JP2011124421A - Organic photoelectric conversion element, solar battery and optical sensor array each using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoelectric conversion element having high photoelectric conversion efficiency and high durability; and to provide a solar battery and an optical sensor array each using the element. <P>SOLUTION: The organic photoelectric conversion element has a transparent electrode, counter-electrodes, and a photoelectric conversion layer in which a p-type semiconductor material and an n-type semiconductor material are mixed. In the element, the photoelectric conversion layer contains a compound containing a partial structure represented by specific general formula. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an organic photoelectric conversion element, a solar cell, and an optical sensor array, and more specifically, an organic photoelectric conversion element having a bulk heterojunction type layer in which a p-type semiconductor material and an n-type semiconductor material are mixed, and the organic The present invention relates to a solar cell and an optical array sensor using a photoelectric conversion element.

  Due to the recent rise in fossil energy, a system that can generate electric power directly from natural energy has been demanded. Solar cells using monocrystalline, polycrystalline, or amorphous Si, compound-based solar cells such as GaAs and 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 the power generation cost of fossil fuel, an electron donor layer (p-type semiconductor layer) and an electron acceptor layer ( A bulk heterojunction photoelectric conversion element having a photoelectric conversion layer mixed with an n-type semiconductor layer has been proposed (see, for example, Non-Patent Document 1 and Patent Document 1).

  Since these bulk heterojunction solar cells are formed by a coating process except for the anode and cathode, it is expected that they can be manufactured at high speed and at low cost, and may solve the above-mentioned problem of power generation cost. There is. Furthermore, unlike the Si-based solar cells, compound semiconductor-based solar cells, and dye-sensitized solar cells described above, there is no process at a temperature higher than 160 ° C., so that it can be formed on a cheap and lightweight plastic substrate. Is done.

  In Non-Patent Document 1, conversion efficiency exceeding 5% has been achieved. This is achieved by utilizing intramolecular charge transfer between a thiophene ring and a benzothiadiazole ring, which is very long wavelength (˜900 nm). This is because it has become possible to absorb a wide range of sunlight until.

  On the other hand, durability is also required for the solar cell, but the durability of the organic thin film solar cell is still insufficient. In another non-patent document 2 using the above material, it is reported that the photoelectric conversion efficiency is reduced by about 40% in 100 hours.

  A compound having a structure similar to the compound used in the present invention has been disclosed (see, for example, Patent Document 2), but it is disclosed here for use as a sensitizing dye in a dye-sensitized solar cell. is there.

  In addition to the existing electron donating polymer and electron accepting compound, as disclosed in Patent Document 3 and the like, attempts have been made to increase the conversion efficiency by containing a third component.

  However, even if the above-described prior art is used, it is difficult to achieve both high conversion efficiency and high durability, and high conversion efficiency and high durability, an organic photoelectric conversion element, and a solar cell and light using the same A sensor array was desired.

JP-T 8-500701 JP 2001-76773 A JP 2007-180190 A

Nature Mat. , Vol. 6 (2007), p497) Science_317_2007_p222)

  The present invention has been made in view of the above problems, and an object thereof is to provide an organic photoelectric conversion element having high photoelectric conversion efficiency and durability, a solar cell using the organic photoelectric conversion element, and an optical sensor array. There is to do.

  The above object of the present invention is achieved by the following configurations.

  1. In an organic photoelectric conversion element having a transparent electrode, a counter electrode, and a photoelectric conversion layer in which a p-type semiconductor material and an n-type semiconductor material are mixed, the photoelectric conversion layer is represented by the following general formulas (1A) to (1C). An organic photoelectric conversion element comprising any one of compounds having a partial structure.

(In the formula, X ₁ and Y _{1 each} represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, or a substituted or unsubstituted carbon atom. R represents a substituent, and n represents an integer of 0 to 4. Z ₁ , Z ₂ and Z ₃ represent a substituted or unsubstituted 5-membered ring or 6-membered ring.
2. 2. The organic photoelectric conversion device according to 1 above, wherein Y ₁ represents a nitrogen atom in the compound having a partial structure represented by the general formulas (1A) to (1C).

  3. 2. The organic photoelectric conversion device according to 1 or 2 above, wherein two or more partial structures represented by the general formulas (1A) to (1C) are contained in one molecule.

  4). The partial structures represented by the general formulas (1A) to (1C) are partial structures represented by the following general formulas (2A), (2B), and (2C), respectively. The organic photoelectric conversion element of any one of these.

(In the formula, X ₁ and Y ₁ represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, and a substituted or unsubstituted carbon atom. Ar represents a substituted or unsubstituted aromatic group. R represents a substituent. N represents an integer of 0 to _4. Z ₁ , Z ₂ , Z ₃ and Z ₄ represent a substituted or unsubstituted 5-membered ring or 6-membered ring, and m represents the degree of polymerization.)
5). The partial structures represented by the general formulas (1A) to (1C) are partial structures represented by the following general formulas (3A), (3B), or (3C), respectively. The organic photoelectric conversion element of any one of these.

(Wherein X ₁ and X ₂ represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, or a substituted or unsubstituted carbon atom, n represents an integer of 0 to 4, R represents a substituent, and m represents a substituent. Represents the degree of polymerization.)
6). The partial structures represented by the general formulas (1A) to (1C) are partial structures represented by the following general formulas (4A), (4B), or (4C), respectively. The organic photoelectric conversion element of any one of these.

(Wherein X ₁ and X ₂ represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, or a substituted or unsubstituted carbon atom, n represents an integer of 0 to 4, R represents a substituent, and m represents a substituent. Represents the degree of polymerization.)
7). 7. The organic photoelectric conversion device according to any one of 1 to 6, wherein n represents 0 or 1 in the partial structure represented by the general formulas (1A) to (4C).

