic photoelectric conversion element will be described.
1. The dye / conductive polymer generates excitons by light absorption,
2. The generated excitons diffuse and move to the contact interface between the p-type semiconductor and the n-type semiconductor,
3. Charge separation into free carriers occurs at the contact interface between the p-type semiconductor and the n-type semiconductor,
4). Among the carriers generated by charge separation, electrons pass through the n-type semiconductor layer and holes pass through the p-type semiconductor layer and are transported to one electrode. As a result, a photocurrent is observed.

The current organic photoelectric conversion element has an internal quantum efficiency of 50 to 60% that can be read from the IPCE spectrum, which is the spectral quantum efficiency, and it cannot be said that the irradiated light is used with sufficiently high efficiency. Conversely, it is considered that there is still room for achieving higher photoelectric conversion efficiency by improving the internal quantum efficiency. As a means of improving internal quantum efficiency,
a. Increase the exciton diffusion length of organic semiconductor materials,
b. A method is conceivable in which the probability of recombination or deactivation of charge-separated holes / electrons before reaching the electrode is reduced.

  In order to improve the rectification property, a method of forming a vapor deposition type pin structure using a specific anthracene or pentacene derivative as a high mobility semiconductor is disclosed (for example, see Patent Document 1). This method not only reduces the cost advantage but also has insufficient photoelectric conversion efficiency, and there is no suggestion about the effect of improving durability.

  Further, as a means for achieving a laminated structure in such a coating process, a heat conversion type semiconductor material is disclosed (for example, refer to Patent Document 2), and by using such a material, p by the coating process is disclosed. Although it is disclosed that a layer and an i layer can be stacked, conversion efficiency is still insufficient, and development of an organic photoelectric conversion element having higher photoelectric conversion efficiency has been an issue.

International Publication No. 2007/15503 JP 2008-16834 A

Nature Mat. , Vol. 6 (2007), p497

  An object of the present invention is to provide an organic photoelectric conversion element, a solar cell, and a photosensor array that can achieve high conversion efficiency and high durability.

  The above object of the present invention can be achieved by the following configuration.

  1. Between the counter electrode and the transparent electrode, at least a p-layer made of a p-type organic semiconductor material alone, an i-layer made of a mixed layer of a p-type organic semiconductor material and an n-type organic semiconductor material, and an n-type organic semiconductor material alone An organic photoelectric conversion element having a photoelectric conversion layer having a p-i-n configuration in which n layers of layers are stacked, and a carrier of an organic semiconductor material used for the p layer or the n layer on the light incident side An organic photoelectric conversion element characterized in that the mobility is lower than the carrier mobility of an organic semiconductor material of the same type as the organic semiconductor material on the light incident side used for the i layer.

  2. 2. The carrier mobility of the organic semiconductor material used for the p layer or n layer on the counter electrode side is larger than the carrier mobility of the organic semiconductor material used for the p layer or n layer on the transparent electrode side. Organic photoelectric conversion element.

  3. 3. The organic photoelectric conversion element as described in 1 or 2 above, which contains a porphyrin derivative as the p-type organic semiconductor material.

  4). 4. The organic photoelectric conversion element as described in any one of 1 to 3 above, which contains a fullerene derivative as the n-type organic semiconductor material.

  5. 5. The organic photoelectric conversion device as described in 4 above, wherein the fullerene derivative is a polymer compound obtained by polymerizing a monomer compound represented by the following general formula (1).

(Wherein R ₁ and R ₂ represent a substituent selected from a substituted or unsubstituted alkyl group, a cycloalkyl group, an aralkyl group, an aryl group, a heteroaryl group, and a silyl group, and L ₁ and L ₂ are substituted or Unsubstituted alkylene group, alkenediyl group, alkynediyl group, cycloalkylene group, arylene group, heteroarylene group, silylene group, ether group, thioether group, carbonyl group, carboxyl group, amino group, amide group, or a combination of these N represents an integer greater than or equal to 2. In the formula, only one hemispherical portion of the spherical fullerene structure is shown, the other hemispherical portion is omitted, and R ₁ substituted with the fullerene structure, (The positional relationship between the first substituent containing L ₁ and the second substituent containing R ₂ and L ₂ is arbitrary.)
6). 6. The organic photoelectric conversion device as described in 4 or 5 above, wherein the fullerene derivative is a compound obtained by polymerizing and crosslinking a monomer having a structure represented by the following general formula (2).

(Wherein R ₃ and R ₄ represent a substituent selected from a substituted or unsubstituted alkyl group, a cycloalkyl group, an aralkyl group, an aryl group, a heteroaryl group, and a silyl group, and L ₃ and L ₄ are substituted or Unsubstituted alkylene group, alkenediyl group, alkynediyl group, cycloalkylene group, arylene group, heteroarylene group, silylene group, ether group, thioether group, carbonyl group, carboxyl group, amino group, amide group, or a combination of these G ₁ and G ₂ are polymerized groups that form a bonding chain of a three-dimensional network structure, where only one hemisphere portion of the spherical fullerene structure is shown, and the other hemisphere portion is omitted. A first substituent containing G ₁ , R ₃ , and L ₃ and a second substitution containing G ₂ , R ₄ , and L _4. The positional relationship of the groups is arbitrary.)
7). The i layer is composed of 2 to 5 layers, and the mass ratios of the p type organic semiconductor material and the n type organic semiconductor material of the 2 to 5 layers are different from each other. The organic photoelectric conversion element as described.

  8). The organic photoelectric conversion device according to any one of 1 to 7, wherein the photoelectric conversion layer is formed by a solution process.

  9. 8. The organic photoelectric conversion element according to any one of 1 to 7, wherein at least one of the photoelectric conversion layers is made of a material that can be insolubilized after being formed by a solution process. .

  10. It consists of the organic photoelectric conversion element of any one of said 1-9, The solar cell characterized by the above-mentioned.

  11. 10. An optical sensor array comprising the organic photoelectric conversion elements according to any one of 1 to 9 arranged in an array.

  According to the present invention, an organic photoelectric conversion element that can achieve high conversion efficiency and high durability, and a solar cell and an optical sensor array using the organic photoelectric conversion element can be provided.

It is sectional drawing which shows the solar cell which consists of a bulk hetero junction type organic photoelectric conversion element. It is sectional drawing which shows the solar cell which consists of an organic photoelectric conversion element provided with the photoelectric converting layer of the three-layer structure of p-i-n. It is sectional drawing which shows the solar cell which consists of an organic photoelectric conversion element provided with a tandem-type bulk heterojunction layer. It is a figure which shows the structure of an optical sensor array.

  The present invention will be described in more detail.

  As a result of intensive studies on the above problems, the inventors of the present invention have at least a p-layer composed of a p-type organic semiconductor material alone, a p-type organic semiconductor material, and an n-type organic semiconductor material between the counter electrode and the transparent electrode. An organic photoelectric conversion element having a photoelectric conversion layer having a pin configuration in which an i layer composed of mixed layers and an n layer composed of an n-type organic semiconductor material alone are stacked, and the light incident side; The organic mobility is such that the carrier mobility of the organic semiconductor material used for the p layer or the n layer is lower than the carrier mobility of the same type of organic semiconductor material as the light incident side organic semiconductor material used for the i layer. The inventors have found that the above-mentioned problems can be achieved by designing the conversion element, and have reached the present invention.

  The present inventors presume the reason why the object effect of the present invention is obtained by adopting the configuration defined in the present invention as follows.

  In the organic photoelectric conversion element, excitons generated by light irradiation are separated into charges and electrons, which are carriers, by charge separation at the interface between the p-type organic semiconductor material and the n-type organic semiconductor material. Although a bulk heterojunction structure in which a p-type organic semiconductor material and an n-type organic semiconductor material coexist is formed as a photoelectric conversion layer and the interface between the p-type organic semiconductor material and the n-type organic semiconductor material increases, charge separation is promoted. In fact, since the p-type and n-type molecules coexist, the probability that the generated carriers are recombined increases.

  That is, when the photoelectric conversion layer has a pin structure, more carriers are generated in the layer on the light incident side, but in the present invention, the p-type organic semiconductor material and the n-type organic semiconductor material coexist. By using a semiconductor material having high carrier mobility for the i layer having a bulk heterojunction structure, the probability of recombination of the generated carriers can be further reduced, and as a result, the thickness of the i layer can be increased. In addition to increasing the amount of carriers reaching the electrode and improving the photoelectric conversion efficiency, the positive electrode and the negative electrode are respectively generated when light is continuously irradiated to generate carriers continuously. It is thought that the imbalance of the carrier carried to the light is improved and the durability during light irradiation is improved. In the present invention, when a photoelectric conversion layer having a p-i-n configuration is sequentially provided from the transparent electrode side that is the light incident side, the i-layer is compared with the p-type organic semiconductor material used for the p-layer. It is necessary that the p-type organic semiconductor material used has a higher carrier mobility.

