JP2011119577A - Organic photoelectric converting element, solar cell and optical sensor array using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoelectric converting element high in photoelectric converting efficiency and durability, a solar cell using the organic photoelectric converting element, and an optical sensor array. <P>SOLUTION: The organic photoelectric converting element has a transparent electrode, a counter electrode, and a photoelectric converting layer in which p-type semiconductor material and n-type semiconductor material are mixed. The photoelectric converting layer contains a compound having a structure expressed by formula (1A)-(1C). The solar cell and the optical sensor array use the same. <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. More specifically, the present invention relates to a bulk heterojunction type organic photoelectric conversion element, a solar cell using the organic photoelectric conversion element, and an optical sensor array.

  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 by fossil fuel, an electron donor layer (p-type semiconductor layer) and an electron acceptor layer (n A bulk heterojunction photoelectric conversion element has been proposed (see, for example, Non-Patent Document 1 and Patent Document 1) sandwiching a photoelectric conversion layer mixed with a semiconductor layer.

  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 document using the above materials, it is reported that the photoelectric conversion efficiency is reduced by about 40% in 100 hours (see, for example, Non-Patent Document 2).

  This is because the HOMO level of the electron donating material (p-type material) becomes shallower than the oxygen level as the wave length (lower band gap) progresses, so that it is easily decomposed by the photooxidation reaction. (See Non-Patent Document 3, for example).

  As such a countermeasure, it is useful to make the HOMO level of the p-type material deeper than the oxygen level by introducing an electron-withdrawing mother nucleus into the p-type material as much as possible. Such a method also contributes to improving the open-circuit voltage (Voc) of the photoelectric conversion element. For example, by introducing a condensed heterocyclic ring having a ketone group, high Voc and high efficiency are obtained. (For example, see Patent Document 2 and Non-Patent Document 4) The diketopyrrolopyrrole group used here has a structure in which a ketone is introduced into a nitrogen-containing five-membered ring system such as a pyrrole group. Since the member ring is basically an electron-rich aromatic, even if a ketone group is introduced, the effect of deepening the HOMO level is insufficient.

  On the other hand, a photoelectric conversion element composed of a quinacridone derivative, which is an electron-deficient nitrogen-containing six-membered ring structure has been disclosed (for example, see Patent Document 3). The film cannot be formed, and the photoelectric conversion efficiency remains low.

  In response to such problems, the present inventors have focused on dyes used in some photographic light-sensitive materials. These dyes had relatively long wave absorption characteristics, and had a structure with high absorbance and durability.

  The present inventors have found that high photoelectric conversion efficiency, durability, and solubility (productivity) can be obtained by applying such a photographic dye mother nucleus to an organic photoelectric conversion element.

  In addition, it is known that the photoelectric conversion efficiency can be improved by adding a specific low molecular weight dye as a third component to a bulk heterojunction organic photoelectric conversion layer comprising an electron donating polymer and an electron accepting fullerene compound. However, (for example, refer to Patent Document 4) In terms of photoelectric conversion efficiency, it is still not sufficient.

  It has been found that the compound of the present invention can achieve higher photoelectric conversion efficiency than existing compounds even when added to the power generation layer as such a third component.

JP-T 8-500701 Special Table 2007-516315 Japanese National Patent Publication No. 10-511991 JP 2007-180190 A

A. Heeger; Nature Mat. , Vol. 6 (2007), p497 Science vol. 317 (2007) p222 J. et al. AM. CHEM. SOC. 2008, 130, p732 Adv. Mater. 2008, 20, p2556

  This invention is made | formed in view of the said subject, The objective is to provide an organic photoelectric conversion element with high photoelectric conversion efficiency and durability, a solar cell using this organic photoelectric conversion element, and an optical sensor array. is there.

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

  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, a structure represented by the following general formulas (1A) to (1C) in the photoelectric conversion layer The organic photoelectric conversion element characterized by containing the compound which has this.

