JP5699524B2 - Organic photoelectric conversion element and solar cell - Google Patents

Description

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

  Due to the recent rise in fossil energy, a system that can generate electric power directly from natural energy has been demanded. Solar cells using single-crystal / polycrystal / amorphous Si, GaAs, CIGS (copper (Cu), indium (In) ), Semiconductor materials such as gallium (Ga) and selenium (Se)), and dye-sensitized photoelectric conversion elements (Gretzel cells) have been proposed and put to 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 this situation, as a solar cell that can achieve a power generation cost that is lower than that of fossil fuel, an electron donor layer (p-type semiconductor layer) and an electron acceptor are interposed between the transparent electrode and the counter electrode. A bulk heterojunction photoelectric conversion element sandwiching a photoelectric conversion layer mixed with a body layer (n-type semiconductor layer) has been proposed, and an efficiency exceeding 5% has been reported (for example, see 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-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.

  On the other hand, although durability is also required for the solar cell, the durability of the organic thin film solar cell is still insufficient, and improvement is expected.

  In response to such a problem, ordinary organic thin-film solar cells are stacked in the reverse order, electrons are extracted from the transparent electrode side, and holes are extracted from the stable metal electrode side having a deep work function. Organic thin-film solar cells have been proposed (see Patent Document 1 and Non-Patent Document 2).

  It is disclosed that such a configuration eliminates the need to use a metal having a shallow work function that is unstable and easily oxidized, prevents deterioration due to the electrode, and can greatly improve the life.

  In such a reverse layer configuration, since it is necessary to coat and laminate the power generation layer on the electron transport layer, the material used for the electron transport layer can be coated and formed and is insoluble in the solvent for coating the power generation layer. Material is required. However, there are few reported examples of such an electron transport material, and TiOx is disclosed as an electron transport material that can be formed by a coating process (Patent Document 1), but the TiOx layer is formed by reacting moisture with titanium alkoxide. However, it is not a preferable material for an organic photoelectric conversion element in which deterioration due to moisture occurs, and there is a problem that a stable film cannot be formed on a production scale.

  An example of using a phosphine oxide compound having a condensed polycyclic group in an electron transport layer is disclosed (Patent Document 2), and it has been reported that the performance of open circuit voltage and short circuit current has been improved due to high carrier mobility. However, durability and conversion efficiency were still not sufficient.

JP 2009-146981 A JP 2006-73583 A

Nature Mat. , Vol. 6 (2007), p497, A.I. Heeger etc. APPLIED PHYSICS LETTERS 89, p143517, NREL Shahen etc.

  An object of the present invention is to provide an organic photoelectric conversion element excellent in photoelectric conversion efficiency and durability, and a solar cell using the same.

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

  1. An organic photoelectric conversion element having a substrate, a cathode, an electron transport layer, a bulk heterojunction type photoelectric conversion layer containing a p-type semiconductor material and an n-type semiconductor material containing a fullerene derivative, and an anode in this order. The layer is a photoelectric conversion layer that performs photoelectric conversion with incident light from the cathode side, and the electron transport layer is adjacent to the photoelectric conversion layer and contains a compound represented by the following general formula (A) An organic photoelectric conversion element.

Formula (A): Q1-L1-Q2
"In the formula, Q1 represents a substituted or unsubstituted aryl group or heteroaryl group, Q2 represents a polycyclic aromatic ring group having 4 to 10 condensed rings, L1 represents an alkylene group, an arylene group, Heteroarylene group, alkenylene group, —O—, —S—, —CO—, —SO ₂ —, —NHCO—, —CONH—, —SiR ₁ R ₂ — (R ₁ and R ₂ are each an alkyl group or aryl. Or a divalent linking group selected from a combination of these groups or a simple bond. "
2. 2. The organic photoelectric conversion device as described in 1 above, wherein Q2 in the general formula (A) is a residue of fluoranthene, pyrene, chrysene, triphenylene, perylene or coranulene.

  3. The organic photoelectric conversion device according to 1 or 2, wherein a Q1-L1 portion of the compound represented by the general formula (A) is represented by the following general formula (1).

“Wherein Y ₀₁ represents O, S or N—R _01, and any one of X ₀₁ , X ₀₂ or R ₀₁ represents L1 in the general formula (A), and X ₀₁ and X ₀₂ are not L1 Each represents an aryl group or a heteroaryl group, and may be different or the same. When R ₀₁ is not L1, it represents an aryl group or a heteroaryl group.
4). The organic photoelectric conversion device according to 1 or 2, wherein a Q1-L1 portion of the compound represented by the general formula (A) is represented by the following general formula (2).