  In addition, when the p layer is provided on the transparent electrode side that is the light incident side, it is preferable to use a semiconductor material having higher carrier mobility for the n layer that is on the counter electrode side than the semiconductor material that is used for the p layer. When the n layer is provided on the transparent electrode side, it is preferable to use a semiconductor material having a higher carrier mobility than the n layer for the p layer on the counter electrode side. By adopting the above configuration, the carrier balance of electrons or holes flowing to the transparent electrode on the light incident side and the counter electrode is improved, and as a result, not only the efficiency is improved, but also the carrier is obtained by continuous irradiation of light. Even when the generation occurs continuously, it is considered that the balance of carriers carried to the positive electrode and the negative electrode is improved and the durability during light irradiation is improved. The mobility is an index representing the speed of carrier diffusion, and the larger the value, the longer the carrier diffusable distance, and the higher the photoelectric conversion efficiency. As a method for measuring the carrier mobility, there is a method (FET method) in which a field effect transistor is produced and evaluated as disclosed in Japanese Patent Application Laid-Open No. 2005-158972. Details are described in the examples below.

  Hereinafter, the present invention will be described in more detail.

  The organic photoelectric conversion element of the present invention includes at least a p-layer composed of a p-type organic semiconductor material alone and an i-layer composed of a mixture of a p-type organic semiconductor material and an n-type organic semiconductor material between a counter electrode and a transparent electrode. And an organic photoelectric conversion element having a photoelectric conversion layer having a p-i-n structure in which n layers made of an n-type organic semiconductor material alone are stacked, and the p layer or the n on the light incident side The carrier mobility of the organic semiconductor material used for the layer needs to be lower than the carrier mobility of the same type of organic semiconductor material as the light incident side organic semiconductor material used for the i layer.

[Layer structure of organic photoelectric conversion element]
FIG. 1 shows a cross-sectional view of a conventional organic photoelectric conversion element. In FIG. 1, an anode (usually a transparent electrode) 12 is deposited on one surface of a substrate 11, and has a hole transport layer 17, a photoelectric conversion layer 14, an electron transport layer 18, and a cathode (approximately the same area). Usually, metal electrodes) 13 are sequentially stacked.

  The holes and electrons generated in the photoelectric conversion layer 14 can be obtained by taking them out to the anode and the cathode, respectively. However, since they are conducted in the opposite direction, the hole transport layer 17 is easy to flow holes. Is interposed between the photoelectric conversion layer 14 and the anode 12, and an electron transport layer 18 that easily allows electrons to flow is sandwiched between the photoelectric conversion layer 14 and the cathode 13, thereby improving the rectification property and improving the photoelectric conversion efficiency. .

  FIG. 2 shows a so-called p-i-n three-layer structure. A normal bulk heterojunction layer is a single i layer 14i in which a p-type organic semiconductor material and an n-type organic semiconductor layer are mixed, but a p-layer 14p made of a single p-type organic semiconductor material, and an n-type organic semiconductor material By sandwiching between n layers 14n consisting of a single substance, the rectification of holes and electrons is further enhanced, loss due to charge-separated hole / electron recombination is reduced, and higher photoelectric conversion efficiency is achieved. ing.

[N-type organic semiconductor materials]
The n-type organic semiconductor material used for the photoelectric conversion layer of the present invention is not particularly limited. For example, perfluoro compounds (perfluorocarbons) in which hydrogen atoms of p-type organic semiconductor materials such as fullerene and octaazaporphyrin are substituted with fluorine atoms. Fluoropentacene, perfluorophthalocyanine, etc.), naphthalenetetracarboxylic anhydride, naphthalenetetracarboxylic acid diimide, perylenetetracarboxylic acid anhydride, perylenetetracarboxylic acid diimide and other aromatic carboxylic acid anhydrides and imidized products thereof Examples thereof include polymer compounds.

  In the present invention, a fullerene-containing polymer compound can also be suitably used. Fullerene-containing polymer compounds include fullerene C60, fullerene C70, fullerene C76, fullerene C78, fullerene C84, fullerene C240, fullerene C540, mixed fullerene, fullerene nanotubes, multi-walled nanotubes, single-walled nanotubes, nanohorns (conical type), etc. Examples thereof include a polymer compound having a skeleton. As the fullerene-containing polymer compound, a polymer compound (derivative) having fullerene C60 as a skeleton is preferable.

  The fullerene-containing polymers are roughly classified into polymers in which fullerene is pendant from a polymer main chain and polymers in which fullerene is contained in the polymer main chain. Fullerene is contained in the polymer main chain. Are preferred. This is because a polymer in which fullerene is pendant has a branched structure, that is, the polymer cannot be packed with high density when solidified, and as a result, high mobility can be obtained. It is presumed that it is due to disappear.

  Specifically, the compound represented by the general formula (1) can be preferably used.

In the general formula (1), R ₁ and R ₂ represent a substituent selected from a substituted or unsubstituted alkyl group, cycloalkyl group, aralkyl group, aryl group, heteroaryl group, and silyl group, and L ₁ , L ₂ Is a substituted or unsubstituted alkylene group, alkenediyl group, alkynediyl group, cycloalkylene group, arylene group, heteroarylene group, silylene group, ether group, thioether group, carbonyl group, carboxyl group, amino group, amide group, or these Represents a structure of multiple connections. n represents an integer of 2 or more. In the formula, only one hemispherical portion of the spherical fullerene structure is shown, and the other hemispherical portion is omitted, the first substituent containing R ₁ and L ₁ substituted for the fullerene structure, R ₂ , positional relationship between the second substituent containing L ₂ is optional.

Specific examples of the substituted or unsubstituted alkyl group, cycloalkyl group, aralkyl group, aryl group, heteroaryl group, and silyl group represented by R ₁ and R ₂ include an alkyl group (for example, methyl group, ethyl group). Group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group etc.), Aralkyl groups (for example, benzyl group, 2-phenethyl group, etc.), aryl groups (for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group) Group, phenanthryl group, indenyl group, pyrenyl group, biphenyl ), Heteroaryl groups (eg, furyl, thienyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, imidazolyl, pyrazolyl, thiazolyl, quinazolinyl, phthalazinyl, etc.), silyl Groups (for example, a trimethylsilyl group, a triethylsilyl group, a tert-butyldimethylsilyl group, a triisopropylsilyl group, a tert-butyldiphenylsilyl group, etc.), and these substituents include an alkyl group, a halogenated alkyl group, As for the alkenyl group, alkynyl group, aryl group, heteroaryl group, and alkylsilyl group, specifically, an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group) , Octyl group, dodecy Group, tridecyl group, tetradecyl group, pentadecyl group, etc.), halogenated alkyl group (eg, trifluoromethyl group, 1,1,1-trifluoropropyl group, etc.), alkenyl group (eg, vinyl group, allyl group, etc.) , Alkynyl groups (eg, ethynyl group, propargyl group, etc.), cycloalkyl groups (eg, cyclopentyl group, cyclohexyl group, etc.), aryl groups (eg, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, Naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), halogenated aryl group (pentafluorophenyl group, pentachlorophenyl group etc.), heteroaryl group (for example, , Furyl group, thienyl group, pyri Zyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, phthalazinyl group, etc.), alkylsilyl group (for example, trimethylsilyl group, triethylsilyl group, tripropyl (i or n) silyl group, tributyl (i, t or n) silyl group, etc.), and these substituents may be further substituted by the above substituents, but a plurality of them may be bonded to each other to form a ring. Also good.

A substituted or unsubstituted alkylene group, alkenediyl group, alkynediyl group, cycloalkylene group, arylene group, heteroarylene group, silylene group, ether group, thioether group, carbonyl group, carboxyl group, amino group represented by L ₁ or L ₂ Groups and amide groups include alkylene groups having 1 to 22 carbon atoms, alkene-1,2-diyl groups, alkyne-1,2-diyl groups, and cycloalkylene groups. Arylene groups include phenylene groups and naphthylene groups. Group, and a phenylene group is preferable. Examples of the heteroarylene group include a furylene group, a thienylene group, a pyridinylene group, a pyridazinylene group, a pyrimidinylene group, a pyrazinylene group, a triazinylene group, an imidazolinylene group, a pyrazolinylene group, a thiazolinylene group, a quinazolinylene group, and a phthalazinylene group. Examples of the silylene group include a dimethylsilylene group and a diphenylsilylene group.

  More preferably, the fullerene derivative is a compound obtained by polymerizing and crosslinking a monomer having a structure represented by the general formula (2).

In the general formula (2), R ₃ and R ₄ are substituted selected from a substituted or unsubstituted alkyl group, cycloalkyl group, aralkyl group, aryl group, heteroaryl group, and silyl group in the same manner as R ₁ and R _2. Represents a group, and those similar to R ₁ and R ₂ described above can be used.

L ₃ and L ₄ are substituted or unsubstituted alkylene group, alkene diyl group, alkyne diyl group, cycloalkylene group, arylene group, heteroarylene group, silylene group, ether group, thioether group, carbonyl, as in L ₁ and L ₂ above. A group, a carboxyl group, an amino group, an amide group, or a structure in which a plurality of these groups are connected can be used, and those similar to the above-described L ₁ and L ₂ can be used.