_(Wherein, X 1 to X ₃ is a substituted or unsubstituted carbon or nitrogen atoms, at least one of _X 1, _{X 2} is a nitrogen atom .Y ₁ is _.R 1 ~ representing a chalcogen atom R ₇ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, a cycloalkyloxy group, an aryloxy group, an acyl group, Alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, ureido group , Phosphoramide group, hydroxy group, Any one selected from a rucapto group, a halogen atom, a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, and a heteroaryl group, R ₁ and R ₂ And R ₃ and R ₄ may each independently represent ═O, ═S, ═N—R ₈ , or ═CR ₉ · R ₁₀ , where R _{8 to} R ₁₀ are each independently And a group having the same meaning as R _{1 to} R ₇ .
2. 2. The organic photoelectric conversion device as described in 1 above, wherein Y ₁ in the general formulas (1A) to (1C) is an oxygen atom.

3. 2. The organic photoelectric conversion device as described in 1 above, wherein at least two of X _{1 to} X ₃ in the general formulas (1A) to (1C) are nitrogen atoms.

  4). The structure represented by the general formulas (1A) to (1C) is a structure represented by the following general formulas (2A) to (2C), The organic photoelectric conversion element as described.

(In the formula, X _{1 to} X ₃ , Y ₁ and R ₇ are synonymous with X _{1 to} X ₃ , Y ₁ and R ₇ in the structures represented by the general formulas (1A) to (1C), and X ₄ to X ₆ represents a substituted or unsubstituted carbon atom or a nitrogen atom.)
5. 5. The organic photoelectric conversion element as described in 4 above, wherein at least three elements among X _{1 to} X ₆ in the general formulas (2A) to (2C) are nitrogen atoms.

6). Formula (1A) ~ organic photoelectric conversion element of any one of the 1 to 4, characterized in that X ₁ in (1C) is a nitrogen atom.

  7). 6. The organic photoelectric conversion device as described in 4 or 5 above, wherein the general formulas (2A) to (2C) are represented by the following general formula (3).

(Wherein, _{Y 2} and _{Y 3} represents a chalcogen _{atom, R 7, X 1, X} 3, X 5, X 6 is the formula in _{(2A) ~ (2C),} R 7, X 1, X 3 , X ₅ and X _6. R _{11 to} R ₁₅ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, Alkoxy group, cycloalkyloxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group , Alkylthio group, arylthio group, sulfonyl group, sulfinyl group, ureido group, phosphorus Amide group, hydroxy group, a mercapto group, a halogen atom, a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, sulfino group, a hydrazino group, an imino group, is either selected from heteroaryl groups.)
8). 8. The organic photoelectric conversion element as described in 7 above, wherein Y ₂ and Y ₃ in the general formula (3) are sulfur atoms.

9. 9. The organic photoelectric conversion device as described in 7 or 8 above, wherein X ₁ , X ₃ and X ₆ in the general formula (3) are nitrogen atoms.

  10. 10. The organic photoelectric conversion element according to any one of 1 to 9, wherein the photoelectric conversion layer is produced by a solution coating method.

  11. 1 to 9 above, wherein the compound having the structure represented by the general formulas (1A) to (1C), the general formulas (2A) to (2C) or the general formula (3) is a polymer compound. The organic photoelectric conversion element of any one of these.

  12 A compound having a structure represented by the general formulas (1A) to (1C), the general formulas (2A) to (2C) or the general formula (3), an electron-accepting fullerene compound, 12. The organic photoelectric conversion device as described in any one of 1 to 11 above, which comprises an electron donating polymer compound.

  13. 13. The compound having the structure represented by the general formulas (1A) to (1C), the general formulas (2A) to (2C), or the general formula (3) is a low molecular compound. Organic photoelectric conversion element.

  14 It consists of the organic photoelectric conversion element of any one of said 1-13, The solar cell characterized by the above-mentioned.

  15. 14. An optical sensor array comprising the organic photoelectric conversion element according to any one of 1 to 13 above.

  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 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 photoelectric conversion layer. It is a figure which shows the structure of an optical sensor array.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  The organic photoelectric conversion element of the present invention is characterized in that the photoelectric conversion layer contains a compound having a structure represented by the general formulas (1A) to (1C).

  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 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 photoelectric conversion layer 14, an electron transport layer 18, and a counter electrode (generally, on one surface of a substrate 11. Cathode) 13 is sequentially laminated.