“In the formula, any one of X21 to X28 represents L1 in the general formula (A), and when X21 to X28 are not L1, they represent a hydrogen atom or a substituent, and may be different or the same.”
5. 2. The organic photoelectric conversion device according to 1 above, wherein the Q1-L1 portion of the compound represented by the general formula (A) is represented by the following general formula (3).

“In the formula, A _{1 to} A ₈ each independently represents a carbon atom or a nitrogen atom (provided that when it is carbon, the ring having A _{1 to} A ₄ or A _{5 to} A ₈ has a conjugated double bond). Y ₃₁ represents MR ₃₁ R ₃₂ , O, S or N—R ₃₃ , M represents a carbon atom, silicon atom, germanium atom, titanium atom or tin atom, and X _{31 to} X ₃₈ represent hydrogen atoms. R ₃₁ and R ₃₂ each represents an alkyl group or an aryl group, R ₃₃ represents an alkyl group, an aryl group, or a heteroaryl group, and Y ₃₁ represents MR _31. When R ₃₂ , any one of R ₃₁ , R ₃₂ , X _{31 to} X ₃₈ represents the divalent linking group L 1 in the general formula (A), and when Y ₃₁ is N—R ₃₃ , R ₃₃ , one of the _X 31 _{~X 38} One represents L1 in general formula _(A), any one of _{Y 31} is O or _X 31 _{to X 38} when the S represents the L1 in formula (A). "
6). 2. The organic photoelectric conversion device according to 1 above, wherein the Q1-L1 portion of the compound represented by the general formula (A) is represented by the following general formula (4).

In _{"wherein, n 01} represents 0 or _1, X 41 _{to X 45} represents a substituent, any one of the better _.X 41 _{to X 45} be the same or different from each other is in the general formula (A) Represents L1. "
7). A solar cell comprising the organic photoelectric conversion device according to any one of 1 to 6 above.

  According to the present invention, an organic photoelectric conversion element excellent in photoelectric conversion efficiency and durability and a solar cell using the same can be provided.

It is a schematic cross section which shows the solar cell which has the organic photoelectric conversion element of a normal layer structure. It is a schematic cross section which shows the solar cell which has the organic photoelectric conversion element of this invention. It is sectional drawing which shows the solar cell which has an organic photoelectric conversion element provided with a tandem type photoelectric conversion layer.

  The present invention is an organic photoelectric conversion element having a substrate, a cathode, an electron transport layer, a bulk heterojunction photoelectric conversion layer containing a p-type semiconductor material and an n-type semiconductor material composed of a fullerene derivative, and an anode in this order. The photoelectric conversion layer is a photoelectric conversion layer that performs photoelectric conversion with incident light from the cathode side, and the electron transport layer is adjacent to the photoelectric conversion layer and contains the compound represented by the general formula (A). And

  In the present invention, in particular, the photoelectric conversion layer has durability and durability by containing the compound represented by the general formula (A) in the electron transport layer with respect to the photoelectric conversion layer that performs photoelectric conversion with incident light from the cathode side. An organic photoelectric conversion element having excellent photoelectric conversion efficiency is obtained.

(Configuration of organic photoelectric conversion element)
FIG. 1 is a cross-sectional view showing a conventional general normal layer 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.

  Since the photoelectrically converted light is incident from the substrate 11 side, the substrate 11 is a member that can transmit the photoelectrically converted light, that is, is transparent to the wavelength of the light to be photoelectrically converted. As the substrate 11, for example, a glass substrate or a resin substrate is used.

  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).

  An electron donor and an electron acceptor are: “When the light is absorbed, the electrons move from the electron donor to the electron acceptor to form a hole-electron pair (charge separation state). It is a “body” and does not simply donate or accept electrons as in the case of an electrode, but donates or accepts electrons by 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 charges have different internal electric fields, 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 and the holes are 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.

  Here, since the work function of the transparent electrode 12 is usually larger than that of the counter electrode 13, holes are transported to the transparent electrode 12 and electrons are transported to the counter electrode 13. That is, the counter electrode 13 needs to use a metal having a small work function and easily oxidized. When this metal is oxidized, the conductivity is lost, or conversely, the work function is increased and the contact resistance between the layers is greatly increased to deteriorate the electrical characteristics of the device. It was a big factor with low nature.