G ₁ and G ₂ are polymerized groups that become a bond chain of a three-dimensional network structure. In the formula, only one hemispherical portion of the spherical fullerene structure is shown, the other hemispherical portion is omitted, and a first substituent containing G ₁ , R ₃ , and L ₃ substituted for the fullerene structure; positional relationship between the second substituent comprising G _{2, R 4, L} 4 is optional.

In the present invention, the three-dimensionally cross-linked network structure is obtained by polymerizing and cross-linking a monomer having two or more polymer groups in the polymer groups G ₁ and G _{2 serving} as a connecting chain of the three-dimensional network structure in the general formula (2) Can be obtained. Preferably, it is a monomer containing 2 to 3 polymerization groups. More preferably, it is a monomer containing two polymerizable groups, and _one monomer is included in each of G ₁ and G ₂ .

  By forming a network structure in which n-type semiconductors are three-dimensionally cross-linked, a highly rigid n-type carrier path structure can be formed, and the phase separation structure of the p-type layer and n-type layer changes over time. As a result, an organic photoelectric conversion element having high durability can be obtained. As a further secondary effect, when the photoelectric conversion layer is multilayered or a hole transport layer, an electron transport layer, a hole block layer, an electron block layer, etc. are formed on the photoelectric conversion layer by a solution process In addition, since the photoelectric conversion layer is not dissolved, the material constituting the layer and the material forming the photoelectric conversion layer are not mixed, and further improvement in efficiency and life can be achieved. .

  Examples of the fullerene-containing monomer capable of forming such a three-dimensional network structure include the following compounds.

  These compounds are described in J. Org. Mater. Chem. , Vol. 15 (2005), p5158, Adv. Mater. , Vol. 20 (2008), p2116, Angewedte Chemie, International Edition, vol. 41 (2002), p838, etc., can be used to synthesize monomers.

Among these compounds, an epoxy group, an oxetane group, an aziridine group, a vinyl group, as a polymer group (G ₁ and G ₂ in the general formula (2)) that does not generate a functional group that becomes a carrier trap after the polymerization crosslinking reaction, A lactone group, a lactam group, etc. are mentioned, The compound which is a vinyl group is preferable.

  In addition, since the polymer compound that forms these three-dimensional networks is insoluble in a solvent, after forming a bulk heterojunction layer in the monomer state, it is exposed to a compound vapor that causes heat, light, radiation, and a polymerization initiation reaction. Can cause a polymerization crosslinking reaction to form a three-dimensional network structure. A polymerization initiator that causes a polymerization initiation reaction by heat, light, radiation, or the like may be mixed in advance. Among these methods, it is preferable to cause a polymerization crosslinking reaction by heat or light, and among them, a compound capable of polymerization crosslinking without using a polymerization initiator is preferable.

  In the present invention, the low molecular weight compound means a single molecule having no distribution in the molecular weight of the compound. On the other hand, the polymer compound means an aggregate of compounds having a certain molecular weight distribution by reacting a predetermined monomer. However, when defining by molecular weight in practice, preferably a compound having a molecular weight of 2000 or less is classified as a low molecular compound. More preferably, it is 1500 or less, More preferably, it is 1000 or less. On the other hand, a compound having a molecular weight of 1000 or more, more preferably 2000 or more, and still more preferably 5000 or more is classified as a polymer compound. The molecular weight can be measured by gel permeation chromatography (GPC). However, in the case of a polymer having a three-dimensional network structure as described later, it is difficult to specify the molecular weight accurately.

[P-type organic semiconductor materials]
Examples of the p-type organic semiconductor material used in the photoelectric conversion layer of the present invention include various condensed polycyclic aromatic low molecular compounds and conjugated polymers.

  Examples of the condensed polycyclic aromatic low-molecular compound include anthracene, tetracene, pentacene, hexacene, heptacene, chrysene, picene, fluorene, pyrene, peropyrene, perylene, terylene, quaterylene, coronene, ovalene, circumanthracene, bisanthene, zesulene, Compounds such as heptazeslen, pyranthrene, violanthene, isoviolanthene, circobiphenyl, anthradithiophene, porphyrin, copper phthalocyanine, tetrathiafulvalene (TTF) -tetracyanoquinodimethane (TCNQ) complex, bisethylenetetrathiafulvalene (BEDTTTTF ) -Perchloric acid complexes, and derivatives and precursors thereof. In the present invention, porphyrin derivatives are preferred.

  Examples of the derivative having the above-mentioned condensed polycycle include WO 03/16599 pamphlet, WO 03/28125 pamphlet, US Pat. No. 6,690,029, JP 2004-107216 A. A pentacene derivative having a substituent described in JP-A No. 2003-136964, a pentacene precursor described in US Patent Application Publication No. 2003/136964, and the like; Amer. Chem. Soc. , Vol127. No. 14.4986, J. MoI. Amer. Chem. Soc. , Vol. 123, p9482; Amer. Chem. Soc. , Vol. 130 (2008), no. 9, acene-based compounds substituted with a trialkylsilylethynyl group described in 2706 and the like.

  Among these compounds, compounds that have high solubility in organic solvents to the extent that solution processing is possible, can form a crystalline thin film after drying, and can achieve high mobility are preferable. More preferably, it is a compound (a compound capable of forming an appropriate phase separation structure) having appropriate compatibility with the n-type organic semiconductor material of the present invention.

  On the other hand, in order to obtain a thicker film or a multi-layered structure composed of a plurality of layers, the target film can be easily obtained if it can be further applied onto the layer once applied. Usually, if a layer is further laminated by a solution process on a layer made of a material having good solubility, there is a problem that it cannot be laminated because the underlying layer is dissolved. Materials that can be insolubilized are preferred.

  Examples of such a material include materials that can be insolubilized by polymerizing and crosslinking the coating film after coating, such as polythiophene having a polymerizable group described in Technical Digest of the International PVSEC-17, Fukuoka, Japan, 2007, P1225. Alternatively, a soluble substituent reacts and becomes insoluble (pigmented) by applying energy such as heat, as described in US Patent Application Publication No. 2003/136964, and Japanese Patent Application Laid-Open No. 2008-16834. Materials etc. can be mentioned.

  Among these, a tetrabenzoporphyrin derivative can be preferably used because it undergoes structural conversion to a semiconductor that is insolubilized by heat treatment after the precursor is applied.

  Examples of tetrabenzoporphyrin derivatives include the following compounds, but the present invention is not limited to these.

  Examples of the tetrabenzoporphyrin derivative precursor include compounds represented by the following general formulas (3) and (4), but the present invention is not limited thereto.

(In General Formulas (3) and (4), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represent a monovalent atom or atomic group, provided that Z ^ia and Z ^ib And R ^{1 to} R ⁴ each independently represents a monovalent atom or atomic group, and Y ¹ to Y ⁴ each independently represent a monovalent atom or atom. M represents an atomic group in which a divalent metal atom or a trivalent or higher metal is bonded to another atom.)
In General Formulas (3) and (4), Z ^ia and Z ^ib (i represents an integer of 1 to 4) each independently represent a monovalent atom or atomic group. As examples of Z ^ia and Z ^ib , examples of the atom include a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom;

  On the other hand, the atomic group includes: hydroxyl group; amino group; alkyl group, aralkyl group, alkenyl group, cyano group, acyl group, alkoxy group, alkoxycarbonyl group, aryloxy group, dialkylamino group, diaralkylamino group, haloalkyl group, And organic groups such as aromatic hydrocarbon ring groups and aromatic heterocyclic groups.

  Among the organic groups, the carbon number of the alkyl group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the alkyl group is too large, the semiconductor characteristics may deteriorate, the solubility may increase, and redissolution may occur during lamination, or the heat resistance may decrease. Examples of the alkyl group include a methyl group and an ethyl group.

  Among the above organic groups, the carbon number of the aralkyl group is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the aralkyl group is too large, the semiconductor characteristics may deteriorate, the solubility may increase, and redissolution may occur during lamination, or the heat resistance may decrease. Examples of the aralkyl group include a benzyl group.

  Among the above organic groups, the carbon number of the alkenyl group is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the alkenyl group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased, and redissolution may be performed at the time of lamination, or the heat resistance may be decreased. Examples of the alkenyl group include a vinyl group.

  Among the above organic groups, the carbon number of the acyl group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the acyl group is too large, the semiconductor characteristics may deteriorate, the solubility may increase, and redissolution may occur during lamination, or the heat resistance may decrease. Examples of this acyl group include formyl group, acetyl group, benzoyl group and the like.

  Among the organic groups, the number of carbon atoms of the alkoxy group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms of the alkoxy group is too large, the semiconductor characteristics may be lowered, the solubility may be increased, and redissolution may be performed at the time of lamination, or the heat resistance may be reduced. Examples of the alkoxy group include a methoxy group and an ethoxy group.

  Among the above organic groups, the carbon number of the alkoxycarbonyl group is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms of the alkoxycarbonyl group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased and redissolved during lamination, or the heat resistance may be decreased. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.