8). 8. The compound having a partial structure represented by the general formulas (1A) to (4C), wherein X ₁ and X ₂ represent a sulfur atom or an oxygen atom, Organic photoelectric conversion element.

  9. 9. The organic photoelectric conversion element as described in any one of 1 to 8 above, wherein the compound having a partial structure represented by the general formulas (1A) to (4C) is a polymer compound.

  10. The photoelectric conversion layer contains an electron-accepting fullerene compound, an electron-donating p-type semiconductor material, and a low-molecular compound having a structure represented by the general formulas (1A) to (1C). 10. The organic photoelectric conversion element according to any one of 1 to 9, which is characterized by the following.

  11. 11. The organic material according to any one of 1 to 10 above, wherein the layer containing a compound having a partial structure represented by the general formulas (1A) to (4C) is produced by a solution coating method. Photoelectric conversion element.

  12 It consists of the organic photoelectric conversion element of any one of said 1-11, The solar cell characterized by the above-mentioned.

  13. The organic photoelectric conversion element of any one of said 1-11 is arrange | positioned at array form, The optical sensor array characterized by the above-mentioned.

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

It is an example of sectional drawing which shows the solar cell which consists of a bulk hetero junction type organic photoelectric conversion element. It is an example of 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 an example of 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 an example of the figure which shows the structure of an optical sensor array.

  Hereinafter, embodiments for carrying out the present invention will be described in detail.

  As a result of intensive studies in view of the above problems, the present inventor has found partial structures represented by general formulas (1A) to (1C) according to the present invention in an organic photoelectric conversion element having a bulk heterojunction type layer. By applying the cyanine dye derivative, which is a compound having a wide range of absorption up to a long wavelength and exhibiting high efficiency and long-life device performance, the cyanine dye derivative according to the present invention can be used for organic thin film solar cells. As a result, the present invention has been found to be effective as a type semiconductor material and has reached the present invention.

  Hereinafter, details of each component according to the present invention will be sequentially described.

  The organic photoelectric conversion element of the present invention is characterized in that a material containing a cyanine derivative structure is used.

  Hereinafter, the material containing the cyanine derivative partial structure according to the present invention will be described.

  In the present invention, a compound having a partial structure represented by general formulas (1A) to (1C) is used in an organic photoelectric conversion element having a bulk heterojunction type layer.

(In the formula, X ₁ and Y _{1 each} represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, or a substituted or unsubstituted carbon atom. R represents a substituent, and n represents an integer of 0 to 4. Z ₁ , Z ₂ and Z ₃ represent a substituted or unsubstituted 5-membered ring or 6-membered ring.
Preferably, the compounds represented by the general formulas (1A) to (1C) have partial structures represented by the general formulas (2A) to (2C), respectively.

(In the formula, X ₁ and Y ₁ represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, and a substituted or unsubstituted carbon atom. Ar represents a substituted or unsubstituted aromatic group. R represents a substituent. N represents an integer of 0 to _4. Z ₁ , Z ₂ , Z ₃ and Z ₄ represent a substituted or unsubstituted 5-membered ring or 6-membered ring, and m represents the degree of polymerization.)
Preferably, the compounds represented by the general formulas (1A) to (1C) have partial structures represented by the general formulas (3A) to (3C), respectively.

(Wherein X ₁ and X ₂ represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, or a substituted or unsubstituted carbon atom, n represents an integer of 0 to 4, R represents a substituent, and m represents a substituent. Represents the degree of polymerization.)
Preferably, the compounds represented by the general formulas (1A) to (1C) have partial structures represented by the general formulas (4A) to (4C), respectively.

(Wherein X ₁ and X ₂ represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, or a substituted or unsubstituted carbon atom, n represents an integer of 0 to 4, R represents a substituent, and m represents a substituent. Represents the degree of polymerization.)
In the general formulas (1A) to (4C), Ar represents a substituted or unsubstituted aromatic group. R represents a substituent. X ₁ and X _{2 each} represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, or a substituted or unsubstituted carbon atom.

  Ar includes, for example, phenyl, indenyl, azulenyl, naphthyl, biphenyl, terphenylyl or quadphenylyl, as-indacenyl, s-indacenyl, acenaphthylenyl, phenanthryl, fluoranthenyl, triphenylenyl, chrysenyl, naphthacene, picenyl, perylenyl, pentaphenyl , Hexacenyl, pyrenyl, anthracenyl, thienyl, benzo [b] thienyl, dibenzo [b, d] thienyl, thiantenyl, furyl, furfuryl, 2H-pyranyl, benzofuranyl, isobenzofuranyl, 2H-chromenyl, xanthenyl, dibenzofuranyl, Phenoxythienyl, pyrrolyl, imidazolyl, pyrazolyl, pyridyl, bipyridyl, triazinyl, pyrimidinyl, pyrazinyl, 1H-pyrrolidinyl, iso Ndolyl, pyridazinyl, indolizinyl, isoindolyl, indolyl, 3H-indolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, indazolyl, purinyl, quinolidinyl, quinolyl, isoquinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinoxalinyl, quinoxalinyl Examples include carbazolyl, carbolinyl, benzotriazolyl, benzoxazolyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl, or phenoxazinyl.