  The substrate 11 is a member that holds the transparent electrode 12, the photoelectric conversion layer 14, and the counter electrode 13 that are sequentially stacked. In the present embodiment, since light photoelectrically converted enters from the substrate 11 side, the substrate 11 can transmit the light subjected to photoelectric conversion, that is, transparent to the wavelength of the light to be photoelectrically converted. It is an important 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 layer 14.

  The photoelectric conversion layer 14 is a layer that converts light energy into electric energy, and includes a photoelectric conversion 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 photoelectric conversion layer of the photoelectric conversion layer 14, and electrons move from the electron donor to the electron acceptor. Thus, a hole-electron pair (charge separation state) is formed. In the case where the generated electric charge has an internal electric field, for example, when the work functions of the transparent electrode 12 and the counter electrode 13 are different, electrons pass between the electron acceptors and holes are transferred between the electron donors due to the potential difference between the transparent electrode 12 and the counter electrode 13. And is carried to different electrodes, and photocurrent is detected.

  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.

  As a more preferable configuration, the photoelectric conversion layer 14 has a so-called p-i-n three-layer configuration (FIG. 2). A normal photoelectric conversion layer is a single 14i layer in which a p-type semiconductor material and an n-type semiconductor layer are mixed, but is sandwiched between a 14p layer made of a single p-type semiconductor material and a 14n layer made of a single n-type semiconductor material. Further, the rectification property of holes and electrons is further increased, 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 a cross-sectional view illustrating an organic photoelectric conversion element including a tandem photoelectric conversion layer.

  In the case of the tandem configuration, the transparent electrode 12 and the first photoelectric conversion layer 14 ′ are sequentially stacked on the substrate 11, the charge recombination layer 15 is stacked, the second photoelectric conversion layer 16, and then the counter electrode 13. By stacking, a tandem structure can be obtained. The second photoelectric conversion layer 16 may be a layer that absorbs the same spectrum as the absorption spectrum of the first photoelectric conversion layer 14 'or may be a layer that absorbs a different spectrum, but is preferably a layer that absorbs a different spectrum. is there. Further, both the first photoelectric conversion layer 14 ′ and the second photoelectric conversion layer 16 may have the above-described three-layer structure of pin.

  Below, the material which comprises these layers is described.

[P-type semiconductor materials]
In the present invention, as the p-type semiconductor material, a compound having a structure represented by the general formulas (1A) to (1C) is used.

In the general formulas (1A) to (1C), X _{1 to} X ₃ are substituted or unsubstituted carbon or a nitrogen atom, and at least _one of X ₁ and X ₂ is a nitrogen atom. In this way, it is possible to prevent the hydrogen bond between the nitrogen atom and the ketone group or thioketone group represented by = Y _{1 from} being infinitely hydrogen-bonded and greatly reducing the solubility. it can.

In order to obtain the effect of deepening the HOMO level as described above, it is preferable that at least two elements of X _{1 to} X ₃ are nitrogen atoms.

Y ₁ represents a chalcogen atom. Examples of the chalcogen atom include an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom, and the like, preferably an oxygen atom and a sulfur atom, and more preferably an oxygen atom.

