JP2010283003A - Organic photoelectric conversion element, solar cell using the same, and optical sensor array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoelectric conversion element which is high in the efficiency of photoelectric conversion and whose relative efficiency is not deteriorated greatly. <P>SOLUTION: The organic photoelectric conversion element includes a transparent electrode, a counter electrode, and a single or a plurality of organic layers between the transparent electrode and the counter electrode. The organic photoelectric conversion element where a compound having a cyclophane structure is contained in the organic layers, a solar battery using the element, and a photosensor array are disclosed. <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 particularly to a bulk heterojunction type organic photoelectric conversion element, a solar cell using the organic photoelectric conversion element, and an optical array sensor.

  Due to the recent rise in fossil energy, a system that can generate electric power directly from natural energy has been demanded. 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 that of fossil fuel, an electron donor layer (p-type semiconductor layer) and an electron acceptor are provided between the transparent electrode and the counter electrode. A bulk heterojunction photoelectric conversion element having a bulk heterojunction layer mixed with a layer (n-type semiconductor layer) has been proposed (see, for example, Non-Patent Document 1).

  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. . Furthermore, unlike the Si solar cells, compound semiconductor solar cells, and dye-sensitized solar cells described above, there is no process at a temperature higher than 160 ° C., so it can be formed on a cheap and lightweight plastic substrate. Is done.

  In addition to the initial manufacturing cost, the power generation cost must be calculated including the power generation efficiency and the durability of the element. In Non-Patent Document 1, in order to efficiently absorb the solar spectrum, a long wavelength is used. By using an organic polymer capable of absorbing up to 5%, conversion efficiency exceeding 5% has been achieved.

  In order to obtain high photoelectric conversion efficiency in an organic thin film solar cell, it is important to form paths for taking out holes and electron carriers to the anode and the cathode, respectively (for example, see Patent Document 1 and Non-Patent Document 2). ) Currently, p-type semiconductor material is crystallized by heating, and crystals are contacted with a certain probability to form a hole carrier path made of p-type semiconductor material, while n-type semiconductor is Hole and electron carrier paths are formed by a method of forming an electron carrier path made of an n-type semiconductor material in a state of filling the gap of the p-type semiconductor material in an amorphous state.

  As a result, since the n-type semiconductor material is a substantially spherical fullerene, even if the n-type material is amorphous, it has a relatively high electron mobility, so that electrons can be extracted from the n-type semiconductor material without relatively loss. Since the p-type semiconductor material is a crystal, holes are easily deactivated at crystal defects and grain boundaries, and as a result, high photoelectric conversion efficiency is not obtained.

  In order to solve such a problem, for example, there is an attempt to solve the problem by using a disk-like molecule having a large π plane area (see, for example, Non-Patent Document 3), but the efficiency has not been greatly improved. This is because discotic liquid crystals and the like are generally very viscous, and it is difficult to spontaneously exhibit homeotropic alignment in which discotic molecules are stacked perpendicular to the substrate surface. For this reason, there is a problem that an orientation defect is generated or a divided polydomain is generated, which impedes charge transport and the like.

  The inventors focused on the cyclophane structure. The cyclophane structure is a compound having a plurality of substantially parallel π-conjugated surfaces that are not coplanar in the molecule. Such a compound is known to be a compound in which conjugation is connected by π conjugation through a space (see, for example, Non-Patent Document 4).

  When a compound having such a structure is crystallized and packed, stacking with one of the π-conjugate planes enables intermolecular π-electron transfer, which prevents intermolecular π-electron transfer even if orientation defects occur. It is expected to have a crystal structure that is difficult to form. That is, it is expected that an organic photoelectric conversion element having high photoelectric conversion efficiency and durability will be obtained.

  Further, not only when used as a power generation layer (bulk heterojunction layer) but also when used as a carrier transport layer existing between the power generation layer and the electrode, the above-described defects of intermolecular π electron transfer are unlikely to occur. From these characteristics, the present inventors have found that it is also useful when used as a carrier transport layer, particularly an electron transport layer.

JP 2006-241124 A

A. Heeger: Nature Mat. Vol. 6 (2007), p497 Nature Mat. vol. 4 (2005), p37 Chem. Lett. , Vol. 37 (2008), p866 Journal of Polymer Science Part A: Polymer Chemistry 2004, 42 (23), 5891-5899

  An object of the present invention is to provide an organic photoelectric conversion element having a high photoelectric conversion efficiency and a small decrease in relative efficiency, and a solar cell using the organic photoelectric conversion element.