  Substituent or R is an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, etc.), cycloalkyl group (for example, cyclohexyl group, cyclopentyl group, etc.) , Alkenyl group, cycloalkenyl group, alkynyl group (for example, propargyl group), glycidyl group, acrylate group, methacrylate group, aromatic group (for example, phenyl group, naphthyl group, anthracenyl group, etc.), heterocyclic group (for example, Pyridyl group, thiazolyl group, oxazolyl group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sriphoranyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, etc.), alkoxy group (for example, methoxy Group, ethoxy group, Propyloxy group, pentyloxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxy) Carbonyl group etc.), aryloxycarbonyl group (eg phenyloxycarbonyl group etc.), sulfonamide group (eg methanesulfonamide group, ethanesulfonamide group, butanesulfonamide group, hexanesulfonamide group, cyclohexanesulfonamide group, Benzenesulfonamido group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group) Group, cyclohexylaminosulfonyl group, phenylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), urethane group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group, 2-pyridylureido group) Etc.), acyl groups (eg acetyl group, propionyl group, butanoyl group, hexanoyl group, cyclohexanoyl group, benzoyl group, pyridinoyl group etc.), carbamoyl groups (eg aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl) Group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), acylamino group (for example, acetyl) Sulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group), amino group (for example, methylamino group, benzoylamino group, methylureido group, etc.) Amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, anilino group, 2-pyridylamino group, etc.), halogen atom (for example, chlorine atom, bromine atom, iodine atom etc.), cyano group, nitro group Group, sulfo group, carboxyl group, hydroxyl group, phosphono group (for example, phosphonoethyl group, phosphonopropyl group, phosphonooxyethyl group) and the like. Further, these groups may be further substituted with these groups.

  Moreover, several R may couple | bond together and it may form the ring structure. Furthermore, R may be different from each other.

In the general formulas (1A) to (1C), when Y ₁ is a nitrogen atom, an element having a high molar extinction coefficient and high conversion efficiency can be obtained, which is preferable. Moreover, it is preferable that two or more partial structures represented by the general formulas (1A) to (1C) are included in one molecule.

  In the general formulas (2A) to (4C), a high molecular compound is preferable because mobility is improved as compared with a low molecular compound. This is considered to be because the crystallinity of the compound is improved. Moreover, since stability of a compound will be impaired when a methine chain is too long generally, n shows the integer of 0-4. n is preferably 0 to 3, and more preferably 0 to 1.

As shown in the general formulas (4A) to (4C), when a thiophene ring is included, the absorption wavelength becomes longer, and sunlight can be used effectively, which is preferable. In addition, the crystallinity of the compound is improved and the mobility is improved. Further, when X ₁ and X ₂ are chalcogen atoms, an element having a high molar absorption coefficient and high conversion efficiency can be obtained. X ₁ and X ₂ are preferably each independently a sulfur atom or an oxygen atom.

  Further, as described in Patent Document 3, a basic carrier path is formed from a known p-type material and n-type fullerene material, and the general formulas (1A) to (1C) of the present invention are used as the third component. The structure which the compound which has the structure represented by this is added may be sufficient. This is because the structures represented by the general formulas (1A) to (1C) of the present invention are excellent in absorbance, so that the photoelectric conversion efficiency can be improved by the effect of improving the external quantum efficiency even by adding to the existing photoelectric conversion layer. It is because it can improve. For such a purpose, when the compound having a structure represented by the general formulas (1A) to (1C) of the present invention is contained in the photoelectric conversion layer, it is preferably a low molecular compound.

  In the present invention, the low molecular weight compound means a single molecule having no distribution in the molecular weight of the compound. If it is a compound which has a partial structure of general formula (1A)-(1C), there will be no restriction | limiting in particular in a minimum.

  In the formula, m is a degree of polymerization and is an integer set so that the total molecular weight is 3000 or more. The degree of polymerization is not particularly limited, but if the degree of polymerization is too high, the solubility in a solvent is lowered, which causes a problem in preparing a coating solution. Therefore, it is preferable to set the molecular weight so as to have an appropriate solubility. It is preferably 1% by mass or more, more preferably 3% by mass or more, based on the solvent used.

  The polymer compound according to the present invention means an aggregate of compounds having a certain molecular weight distribution by reacting a predetermined monomer. However, when defining by molecular weight in practice, a compound having a molecular weight of less than 3000 is classified as a low molecular weight compound. More preferably, it is less than 2500, More preferably, it is less than 2000. On the other hand, a compound having a molecular weight of 3000 or more, more preferably 4000 or more, and further preferably 5000 or more is classified as a polymer compound. The molecular weight can be measured by gel permeation chromatography (GPC).

  Hereinafter, although the specific example of the compound represented by general formula (1A)-(4C) of this invention is given, this invention is not limited to these.

  These compounds are described in Org. Lett. , Vol. 6, no. 6, 2004, p909, and Adv. Mater. 2007, 19, 2295-2300.

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

[Configuration of organic photoelectric conversion element and solar cell]
FIG. 1 is a cross-sectional view showing an example of a solar cell composed of a bulk heterojunction organic photoelectric conversion element. In FIG. 1, a bulk heterojunction type organic photoelectric conversion element 10 includes a transparent electrode (generally an anode) 12, a hole transport layer 17, a bulk heterojunction layer photoelectric conversion unit 14, and an electron transport layer 18 on one surface of a substrate 11. And a counter electrode (generally a cathode) 13 are sequentially stacked.

  The substrate 11 is a member that holds the transparent electrode 12, the photoelectric conversion unit 14, and the counter electrode 13 that are sequentially stacked. In the present embodiment, since light that is photoelectrically converted enters from the substrate 11 side, the substrate 11 can transmit the light that is photoelectrically converted, that is, with respect to the wavelength of the light to be photoelectrically converted. It is a transparent member. As the substrate 11, for example, a glass substrate or a resin substrate is used. The substrate 11 is not essential. For example, the bulk heterojunction type organic photoelectric conversion element 10 may be configured by forming the transparent electrode 12 and the counter electrode 13 on both surfaces of the photoelectric conversion unit 14.