R _{1 to} R ₁₀ and the substituent include, for example, an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms. For example, methyl, ethyl , Iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, etc.), a cycloalkyl group (preferably having 4 to 8 carbon atoms, such as cyclopentyl, cyclohexyl, etc.). ), An alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, and examples thereof include vinyl, allyl, 2-butenyl, 3-pentenyl and the like. ), An alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms, Propargyl, 3-pentenyl, etc.), aryl groups (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, particularly preferably having 6 to 12 carbon atoms, such as phenyl and p-methyl) Phenyl, naphthyl, etc.), an amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, dimethylamino, Diethylamino, dibenzylamino, etc.), alkoxy groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy ), A cycloalkyloxy group (preferably having 4 to 8 carbon atoms, for example, cyclopentyloxy Cyclohexyloxy, etc.), aryloxy groups (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 2-naphthyloxy, etc. An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, pivaloyl, and the like. An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl and ethoxycarbonyl), aryl Oxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferred Or having 7 to 10 carbon atoms, such as phenyloxycarbonyl. ), An acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms such as acetoxy and benzoyloxy), an acylamino group (preferably 2-20 carbon atoms, more preferably 2-16 carbon atoms, particularly preferably 2-10 carbon atoms, and examples thereof include acetylamino, benzoylamino and the like, and an alkoxycarbonylamino group (preferably having 2 carbon atoms). To 20, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino and the like, aryloxycarbonylamino group (preferably 7 to 20 carbon atoms, more Preferably it has 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms. And sulfonylamino groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino, benzenesulfonylamino, etc.) ), A sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms. For example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl , Phenylsulfamoyl, etc.), a carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl, methylcarbamoyl, And diethylcarbamoyl, phenylcarbamoyl, etc.), al A ruthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio and ethylthio), an arylthio group (preferably having a carbon number) 6 to 20, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, including, for example, phenylthio and the like, a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably carbon number). 1 to 16, particularly preferably 1 to 12 carbon atoms, for example, mesyl, tosyl, etc.), sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably C1-C12, for example, methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably C1-C2) 0, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include ureido, methylureido, and phenylureido. ), Phosphoric acid amide groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include diethyl phosphoric acid amide and phenyl phosphoric acid amide. .), Hydroxy group, mercapto group, halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group Group, heteroaryl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, And pyridyl, quinolyl, furyl, piperidyl, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc. ), And the like. These substituents may be further substituted. R ₁ and R ₂ and R ₃ and R ₄ may each independently represent ═O, ═S, ═N—R ₈ , or ═CR ₉ (R ₁₀ ). At this time, R _{8 to} R ₁₀ are each independently a group having the same meaning as R _{1 to} R ₇ .

  More preferably, the structures represented by the general formulas (1A) to (1C) are structures represented by the general formulas (2A) to (2C).

In the general formulas (2A) to (2C), X _{1 to} X ₃ , Y ₁ and R ₇ are X _{1 to} X ₃ , Y ₁ and R _{7 in the} structures represented by the general formulas (1A) to (1C). X _{4 to} X ₆ represent a substituted or unsubstituted carbon atom or a nitrogen atom. By adopting such a condensed ring structure, the electron donating material (p-type material) has high planarity. Thus, stacking is facilitated so that the π-conjugated planes of the p-type material overlap, so that the hole mobility can be improved and the photoelectric conversion efficiency can be further improved.

More preferably, at least three of X _{1 to} X ₆ are nitrogen atoms so that the HOMO level of the electron donating material (p-type material) can be deeper. Among these, X ₁ is preferably a nitrogen atom. This is because an improvement in solubility can be expected by placing a nitrogen atom, which tends to cause a decrease in solubility due to hydrogen bonding, at a bridgehead where hydrogen bonding is unlikely to occur.

  Among these, the structure represented by the general formula (3) is preferable.

In General Formula (3), Y ₂ and Y ₃ represent a chalcogen atom, and R ₇ , X ₁ , X ₃ , X ₅ , and X ₆ are R ₇ , X ₁ in General Formulas (2A) to (2C), respectively. , X ₃ , X ₅ , and X ₆ . Y ₁ is preferably an oxygen atom as described above, but Y ₂ and Y ₃ are preferably sulfur atoms from the viewpoint of hole transportability. Examples of R _{11 to} R ₁₅ include the same groups as those described above for R _{1 to} R ₁₀ .

In addition, at least three of X ₁ , X ₃ , X ₅ , and X ₆ are preferably nitrogen atoms, and more preferably, X ₁ , X ₃ , and X ₆ are nitrogen atoms.

  The electron-donating compound containing these structures may be a low-molecular or high-molecular compound, but when formed by a coating method with excellent productivity, it is appropriate to use an n-type material that is an electron-accepting compound. Since it is necessary to form a phase separation structure to form a carrier transport path (carrier path), the electron donating material (p-type material) is preferably a polymer material.