  In the present invention, the work function of the counter electrode 13 is made larger than the work function of the transparent electrode 12, that is, the work function of the transparent electrode is made smaller than the work function of the counter electrode, and the electrons are transferred to the transparent electrode 12 as a cathode. By designing the holes so as to transport holes to the counter electrode 13 as an anode, it is possible to use a metal having a high work function that is difficult to be oxidized and stable.

  That is, the configuration of the organic photoelectric conversion device of the present invention reverses the work function relationship of the electrodes with respect to the incident direction of light as described above, and further positions of the hole transport layer 17 and the electron transport layer 18 in FIG. Is an organic photoelectric conversion element having a reverse layer configuration as shown in FIG.

  Although not shown in FIGS. 1 and 2, 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.

  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, the electron transport layer 18, and the first photoelectric conversion layer 14 ′ are sequentially stacked on the substrate 11, the charge recombination layer 15 is stacked, and then the second photoelectric conversion layer 16. Then, by stacking the counter electrode 13, a tandem configuration 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. Moreover, you may have the positive hole transport layer 17 between 1st photoelectric converting layer 14 ', 2nd photoelectric converting layer 16, and each electrode.

  Below, the material which comprises these layers is described.

(Electron transport layer)
The organic photoelectric conversion device of the present invention can more efficiently extract charges generated in the bulk heterojunction photoelectric conversion layer by forming an electron transport layer between the bulk hetero junction photoelectric conversion layer and the cathode. it can.

  In the present invention, the electron transport layer is adjacent to the photoelectric conversion layer, which means that the electron transport layer is in contact with the photoelectric conversion layer.

  In this invention, the effect that a photoelectric conversion efficiency and durability improve can be acquired by containing the compound represented by general formula (A) in an electron carrying layer.

  Hereinafter, the compound represented by formula (A) will be described.

  In the general formula (A), Q1 represents a substituted or unsubstituted aryl group (for example, phenyl group, naphthyl group, fluorenyl group, etc.) or heteroaryl group (for example, pyridyl group, pyrimidyl group, triazyl group, thienyl group, oxadiazolyl group) , Triazolyl group, thiazolyl group, phosphoryl group, phenanthryl group, carbazolyl group, azafluorenyl group, dibenzofuryl group and the like.

  Examples of the substituent that may substitute these groups include an alkyl group, a cycloalkyl group, an aryl group, an alkylsilyl group, and an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly Preferably it is C2-C8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl etc.), an alkynyl group (preferably C2-C20, more preferably C2-C12, Particularly preferably, it has 2 to 8 carbon atoms, and examples thereof include propargyl, 3-pentenyl, etc.), an alkoxy group (preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably carbon numbers). 1-8, for example, methoxy, ethoxy, butoxy, etc.), cycloalkyloxy groups (preferably having 4-8 carbon atoms, examples For example, cyclopentyloxy, cyclohexyloxy, etc.), an aryloxy group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, and particularly preferably 6 to 12 carbon atoms. For example, phenyloxy , 2-naphthyloxy, etc.), acyl groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as acetyl, benzoyl, formyl And pivaloyl), alkoxycarbonyl groups (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). An aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, such as phenyloxycarbonyl, etc.), acyloxy groups (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, especially Preferably it has 2 to 10 carbon atoms, such as acetoxy, benzoyloxy, etc.), acylamino group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms). For example, acetylamino, benzoylamino, etc.), an alkoxycarbonylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, For example, methoxycarbonylamino and the like), an aryloxycarbonylamino group (preferably having a carbon number) It has 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, and particularly preferably 7 to 12 carbon atoms. Examples thereof include phenyloxycarbonylamino. ), A sulfonylamino 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 methanesulfonylamino and benzenesulfonylamino). Sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as 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, diethylcarbamoyl, phenylcarbamoyl, etc. An alkylthio group (preferably having 1 carbon atom) 20, More preferably, it is C1-C16, Most preferably, it is C1-C12, for example, a methylthio, ethylthio, etc. are mentioned, An arylthio group (Preferably C6-C20, More preferably C 6 to 16, particularly preferably 6 to 12 carbon atoms, for example, phenylthio, etc.), a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably carbon numbers). 1 to 12, for example, mesyl, tosyl, etc.), sulfinyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, , Methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably having 1 to 20 carbon atoms, more preferably 1 to carbon atoms). 6, particularly preferably having 1 to 12 carbon atoms, such as ureido, methylureido, phenylureido, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms). Particularly preferably having 1 to 12 carbon atoms, such as diethyl phosphoric acid amide and phenylphosphoric acid amide), hydroxy group, mercapto group, halogen atom (for example, 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, and the like.