  The photoelectric conversion unit 14 is a layer that converts light energy into electric energy, and includes a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are uniformly mixed. The p-type semiconductor material functions relatively as an electron donor (donor), and the n-type semiconductor material functions relatively as an electron acceptor (acceptor). Here, the electron donor and the electron acceptor are “an electron donor in which, when light is absorbed, electrons move from the electron donor to the electron acceptor to form a hole-electron pair (charge separation state)”. And an electron acceptor ”, which does not simply donate or accept electrons like an electrode, but donates or accepts electrons by a photoreaction.

  In FIG. 1, light incident from the transparent electrode 12 through the substrate 11 is absorbed by the electron acceptor or electron donor in the bulk heterojunction layer of the photoelectric conversion unit 14, and electrons move from the electron donor to the electron acceptor. Thus, a hole-electron pair (charge separation state) is formed. The generated electric charge is caused by an internal electric field, for example, when the work functions of the transparent electrode 12 and the counter electrode 13 are different, the electrons pass between the electron acceptors due to the potential difference between the transparent electrode 12 and the counter electrode 13, and the holes are The photocurrent is detected by passing between the donors and being carried to different electrodes. For example, when the work function of the transparent electrode 12 is larger than the work function of the counter electrode 13, electrons are transported to the transparent electrode 12 and holes are transported to the counter electrode 13. If the magnitude of the work function is reversed, electrons and holes are transported in the opposite direction. In addition, by applying a potential between the transparent electrode 12 and the counter electrode 13, the transport direction of electrons and holes can be controlled.

  Although not shown in FIG. 1, other layers such as a hole blocking layer, an electron blocking layer, an electron injection layer, a hole injection layer, or a smoothing layer may be included.

  A more preferable configuration is an example (FIG. 2) in which the photoelectric conversion unit 14 has a so-called p-i-n three-layer configuration. A normal bulk heterojunction layer is a 14i layer composed of a mixture of a p-type semiconductor material and an n-type semiconductor layer, but a 14p layer composed of a single p-type semiconductor material and a 14n layer composed of a single n-type semiconductor material. By sandwiching, the rectification of holes and electrons becomes higher, loss due to recombination of charge-separated holes and electrons is reduced, and higher photoelectric conversion efficiency can be obtained.

  Furthermore, it is good also as a tandem-type structure which laminated | stacked such a photoelectric conversion element for the purpose of the improvement of sunlight utilization factor (photoelectric conversion efficiency). FIG. 3 is an example of a cross-sectional view illustrating a solar cell including an organic photoelectric conversion element including a tandem bulk heterojunction layer. In the case of the tandem configuration, the transparent electrode 12 and the first photoelectric conversion unit 14 ′ are sequentially stacked on the substrate 11, the charge recombination layer 15 is stacked, the second photoelectric conversion unit 16, and then the counter electrode. By stacking 13, a tandem configuration can be obtained. The second photoelectric conversion unit 16 may be a layer that absorbs the same spectrum as the absorption spectrum of the first photoelectric conversion unit 14 'or may be a layer that absorbs a different spectrum, but is preferably a layer that absorbs a different spectrum. is there. Further, the first photoelectric conversion unit 14 ′ and the second photoelectric conversion unit 16 may both have the above-described three-layer configuration of pin.

Below, the material which comprises these layers is described.
[P-type semiconductor materials]
The present invention includes a compound having a partial structure represented by general formulas (1A) to (1C). Examples of p-type semiconductor materials that can be used in combination include the following.

  Examples of general p-type semiconductor materials include various condensed polycyclic aromatic low-molecular compounds and conjugated polymers.

  Examples of the condensed polycyclic aromatic low molecular weight compound include anthracene, tetracene, pentacene, hexacene, heptacene, chrysene, picene, fluorene, pyrene, peropyrene, perylene, terylene, quaterylene, coronene, ovalene, circumanthanthene, bisanthene, zeslene. , Compounds such as heptazesulene, pyranthrene, violanthene, isoviolanthene, cacobiphenyl, anthradithiophene, porphyrin, copper phthalocyanine, tetrathiafulvalene (TTF) -tetracyanoquinodimethane (TCNQ) complex, bisethylenetetrathiafulvalene ( BEDTTTTF) -perchloric acid complexes, and derivatives and precursors thereof.

  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.

  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, a polythiophene-thienothiophene copolymer, a polythiophene-diketopyrrolopyrrole copolymer described in WO2008000664, 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.

  In addition, oligomeric materials, not polymer materials, include thiophene hexamer α-seccithiophene α, ω-dihexyl-α-sexualthiophene, α, ω-dihexyl-α-kinkethiophene, α, ω-bis (3 Oligomers such as -butoxypropyl) -α-sexithiophene can be preferably used.

  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 fullerene derivative of the n-type organic semiconductor material which is a preferred embodiment of the present invention.

  On the other hand, in order to obtain a thicker film, a thick film can be easily obtained if it can be further coated on a layer that has been coated once. When a layer is used by lamination by a solution process, there is a problem that the layer cannot be laminated because the underlying layer is dissolved. Therefore, a material that can be insolubilized after application by a solution process is preferable.

  Examples of such materials include materials that can be insolubilized by polymerizing 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. Or a material in which soluble substituents react and become 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 Etc.

  Among these, materials that can be pigmented after coating with high mobility after insolubilization are preferable, and among them, porphyrin compounds described in JP-A-2008-16834 are preferably used. This porphyrin-based compound (BP-1 precursor) has four sterically bulky bicyclo groups at the molecular end at the time of coating. However, when energy such as heat is applied, the reverse Diels-Alder reaction is performed. Then, the bicyclo group part reacts to release 4 molecules of ethylene gas, which is converted into a benzoporphyrin derivative (BP-1) insoluble in the solvent.