  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, in practical terms, when defining by molecular weight, a compound having a molecular weight of 3000 or less is preferably classified as a low molecular compound. More preferably, it is 2500 or less, More preferably, it is 2000 or less. On the other hand, a compound having a molecular weight of 2000 or more, more preferably 3000 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). Purification according to molecular weight can also be performed by preparative gel permeation chromatography (GPC).

  On the other hand, as described in Patent Document 4, a basic carrier path is formed from a known p-type polymer material and an n-type fullerene material, and the low-molecular or polymer compound of the present invention is used as the third component. It may be configured such that is added. This is because the structure of the present invention is excellent in absorbance and solubility, so that the photoelectric conversion efficiency can be improved by the effect of improving the external quantum efficiency even if it is added to the existing photoelectric conversion layer.

  Hereinafter, specific examples of the compounds represented by the general formulas (1A) to (1C), the general formulas (2A) to (2C) and the general formula (3) of the present invention will be given, but the present invention is not limited thereto.

  Compounds having such a structure are described in, for example, Journal of Heterocyclic Chemistry, vol. 23 (1986), p349, Journal of Heterocyclic Chemistry, vol. 22 (1985), p601, Journal of Pharmaceutical Sciences, vol. 82 (1993), p480, Polish Journal of Chemistry, vol. 58 (1984), p411 and the like, and corresponding monomers can be synthesized. Furthermore, a corresponding polymer can be obtained with reference to the aforementioned Patent Document 2, Non-Patent Document 4, and the like.

  As described above, when the compound of the present invention is applied as the third component, the p-type material used for the existing photoelectric conversion layer includes various condensed polycyclic aromatic low molecular compounds and conjugated systems as described below. 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, thacumanthracene, bisanthene, zeslene. , Heptazethrene, pyranthrene, violanthene, isoviolanthene, cacobiphenyl, anthradithiophene, etc., 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 condensed polycycle include International Publication No. 03/16599, International Publication No. 03/28125, US Pat. No. 6,690,029, Japanese Patent Application Laid-Open No. 2004-107216. 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 Mat. , (2006), vol. 5, p328, polythiophene-thienothiophene copolymer, polythiophene-diketopyrrolopyrrole copolymer described in WO08 / 664, Adv Mater. , 2007, p4160, a polythiophene-thiazolothiazole copolymer, Nature Mat. , Vol. 6 (2007), p497 described in PCPDTBT, 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.

[N-type semiconductor materials]
The n-type semiconductor material used in the photoelectric conversion layer according to the present invention is not particularly limited. For example, a perfluoro compound (perfluoropentacene) in which hydrogen atoms of a p-type semiconductor such as fullerene and octaazaporphyrin are substituted with fluorine atoms. And perfluorophthalocyanine), naphthalenetetracarboxylic acid anhydride, naphthalenetetracarboxylic acid diimide, perylenetetracarboxylic acid anhydride, perylenetetracarboxylic acid diimide and other aromatic carboxylic acid anhydrides and imidized polymers thereof as a skeleton A compound etc. can be mentioned.

  However, fullerene derivatives that can perform charge separation with various p-type semiconductor materials at high speed (up to 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, US Pat. No. 7,329,709, etc. It is preferable to use a fullerene derivative having a substituent and having improved solubility, such as fullerene having a cyclic ether group such as a calligraphy.

[Method for forming photoelectric conversion layer]
Examples of the method for forming a photoelectric conversion layer in which an electron acceptor and an electron donor are mixed include a vapor deposition method and a coating method (including a casting method and a spin coating method). 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. Also, the coating method is 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 photoelectric conversion layer can have an appropriate phase separation structure. As a result, the carrier mobility of the photoelectric conversion layer is improved and high efficiency can be obtained.

  The photoelectric conversion layer may be composed of a single layer in which an electron acceptor and an electron donor are uniformly mixed, or may be composed of a plurality of layers in which the mixing ratio of the electron acceptor and the electron donor is changed. Good. 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]
In the organic photoelectric conversion element of the present invention, by forming an electron transport layer between the photoelectric conversion layer and the cathode, it becomes possible to more efficiently take out the charges generated in the photoelectric conversion layer. It is preferable to have.