  Among the above organic groups, the carbon number of the aryloxy group is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms of the aryloxy group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased, and redissolution may be performed at the time of lamination, or the heat resistance may be decreased. Examples of the aryloxy group include a phenoxy group and a benzyloxy group.

  Among the above organic groups, the carbon number of the dialkylamino group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the dialkylamino group is too large, the semiconductor characteristics may deteriorate, the solubility may increase, and redissolution may occur during lamination, or the heat resistance may decrease. Examples of the dialkylamino group include a diethylamino group and a diisopropylamino group.

  Among the above organic groups, the carbon number of the diaralkylamino group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms in the diaalkylamino group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased, and redissolution may be performed during lamination, or the heat resistance may be decreased. Examples of the diaralkylamino group include a dibenzylamino group and a diphenethylamino group.

  Among the organic groups, the carbon number of the haloalkyl group is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 12 or less, preferably 8 or less. If the number of carbon atoms of the haloalkyl group is too large, the semiconductor characteristics may be reduced, the solubility may be increased, and redissolution may be performed at the time of lamination, or the heat resistance may be reduced. Examples of the haloalkyl group include α-haloalkyl groups such as a trifluoromethyl group.

  Among the organic groups, the number of carbon atoms of the aromatic hydrocarbon ring group is arbitrary as long as the effects of the present invention are not significantly impaired, but usually 6 or more, preferably 10 or more, and usually 30 or less, preferably 20 It is as follows. If the number of carbon atoms in the aromatic hydrocarbon ring group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased and redissolved during lamination, or the heat resistance may be decreased. Examples of the aromatic hydrocarbon ring group include a phenyl group and a naphthyl group.

  Among the organic groups, the carbon number of the aromatic heterocyclic group is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 2 or more, preferably 5 or more, and usually 30 or less, preferably 20 or less. It is. If the number of carbon atoms in the aromatic heterocyclic group is too large, the semiconductor characteristics may be deteriorated, the solubility may be increased and redissolved during lamination, or the heat resistance may be decreased. Examples of the aromatic heterocyclic group include a thienyl group and a pyridyl group.

  Furthermore, the above atomic group may have an arbitrary substituent as long as the effects of the present invention are not significantly impaired. Examples of the substituent include a halogen atom such as a fluorine atom; an alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group; an alkenyl group such as a vinyl group; and a carbon number of 1 such as a methoxycarbonyl group and an ethoxycarbonyl group. An alkoxycarbonyl group having 1 to 6 carbon atoms such as a methoxy group or an ethoxy group; an aryloxy group such as a phenoxy group or a benzyloxy group; a dialkylamino group such as a dimethylamino group or a diethylamino group; an acetyl group An acyl group; a haloalkyl group such as a trifluoromethyl group; a cyano group, and the like. In addition, as for this substituent, 1 type may be substituted by single or multiple, and 2 or more types may be substituted by arbitrary combinations and ratios.

Z ^ia and Z ^ib may combine to form a ring. When Z ^ia and Z ^ib are combined to form a ring, examples of the ring containing Z ^ia and Z ^ib (that is, a ring having a structure represented by Z ^ia —CH═CH—Z ^ib ) Aromatic hydrocarbon rings optionally having substituents such as benzene ring, naphthalene ring and anthracene ring; aromatics optionally having substituents such as pyridine ring, quinoline ring, furan ring and thiophene ring Non-aromatic cyclic hydrocarbons such as cyclohexane ring; and the like.

The above-mentioned substituents included in the ring formed by combining Z ^ia and Z ^ib are optional as long as the effects of the present invention are not significantly impaired. Examples thereof include the same substituents as those exemplified as the substituent of the atomic group constituting Z ^ia and Z ^ib . In addition, as for this substituent, 1 type may be substituted by single or multiple, and 2 or more types may be substituted by arbitrary combinations and ratios.

Among Z ^ia and Z ^ib described above, a hydrogen atom is particularly preferable. This is because the crystal packing is good and high semiconductor characteristics can be expected.

In the general formulas (3) and (4), R ^{1 to} R ⁴ each independently represents a monovalent atom or atomic group.

Examples of R ¹ to R ^4, are the same as those of the ^{Z ia} and ^{Z ib} described above. Moreover, when R < ¹ > -R < ⁴ > is an atomic group, the said atomic group may have arbitrary substituents, unless the effect of this invention is impaired remarkably. As an example of this substituent, the same thing as the substituent of said Z ^ia and Z ^ib is mentioned. In addition, as for this substituent, 1 type may be substituted by single or multiple, and 2 or more types may be substituted by arbitrary combinations and ratios. However, R ^{1 to} R ⁴ are preferably selected from atoms such as a hydrogen atom and a halogen atom in order to improve the planarity of the molecule.

In the general formula (4), M represents a divalent metal atom or an atomic group in which a trivalent or higher valent metal is bonded to another atom. When M is a divalent metal atom, examples thereof include Zn, Cu, Fe, Ni, Co and the like. On the other hand, when M is an atomic group in which a trivalent or higher-valent metal and other atoms are bonded, examples thereof include Fe—B ¹ , Al—B ² , Ti═O, Si—B ³ B ^{4, and the} like. Can be mentioned. Here, B ¹ , B ² , B ³ and B ⁴ represent a monovalent group such as a halogen atom, an alkyl group, or an alkoxy group.

In the general formulas (3) and (4), Y ^{1 to} Y ⁴ each independently represent a monovalent atom or atomic group. In the general formulas (2) and (3), there are four Y ^{1 to} Y ^4, but Y ¹ , Y ² , Y ³ , and Y ⁴ may be the same. , May be different.

Examples of Y ¹ to Y ^4, as the atoms and the like hydrogen atom.

  On the other hand, examples of the atomic group include a hydroxyl group and an alkyl group. Here, the carbon number of the alkyl group is arbitrary as long as the effects of the present invention are not significantly impaired, but it is usually 1 or more, usually 10 or less, preferably 6 or less, more preferably 3 or less. When the carbon number of the alkyl group is too large, the leaving group becomes large, so that the leaving group is difficult to volatilize and may remain in the film. Examples of the alkyl group include a methyl group and an ethyl group.

Also, if Y ¹ to Y ⁴ each are an atomic group, the atomic groups, unless significantly impairing the effects of the present invention may have an arbitrary substituent. As an example of this substituent, the same thing as the substituent of said Z ^ia and Z ^ib is mentioned. In addition, as for this substituent, 1 type may be substituted by single or multiple, and 2 or more types may be substituted by arbitrary combinations and ratios.

Among Y ¹ to Y ⁴ described above, a hydrogen atom or an alkyl group having 10 or less carbon atoms is preferable. Further, among them, all of Y ^{1 to} Y ⁴ are hydrogen atoms, or at least one of (Y ¹ , Y ² ) and (Y ³ , Y ⁴ ) is an alkyl having 10 or less carbon atoms. Particularly preferred is a group. This is because the solubility is increased and the film formability is improved.

  The precursor according to the present invention is converted into the benzoporphyrin derivative according to the present invention by heat treatment. There is no limitation on what kind of reaction occurs during the heat treatment. For example, in the case of the precursors represented by the general formulas (3) and (4), the compound represented by the following general formula (5) can be obtained by applying heat. Is detached. This elimination reaction proceeds quantitatively. And by this elimination reaction, the precursor according to the present invention is converted into the benzoporphyrin derivative according to the present invention.

The heat treatment will be specifically described by taking the benzoporphyrin derivative BP-1 exemplified above as an example. As a precursor of the benzoporphyrin derivative BP-1, for example, in the general formulas (3) and (4), Z ^ia , Z ^ib , R ^{1 to} R ⁴ and Y ^{1 to} Y ⁴ are all hydrogen atoms ( Hereinafter, “BP-1 precursor”) can be used. However, the precursor of the benzoporphyrin derivative BP-1 is not limited to this BP-1 precursor.

  When the BP-1 precursor is heated, the ethylene group is released from each of the four rings bonded to the porphyrin ring. The benzoporphyrin derivative BP-1 is obtained by this deethyleneation reaction. This conversion is represented by the following reaction formula.

  When the precursor according to the present invention is converted into the benzoporphyrin derivative according to the present invention by heat treatment, the temperature condition is not limited as long as the above reaction proceeds, but is usually 100 ° C or higher, preferably 150 ° C or higher. If the temperature is too low, the conversion takes time, which may be undesirable in practice. Although an upper limit is arbitrary, it is 400 degrees C or less normally, Preferably it is 300 degrees C or less. This is because decomposition may occur if the temperature is too high.

  When the precursor according to the present invention is converted into the benzoporphyrin derivative according to the present invention by heat treatment, the heating time is not limited as long as the reaction proceeds, but usually 10 seconds or more, preferably 30 seconds or more, Usually, it is 10 hours or less, preferably 1 hour or less. This is because if the heating time is too short, conversion may be insufficient, and if it is too long, decomposition may occur.