  Examples of such a material that can be converted into an insoluble pigment after coating include compounds described in paragraph numbers 0044 and 0045 of JP-A-2008-16834.

  Such porphyrin-based compounds are disclosed in JP 2008-16834 A, Chem. Commun. 1998, p1661 etc. can be synthesized with reference.

[N-type semiconductor materials]
The n-type semiconductor material used in the bulk heterojunction layer of the present invention is not particularly limited. For example, a perfluoro compound (perfluoro compound) in which hydrogen atoms of a p-type semiconductor such as fullerene and octaazaporphyrin are substituted with fluorine atoms. Pentacene, perfluorophthalocyanine, etc.), naphthalene tetracarboxylic anhydride, naphthalene tetracarboxylic diimide, perylene tetracarboxylic anhydride, perylene tetracarboxylic diimide Examples thereof include molecular compounds.

  However, fullerene derivatives that can perform charge separation with various p-type semiconductor materials at high speed (˜50 fs) and efficiently are preferable. Fullerene derivatives 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), and the like. Partially by hydrogen atom, halogen atom, substituted or unsubstituted alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, cycloalkyl group, silyl group, ether group, thioether group, amino group, silyl group, etc. Examples thereof include substituted fullerene derivatives.

  Among them, [6,6] -phenyl C61-butyric acid methyl ester (abbreviation PCBM), [6,6] -phenyl C61-butyric acid-nbutyl ester (PCBnB), [6,6] -phenyl C61-buty Rick acid-isobutyl ester (PCBiB), [6,6] -phenyl C61-butyric acid-n hexyl ester (PCBH), Adv. Mater. , Vol. 20 (2008), p2116, etc., aminated fullerenes such as JP-A 2006-199674, metallocene fullerenes such as JP-A 2008-130889, and cyclics such as US Pat. No. 7,329,709. It is preferable to use a fullerene derivative having a substituent and having improved solubility, such as fullerene having an ether group.

[Method for forming photoelectric conversion layer]
In the present invention, the organic photoelectric conversion element has a photoelectric conversion layer in which a p-type semiconductor material and an n-type semiconductor material are mixed. As a method of forming a photoelectric conversion layer in which this electron acceptor (p-type semiconductor) and electron donor (n-type semiconductor) are mixed, that is, a bulk heterojunction layer, an evaporation method, a coating method (cast method, spin coating method) is used. And the like. Among these, the coating method is preferable in order to increase the area of the interface where charges and electrons are separated from each other as described above and to produce a device having high photoelectric conversion efficiency. The coating method is also excellent in production speed.

  After coating, it is preferable to perform heating in order to cause removal of residual solvent, moisture and gas, and improvement of mobility and absorption longwave due to crystallization of the semiconductor material. When annealing is performed at a predetermined temperature during the manufacturing process, a part of the particles is microscopically aggregated or crystallized, and the bulk heterojunction layer can have an appropriate phase separation structure. As a result, the carrier mobility of the bulk heterojunction layer is improved and high efficiency can be obtained.

  The photoelectric conversion part (bulk heterojunction layer) 14 may be composed of a single layer in which the electron acceptor and the electron donor are uniformly mixed, but a plurality of the mixture ratios of the electron acceptor and the electron donor are changed. It may consist of layers. In this case, it can be formed by using a material that can be insolubilized after coating as described above.

[Electron transport layer / hole blocking layer]
Since the organic photoelectric conversion element 10 of the present invention can take out charges generated in the bulk heterojunction layer more efficiently by forming the electron transport layer 18 between the bulk heterojunction layer and the cathode. It is preferable to have this layer.

  As the electron transport layer 18, octaazaporphyrin and a p-type semiconductor perfluoro material (perfluoropentacene, perfluorophthalocyanine, etc.) can be used. Similarly, a HOMO of a p-type semiconductor material used for a bulk heterojunction layer. The electron transport layer having a HOMO level deeper than the level is given a hole blocking function having a rectifying effect so that holes generated in the bulk heterojunction layer do not flow to the cathode side. More preferably, a material deeper than the HOMO level of the n-type semiconductor is used as the electron transport layer. Moreover, it is preferable to use a compound with high electron mobility from the characteristic of transporting electrons.

  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 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 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.

[Hole Transport Layer / Electron Blocking Layer]
In the organic photoelectric conversion element 10 of the present invention, the hole transport layer 17 can be taken out between the bulk heterojunction layer and the anode, and charges generated in the bulk heterojunction layer can be taken out more efficiently. It is preferable to have.

  As a material constituting these layers, for example, as the hole transport layer 17, PEDOT such as trade name BaytronP, polyaniline and its doped material, cyan compounds 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 semiconductor material used for the bulk heterojunction layer has a rectifying effect that prevents electrons generated in the bulk heterojunction layer from flowing to the anode side. It has an electronic block function. Such a hole transport layer is also called an electron block layer, and it is 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. A layer made of a single p-type 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. 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.

[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 injection layer, an electron injection layer, an exciton block layer, a UV absorption layer, a light reflection layer, and a wavelength conversion layer.

<Electrode>
The photoelectric conversion element according to the present invention has at least an anode and a cathode. Further, when a tandem configuration is adopted, the tandem configuration can be achieved by using an intermediate electrode. In the present invention, an electrode through which holes mainly flow is called an anode, and an electrode through which electrons mainly flow is called a cathode.

  Further, because of the function of whether or not there is a light-transmitting property, a light-transmitting electrode may be referred to as a transparent electrode, and an electrode that does not transmit light may be referred to as a counter electrode. Usually, the anode is a translucent transparent electrode, and the cathode is a non-translucent counter electrode.