  As the electron transport layer, octaazaporphyrin and p-type semiconductor perfluoro compounds (perfluoropentacene, perfluorophthalocyanine, etc.) can be used. Similarly, the HOMO level of the p-type semiconductor material used for the photoelectric conversion layer is used. The electron transport layer having the HOMO level deeper than the level is given a hole blocking function having a rectifying effect so that holes generated in the photoelectric conversion 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. Moreover, the layer which consists of a n-type semiconductor material single-piece | unit used for the photoelectric converting 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]
The organic photoelectric conversion element of the present invention has a hole transport layer between the photoelectric conversion layer and the anode, and it is possible to take out charges generated in the photoelectric conversion layer more efficiently. It is preferable.

  Examples of the material constituting these layers include, as the hole transport layer, PEDOT such as Stark Vuitec, trade name BaytronP, polyaniline and its doped material, cyan described in International Publication No. 06/019270, etc. Compounds, 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 photoelectric conversion layer has a rectifying effect that prevents electrons generated in the photoelectric conversion 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. Moreover, the layer which consists of a p-type semiconductor material single-piece | unit used for the photoelectric converting 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 a coating film in the lower layer before forming the photoelectric conversion 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 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.

〔electrode〕
The organic photoelectric conversion element of the present invention has at least an anode and a cathode. Moreover, when taking a tandem configuration, 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.

  In addition, from the function of whether or not there is translucency, the translucent electrode is called a transparent electrode, and the non-translucent electrode is called a counter electrode. In the present invention, the anode is a translucent transparent electrode. And the cathode is a non-translucent counter electrode.

[Transparent electrode (anode)]
The anode of the present invention 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 selected from the group consisting of derivatives of polypyrrole, polyaniline, polythiophene, polythienylene vinylene, polyazulene, polyisothianaphthene, polycarbazole, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, polyphenylacetylene, polydiacetylene and polynaphthalene. Conductive polymers can also be used. Further, a plurality of these conductive compounds can be combined to form an anode.

[Counter electrode (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. Improved and preferable.

  The cathode may be a metal (for example, gold, silver, copper, platinum, rhodium, ruthenium, aluminum, magnesium, indium, etc.), carbon nanoparticles, nanowires, nanostructures, or a nanowire dispersion. If so, a transparent and highly conductive cathode can be formed by a coating method, which is preferable.

  When the cathode side is made light transmissive, for example, a conductive material suitable for the cathode, such as aluminum and aluminum alloy, silver and silver compound, is formed with a thin film thickness of about 1 to 20 nm, and By providing a film of the conductive light-transmitting material mentioned in the description, a light-transmitting cathode 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. Transparent metal oxides such as ITO, AZO, FTO, titanium oxide, very thin metal layers such as Ag, Al, Au, or layers containing nanoparticles / nanowires, conductive polymer materials such as PEDOT: PSS, 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. Is preferable.

〔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 them, 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. More preferred are a stretched polyethylene terephthalate film and a biaxially stretched polyethylene naphthalate film.

  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 photoelectric conversion layer and a transport layer, only unnecessary portions may be wiped after the entire surface of die coating, dip coating, etc., or patterning is directly performed 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 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 is not deteriorated by oxygen, moisture, or the like 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 an organic photoelectric conversion element are pasted with an adhesive. Method, spin coating of organic polymer material with high gas barrier property (polyvinyl alcohol, etc.), inorganic thin film with high gas barrier property (silicon oxide, aluminum oxide, etc.) or organic film (parylene etc.) are deposited under vacuum. Examples thereof include a method 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 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 that converts light energy into electric energy, and an anode 22 on a substrate 21 as a holding member. The cathode 23 is sequentially laminated. The photoelectric conversion unit 24 includes two layers of a photoelectric conversion layer 24b 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 unit 24 b, and the cathode 23 have the same configuration and role as the anode 12, the photoelectric conversion layer 14, and the cathode 13 in the bulk heterojunction organic 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 BP-1 precursor is used for the p-type semiconductor material of the photoelectric conversion layer 24b, and for example, the exemplified compound 11 is used for the n-type semiconductor material. The buffer layer 24a is made of PEDOT (poly-3,4-ethylenedioxythiophene) -PSS (polystyrene sulfonic acid) conductive polymer (trade name Baytron P, 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: 4 mixed film of Exemplified Compound 11 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, Example Compound 11 and PCBM were mixed in a chlorobenzene solvent at a ratio of 1: 4, and a mixture obtained by stirring (5 minutes) was used. After forming the mixed film of P3HT and PCBM, 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 P3HT and PCBM after the annealing treatment was 70 nm.