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

  1. An organic photoelectric conversion element having a transparent electrode, a counter electrode, and one or more organic layers between the transparent electrode and the counter electrode, wherein the organic layer contains a compound having a cyclophane structure Organic photoelectric conversion element.

  2. 2. The organic photoelectric conversion device according to 1 above, wherein the compound having a cyclophane structure is present in a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are mixed.

  3. 2. The organic photoelectric conversion element as described in 1 above, wherein the cyclophane structure is a [2,2] -paracyclophane structure.

  4). 4. The organic photoelectric conversion device according to any one of 1 to 3, wherein the cyclophane structure is represented by the following general formula (1).

(Wherein A _{1 to} A ₄ each represents a substituted or unsubstituted group selected from an alkenyl group, an alkynyl group, an aryl group, and a heteroaryl group.)
5). The group represented by A _{1 to} A ₄ in the general formula (1) is a group represented by the following general formula (2). Photoelectric conversion element.

(Wherein R _{1 to} R ₅ each represents a substituted or unsubstituted alkyl group, cycloalkyl group, alkyloxy group, aryl group, or heteroaryl group. B ₁ represents a nitrogen-containing heteroaryl group, respectively. P represents 1 to 3, q represents 1 or 2, and r represents a positive integer of 1 to 3.)
6). 5. The organic photoelectric conversion device according to any one of 1 to 4, wherein the group represented by R ₅ in the general formula (2) is a substituted or unsubstituted phenyl group.

  7). An organic photoelectric conversion element having a transparent electrode, a counter electrode, and a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are mixed between the transparent electrode and the counter electrode, the bulk heterojunction layer and the transparent electrode Alternatively, the electron transport layer is provided between the counter electrode and the compound having the cyclophane structure is present in the electron transport layer. Organic photoelectric conversion element.

  8). 8. The organic photoelectric conversion device as described in 7 above, wherein the compound having a cyclophane structure as described in 7 is represented by the following general formula (3).

(In the formula, X _{1 to} X ₈ each represent a substituted or unsubstituted carbon atom or a nitrogen atom. L represents a single bond or a divalent linking group.)
9. 9. The organic photoelectric conversion device according to 7 or 8, wherein at least one of X _{1 to} X ₈ of the compound represented by the general formula (3) is a nitrogen atom.

  10. 10. The organic photoelectric conversion element according to any one of 2 to 9, wherein the bulk hetero junction layer is produced by a solution coating method.

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

  12 The organic photoelectric conversion element of any one of said 1-10 is arrange | positioned at array form, The optical sensor array characterized by the above-mentioned.

  According to the present invention, an organic thin-film solar cell material capable of achieving a high conversion efficiency, having high durability, and capable of being applied to a coating process that enables low-cost manufacturing can be provided.

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

  The present inventors diligently examined the above problem, and found that the above problem can be achieved by the presence of the compound represented by the general formula (1) in the bulk heterojunction layer.

  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 , Passed between the electron donors and 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 unit 14 has a so-called p-i-n three-layer configuration (FIG. 2). 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 is sandwiched between a 14p layer composed of a single p-type semiconductor material and a 14n layer composed of a single n-type semiconductor material. As a result, 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 a cross-sectional view showing a solar cell composed of 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 p-type semiconductor material used for the bulk heterojunction layer of the present invention preferably contains a compound having a cyclophane structure.

  The cyclophane structure is generally described as [x, y-paracyclophane] when the length of the alkylene group connecting two rings is x and y, and the connecting positions are each in the para position. In the meta position, it is [x, y-metacyclophane].

  Since these two aromatic rings connected to each other cause steric hindrance, depending on the position of the substitution, the two rings are not parallel, and the π-π interaction through the space between the two rings decreases. There is a case. It is [2,2-paracyclophane] that has the highest degree of parallelism and shows π-π interaction through the space between the two rings. Therefore, the p-type semiconductor material of the present invention is preferably a compound containing a [2,2-paracyclophane] structure.

  More preferably, the compound represented by the general formula (1) is preferable.

In the general formula (1), the groups represented by A _{1 to} A ₄ are each a substituted or unsubstituted substituent selected from an alkenyl group, an alkynyl group, an aryl group, and a heteroaryl group.

The alkenyl group represented by A ₁ to A _4, for example, a vinyl group, an allyl group, 1,2-dichloroethylene group.