  When the precursor according to the present invention is converted into the benzoporphyrin derivative according to the present invention by heat treatment, the atmosphere is not limited as long as the reaction proceeds, but an inert atmosphere is preferable. Examples of the inert gas that can be used at this time include nitrogen and rare gases. In addition, an inert gas may use only 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The precursor according to the present invention has high solubility in a solvent such as an organic solvent. The specific degree of solubility depends on the type of solvent, but the solubility in chloroform at 25 ° C. is usually 0.1 g / l or more, preferably 0.5 g / l or more, more preferably 1 g / l or more. . In addition, although there is no restriction | limiting in an upper limit, Usually, it is 1000 g / l or less.

While the precursor according to the present invention has high solubility in a solvent, the benzoporphyrin derivative according to the present invention derived therefrom has very low solubility in a solvent such as an organic solvent. This is because the structure of the precursor according to the present invention is not a planar structure, so the solubility is high and it is difficult to crystallize, whereas the benzoporphyrin derivative according to the present invention has a planar structure. Inferred. Therefore, using such a difference in solubility in a solvent, a layer containing the benzoporphyrin derivative can be easily formed by a coating method. For example, it can be produced by the following method. That is, the precursor according to the present invention is dissolved in a solvent to prepare a solution, and the solution is applied to form an amorphous layer or a good layer close to an amorphous layer. And the layer of a benzoporphyrin derivative with high planarity can be obtained by heat-treating this layer and converting the precursor according to the present invention by thermal conversion. At this time, as in the above-described example, among the compounds represented by the general formulas (3) and (4), compounds in which Y ^{1 to} Y ⁴ are all hydrogen atoms are used as precursors. Since it is an ethylene molecule, it is unlikely to remain in the system and is suitable in terms of toxicity and safety.

  There is no restriction | limiting in the manufacturing method of the precursor based on this invention, A well-known method can be employ | adopted arbitrarily. For example, taking the BP-1 precursor as an example, it can be produced through the following synthesis route. Here, Et represents an ethyl group, and t-Bu represents a t-butyl group.

  Furthermore, the tetrabenzoporphyrin derivative according to the present invention includes, for example, one atom shared by two porphyrin rings and two porphyrin rings sharing one or more atoms or atomic groups. May be combined, or three or more of them may be combined and connected on a long chain.

  In addition, as the conjugated polymer, for example, a polythiophene such as poly-3-hexylthiophene (P3HT) and an oligomer thereof, or a technical group described in Technical Digest of the International PVSEC-17, Fukuoka, Japan, 2007, P1225. Polythiophene, Nature Material, (2006) vol. 5, p328, polythiophene-thienothiophene copolymer, polythiophene-diketopyrrolopyrrole copolymer described in WO08 / 000664, Adv. Mater, 2007, p4160, polythiophene-thiazolothiazole copolymer, Nature Mat. vol. 6 (2007), p497 described in PCPDTBT, etc., polypyrrole and its oligomer, polyaniline, polyphenylene and its oligomer, polyphenylene vinylene and its oligomer, polythienylene vinylene and its oligomer, polyacetylene, polydiacetylene, Examples thereof include polymer materials such as σ-conjugated polymers such as polysilane and polygermane.

  Oligomer materials, not polymer materials, include thiophene hexamers α-sexual thiophene α, ω-dihexyl-α-sexual thiophene, α, ω-dihexyl-α-kinkethiophene, α, ω-bis (3-butoxy Oligomers such as propyl) -α-sexithiophene can be suitably used.

[Method for forming photoelectric conversion layer]
Examples of the method for forming the photoelectric conversion layer include a vacuum deposition method and a solution coating method (including a casting method and a spin coating method), but a coating method using a solution process is preferable from the viewpoint of productivity.

  Although there is no restriction | limiting in the coating method used in this case, For example, a spin coat method, the casting method from a solution, a dip coat method, a blade coat method, a wire bar coat method, a gravure coat method, a spray coat method etc. are mentioned. Furthermore, patterning can also be performed by a printing method such as an ink jet method, a screen printing method, a relief printing method, an intaglio printing method, an offset printing method, or a flexographic printing method.

  After the formation of the coating film, it is preferable to perform annealing treatment by heating in order to cause removal of residual solvent, moisture and gas, and improvement of mobility and absorption absorption by crystallization of the semiconductor material. When annealing is performed at a predetermined temperature during the manufacturing process, microscopically a part of the material is aggregated or crystallized, and in particular, an i layer composed of a layer in which a p-type organic semiconductor material and an n-type organic semiconductor material are mixed. In forming, a bulk heterojunction layer having a microphase separation structure of an appropriate p-type organic semiconductor and n-type organic semiconductor can be formed. As a result, the carrier mobility of the bulk heterojunction layer and the i layer of the present invention is improved, and high efficiency can be obtained.

  The i layer (bulk heterojunction layer) in the photoelectric conversion layer 14 may be a single layer in which a p-type organic semiconductor material and an n-type organic semiconductor material are uniformly mixed. You may comprise in multiple layers from which the mixing ratio with n type organic-semiconductor material was changed. In this case, it can be formed by using a material that can be insolubilized after coating as described above.

  When the i layer is composed of 2 to 5 layers, the mass ratio of the p-type organic semiconductor material and the n-type organic semiconductor material may be different from each other. It is preferable to increase the mass ratio of the p-type organic semiconductor in the i layer closer to the layer, and to increase the mass ratio of the n-type semiconductor material in the i layer closer to the n layer. The mass ratio of the p-type organic semiconductor material and the n-type organic semiconductor material is more preferably 1: 4 to 4: 1.

  In the present invention, it is also a preferred embodiment that the carrier mobility of the n layer or p layer on the counter electrode side is made larger than that of the p layer or n layer on the incident light side.

[Hole Transport Layer / Electron Blocking Layer]
The organic photoelectric conversion element 10 of the present invention has a hole transport layer 17 between the bulk heterojunction layer and the anode, since it is possible to more efficiently take out the charges generated in the bulk heterojunction layer. It is preferable.

  As a material constituting these layers, for example, as the hole transport layer 17, PEDOT such as trade name BaytronP manufactured by Stark Vitec, polyaniline and its doping material, cyan compound described in WO2006 / 019270, etc. , Etc. can be used. Note that the hole transport layer having a LUMO level shallower than the LUMO level of the n-type organic semiconductor material used for the bulk heterojunction layer has a rectifying effect so that electrons generated in the bulk heterojunction layer do not flow to the anode side. An electronic block function can be provided. In order to exhibit the electron blocking function more, it is more preferable to have a LUMO level shallower than the LUMO level of the p-type organic semiconductor material. Such a hole transport layer is also called an electron block layer, and it is more preferable to use a hole transport layer having such a function. As such a material, a triarylamine compound described in JP-A-5-271166 or a metal oxide such as molybdenum oxide, nickel oxide, or tungsten oxide can be used. Moreover, the layer which consists of a p-type organic-semiconductor material single-piece | unit used for the bulk heterojunction layer can also be used. The means for forming these layers may be either a vacuum deposition method or a solution coating method, but is preferably a solution coating method. Forming the coating film in the lower layer before forming the bulk heterojunction layer is preferable because it has the effect of leveling the coating surface and reduces the influence of leakage and the like.

[Electron transport layer / hole blocking layer]
In the organic photoelectric conversion element 10 of the present invention, by forming the electron transport layer 18 between the bulk heterojunction layer and the cathode, it becomes possible to more efficiently take out the charges generated in the bulk heterojunction layer. It is preferable to have these layers.

  The electron transport layer 18 may be octaazaporphyrin, a perfluoro product in which a hydrogen atom of a p-type organic semiconductor material is substituted with a fluorine atom (perfluoropentacene, perfluorophthalocyanine, etc.), and the like. The electron transport layer having a HOMO level deeper than the HOMO level of the p-type organic semiconductor material used for the bulk heterojunction layer has a rectifying effect so that holes generated in the bulk heterojunction layer do not flow to the cathode side. The hole blocking function is imparted. In order to further develop the hole blocking function, it is more preferable to have a HOMO level deeper than the HOMO level of the n-type semiconductor. Such an electron transport layer is also called a hole blocking layer, and it is preferable to use an electron transport layer having such a function. Examples of such materials include phenanthrene compounds such as bathocuproine, n-type organic semiconductor materials such as naphthalenetetracarboxylic acid anhydride, naphthalenetetracarboxylic acid diimide, perylenetetracarboxylic acid anhydride, perylenetetracarboxylic acid diimide, and titanium oxide. N-type inorganic oxides such as zinc oxide and gallium oxide, and alkali metal compounds such as lithium fluoride, sodium fluoride, and cesium fluoride can be used. A layer made of a single n-type organic semiconductor material used for the bulk heterojunction layer can also be used. The means for forming these layers may be either a vacuum deposition method or a solution coating method, but is preferably a solution coating method.

[Other layers]
For the purpose of improving energy conversion efficiency and improving the lifetime of the element, a structure having various intermediate layers in the element may be employed. Examples of the intermediate layer include a hole block layer, an electron block layer, a hole injection layer, an electron injection layer, an exciton block layer, a UV absorption layer, a light reflection layer, and a wavelength conversion layer.