  Thereafter, using a metal mask having a predetermined pattern opening, 5 nm of bathocuproine is deposited as an electron transport layer on the mixed film of Exemplified Compound 11 and PCBM, 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.

Example 1: Use as a polymer compound [Preparation 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.

  As a p-type semiconductor material in chlorobenzene, 0.6% by mass of the compound (pBBTDPP2: synthesized according to the literature) described in Patent Document 2 (Japanese Patent Publication No. 2007-516315) and PCBM (frontier carbon as an n-type semiconductor material) Manufactured by NANOM SPECTRA E100H) and spin-coated at 700 rpm for 60 seconds and then at 2200 rpm for 1 second while being filtered through a 0.45 μm filter, and at room temperature for 30 minutes. It dried and obtained the photoelectric converting 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 using an aluminum cap and a UV curable resin (manufactured by Nagase ChemteX Corporation, UV RESIN XNR5570-B1) in a nitrogen atmosphere.

[Production of organic photoelectric conversion elements 2 to 8]
In the production of the organic photoelectric conversion element 1, the organic photoelectric conversion element is the same as the organic photoelectric conversion element 1 except that the p-type semiconductor material is changed to the exemplified compound according to the present invention described in Table 1 instead of pBBTDPP2. 2-8 were obtained.

  The obtained organic photoelectric conversion elements 2 to 8 were sealed using an aluminum cap and a UV curable resin in a nitrogen atmosphere in the same manner as the organic photoelectric conversion element 1 described above.

(Evaluation of conversion efficiency)
The organic photoelectric conversion device 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 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 average values were obtained. Further, energy conversion efficiency η (%) was obtained from Jsc, Voc, and FF according to Equation 1, and the results are shown in Table 1.

Formula 1 Jsc (mA / cm ² ) × Voc (V) × FF = η (%)
(Durability evaluation)
With the resistor connected between the anode and the cathode, the conversion efficiency after being exposed for 1000 h at an irradiation intensity of 100 mW / cm ² (exposure) was evaluated. The relative efficiency drop was calculated and the results are shown in Table 1.

Formula 2
Relative efficiency reduction (%) = 100− (conversion efficiency after exposure / conversion efficiency before exposure) × 100

  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 (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 11 was sealed using an aluminum cap and a UV curable resin (manufactured by Nagase ChemteX Corporation, UV RESIN XNR5570-B1) in a nitrogen atmosphere, and then the same as in Example 1. The voltage-current characteristics were measured, the initial conversion efficiency was measured, and the results are shown in Table 2.

[Production of organic photoelectric conversion elements 12 to 15]
In the production of the organic photoelectric conversion element 11, the organic photoelectric conversion device of Comparative Example 1 was added except that N719 listed in Table 2 and the exemplary compound according to the present invention were further added in an amount of 0.05 mass% with respect to the solvent. Organic photoelectric conversion elements 12 to 15 were obtained in the same manner as the conversion element 11. For N719, CAS Number 207347-46-4 ([RuL ₂ (NCS) ₂ ]: 2TBA L = _2, 2′-bipyridyl-4, 4′-dicarboxylic acid TBA = tetra-n-butylaluminum) was used. .

The obtained organic photoelectric conversion elements 12 to 15 were sealed with 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 are measured, the initial conversion efficiency is measured, the voltage-current characteristics are measured, the initial conversion efficiency is measured, and the results are displayed in the same manner as in Example 1. It is shown in 2.