Q2 represents a residue of a polycyclic aromatic ring group having 4 to 10 condensed rings. Examples of the polycyclic aromatic ring group include fluoranthene, acephenanthrylene, chrysene, acanthrylene, tetracene, benzo [ a) anthracene, pyrene, triphenylene, perylene, benzo [ghi] fluoranthene, benzo [c] phenanthrylene, benzo [def] chrysene, coranulene, indenopyrene, acenaphthofluoranthene, coronene, terylene, decacyclene, ovalen, etc. Preferably, it represents fluoranthene, pyrene, chrysene, triphenylene, perylene, coranulene. L1 represents a divalent linking group or a simple bond. Examples of the divalent linking group include an alkylene group (eg, methylene group, ethylene group, propane-1,3-diyl group, etc.), vinylene group, ethynyl group, arylene group, oxygen atom, sulfur atom, —SO ₂ —. , —NR ″ — (R ″ represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, a sulfonyl group, etc.) and a divalent group formed by combining a plurality of these divalent linking groups. L1 preferably represents a simple bond or an alkylene group.

  As the Q1-L1 portion of the compound represented by the general formula (A), structures represented by the above general formula (1) to general formula (4) are preferable.

In General Formula (1), Y ₀₁ represents O, S, or N—R _01, and any one of X ₀₁ , X _02, or R ₀₁ represents L1 in General Formula (A), and X ₀₁ and X ₀₂ When is not L1, it represents an aryl group or a heteroaryl group, which may be different or the same. When R ₀₁ is not L1, it represents an aryl group or a heteroaryl group.

  As a preferable compound of the compound represented by General formula (1), the compound represented by following General formula (5) is mentioned.

  In the general formula (5), Q is an alkyl group (for example, methyl group, ethyl group, butyl group, hexyl group, etc.), aryl group or heteroaryl group (for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group) , Xylyl, naphthyl, anthryl, azulenyl, acenaphthenyl, fluorenyl, phenanthryl, indenyl, pyrenyl, biphenylyl, pyridyl, pyrimidinyl, furyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrazolyl Group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, Isoxazolyl, isothiazolyl, furazanyl, thie Group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, benzothiadiazolyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (the carboline ring of the carbolinyl group is One in which one of the constituent carbon atoms is replaced with a nitrogen atom), and an aryl group or a heteroaryl group is more preferable.

X is selected from an oxygen atom, a sulfur atom or N-Rx, and Rx is a substituted or unsubstituted aryl or heteroaryl group (for example, the same as the examples of the aryl group or heteroaryl group of Q) Represent. R _{1 to} R ₇ represent a substituent selected from a hydrogen atom, a fluorine atom, a cyano group, an alkyl group, a substituted or unsubstituted aryl or heteroaryl group, and adjacent R ₃ and R ₄ are linked to form a ring. You may do it.

  In the general formula (2), any one of X21 to X28 represents L1 in the general formula (A), and when X21 to X28 are not L1, each represents a hydrogen atom or a substituent, good. Examples of the substituent include the same substituents that may be substituted with Q1 in the general formula (A).

In General Formula (3), A _{1 to} A ₈ each independently represent a carbon atom or a nitrogen atom (provided that when it is carbon, the ring having A _{1 to} A ₄ and A _{5 to} A ₈ is conjugated Having a double bond). Y ₃₁ represents MR ₃₁ R ₃₂ , O, S or N—R ₃₃ , M represents a carbon atom, silicon atom, germanium atom, titanium atom or tin atom, and X _{31 to} X ₃₈ represent a hydrogen atom or a substituent. Each may be different or the same. Examples of the substituent include the same substituents that may be substituted with Q1 in the general formula (A).

R ₃₁ and R ₃₂ represent an alkyl group (methyl group, ethyl group, propyl group, octyl group, etc.) or an aryl group (phenyl group etc.), and R ₃₃ represents an alkyl group (methyl group, ethyl group, propyl group, octyl group). Etc.), an aryl group (such as a phenyl group), or a heteroaryl group (such as a pyridyl group). When Y ₃₁ is MR ₃₁ R ₃₂ , any one of R ₃₁ , R ₃₂ , X _{31 to} X ₃₈ represents the divalent linking group L1 in the general formula (A), and Y ₃₁ is N—R ₃₃ . When, R ₃₃ , any one of X _{31 to} X ₃₈ represents L1 in the general formula (A), and when Y ₃₁ is O or S, any one of X _{31 to} X ₃₈ is the general formula (A). L1 in

In the general formula (4), n ₀₁ represents 0 or 1, and X _{41 to} X ₄₅ represent substituents, which may be different or the same. Any one of X _{45 to} X ₄₄ represents L1 in the general formula (A). Examples of the substituent include the same substituents that may be substituted with Q1 in the general formula (A). Adjacent X _{41 to} X ₄₅ may combine to form a ring.