  In the present invention, the transparent electrode refers to an electrode that transmits light of 380 to 800 nm and has a total light transmittance of 50% or more. It is preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more. The total light transmittance can be measured according to a known method using a spectrophotometer or the like.

〔anode〕
The anode of the present invention is preferably a transparent electrode. 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. Further, a plurality of these conductive compounds can be combined to form an anode.

〔cathode〕
The cathode 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 a conductive material for the cathode, a material having a work function (4 eV or less) metal, alloy, electrically conductive compound, and a mixture thereof as an electrode material 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 cathode 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 cathode, the light coming to the cathode side is reflected and reflected to the first electrode side, and this light can be reused and absorbed again by the photoelectric conversion layer, further improving the photoelectric conversion efficiency. It is preferable.

  Further, the cathode 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. A dispersion is preferable because a transparent and highly conductive cathode can be formed by a coating method.

  In the case where the cathode side is a transparent electrode, for example, a conductive material suitable for the cathode such as aluminum and aluminum alloy, silver and silver compound is made thin with a thickness of about 1 to 20 nm, and then the anode is explained. A transparent electrode can be obtained by providing the film of the conductive light-transmitting material mentioned above.

[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. 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 polymer materials such as PEDOT: PSS and polyaniline 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 light condensing layer such as an antireflection film or a microlens array, or a light diffusion layer that can scatter light reflected by the cathode and enter the power generation layer again may be provided. .

  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]
The method and process for patterning the electrode, the power generation layer, the hole transport layer, the electron transport layer, and the like according to the present invention are not particularly limited, and known methods can be appropriately applied.

  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 application such as die coating or dip coating, or directly at the time of application using a method such as an ink jet method or screen printing. Patterning may be performed.

  In the case of an insoluble material such as an electrode material, the electrode can be patterned by a known method such as mask evaporation at the time of 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, an optical sensor array 20 is paired with an anode 22 as a lower electrode, a photoelectric conversion unit 24 for converting light energy into electrical energy, and an anode 22 on a substrate 21 as a holding member. The cathode 23 is sequentially laminated. Reference numeral 26 denotes the direction of incident light. Incident light is received by the measuring unit 25 having a light receiving area of 5 mm square, for example. The photoelectric conversion unit 24 includes two layers, a photoelectric conversion layer 24b having a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are uniformly mixed, and a buffer layer 24a. In the example shown in FIG. 4, six bulk heterojunction type organic photoelectric conversion elements are formed.

  The substrate 21, the anode 22, the photoelectric conversion layer 24b, and the cathode 23 have the same configuration and role as the anode 12, the photoelectric conversion unit 14, and the cathode 13 in the bulk heterojunction photoelectric conversion element 10 described above.

  For example, glass is used for the substrate 21, ITO is used for the anode 22, and aluminum is used for the cathode 23, for example. For example, the compound 304 of the present invention is used as the p-type semiconductor material of the photoelectric conversion layer 24b, and the PCBM is used as the n-type semiconductor material, for example. The buffer layer 24a is made of PEDOT (poly-3,4-ethylenedioxythiophene) -PSS (polystyrene sulfonic acid) conductive polymer (trade name BaytronP, manufactured by Stark Vitec). Such an optical sensor array 20 was manufactured as follows.

  An ITO film was formed on the glass substrate by sputtering and processed into a predetermined pattern shape by photolithography. The thickness of the glass substrate was 0.7 mm, the thickness of the ITO film was 200 nm, and the measurement area (light receiving area) of the ITO film after photolithography was 0.5 mm × 0.5 mm. Next, a PEDOT-PSS film was formed on the glass substrate 21 by a spin coating method (conditions: rotation speed = 1000 rpm, filter diameter = 1.2 μm). Thereafter, the substrate was heated in an oven at 140 ° C. for 10 minutes and dried. The thickness of the PEDOT-PSS film after drying was 30 nm.

  Next, a 1: 1 mixed film of the compound 304 of the present invention and PCBM was formed on the PEDOT-PSS film by a spin coating method (conditions: rotational speed = 3300 rpm, filter diameter = 0.8 μm). In this spin coating, a compound liquid obtained by mixing the compound 304 of the present invention and PCBM with a chlorobenzene solvent in a ratio of 1: 1 and stirring (5 minutes) was used. After the formation of the mixed film of the compound 304 and PCBM of the present invention, annealing was performed by heating in an oven at 180 ° C. for 30 minutes in a nitrogen gas atmosphere. The thickness of the mixed film of the compound 304 of the present invention and PCBM after the annealing treatment was 70 nm.

  Then, using a metal mask having a predetermined pattern opening, 5 ml of the bathocuproine is deposited as an electron transport layer on the mixed film of the compound 304 and PCBM of the present invention, and then an aluminum layer as a cathode is formed by a deposition method. (Thickness = 10 nm). Thereafter, 1 μm of PVA (polyvinyl alcohol) was formed by spin coating and baked at 150 ° C. to prepare a passivation layer (not shown). The optical sensor array 20 was produced as described above.

  When this photosensor array 20 was irradiated with light having a predetermined pattern, it was confirmed that the photocurrent was detected only from the cells that were exposed to light and functioned as a photosensor.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1: Use as p-type semiconductor material [Production of organic photoelectric conversion element 1]
An indium tin oxide (ITO) transparent conductive film deposited on a glass substrate with a thickness of 110 nm (sheet resistance 13 Ω / □) is patterned to a width of 2 mm using a normal photolithography technique and hydrochloric acid etching, and transparent An electrode was formed.

  The patterned transparent electrode was washed in the order of ultrasonic cleaning with a surfactant and ultrapure water, followed by ultrasonic cleaning with ultrapure water, dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning. On this transparent substrate, Baytron P4083 (manufactured by Starck Vitec), which is a conductive polymer, was spin-coated with a film thickness of 30 nm, and then dried by heating at 140 ° C. in the atmosphere for 10 minutes.