  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 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 layer 15 Charge recombination layer 16 2nd photoelectric conversion layer 17 Hole transport layer 18 Electron transport layer 20 Photosensor array 21 Substrate 22 Anode 23 Cathode 24 Photoelectric conversion unit 24a Buffer layer 24b Photoelectric conversion layer

Claims (15)

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, a structure represented by the following general formulas (1A) to (1C) in the photoelectric conversion layer The organic photoelectric conversion element characterized by containing the compound which has this.

_(Wherein, X 1 to X ₃ is a substituted or unsubstituted carbon or nitrogen atoms, at least one of _X 1, _{X 2} is a nitrogen atom .Y ₁ is _.R 1 ~ representing a chalcogen atom R ₇ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, an alkoxy group, a cycloalkyloxy group, an aryloxy group, an acyl group, Alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, ureido group , Phosphoramide group, hydroxy group, Any one selected from a rucapto group, a halogen atom, a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, and a heteroaryl group, R ₁ and R ₂ And R ₃ and R ₄ may each independently represent ═O, ═S, ═N—R ₈ , or ═CR ₉ · R ₁₀ , where R _{8 to} R ₁₀ are each independently And a group having the same meaning as R _{1 to} R ₇ . 2. The organic photoelectric conversion device according to claim ₁ , wherein Y ₁ in the general formulas (1A) to (1C) is an oxygen atom. The organic photoelectric conversion device according to claim 1, wherein at least two elements among X _{1 to} X ₃ in the general formulas (1A) to (1C) are nitrogen atoms. The structure represented by the general formulas (1A) to (1C) is a structure represented by the following general formulas (2A) to (2C). The organic photoelectric conversion element as described in 2.

(In the formula, X _{1 to} X ₃ , Y ₁ and R ₇ are synonymous with X _{1 to} X ₃ , Y ₁ and R ₇ in the structures represented by the general formulas (1A) to (1C), and X ₄ to X ₆ represents a substituted or unsubstituted carbon atom or a nitrogen atom.) 5. The organic photoelectric conversion device according to claim 4, wherein at least three elements among X _{1 to} X ₆ in the general formulas (2A) to (2C) are nitrogen atoms. Formula (1A) The organic photoelectric conversion element according to any one of claims 1 to 4, X ₁ in ~ (1C) is characterized in that it is a nitrogen atom. 6. The organic photoelectric conversion device according to claim 4, wherein the general formulas (2A) to (2C) are represented by the following general formula (3).

(Wherein, _{Y 2} and _{Y 3} represents a chalcogen _{atom, R 7, X 1, X} 3, X 5, X 6 is the formula in _{(2A) ~ (2C),} R 7, X 1, X 3 , X ₅ and X _6. R _{11 to} R ₁₅ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, an amino group, Alkoxy group, cycloalkyloxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group , Alkylthio group, arylthio group, sulfonyl group, sulfinyl group, ureido group, phosphorus Amide group, hydroxy group, a mercapto group, a halogen atom, a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, sulfino group, a hydrazino group, an imino group, is either selected from heteroaryl groups.) The organic photoelectric conversion device according to claim 7, wherein in the general formula (3), Y ₂ and Y ₃ is characterized in that it is a sulfur atom. The organic photoelectric conversion device according to claim 7 or 8, wherein X ₁ , X ₃ , and X ₆ in the general formula (3) are nitrogen atoms.   The organic photoelectric conversion element according to claim 1, wherein the photoelectric conversion layer is produced by a solution coating method.   The compound having a structure represented by the general formulas (1A) to (1C), the general formulas (2A) to (2C), or the general formula (3) is a polymer compound. 10. The organic photoelectric conversion element according to any one of 9 above.   A compound having a structure represented by the general formulas (1A) to (1C), the general formulas (2A) to (2C) or the general formula (3), an electron-accepting fullerene compound, The organic photoelectric conversion element according to claim 1, comprising an electron-donating polymer compound.   The compound having a structure represented by the general formulas (1A) to (1C), the general formulas (2A) to (2C), or the general formula (3) is a low molecular compound. Organic photoelectric conversion element.   It consists of an organic photoelectric conversion element of any one of Claims 1-13, The solar cell characterized by the above-mentioned.   An optical sensor array comprising the organic photoelectric conversion element according to any one of claims 1 to 13.

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