  Specific examples of the compound represented by formula (A) are shown below, but the present invention is not limited thereto.

  The compound used in the present invention can be easily synthesized by those skilled in the art with reference to a known production method. For example, the compound can be synthesized by the following method.

  (Synthesis Example 1: Synthesis Method of Compound Example 06)

  (Synthesis Example 2: Synthesis Method of Compound Example 35)

  (Synthesis Example 3: Synthesis Method of Compound Example 60)

  (Synthesis Example 4: Synthesis Method of Compound Example 113)

  The means for forming the electron transport layer of the present invention may be either a vacuum vapor deposition method or a solution coating method, but is preferably a solution coating method.

  That is, in the present invention, as a method for producing the organic photoelectric conversion element of the present invention, an electron transport layer is formed by using an electron transport layer coating liquid containing the components contained in the electron transport layer. A production method having a forming step is preferably applicable.

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

  The film thickness of the formed electron transport layer is 5 nm to 5 μm, preferably 5 to 200 nm.

  In this invention, a fill factor (curve factor) and photoelectric conversion efficiency can be improved by containing the compound represented by General formula (1) in an electron carrying layer.

  Although the cause of the effect of the present invention is not certain, when forming the photoelectric conversion device of the present invention, a film having a polycyclic aromatic functional group having 4 to 10 condensed rings is formed as an electron transport layer. In addition, since a photoelectric conversion layer containing fullerene is formed by solution coating, a polycyclic aromatic functional group having 4 to 10 condensed rings interacts with fullerene, and fullerene segregates on the electron transport side. As a result, it is presumed that the recombination of charges is suppressed and the above-mentioned effect is obtained.

  The electron transport layer of the present invention may contain a plurality of known electron transport materials in addition to the compound represented by the general formula (A) of the present invention. Although it does not specifically limit as a well-known electron transport material, It is desirable for electron injection efficiency to be high and to transport an electron efficiently, Specifically, a quinolinol derivative metal complex (8-hydroxyquinoline aluminum etc.), condensed ring tetracarboxylic acid Diimides (naphthalene-1,4,5,8-tetracarboxylic acid diimide, perylene-3,4,9,10-tetracarboxylic acid diimide, etc.), oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, fullerenes (C60) , C70, etc.).

  The electron transport layer according to the present invention may be formed by adding an alkali metal (lithium, sodium, potassium, cesium, etc.) or a salt thereof, an alkaline earth metal (calcium, strontium, etc.) or a salt thereof. . As these addition methods, a method of forming an organic layer in advance and forming it later by vapor phase doping or liquid layer doping, a co-evaporation method at the time of forming the organic layer, sputtering or a mixed solution using a binary target Although the method of forming simultaneously by these apply | coating methods is mentioned, It does not specifically limit.

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

  Examples of the condensed polycyclic aromatic compound include oligothiophene, oligoparaphenylene, fluorene, carbazole, anthracene, tetracene, pentacene, hexacene, heptacene, chrysene, picene, fluorene, pyrene, peropyrene, perylene, terylene, quaterylene, coronene, Ovalene, circumcamanthracene, bisanthene, zestrene, heptazethrene, pyranthrene, violanthene, isoviolanthene, cacobiphenyl, thienothiophene, benzodithiophene, cyclopentadithiophene, dithienopyrrole, dithienosilole, dithienonaphthalene, benzothiophenobenzothiophene Compounds such as tradithiophene, thienopyrazine, benzothiadiazole, diketopyrrolopyrrole, pyrazolotriazole, Firin, copper phthalocyanine, tetrathiafulvalene (TTF) - tetracyanoquinodimethane (TCNQ), bis-ethylenedioxy-thia tetrathiafulvalene (BEDTTTF), and may be derivatives thereof.

  The low molecular 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 5000 or more is preferably classified as a polymer compound. More preferably, it is 10,000 or more, More preferably, it is 30000 or more. On the other hand, since the solubility decreases as the molecular weight increases, the molecular weight is preferably 1,000,000 or less, more preferably 100,000 or less. 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).

  A more preferable p-type semiconductor material is a donor-acceptor type conjugated polymer in which a donor unit and an acceptor unit are copolymerized. Since such a polymer has an absorption wavelength that extends to a long wavelength and can absorb a wide range of sunlight, generation of a high current density can be expected.