[Transparent electrode]
The transparent electrode of the present invention is not particularly limited to the cathode and the anode, and can be selected depending on the element configuration. For example, when used as an anode, it is preferably an electrode that transmits light of 380 to 800 nm. As the material, for example, transparent conductive metal oxides such as indium tin oxide (ITO), SnO ₂ and ZnO, metal thin films such as gold, silver and platinum, metal nanowires and carbon nanotubes can be used.

  Also, a conductive material selected from the group consisting of polypyrrole, polyaniline, polythiophene, polythienylene vinylene, polyazulene, polyisothianaphthene, polycarbazole, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, polyphenylacetylene, polydiacetylene, and polynaphthalene. A functional polymer can also be used. A plurality of these conductive compounds can be combined to form a transparent electrode.

[Counter electrode]
The counter electrode may be a single layer of a conductive material, but in addition to a conductive material, a resin that holds these may be used in combination. As the conductive material of the counter electrode, a material having a small work function (4 eV or less) metal, alloy, electrically conductive compound and a mixture thereof is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the viewpoint of electron extraction performance and durability against oxidation, etc., a mixture of these metals and a second metal which is a stable metal having a larger work function value than this, for example, a magnesium / silver mixture, magnesium / Aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The counter electrode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm.

  If a metal material is used as the conductive material of the counter electrode, the light coming to the counter electrode side is reflected and reflected to the first electrode side, and this light can be reused and is absorbed again by the photoelectric conversion layer, and more photoelectric conversion efficiency Is preferable.

  The counter electrode 13 may be a metal (for example, gold, silver, copper, platinum, rhodium, ruthenium, aluminum, magnesium, indium, etc.), a nanoparticle made of carbon, a nanowire, or a nanostructure. If the dispersion is, a transparent and highly conductive counter electrode can be formed by a coating method.

  Moreover, when making the counter electrode side light-transmitting, for example, after forming a conductive material suitable for the counter electrode such as aluminum and aluminum alloy, silver and silver compound in a thin film thickness of about 1 to 20 nm, By providing a film of the conductive light transmissive material mentioned in the description of the transparent electrode, a light transmissive counter electrode can be obtained.

[Intermediate electrode]
The intermediate electrode material required in the case of the tandem structure as shown in FIG. 3 is preferably a layer using a compound having both transparency and conductivity, and the material used in the transparent electrode. (Transparent metal oxides such as ITO, AZO, FTO and titanium oxide, very thin metal layers such as Ag, Al and Au, or layers containing nanoparticles / nanowires, conductive polymers such as PEDOT: PSS and polyaniline Material etc.) can be used.

  In addition, in the hole transport layer and the electron transport layer described above, there is also a combination that works as an intermediate electrode (charge recombination layer) by appropriately combining and laminating, and with such a configuration, the process of forming one layer This is preferable because it can be omitted.

〔substrate〕
When light that is photoelectrically converted enters from the substrate side, the substrate is preferably a member that can transmit the light that is photoelectrically converted, that is, a member that is transparent to the wavelength of the light to be photoelectrically converted. As the substrate, for example, a glass substrate, a resin substrate and the like are preferably mentioned, but it is desirable to use a transparent resin film from the viewpoint of light weight and flexibility. There is no restriction | limiting in particular in the transparent resin film which can be preferably used as a transparent substrate by this invention, The material, a shape, a structure, thickness, etc. can be suitably selected from well-known things. For example, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) modified polyester, polyethylene (PE) resin film, polypropylene (PP) resin film, polystyrene resin film, polyolefin resins such as cyclic olefin resin Film, vinyl resin film such as polyvinyl chloride, polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysulfone (PSF) resin film, polyether sulfone (PES) resin film, polycarbonate (PC) resin film, A polyamide resin film, a polyimide resin film, an acrylic resin film, a triacetyl cellulose (TAC) resin film, and the like can be given. If the resin film transmittance of 80% or more at ~800nm), can be preferably applied to a transparent resin film according to the present invention. Among these, from the viewpoint of transparency, heat resistance, ease of handling, strength and cost, it is preferably a biaxially stretched polyethylene terephthalate film, a biaxially stretched polyethylene naphthalate film, a polyethersulfone film, or a polycarbonate film, and biaxially stretched. More preferred are polyethylene terephthalate films and biaxially stretched polyethylene naphthalate films.

  The transparent substrate used in the present invention can be subjected to a surface treatment or an easy adhesion layer in order to ensure the wettability and adhesiveness of the coating solution. A conventionally well-known technique can be used about a surface treatment or an easily bonding layer. For example, the surface treatment includes surface activation treatment such as corona discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, and laser treatment. Examples of the easy adhesion layer include polyester, polyamide, polyurethane, vinyl copolymer, butadiene copolymer, acrylic copolymer, vinylidene copolymer, and epoxy copolymer.

  Further, for the purpose of suppressing the permeation of oxygen and water vapor, a barrier coat layer may be formed in advance on the transparent substrate, or a hard coat layer may be formed in advance on the opposite side to which the transparent conductive layer is transferred. Good.

(Optical function layer)
The organic photoelectric conversion element of the present invention may have various optical functional layers for the purpose of more efficient reception of sunlight. As the optical functional layer, for example, a condensing layer such as an antireflection film or a microlens array, or a light diffusion layer that can scatter the light reflected by the cathode and enter the photoelectric conversion layer again can be provided. good.

  Various known antireflection layers can be provided as the antireflection layer. For example, when the transparent resin film is a biaxially stretched polyethylene terephthalate film, the refractive index of the easy adhesion layer adjacent to the film is 1.57. It is more preferable to set it to ˜1.63 because the interface reflection between the film substrate and the easy adhesion layer can be reduced and the transmittance can be improved. The method for adjusting the refractive index can be carried out by appropriately adjusting the ratio of the oxide sol having a relatively high refractive index such as tin oxide sol or cerium oxide sol and the binder resin. The easy adhesion layer may be a single layer, but may be composed of two or more layers in order to improve adhesion.

  As the condensing layer, for example, it is processed so as to provide a structure on the microlens array on the sunlight receiving side of the support substrate, or the amount of light received from a specific direction is increased by combining with a so-called condensing sheet. Conversely, the incident angle dependency of sunlight can be reduced.

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

  Examples of the light scattering layer include various antiglare layers, layers in which nanoparticles or nanowires such as metals or various inorganic oxides are dispersed in a colorless and transparent polymer, and the like.

[Patterning]
There is no restriction | limiting in particular in the method and process of patterning the electrode concerning this invention, a photoelectric converting layer, a positive hole transport layer, an electron carrying layer, etc., A well-known method can be applied suitably.

  If it is a soluble material such as a bulk heterojunction layer and a transport layer, only unnecessary portions may be wiped after the entire surface of die coating, dip coating, etc., or direct patterning at the time of coating using a method such as an ink jet method or screen printing. May be.

  In the case of an insoluble material such as an electrode material, the electrode can be patterned by a known method such as mask vapor deposition during vacuum deposition or etching or lift-off. Alternatively, the pattern may be formed by transferring a pattern formed on another substrate.

[Sealing]
Moreover, since the produced organic photoelectric conversion element 10 does not deteriorate with oxygen, moisture, etc. in the environment, it is preferable to seal not only the organic photoelectric conversion element but also an organic electroluminescence element by a known method. For example, a method of sealing a cap made of aluminum or glass by bonding with an adhesive, a plastic film on which a gas barrier layer such as aluminum, silicon oxide, or aluminum oxide is formed and the organic photoelectric conversion element top 10 with an adhesive Method of bonding, spin coating of organic polymer materials with high gas barrier properties (polyvinyl alcohol, etc.), inorganic thin films with high gas barrier properties (silicon oxide, aluminum oxide, etc.) or organic films (parylene, etc.) deposited under vacuum And a method of laminating these in a composite manner.

[Optical sensor array]
Next, an optical sensor array to which the bulk heterojunction type organic photoelectric conversion element 10 described above is applied will be described in detail. The optical sensor array is produced by arranging the photoelectric conversion elements in a fine pixel form by utilizing the fact that the bulk heterojunction type organic photoelectric conversion elements generate a current upon receiving light, and projected onto the optical sensor array. A sensor having an effect of converting an image into an electrical signal.

  FIG. 4 is a diagram showing the configuration of the photosensor array. 4A is a top view, and FIG. 4B is a cross-sectional view taken along the line A-A ′ of FIG.

  In FIG. 4, the optical sensor array 20 is paired with a transparent electrode 22 as a lower electrode, a photoelectric conversion unit 24 that converts light energy into electric energy, and a transparent electrode 22 on a substrate 21 as a holding member. The counter electrode 23 is sequentially laminated. The photoelectric conversion unit 24 includes two layers of a photoelectric conversion layer 24b having a bulk heterojunction layer in which a p-type organic semiconductor material and an n-type organic semiconductor material are uniformly mixed, and a hole transport layer 24a. The In the example shown in FIG. 4, six bulk heterojunction type organic photoelectric conversion elements are formed.