Examples of the alkynyl group represented by A _{1 to} A ₄ include ethynyl group, propargyl group, and diethynyl group.

Examples of the aryl group represented by A _{1 to} A ₄ include a phenyl group, a p-chlorophenyl group, a tolyl group, a xylyl group, a mesityl group, a biphenylyl group, a naphthalene ring, an anthracene ring, an azulene ring, an acenaphthene ring, Fluorene ring, phenanthrene ring, indene ring, pyrene ring, tetracene ring, pentacene ring, hexacene ring, benzopyrene ring, benzoazulene ring, chrysene ring, benzochrysene ring, acenaphthene ring, acenaphthylene ring, triphenylene ring, coronene ring, benzocoronene ring, hexa Benzocoronene ring, benzofluorene ring, fluoranthene ring, perylene ring, naphthoperylene ring, pentabenzoperylene ring, benzoperylene ring, pentaphen ring, picene ring, pyrantolen ring, coronene ring, naphthocoronene ring, ovalen ring, anthra It can be exemplified a substituent group is replaced a part of the hydrogen of the condensed aromatic hydrocarbon ring Ntoren ring.

Examples of the heteroaryl group represented by A _{1 to} A ₄ include a pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, tetrazine ring, quinoline ring, isoquinoline ring, acridine ring, phenanthridine ring, and quinoxaline. Ring, cinnoline ring, phthalazine ring, quinazoline ring, naphthyridine ring, pteridine ring, phenazine ring, phenanthroline ring, pyrrole ring, pyrazole ring, imidazole ring, triazole ring, indole ring, benzimidazole ring, carbazole ring, purine ring, pyrrolopyrrole Ring, pyrazolotriazole ring, benzoquinoline ring, carbazole ring, azacarbazole ring, phenazine ring, phenanthridine ring, phenanthroline ring, carboline ring, cyclazine ring, quindrine ring, tepenidine ring, quinindrin ring, Phenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, diazacarbazole ring (representing any one of the carbon atoms constituting the carboline ring replaced by a nitrogen atom), phenanthroline ring, furan Ring, benzofuran ring, isobenzofuran ring, dibenzofuran ring, oxazole ring, isoxazole ring, oxadiazole ring, furazane ring, thiophene ring, benzothiophene ring, thieno [2,3-a] thiophene ring, thieno [2,3 -B] part of hydrogen of a condensed aromatic hydrocarbon ring such as a thiophene ring, anthradithiophene ring, dithiafulvene ring, thiazole ring, benzothiazole ring, dibenzothiophene ring, benzodithiophene ring, anthradithiophene ring, thiothiophene ring Replace with And the like can be given.

A compound having such a 4-substituted paracyclophane structure becomes a substantially discotic compound, and the intermolecular connection is improved, so that high photoelectric conversion efficiency is expected. As the substituent of the group represented by the substituents A _{1 to} A ₄ , a substituent represented by the following general formula (2) is preferable.

In the general formula (2), R _{1 to} R ₅ each represents a substituted or unsubstituted alkyl group, cycloalkyl group, alkyloxy group, aryl group, or heteroaryl group. B ₁ represents a nitrogen-containing heteroaryl group. P represents 1 to 3, q represents 1 or 2, and r represents a positive integer of 1 to 3, respectively.

  As shown in the general formula (2), the thiophene ring that is electron-donating and the nitrogen-containing heteroaryl group that is electron-accepting are alternately connected, so that intramolecular charge transfer occurs and the band gap is small. Easy to do. Among these, a non-shared electron pair is preferably a nitrogen-containing heteroaryl group containing a nitrogen atom that does not participate in the π-electron system.

Examples of the alkyl group represented by R _{1 to} R ₅ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, a dodecyl group, A tridecyl group, a tetradecyl group, a pentadecyl group and the like can be mentioned. In order to obtain the above-mentioned fastener effect, a C6-C20 linear alkyl group (n-hexyl group, n-octyl group, n-dodecyl group, etc.) is used. It is preferable.

Examples of the cycloalkyl group represented by R _{1 to} R ₅ include a cyclopentyl group and a cyclohexyl group.

Examples of the alkyloxy group represented by R _{1 to} R ₅ include a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, and a dodecyloxy group.

Examples of the aryl group and heteroaryl group represented by R _{1 to} R ₅ include the groups exemplified in the general formula (1).