  Examples of such polymers include, for example, polythiophenes such as poly-3-hexylthiophene (P3HT) represented by the following structural formula, 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, poly (cyclopentadithiophene-benzothiadiazole) copolymer (PCPDTBT), and the like, poly (silacyclopentadithiophene-benzothiadiazole) copolymer described in US20080873324, Adv. Mater. 2010, p22, poly (benzodithiophene-thienothiophene) copolymer, Adv. Mater. And polycarbazole derivatives described in 2007, 19, p2295, and the like.

  Among these compounds, compounds that have high solubility in organic solvents to the extent that solution processing is possible, can form a crystalline thin film after drying, and can achieve high mobility are preferable.

  In addition, when a hole transport layer is formed on a photoelectric conversion layer by coating, there is a problem that the hole transport layer solution dissolves the photoelectric conversion layer. Therefore, a material that can be insolubilized after coating by a solution process is used. It may be used.

  Examples of such materials include materials that can be insolubilized by polymerizing the coating film after coating, such as polythiophene having a polymerizable group described in Technical Digest of the International PVSEC-17, Fukuoka, Japan, 2007, P1225. Or a material in which soluble substituents react and become insoluble (pigmented) by applying energy such as heat, as described in US Patent Application Publication No. 2003/136964, and Japanese Patent Application Laid-Open No. 2008-16834 And so on.

[N-type semiconductor materials]
The n-type semiconductor material used for the photoelectric conversion layer according to the present invention is an n-type semiconductor material containing a fullerene derivative.

  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, N-methylfullropyrrolidine, [6,6] -phenyl C61-butyric acid methyl ester (abbreviated as PCBM), [6,6] -phenyl C61-butyric acid-n-butyl ester (PCBnB) represented by the following structural formula [6,6] -phenyl C61-butyric 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. Fullerene having a cyclic ether group such as Amer. Chem. Soc. (2009) voL130, p15429, SIMEF, Appl. Phys. Lett. , Vol. 87 (2005), C60MC12 described in p203504, and the like. It is preferable to use a fullerene derivative having a substituent and having improved solubility.

[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.

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

  After 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 mobility of holes and electrons (carriers) in 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.

  The film thickness of the photoelectric conversion layer is 2 nm to 5 μm, preferably 2 to 200 nm, more preferably 5 to 20 nm.

(Hole transport layer)
The organic photoelectric conversion element of the present invention preferably has a hole transport layer between the photoelectric conversion layer and the anode.

  For the hole transport layer, PEDOT (poly-3,4-ethylenedioxythiophene) -PSS (polystyrene sulfonic acid), such as trade name BaytronP, manufactured by Stark Vitec, polyaniline and its doping material, International Publication No. 06/019270 Cyanide compounds described in No. pamphlets and the like 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.

Similarly, it preferably has a hole mobility higher than 10 ⁻⁴ due to the property of transporting holes, and a compound with electron mobility lower than 10 ⁻⁶ due to the property of blocking electrons. It is preferable to use it.

  About the film thickness of a positive hole transport layer, 5 nm-5 micrometers, Preferably the range of 5-200 nm is preferable.

[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, the translucent electrode is called a transparent electrode and the non-translucent electrode is called a counter electrode because of the function of whether or not it has translucency. In this invention, since it is a reverse layer structure, a cathode is a transparent electrode and an anode does not require transparency.

[Cathode (transparent electrode)]
The cathode (transparent electrode) of the present invention is an electrode that transmits light of 380 to 800 nm. Examples of the material include transparent metal oxides such as indium tin oxide (ITO), AZO, FTO, SnO ₂ , ZnO, and titanium oxide, very thin metal layers such as Ag, Al, Au, and Pt, metal nanowires, and carbon Nanowires such as nanotubes, layers containing nanoparticles, conductive polymer materials such as PEDOT: PSS, polyaniline, and the like 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 a 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.

〔anode〕
Since the work function of the transparent electrode as the cathode is about −5.0 to −4.0 eV, the carriers generated in the bulk heterojunction layer diffuse and reach each electrode. It is preferable that the work function difference between the cathodes is as large as possible.

  Therefore, as the conductive material for the anode, a material having a work function of a metal, an alloy, an electrically conductive compound, or a mixture thereof is used. Specific examples of such an electrode material include gold, silver, copper, platinum, rhodium, indium, nickel, palladium, and the like.

  Among these, silver is most preferable from the viewpoint of hole extraction performance, light reflectivity, and durability against oxidation and the like.

  The anode 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.