  The substrate 21, the transparent electrode 22, the photoelectric conversion layer 24 b, and the counter electrode 23 have the same configuration and role as the substrate 11, the transparent electrode 12, the photoelectric conversion layer 14, and the counter electrode 13 in the bulk heterojunction photoelectric conversion element 10 described above. Is shown.

  For example, glass is used for the substrate 21, ITO is used for the transparent electrode 22, and aluminum is used for the counter electrode 23, for example. For example, the BP-1 precursor is used for the p-type organic semiconductor material of the photoelectric conversion layer 24b, and for example, the exemplified compound 13 is used for the n-type organic semiconductor material. The hole transport layer 24a is made of PEDOT (poly-3,4-ethylenedioxythiophene) -PSS (polystyrene sulfonic acid) conductive polymer (trade name Baytron P4083 manufactured by Stark Vitec Co., Ltd.).

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1
<< Production of Organic Photoelectric Conversion Element STA-1 >>
Using a PEN film with a barrier layer (total light transmittance of 90%) as a substrate, the transparent electrode patterned with ITO as an anode is subjected to ultrasonic cleaning with a surfactant and ultra pure water, and ultrasonic cleaning with ultra pure water. After washing in this order, it was dried with nitrogen blow, and finally ultraviolet ozone cleaning was performed.

  On this transparent substrate, Baytron P4083 (manufactured by Starck Vitec), which is a conductive polymer, was spin-coated so as to have a film thickness of 40 nm, and then heated and dried at 140 ° C. in the atmosphere for 10 minutes.

  After forming a Baytron P4083 layer and transferring it under nitrogen, three p-i-n layers were formed as follows.

[P layer]
First, as a p-layer, a BP-1 precursor as a p-type organic semiconductor material is dissolved in chlorobenzene at 0.5% by mass, filtered through a 0.45 μm filter, and then spun to a film thickness of 25 nm. By coating and heating at 180 ° C. for 20 minutes, the BP-1 precursor was converted to BP-1 according to the scheme described in Chemical Formula 12, and a p-layer was obtained.

[I layer]
Next, a liquid in which 1.2% by mass of the BP-1 precursor and 1.0% by mass of Exemplified Compound 1 as the n-type organic semiconductor material was dissolved as an i layer was prepared, and filtered through a 0.45 μm filter. Then, the i layer was obtained by spin-coating to a thickness of 70 nm and heating at 180 ° C. for 20 minutes. Since the molecular weight of the BP-1 precursor is about 5/6 when converted to BP-1, p-type organic semiconductor material: n-type organic semiconductor material = 1: 1.

[N layers]
Finally, as an n-layer, a liquid in which Exemplified Compound 1 was dissolved in toluene at 1.2% by mass was prepared, filtered through a 0.45 μm filter, and then spin-coated to a film thickness of 60 nm. An n layer was obtained by heating at 0 ° C. for 30 minutes.

The board | substrate provided to the said pin layer was moved to the vapor deposition machine, without being exposed to air | atmosphere, and was pressure-reduced to 4 * 10 < ^-4 > Pa. Aldrich's bathocuproine and aluminum were placed in a resistance heating boat made of tantalum and a resistance heating boat made of tungsten, and mounted in a vapor deposition machine.

  Next, the tantalum resistance heat boat was energized and heated, and an electron transport layer of bathocuproine was formed to 6 nm on the substrate. Subsequently, the tungsten tantalum heating boat was energized and heated, and an Al electrode serving as a cathode having a film thickness of 100 nm was deposited at a deposition rate of 1 to 2 nm / second so as to be orthogonal to the transparent conductive film.

  The obtained organic photoelectric conversion element STA-1 is a flexible sealing using a PEN film as a base material, except for the edge part, so that an external extraction terminal of the cathode and the anode can be formed, and an adhesive is applied around the cathode. After pasting the members, the adhesive was cured by heat treatment.

<< Production of Organic Photoelectric Conversion Elements STA-2 to 9 >>
STA-2 to 9 are the same as in the production of the organic photoelectric conversion element STA-1, except that the p-type and n-type organic semiconductor materials of the p-layer, i-layer and n-layer are replaced with the semiconductor materials described in Table 2. Was made.

  The p layer of STA-7 was pentacene by using a pentacene precursor and heating at 180 ° C. for 20 minutes. The compounds used are shown below.

(Preparation of polymer 1)
Adv. Mater. , Vol. Bis-PCBM was synthesized with reference to 20 (2008), p2116. Next, J.H. Mater. Chem. , Vol. 15 (2005), p5158, bis-PCBM was chlorinated to synthesize the following monomer 1, and 0.95 equivalents of 2,5-bis (octyloxy) -1,4-bis in the following scheme: (Hydroxymethyl) benzene, 1 equivalent of monomer 1 and a polycondensation reaction in the presence of a base, after completion of the reaction, methanol is added to stop the reaction, and a polymer of general formula (1) which is a fullerene-containing polymer 1 (Mn = 5500) was obtained.

[Evaluation of carrier mobility of organic semiconductors]
The average mobility of carriers in organic semiconductors was evaluated using the following FET method.

<Preparation of substrate for organic thin film transistor>
W is formed from Au having a thickness of 100 nm on a n-type Si wafer having a specific resistance of 0.02 Ω · cm having a silicon oxide film having a thickness of 200 nm formed by thermal oxidation, using a known lithography technique. A source / drain electrode pattern having a shape of = 220 μm and L = 10 μm was formed.

<Preparation of organic thin film transistor array 1>
The substrate having the source / drain electrode pattern was washed with acetone / isopropanol, and then dry-cleaned at 70 ° C. for 10 minutes using a UV ozone cleaner UV-1 manufactured by SAMCO.

  After dry cleaning, a monomolecular film made of pentafluorobenzenethiol (hereinafter sometimes abbreviated as PFBT) was formed on the source / drain electrodes in the following steps.

  The substrate subjected to dry cleaning was set in a vacuum chamber, and then the inside of the chamber was decompressed to 2 torr at room temperature. At this point, the valve connected to the container containing PFBT was opened and PFBT vapor was introduced into the chamber for 5 minutes. Next, the valve connected to the PFBT was closed, nitrogen purge and decompression were repeated several times, the chamber was returned to atmospheric pressure, the substrate was taken out, and washed with ethanol several times.

  Next, hexamethyldisilazane (HMDS) is spin-coated at 4000 rpm for 30 seconds on the above substrate, dried at 90 ° C. for 90 seconds, washed with toluene, and a single molecule composed of HMDS on the silicon oxide film surface. A film was formed.

  Next, the target organic semiconductor material was dissolved in chlorobenzene at a concentration of 2.5% by mass, and this solution was spin-coated at 1200 rpm for 30 seconds to form an organic semiconductor layer.

<Measurement of carrier mobility>
For each organic semiconductor material, using each organic thin film transistor, carrier characteristics are obtained from IV characteristics when a drain bias is swept from −40 V and a gate bias from −40 V to 40 V using a semiconductor parameter measuring apparatus B1500 manufactured by Agilent Technologies. The mobility was calculated, and the average value for the 10 elements was calculated and used as the carrier mobility of the organic semiconductor material.

  The results obtained are shown in Table 1.

  In the following table, carrier mobility is abbreviated as mobility.

[Evaluation of organic photoelectric conversion elements]
<< Photoelectric conversion efficiency >>
An organic photoelectric conversion element sealed with a glass sealing cap and a UV curable resin is irradiated with light from a solar simulator (AM1.5G) at an intensity of 100 mW / cm ² to obtain voltage-current characteristics. The photoelectric conversion efficiency was determined by measurement. That is, for each organic photoelectric conversion element, current-voltage characteristics are measured at room temperature using an IV tester, and the form factor (F) correlates with short-circuit current density (Jsc), open-circuit voltage (Voc), and rectification. F.) and the photoelectric conversion efficiency (η (%)) was determined from these. In addition, the photoelectric conversion efficiency ((eta) (%)) of the solar cell was computed based on the following formula (A).

η = 100 × (Voc × Jsc × FF) / P (A)
Here, P is the incident light intensity [mW / cm ² ], Voc is the open circuit voltage [V], Jsc is the short-circuit current density [mA / cm ² ], F.I. F. Indicates a form factor.

《Durability evaluation》
A solar simulator (AM1.5G) was irradiated at an irradiation intensity of 100 mW / cm ² , voltage-current characteristics were measured, and initial conversion efficiency was measured. Furthermore, assuming that the initial conversion efficiency at this time is 100, the conversion efficiency after being continuously irradiated for 500 h at an irradiation intensity of 100 mW / cm ² with a resistor connected between the anode and the cathode was evaluated, and the relative reduction efficiency was calculated. . From this result, durability (light irradiation) was evaluated according to the following evaluation criteria.

Formula Relative reduction efficiency (%) = (1−conversion efficiency after exposure / conversion efficiency before exposure) × 100
Evaluation criteria ○: Relative reduction efficiency is less than 20% Δ: Relative reduction efficiency is 20% or more and 40% or less ×: Relative reduction efficiency is 40% or more Table 2 shows the results obtained. In the following tables, organic photoelectric conversion elements, p-type organic semiconductor materials, and n-type organic semiconductor materials are abbreviated as photoelectric conversion elements, p-type semiconductors, and n-type semiconductors, respectively.