Examples of the nitrogen-containing heteroaryl group represented by B ₁ include pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, tetrazine ring, quinoline ring, isoquinoline ring, acridine ring, phenanthridine ring, quinoxaline ring, Cinnoline ring, phthalazine ring, quinazoline ring, naphthyridine ring, pteridine ring, phenazine ring, phenanthroline ring, pyrrole ring, pyrazole ring, imidazole ring, triazole ring, benzimidazole ring, purine ring, diketopyrrolopyrrole ring, pyrazolotriazole ring Benzoquinoline ring, azacarbazole ring, phenazine ring, phenanthridine ring, phenanthroline ring, carboline ring, cyclazine ring, kindrin ring, tepenidine ring, quinindrine ring, triphenodithiazine ring, triphenodioxazine ring , Phenanthrazine ring, anthrazine ring, perimidine ring, diazacarbazole ring (representing any one of carbon atoms constituting the carboline ring replaced by a nitrogen atom), oxazole ring, isoxazole ring, oxadiazole ring , Furazane ring, thiazole ring, benzothiazole ring, benzothiadiazole ring and the like.

  Hereinafter, although the specific example of a compound represented by General formula (1) of this invention is given, this invention is not limited to these.

  These; Chemische Berichte; England; 126; 7; 1993; 1643; Journal of the American Chemical Society; enlist; 122; 7; 2000; 1289; Journal; 5183, etc. can be synthesized with reference.

  In this invention, the addition amount of the compound which has a cyclophane structure is 10-75 mass% of the total solid in a bulk heterojunction layer, Preferably it is 20-50 mass%.

  As the organic photoelectric conversion element of the present invention, not only the above cyclophane compound but also various known p-type semiconductor materials (such as condensed polycyclic aromatic low molecular weight compounds and conjugated polymers) can be used in combination. . As will be described later, when the cyclophane compound of the present invention is used as a carrier transport layer, all of the p-type semiconductor materials of the bulk heterojunction layer may be known compounds.

  Examples of the condensed polycyclic aromatic low-molecular compound include anthracene, tetracene, pentacene, hexacene, heptacene, chrysene, picene, fluorene, pyrene, peropyrene, perylene, terylene, quaterylene, coronene, ovalene, circumanthracene, bisanthene, zeslen, Compounds such as heptazeslen, 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. No. 9, 2706 and the like, and a heat conversion type porphyrin compound as described in JP-A No. 2008-16834 and the like, such as an acene compound substituted with a trialkylsilylethynyl group.

  Examples of the conjugated polymer include 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 described in WO 2008/000664, a polythiophene-diketopyrrolopyrrole copolymer described in WO 2008/000664, a polythiophene-thiazolothiazole copolymer described in Adv Mater, 2007 p4160, 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, Σ conjugated polymers such as polysilane and polygerman, and polymer materials such as polythiophene having a polymerizable group described in Technical Digest of the International PVSEC-17, Fukuoka, Japan, 2007, P1225.

  In addition, oligomer 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.

  In the present invention, the p-type semiconductor material is preferably a low-molecular compound from the viewpoint that high-purity purification is possible and a thin film having high mobility can be obtained. 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 further preferably 5000 or more is classified as a polymer compound. The molecular weight can be measured by gel permeation chromatography (GPC).

[N-type semiconductor materials]
The n-type semiconductor material used for the bulk heterojunction layer of the present invention is not particularly limited. Perfluorophthalocyanine), naphthalenetetracarboxylic anhydride, naphthalenetetracarboxylic acid diimide, perylenetetracarboxylic acid anhydride, perylenetetracarboxylic acid diimide and other aromatic carboxylic acid anhydrides and imidized compounds thereof as a skeleton Etc.

  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 of forming bulk heterojunction layer]
Examples of a method for forming a bulk heterojunction 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. 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 the electric 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 (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.

  More preferably, a cyclophane compound having a high carrier transport property is used as the electron transport layer / hole blocking layer. However, when used as an electron transport layer, unlike the case of using it as a power generation layer, a function of absorbing light is not necessarily required, and a compound focused only on carrier transport properties may be used. From such a viewpoint, when used as an electron transport layer / hole blocking layer, a compound represented by the general formula (3) is preferable.