[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, SnO ₂ , ZnO and titanium oxide, very thin metal layers such as Ag, Al, Au and Pt, or layers containing nanowires and nanoparticles such as metal nanowires and carbon nanotubes PEDOT: PSS, conductive polymer materials such as 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〕
Since light that is photoelectrically converted enters from the substrate side, the substrate is a member that can transmit the light that is photoelectrically converted, that is, 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 board | substrate, About the material, a shape, a structure, thickness, etc., it can select suitably from well-known things.

  For example, polyolefins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester resin film such as modified polyester, polyethylene (PE) resin film, polypropylene (PP) resin film, polystyrene resin film, cyclic olefin resin, etc. Resin films, vinyl resin films such as polyvinyl chloride and polyvinylidene chloride, polyether ether ketone (PEEK) resin films, polysulfone (PSF) resin films, polyether sulfone (PES) resin films, polycarbonate (PC) resin films , Polyamide resin film, polyimide resin film, acrylic resin film, triacetyl cellulose (TAC) resin film, and the like. If the resin film transmittance of 80% or more in from zero to eight hundred nanomolar), 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. 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.

  In addition, for the purpose of suppressing 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 of the substrate.

(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 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]
There is no particular limitation on the method and process for patterning the cathode, anode, photoelectric conversion layer, hole transport layer, electron transport layer and the like according to the present invention, 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, it is preferable to seal with the gas barrier material so that the produced organic photoelectric conversion element does not deteriorate with oxygen, moisture, etc. in the environment.

  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.

(Solar cell)
The organic photoelectric conversion element of the present invention is used as a solar cell by adding a case, a current extraction circuit, and the like as necessary.

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

Example 1
[Production of Organic Photoelectric Conversion Device SC-101: Comparative Example]
With reference to Patent Document 1 (Japanese Patent Laid-Open No. 2009-146981), an inverted layer type organic photoelectric conversion element was produced.

  On a glass substrate, an indium tin oxide (ITO) transparent conductive film deposited with a thickness of 110 nm (surface resistivity 13 Ω / □) is patterned to a width of 2 mm using a normal photolithography technique and hydrochloric acid etching, A transparent 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.

  Next, the substrate is brought into a glove box, and a 150 mM / L TiOx precursor solution prepared by the following procedure is spin-coated (rotation speed 2000 rpm, rotation time 60 s) on the transparent substrate in a nitrogen atmosphere, and a predetermined pattern is obtained. Wipe off.

  Next, the TiOx precursor was hydrolyzed by being left in the air. Next, the TiOx precursor was heat-treated at 150 ° C. for 1 hour to obtain a 30 nm TiOx layer.

<< Preparation of TiOx precursor: Sol-gel method >>
First, 12.5 ml of 2-methoxyethanol and 6.25 mmol of titanium tetraisopropoxide were placed in a 100 ml three-necked flask and cooled in an ice bath for 10 minutes. Next, 12.5 mmol of acetylacetone was slowly added and stirred in an ice bath for 10 minutes. Next, the mixed solution was heated at 80 ° C. for 2 hours and then refluxed for 1 hour. Finally, it was cooled to room temperature and adjusted to a predetermined concentration (150 mM / L) using methoxyethanol. A TiOx precursor was obtained. The above steps were all performed in a nitrogen atmosphere.

  Next, on the TiOx layer, 1.0% by mass of P3HT (Plextronics, Plexcore OS2100) is used as a p-type semiconductor material on chlorobenzene, and PCBM (Nonon Spectra E100H, manufactured by Frontier Carbon) is used as an n-type semiconductor material. A 0.8 wt% dissolved solution was prepared, applied with an extrusion coater so that the dry film thickness was 100 nm, and dried to obtain a photoelectric conversion layer.

  Next, an organic solvent-based PEDOT: PSS dispersion (Enocoat HC200, manufactured by Kaken Sangyo Co., Ltd.) was spin-coated (2000 rpm, 60 s) on the organic semiconductor layer and air-dried to form a hole transport layer.

  Next, after vacuum-depositing a silver electrode layer on the conductive polymer layer so as to have a film thickness of about 100 nm, a heat treatment is performed at 150 ° C. for 10 minutes, so that the reverse layer type organic photoelectric conversion element is obtained. Produced.

[Production of Organic Photoelectric Conversion Element SC-102: Comparative Example]
On a glass substrate, an indium tin oxide (ITO) transparent conductive film deposited with a thickness of 110 nm (surface resistivity 13 Ω / □) is patterned to a width of 2 mm using a normal photolithography technique and hydrochloric acid etching, A transparent 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.