  As is apparent from Table 2, it can be seen that the organic photoelectric conversion element of the present invention has improved photoelectric conversion efficiency and durability mainly due to improvement in short-circuit current density.

Example 2
<< Production of Organic Photoelectric Conversion Element STA-21 >>
[Metal electrode]
Using a PEN film with a barrier layer (total light transmittance of 90%) as a substrate, the transparent electrode patterned with ITO as a cathode is ultrasonically cleaned with a surfactant and ultrapure water, and ultrasonically cleaned with ultrapure water. After washing in this order, it was dried with nitrogen blow, and finally ultraviolet ozone cleaning was performed.

  On a transparent electrode, a solution in which Ti-isopropoxide is dissolved in ethanol to 0.05 mol / L is prepared, masked, and then applied to a film thickness of 20 nm, and nitrogen having an adjusted water vapor amount. An electron transport layer was formed by standing in the middle.

  After this, the substrate was brought into the glove box and worked under a nitrogen atmosphere. First, the substrate was heat-treated at 180 ° C. for 3 minutes in a nitrogen atmosphere.

[N layers]
As an n layer, a liquid in which Exemplified Compound 1 was dissolved in toluene at 1.2% by mass was prepared, filtered through a 0.45 μm filter, spin-coated to a film thickness of 60 nm, and 180 ° C. The n layer was obtained by heating for 30 minutes.

[I layer]
Next, a liquid in which 1.2% by mass of the BP-1 precursor and 1.0% by mass of Exemplified Compound 1 as the n-type organic semiconductor material was dissolved as an i layer was prepared, and filtered through a 0.45 μm filter. Then, the i layer was obtained by spin-coating to a thickness of 70 nm and heating at 180 ° C. for 20 minutes. Since the molecular weight of the BP-1 precursor is about 5/6 when converted to BP-1, p-type organic semiconductor material: n-type organic semiconductor material = 1: 1.

[P layer]
As a p-layer, BP-1 precursor as a p-type organic semiconductor material is dissolved in chlorobenzene at 0.5% by mass, filtered through a 0.45 μm filter, and spin-coated so as to have a film thickness of 25 nm. And by heating at 180 degreeC for 20 minute (s), the BP-1 precursor was converted into BP-1 similarly to Example 1, and the p layer was obtained.

  On a transparent electrode, Baytron P4083 (manufactured by Starck Vitec), which is a conductive polymer, was spin-coated so as to have a film thickness of 40 nm, and then dried by heating at 140 ° C. in the atmosphere for 10 minutes.

Subsequently, the substrate provided up to the hole transport layer was moved to a vapor deposition machine without being exposed to the atmosphere, and the pressure was reduced to 4 × 10 ⁻⁴ Pa.

TA-21 on which the electron transport layer, the photoelectric conversion layer, and the hole transport layer were formed was placed in a vacuum deposition apparatus. An element is set so as to be orthogonal to TA-21, and the inside of the vacuum deposition apparatus is depressurized to 10 ⁻³ Pa or less, and then Au is deposited to 150 nm to form an anode, thereby forming an organic photoelectric conversion element having a size of 2 mm square. STA-21 was obtained.

  The obtained organic photoelectric conversion element STA-21 was coated with an adhesive and bonded with a flexible sealing member using a PEN film as a base material, except for the ends so that external lead terminals for the cathode and anode could be formed. After that, the adhesive was cured by heat treatment.

<< Preparation of Organic Photoelectric Conversion Element STA-22-24 >>
In the same manner as in the manufacture of the organic photoelectric conversion element STA-21, except that the p-type and n-type organic semiconductor materials of the p-layer, i-layer, and n-layer were replaced with the semiconductor materials described in Table 3, STA-22-24 Was made.

  As in Example 1, it can be seen from Table 3 that the organic photoelectric conversion element of the present invention has improved photoelectric conversion efficiency and durability mainly due to improved short-circuit current density.

Example 3
In the i layer of Example 1, the organic photoelectric layer is formed in the same manner as in Example 1 except that the mixing ratio of the p-type organic semiconductor material and the n-type organic semiconductor material is changed as shown in Table 4 so that the i layer has a three-layer structure. Conversion element STA-41 was produced and evaluated. In the table, the layer No. 1-3 were laminated in order from the light incident side.

  It can be seen that STA-41 is more preferable than STA-6 of Example 1.

DESCRIPTION OF SYMBOLS 10 Bulk heterojunction type organic photoelectric conversion element 11 Substrate 12 Transparent electrode 13 Counter electrode 14 Photoelectric conversion layer 14p p layer 14i i layer 14n n layer 14 '1st photoelectric conversion part 15 Charge recombination layer 16 2nd photoelectric conversion part 17 Hole transport layer 18 Electron transport layer 20 Photosensor array 21 Substrate 22 Transparent electrode 23 Counter electrode 24 Photoelectric conversion part 24a Hole transport layer 24b Photoelectric conversion layer

Claims (11)

Between the counter electrode and the transparent electrode, at least a p-layer made of a p-type organic semiconductor material alone, an i-layer made of a mixed layer of a p-type organic semiconductor material and an n-type organic semiconductor material, and an n-type organic semiconductor material alone Carrier mobility of a p-type organic semiconductor material, which is an organic photoelectric conversion element having a p-i-n photoelectric conversion layer in which n layers of layers are stacked and used for the p layer on the light incident side but the i layer rather low from the p-type organic semiconductor materials carrier mobility used, the carrier mobility of the n-type organic semiconductor material used in the n-layer, n-type organic semiconductor material used in the i layer the organic photoelectric conversion element characterized in carrier mobility equal to or lower Ikoto. The carrier mobility of the n-type organic semiconductor material used for the n-layer, an organic photoelectric conversion element according to claim 1, wherein the low Ikoto than the carrier mobility of the n-type organic semiconductor material used in the i layer. The i layer is composed of 2 to 5 layers, the mass ratio of the p-type organic semiconductor material in the i layer near the p layer is increased, and the mass ratio of the n-type organic semiconductor material in the i layer near the n layer The organic photoelectric conversion element according to claim 1, wherein the organic photoelectric conversion element is high. The organic photoelectric conversion device according to any one of claims 1 to 3, wherein the p-type organic semiconductor material contains a porphyrin derivative. The n-type organic as a semiconductor material, organic photoelectric conversion element of any one of claims 1-4, characterized in that it contains the fullerene derivative. 6. The organic photoelectric conversion device according to claim 5 , wherein the fullerene derivative is a polymer compound obtained by polymerizing a monomer compound represented by the following general formula (1).
(In the formula, R ₁ and R ₂ represent a substituent selected from a substituted or unsubstituted alkyl group, a cyclized alkyl group, an aralkyl group, an aryl group, a heteroaryl group, and a silyl group, and L ₁ and L ₂ are substituted. Or an unsubstituted alkylene group, an alkenediyl group, an alkynediyl group, a cyclene alkylene group, an arylene group, a heteroarylene group, a silylene group, an ether group, a thioether group, a strong carbonyl group, a strong ruboxyl group, an amino group, an amide group, or these Represents a structure in which a plurality are connected, and n represents an integer greater than or equal to 2. In the formula, only one hemispherical portion of the spherical fullerene structure is shown, the other hemispherical portion is omitted, and the fullerene structure is substituted. The positional relationship between the first substituent containing R ₁ and L ₁ and the second substituent containing R ₂ and L ₂ is arbitrary. The organic photoelectric conversion device according to claim 5 or 6 , wherein the fullerene derivative is a compound obtained by polymerizing and crosslinking a monomer having a structure represented by the following general formula (2).
(Wherein R ₃ and R ₄ represent a substituent selected from a substituted or unsubstituted alkyl group, a cyclized alkyl group, an aralkyl group, an aryl group, a heteroaryl group, and a silyl group, and L ₃ and L ₄ are substituted. Or an unsubstituted alkylene group, an alkenediyl group, an alkynediyl group, a cyclene alkylene group, an arylene group, a heteroarylene group, a silylene group, an ether group, a thioether group, a strong carbonyl group, a strong ruboxyl group, an amino group, an amide group, or these And G ₁ and G ₂ are polymerized groups that form a connecting chain of a three-dimensional network structure, where only one hemisphere portion of the spherical fullerene structure is shown, and the other hemisphere portion is omitted, the second replacement comprising a first substituent comprising _{G 1,} R 3, _{L 3} is substituted fullerene _structure, a G _2, R 4, L4 The positional relationship is arbitrary.).   The organic photoelectric conversion element according to claim 1, wherein the photoelectric conversion layer is formed by a solution process.   The organic photoelectric conversion according to claim 1, wherein at least one of the photoelectric conversion layers is made of a material that can be insolubilized after being formed by a solution process. element.   It consists of an organic photoelectric conversion element of any one of Claims 1-9, The solar cell characterized by the above-mentioned.   10. An optical sensor array comprising the organic photoelectric conversion elements according to claim 1 arranged in an array.