  After this, the substrate was brought into the glove box and operated under a nitrogen atmosphere. First, the substrate was heat-treated at 140 ° C. for 3 minutes in a nitrogen atmosphere.

  A solution is prepared by dissolving 1.0% by mass of P3HT (Plectotronics, Plexcore OS2100) as p-type semiconductor material and 0.8% by mass of PCBM (from Frontier Carbon) as n-type semiconductor material in chlorobenzene. Then, spin filtration was performed at 700 rpm for 60 seconds and then at 2200 rpm for 1 second while being filtered through a 0.45 μm filter, followed by drying at room temperature for 30 minutes to obtain a photoelectric conversion layer.

Next, the substrate on which the organic layer was formed was placed in a vacuum evaporation apparatus. The element was set so that the shadow mask with a width of 2 mm was orthogonal to the transparent electrode, and the inside of the vacuum deposition apparatus was depressurized to 10 ⁻³ Pa or less, and then 0.5 nm of lithium fluoride and 80 nm of Al were evaporated. Finally, the heating for 30 minutes was performed at 120 degreeC, and the comparative organic photoelectric conversion element 1 was obtained. The vapor deposition rate was 2 nm / second for all, and the size was 2 mm square.

The obtained organic photoelectric conversion element 1 was sealed with an aluminum cap and a UV curable resin (manufactured by Nagase ChemteX Corporation, UV RESIN XNR5570-B1) in a nitrogen atmosphere, and then 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.

[Preparation of organic photoelectric conversion elements 2 to 10]
In the production of the organic photoelectric conversion element 1, the p-type semiconductor material was changed to the comparative compound described in Table 1 and the exemplified compound according to the present invention instead of P3HT. Organic photoelectric conversion elements 2 to 10 were obtained.

The resulting organic photoelectric conversion element 2 to 10, after the sealing with aluminum caps and UV curable resin under a nitrogen atmosphere was taken out under the atmosphere, the light of solar simulator (AM1.5G) 100mW / cm ² The voltage-current characteristics were measured by irradiation with an irradiation intensity of 1, and the initial conversion efficiency was measured.

(Evaluation of conversion efficiency)
Photoelectric conversion elements prepared above, was irradiated with light having an intensity of 100 mW / cm ² solar simulator (AM1.5G filter), a superposed mask in which the effective area 4.0 mm ² on the light receiving portion, the short circuit current density Jsc ( The four light-receiving portions formed on the same element were measured for mA / cm ² ), open-circuit voltage Voc (V), and fill factor (fill factor) FF, and the average value was obtained. Further, energy conversion efficiency η (%) was obtained from Jsc, Voc, and FF according to Equation 1.

Formula 1 Jsc (mA / cm ² ) × Voc (V) × FF = η (%)
(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. Further, assuming that the initial conversion efficiency at this time is 100, the conversion efficiency after continuing the irradiation for 1000 h at the irradiation intensity of 100 mW / cm ² with the resistance connected between the anode and the cathode, the relative efficiency decrease was calculated. . This decrease in efficiency was used as an index of durability. A small value indicates that there is little decrease in efficiency and good durability.

Formula 2 Relative efficiency reduction (%) = (1−conversion efficiency after exposure / conversion efficiency before exposure) × 100
The molecular weight was measured by GPC (Waters 2695, manufactured by Waters).

<GPC measurement conditions>
Apparatus: Wagers 2695 (Separations Module)
Detector: Waters 2414 (Refractive Index Detector)
Column: Shodex Asahipak GF-7M HQ
Eluent: Dimethylformamide (20 mM LiBr)
Flow rate: 1.0 ml / min
Temperature: 40 ° C
The results are shown in Table 1.

  From Table 1, it can be seen that the use of the p-type semiconductor material according to the present invention provides a higher conversion efficiency and higher durability.

Example 2: Use as additive component (low molecular weight compound) [Preparation of organic photoelectric conversion element 11]
An indium tin oxide (ITO) transparent conductive film deposited on a glass substrate with a thickness of 110 nm (sheet resistance 13 Ω / □) is patterned to a width of 2 mm using a normal photolithography technique and hydrochloric acid etching, and transparent An electrode was formed.

  The patterned transparent electrode was washed in the order of ultrasonic cleaning with a surfactant and ultrapure water, followed by ultrasonic cleaning with ultrapure water, dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning. On this transparent substrate, Baytron P4083 (manufactured by Starck Vitec), which is a conductive polymer, was spin-coated with a film thickness of 30 nm, and then dried by heating at 140 ° C. in the atmosphere for 10 minutes.

  After this, the substrate was brought into the glove box and operated under a nitrogen atmosphere. First, the substrate was heat-treated at 140 ° C. for 3 minutes in a nitrogen atmosphere.

  A solution is prepared by dissolving 1.0% by mass of P3HT (Plectotronics, Plexcore OS2100) as p-type semiconductor material and 0.8% by mass of PCBM (from Frontier Carbon) as n-type semiconductor material in chlorobenzene. Then, spin filtration was performed at 700 rpm for 60 seconds and then at 2200 rpm for 1 second while being filtered through a 0.45 μm filter, followed by drying at room temperature for 30 minutes to obtain a photoelectric conversion layer.

Next, the substrate on which the organic layer was formed was placed in a vacuum evaporation apparatus. The element was set so that the shadow mask with a width of 2 mm was orthogonal to the transparent electrode, and the inside of the vacuum deposition apparatus was depressurized to 10 ⁻³ Pa or less, and then 0.5 nm of lithium fluoride and 80 nm of Al were evaporated. Finally, the heating for 30 minutes was performed at 120 degreeC, and the comparative organic photoelectric conversion element 11 was obtained. The vapor deposition rate was 2 nm / second for all, and the size was 2 mm square.