  Next, the substrate on which the transparent electrode is formed is brought into a vacuum vapor deposition machine, and the comparative compound 1 is deposited on the transparent electrode so as to have a film thickness of 20 nm, thereby forming an electron transport layer (hole blocking layer). Was formed.

  Next, on the hole blocking layer, 1.0% by mass of P3HT (Plextronics, Plexcore OS2100) is used as a p-type semiconductor material on chlorobenzene, and PCBM (Frontier Carbon, Nano Spectra E100H is used as an n-type semiconductor material. ) Was dissolved in 0.8 mass%, and a film was formed by an extrusion coater so that the dry film thickness was 100 nm, to obtain a photoelectric conversion layer.

  Next, an organic solvent-based PEDOT: PSS dispersion (Enocoat HC200, manufactured by Kaken Sangyo Co., Ltd.) was spin-coated (2000 rpm, 60 s) on the organic semiconductor layer and air-dried to form a hole transport layer.

  Next, after vacuum-depositing a silver electrode layer on the conductive polymer layer so as to have a film thickness of about 100 nm, a heat treatment is performed at 150 ° C. for 10 minutes, whereby a reverse layer type organic photoelectric conversion element SC is obtained. -102 was produced.

[Production of Organic Photoelectric Conversion Device SC-103 (Comparative Example) and SC-104 to 111 (Invention)]
In the production of the organic photoelectric conversion element SC-102, organic photoelectric conversion elements SC-103 to 118 were produced in the same manner as the organic photoelectric conversion element SC-102 except that the comparative compound 1 was changed to the compounds shown in Table 1. .

[Evaluation of Organic Photoelectric Conversion Elements SC-101 to SC-118]
The obtained organic photoelectric conversion elements SC-101 to SC-118 were sealed with an epoxy resin and a glass cap, and the following conversion efficiency and durability were evaluated.

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

Formula 1 Jsc (mA / cm ² ) × Voc (V) × FF = η (%)
(durability)
Solar simulator (AM1.5G) light was irradiated at an irradiation intensity of 100 mW / cm ² , voltage-current characteristics were measured, and initial conversion efficiency was measured. Furthermore, assuming that the initial conversion efficiency at this time is 100, the conversion efficiency after 100 hours of irradiation with an irradiation intensity of 100 mW / cm ² with the resistance connected between the anode and the cathode is evaluated, and the relative reduction efficiency according to Equation 2 Was used as an index of durability.

Formula 2 Relative reduction efficiency (%) = (1−conversion efficiency after exposure / conversion efficiency before exposure) × 100
The evaluation results are shown in Table 1.

  From Table 1, it can be seen that the organic photoelectric conversion element of the present invention has good fill factor and Voc, excellent photoelectric conversion efficiency, and good durability.

DESCRIPTION OF SYMBOLS 10 Organic photoelectric conversion element 11 Board | substrate 12 Transparent electrode 13 Counter electrode 14, 14 'Photoelectric conversion layer 15 Charge recombination layer 16 2nd photoelectric conversion layer 17 Hole transport layer 18 Electron transport layer

Claims (2)

An organic photoelectric conversion element having a substrate, a cathode, an electron transport layer, a bulk heterojunction type photoelectric conversion layer containing a p-type semiconductor material and an n-type semiconductor material containing a fullerene derivative, and an anode in this order. The layer is a photoelectric conversion layer that performs photoelectric conversion with incident light from the cathode side, and the electron transport layer is adjacent to the photoelectric conversion layer and contains a compound represented by the following general formula (A) An organic photoelectric conversion element.
Formula (A): Q1-L1-Q2
During the "formula, it is intended to satisfy the requirements of the lower SL (2).
(2) The Q1-L1 moiety is represented by the following general formula (4), and Q2 represents a residue of fluoranthene, pyrene, chrysene, triphenylene, perylene, or coranulene . "
“Wherein n ₀₁ represents 0 or 1, and X _{41 to} X ₄₅ represent substituents (provided that X _{41 to} X ₄₅ do not form a ring by bonding), and may be different or the same. Any one of X _{41 to} X ₄₅ is an alkylene group, an arylene group, a heteroarylene group, an alkenylene group, —O—, —S—, —CO—, —SO ₂ —, —NHCO—, —CONH—, — SiR ₁ R ₂ — (R ₁ and R ₂ each represents an alkyl group or an aryl group), or a divalent linking group selected from a combination of these groups or a simple bond ” A solar cell comprising the organic photoelectric conversion device according to claim 1 .