In the general formula _(3), X 1 ~X ₈ each represents a substituted or unsubstituted carbon atom or a nitrogen atom. L represents a single bond or a divalent linking group. Examples of the divalent linking group include an alkylene group, an alkenylene group, an alkynylene group, an arylene group, a heteroarylene group, and a silylene group. More preferably, it is a compound in which at least one of X _{1 to} X ₈ is a nitrogen atom, and further preferred is a compound in which at least one of X _{3 to} X ₆ is a nitrogen atom. Most preferred is a compound wherein X ₃ and X ₆ are nitrogen atoms.

  Hereinafter, although the specific example of a compound represented by General formula (3) of this invention is shown, this invention is not limited to these.

  In the present invention, the hole blocking layer material is preferably a low-molecular compound from the viewpoint that high-purity purification is possible and a thin film with high mobility can be obtained. 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 further preferably 5000 or more is classified as a polymer compound. The molecular weight can be measured by gel permeation chromatography (GPC).

  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 the material constituting these layers, for example, as the hole transport layer 17, PEDOT such as trade name BaytronP, polyaniline and its doped material, a cyanide compound described in WO2006 / 019270, etc. Etc. can be used. Note that the hole transport layer having a LUMO level shallower than the LUMO level of the n-type 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 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 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 called a transparent electrode, and a non-light-transmitting electrode may be called a counter electrode. Usually, the anode is a translucent transparent electrode, and the cathode is a non-translucent counter 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, 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₎ mixture, indium, a lithium / aluminum mixture, and rare earth metals. Among these, in view 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.

  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 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 lightness 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), 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. A polyethylene terephthalate film and a biaxially stretched polyethylene naphthalate film are more preferable.

  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 is smaller than this, the effect of diffraction is generated and colored.

  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 of die coating, dip coating, etc., or direct patterning at the time of coating using a method such as an ink jet method or screen printing. May be.

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

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

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

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

  In FIG. 4, 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. 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 BP-1 precursor is used for the p-type semiconductor material of the photoelectric conversion layer 24b, and for example, the exemplified compound 13 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 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 spin coating (conditions: rotational 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 Exemplary Compound 3 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, P3HT and PCBM were mixed with a chlorobenzene solvent in a ratio of 1: 1, and a mixture obtained by stirring (5 minutes) was used. After forming the mixed film of Exemplified Compound 3 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 Exemplary Compound 3 and PCBM after the annealing treatment was 70 nm.

  Then, using a metal mask having a predetermined pattern opening, 5 nm of the compound 16 of the present invention is deposited as an electron transport layer on a mixed film of P3HT 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.

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

Example 1 Application to Bulk Heterojunction Layer <Production of Comparative 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 (water-soluble polythiophene compound) (manufactured by Starck Vitec), which is a conductive polymer, was spin-coated at a film thickness of 30 nm, and then heat-dried at 140 ° C. in the air for 10 minutes.

  After this, the substrate was brought into the glove box and worked 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 (Plexcore OS2100 made by Plextronics) as a p-type semiconductor material and 0.8% by mass of the following PCBM (made by Frontier Carbon Co.) as an n-type semiconductor material in chlorobenzene. Then, spin-coating was performed at 700 rpm for 60 seconds and then at 2200 rpm for 1 second while being filtered with a 0.45 μm filter, and dried at 120 degrees for 5 minutes.

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, heating was performed at 140 ° C. for 30 minutes to obtain a comparative organic photoelectric conversion element 1. 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, and then converted efficiency and a fill factor described below. The results are shown in Table 1.

<Preparation of the organic photoelectric conversion elements 2 to 5 of the present invention>
In the production of the organic photoelectric conversion element 1, the organic material was the same as the comparative organic photoelectric conversion element 1 except that the p-type semiconductor material was changed to the exemplary compound of the present invention described in Table 1 instead of the comparative compound 1. Photoelectric conversion elements 2 to 5 were obtained.

  The obtained organic photoelectric conversion elements 2 to 5 were sealed using an aluminum cap and a UV curable resin under a nitrogen atmosphere, and then evaluated for the following conversion efficiency and curve factor. The results are summarized in Table 1. .

(Evaluation of conversion efficiency and fill factor)
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 (%)
Furthermore, the initial conversion efficiency at this time was set to 100, and the conversion efficiency after 100 hours of irradiation with an irradiation intensity of 100 mW / cm ² with the resistance connected between the anode and the cathode was evaluated.

  From Table 1, it can be seen that using the p-type semiconductor material of the present invention can improve the conversion efficiency and reduce the relative efficiency.