The obtained organic photoelectric conversion element 1 was sealed with an aluminum cap and a UV curable resin (manufactured by Nagase ChemteX Corporation, UV RESIN XNR5570-B1) in a nitrogen atmosphere, and then 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.

[Production of organic photoelectric conversion elements 12 to 18]
In the production of the organic photoelectric conversion element 1, an organic compound similar to that of the comparative organic photoelectric conversion element 11 was added except that the exemplary compound according to the present invention described in Table 2 was further added to the solvent by 0.05%. Photoelectric conversion elements 12 to 18 were obtained.

The obtained organic photoelectric conversion elements 11 to 18 were sealed using an aluminum cap and a UV curable resin in a nitrogen atmosphere, and then taken out to the atmosphere, and light from a solar simulator (AM1.5G) was 100 mW / cm ^2. The voltage-current characteristics were measured by irradiation with an irradiation intensity of 1, and the initial conversion efficiency was measured. The results are shown in Table 2.

  N719 in the comparative example is a sensitizing dye compound represented by the following structure. It has a maximum absorption wavelength near 540 nm and is often used for dye-sensitized solar cells. A solution of acetonitrile: t-butanol = 1: 1 was used.

  From Table 2, it can be seen that the conversion efficiency can be improved by adding the low molecular weight compound having the structure according to the present invention.

DESCRIPTION OF SYMBOLS 10 Solar cell using bulk heterojunction type organic photoelectric conversion element 11 Substrate 12 Anode 13 Cathode 14 Photoelectric conversion part (bulk heterojunction layer)
14 p p layer 14 i i layer 14 n n layer 14 ′ first photoelectric conversion unit 15 charge recombination layer 16 second photoelectric conversion unit 17 hole transport layer 18 electron transport layer 20 photosensor array 21 substrate 22 anode (lower electrode)
23 Cathode (upper electrode)
24 photoelectric conversion part 24a buffer layer 24b photoelectric conversion layer 25 measurement part (light receiving part: light receiving area 5 mm □)
26 Direction of incident light

Claims (13)

In an organic photoelectric conversion element having a transparent electrode, a counter electrode, and a photoelectric conversion layer in which a p-type semiconductor material and an n-type semiconductor material are mixed, the photoelectric conversion layer is represented by the following general formulas (1A) to (1C). An organic photoelectric conversion element comprising any one of compounds having a partial structure.

(In the formula, X ₁ and Y _{1 each} represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, or a substituted or unsubstituted carbon atom. R represents a substituent, and n represents an integer of 0 to 4. Z ₁ , Z ₂ and Z ₃ represent a substituted or unsubstituted 5-membered ring or 6-membered ring. 2. The organic photoelectric conversion device according to claim ₁ , wherein Y ₁ represents a nitrogen atom in the compound having a partial structure represented by the general formulas (1A) to (1C).   The organic photoelectric conversion device according to claim 1, wherein two or more partial structures represented by the general formulas (1A) to (1C) are contained in one molecule. The partial structures represented by the general formulas (1A) to (1C) are partial structures represented by the following general formulas (2A), (2B), and (2C), respectively. 4. The organic photoelectric conversion element according to any one of 3 above.

(In the formula, X ₁ and Y ₁ represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, and a substituted or unsubstituted carbon atom. Ar represents a substituted or unsubstituted aromatic group. R represents a substituent. N represents an integer of 0 to _4. Z ₁ , Z ₂ , Z ₃ and Z ₄ represent a substituted or unsubstituted 5-membered ring or 6-membered ring, and m represents the degree of polymerization.) The partial structures represented by the general formulas (1A) to (1C) are partial structures represented by the following general formulas (3A), (3B), or (3C), respectively. 4. The organic photoelectric conversion element according to any one of 3 above.

(Wherein X ₁ and X ₂ represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, or a substituted or unsubstituted carbon atom, n represents an integer of 0 to 4, R represents a substituent, and m represents a substituent. Represents the degree of polymerization.) The partial structures represented by the general formulas (1A) to (1C) are partial structures represented by the following general formulas (4A), (4B), or (4C), respectively. 4. The organic photoelectric conversion element according to any one of 3 above.

(Wherein X ₁ and X ₂ represent a chalcogen atom, a substituted or unsubstituted nitrogen atom, or a substituted or unsubstituted carbon atom, n represents an integer of 0 to 4, R represents a substituent, and m represents a substituent. Represents the degree of polymerization.)   The organic photoelectric conversion device according to claim 1, wherein n represents 0 or 1 in the partial structures represented by the general formulas (1A) to (4C). 8. The compound according to claim ₁ , wherein X ₁ and X ₂ represent a sulfur atom or an oxygen atom in the compound having a partial structure represented by the general formulas (1A) to (4C). The organic photoelectric conversion element as described.   The organic photoelectric conversion element according to any one of claims 1 to 8, wherein the compound having a partial structure represented by the general formulas (1A) to (4C) is a polymer compound.   The photoelectric conversion layer contains an electron-accepting fullerene compound, an electron-donating p-type semiconductor material, and a low-molecular compound having a structure represented by the general formulas (1A) to (1C). The organic photoelectric conversion device according to any one of claims 1 to 9, wherein   The layer containing a compound having a partial structure represented by the general formulas (1A) to (4C) is produced by a solution coating method. Organic photoelectric conversion element.   It consists of the organic photoelectric conversion element of any one of Claims 1-11, The solar cell characterized by the above-mentioned.   The organic photoelectric conversion element of any one of Claims 1-11 is arrange | positioned at array form, The optical sensor array characterized by the above-mentioned.

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