Example 2 Application to Electron Transport Layer <Production of Organic Photoelectric Conversion Elements 6-8 of the Present Invention>
Similarly to the production of the comparative organic photoelectric conversion element 1, Baytron P4083 (manufactured by Starck Vitec) was formed and fired at a film thickness of 30 nm.

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

  A solution was prepared by dissolving 1.0 mass% of plexcores OS2100 manufactured by Plextronics Co., Ltd. in chlorobenzene and 0.8 mass% of PCBM (manufactured by Frontier Carbon Co.) as the n-type semiconductor material. While being filtered through a .45 μm filter, spin coating was performed at 700 rpm for 60 seconds, then at 2200 rpm for 1 second, and dried at 120 degrees for 5 minutes.

  Next, the compounds shown in Table 2 were dissolved in tetrafluoroisopropanol at a concentration of 0.2%, spin-coated at 3000 rpm for 30 seconds, and dried at 120 degrees for 5 minutes.

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 80 nm of Al was deposited. Finally, heating was performed at 140 ° C. for 30 minutes to obtain an organic photoelectric conversion element 6 of the present invention. The vapor deposition rate was 2 nm / second for all, and the size was 2 mm square.

The obtained organic photoelectric conversion element 6 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 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.

  In addition, since the improvement of the rectification property of an organic photoelectric conversion element, the fall of resistance between layers, etc. are anticipated as the effect which changed the electron carrying layer, a fill factor (FF) was also evaluated as the parameter | index.

  From Table 2, it can be seen that the use of the electron transport layer / hole blocking layer of the present invention improves the fill factor and provides high conversion efficiency.

10 Bulk heterojunction organic photoelectric conversion element 11 Substrate 12 Transparent electrode (anode)
13 Counter electrode (cathode)
14 Photoelectric conversion part (bulk heterojunction layer)
14p p layer 14i i layer 14n n layer 14 'first photoelectric conversion part 15 charge recombination layer 16 second photoelectric conversion part 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 (12)

  An organic photoelectric conversion element having a transparent electrode, a counter electrode, and one or more organic layers between the transparent electrode and the counter electrode, wherein the organic layer contains a compound having a cyclophane structure Organic photoelectric conversion element.   The organic photoelectric conversion device according to claim 1, wherein the compound having a cyclophane structure is present in a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are mixed.   The organic photoelectric conversion device according to claim 1, wherein the cyclophane structure is a [2,2] -paracyclophane structure. The organic photoelectric conversion device according to claim 1, wherein the cyclophane structure is represented by the following general formula (1).

(Wherein A _{1 to} A ₄ each represents a substituted or unsubstituted group selected from an alkenyl group, an alkynyl group, an aryl group, and a heteroaryl group.) 4. The group represented by A _{1 to} A ₄ in the general formula (1) is a group represented by the following general formula (2). 5. Organic photoelectric conversion element.

(Wherein R _{1 to} R ₅ each represents a substituted or unsubstituted alkyl group, cycloalkyl group, alkyloxy group, aryl group, or heteroaryl group. B ₁ represents a nitrogen-containing heteroaryl group, respectively. P represents 1 to 3, q represents 1 or 2, and r represents a positive integer of 1 to 3.) The organic photoelectric conversion device according to claim 1, wherein the group represented by R ₅ in the general formula (2) is a substituted or unsubstituted phenyl group.   An organic photoelectric conversion element having a transparent electrode, a counter electrode, and a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are mixed between the transparent electrode and the counter electrode, the bulk heterojunction layer and the transparent electrode Or it has an electron carrying layer between counter electrodes, and the compound which has the said cyclophane structure exists in this electron carrying layer, The any one of Claims 1-6 characterized by the above-mentioned. Organic photoelectric conversion element. The organic photoelectric conversion element according to claim 7, wherein the compound having a cyclophane structure according to claim 7 is represented by the following general formula (3).

(In the formula, X _{1 to} X ₈ each represent a substituted or unsubstituted carbon atom or a nitrogen atom. L represents a single bond or a divalent linking group.) 9. The organic photoelectric conversion device according to claim 7, wherein at least one of X _{1 to} X ₈ of the compound represented by the general formula (3) is a nitrogen atom.   The organic photoelectric conversion element according to claim 2, wherein the bulk heterojunction layer is produced by a solution coating method.   It consists of the organic photoelectric conversion element of any one of Claims 1-10, The solar cell characterized by the above-mentioned.   The organic photoelectric conversion element of any one of Claims 1-10 is arrange | positioned at array form, The optical sensor array characterized by the above-mentioned.

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