WO2011142314A1

WO2011142314A1 - Photoelectric conversion element

Info

Publication number: WO2011142314A1
Application number: PCT/JP2011/060650
Authority: WO
Inventors: 邦仁三宅; 明子岸田; 伊藤　紳三郎; 英生大北; 宏明辨天
Original assignee: 住友化学株式会社; 国立大学法人京都大学
Priority date: 2010-05-10
Filing date: 2011-05-09
Publication date: 2011-11-17
Also published as: JP2011238762A; JP5639783B2

Abstract

Disclosed is a photoelectric conversion element of which the photoelectric conversion efficiency is high. The photoelectric conversion element: has a cathode, an anode, and an organic active layer provided between said anode and said cathode; has an electron donor compound and an electron acceptor compound in the organic active layer; and in an image that is of the organic active layer observed with a transmission electron microscope and that binarizes the light and dark, has a join length between the electron donor compound and the electron acceptor compound of at least 100 µm per 1 µm² of the image of the organic active layer.

Description

Photoelectric conversion element

The present invention relates to a photoelectric conversion element used for a photoelectric device such as a solar cell or an optical sensor.

The photoelectric conversion element is an element including a pair of electrodes including an anode and a cathode, and an organic active layer provided between the pair of electrodes. In the photoelectric conversion element, one of the electrodes is made of a transparent or translucent material, and light is incident on the organic active layer from the transparent or translucent electrode side. Charges (holes and electrons) are generated in the organic active layer by the energy (hν) of light incident on the organic active layer, and the generated holes are directed to the anode and the electrons are directed to the cathode. By connecting an external circuit to the electrode, current (I) is supplied to the external circuit.

The organic active layer is composed of an electron-accepting compound (n-type semiconductor) and an electron-donating compound (p-type semiconductor). An organic active layer in which an electron-accepting compound (n-type semiconductor) and an electron-donating compound (p-type semiconductor) are mixed and used is called a bulk hetero-type organic active layer.

In the bulk hetero organic active layer, the electron-accepting compound and the electron-donating compound constitute a phase of a fine and complex shape that continues from one electrode side to the other electrode side, and It forms a complex interface while separating.

An organic material used for the organic active layer of the photoelectric conversion element is an organic compound that absorbs light based on a π-π ^* transition. For example, a photoelectric conversion element including an organic active layer manufactured by applying a solution using an electron donating compound, an electron accepting compound, xylene and the like as a solvent on a substrate has been proposed (see Non-Patent Document 1).

That is, the present invention provides the following [1] to [9].
[1] An anode, a cathode, and an organic active layer provided between the anode and the cathode. The organic active layer includes an electron-donating compound and an electron-accepting compound. In the image of the organic active layer observed and the image of the organic active layer binarized, the bond length between the electron-donating compound and the electron-accepting compound is about 1 μm ² per area of the organic active layer image. The photoelectric conversion element which is 100 micrometers or more.
[2] having an anode, a cathode, and an organic active layer provided between the anode and the cathode, having an electron donating compound and an electron accepting compound in the organic active layer, and using a transmission electron microscope The image of the observed organic active layer in the range of 900 nm × 900 nm, in which the image obtained by binarizing the brightness and forming the white portion and the black portion is divided into nine sections having an equal area. The photoelectric conversion element whose standard deviation computed from the area fraction of the black part is 0.09 or less.
[3] having an anode, a cathode, and an organic active layer provided between the anode and the cathode, having an electron donating compound and an electron accepting compound in the organic active layer, The photoelectric conversion element whose lifetime of the excited state of at least one of an electron-donating compound and the electron-accepting compound in an organic active layer is 1 ns or less.
[4] An anode, a cathode, an organic active layer provided between the anode and the cathode, an electron-donating compound and an electron-accepting compound in the organic active layer, A photoelectric conversion element wherein the fluorescence quenching rate of at least one of the electron donating compound and the electron accepting compound in the organic active layer is 60% or more.
[5] [1] to [4] including a step of producing an organic active layer by applying a solution containing an electron donating compound, an electron accepting compound, and a solvent having a boiling point of 100 ° C. or less on the anode or the cathode. ] The manufacturing method of the photoelectric conversion element as described in any one of.
[6] A step of producing an organic active layer by applying a solution containing an electron-donating compound, an electron-accepting compound, and a solvent having a boiling point of 100 ° C. or less on the anode or the cathode, and comprising an electron-donating compound and an electron At least one compound with the accepting compound is a polymer compound containing a repeating unit represented by the formula (I), and is represented by the formula (I) among all repeating units contained in the polymer compound. A method for producing a photoelectric conversion element, which is a polymer compound having the largest repeating unit ratio.

(In the formula (I), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each independently represents a hydrogen atom or a substituent. Also, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ may be linked to each other to form a cyclic structure, and X ₁ , X ₂ and X ₃ are each independently a sulfur atom, an oxygen atom, a selenium atom, —N ( R ₇ ) — or —C (R ₈ ) ═C (R ₉ ) — R _7, R ₈ and R ₉ each independently represents a hydrogen atom or a substituent, n and m each independently Represents an integer of 0 to 5. When there are a plurality of R ₁ , R ₂ , R ₅ , R ₆ , X ₁ and X ₃ , they may be the same or different.

[7] A photoelectric conversion element obtainable by the production method according to [6].
[8] A solar cell module including the photoelectric conversion element according to any one of [1] to [4] and [7].
[9] An image sensor including the photoelectric conversion element according to any one of [1] to [4] and [7].

The photoelectric conversion element of the present invention has an anode, a cathode, and an organic active layer provided between the anode and the cathode, and has an electron donating compound and an electron accepting compound in the organic active layer, In the image of the organic active layer observed with a transmission electron microscope and the image of the organic active layer binarized in brightness, the bond length between the electron-donating compound and the electron-accepting compound is It is 100 μm or more per 1 μm ² area.

Concerning the photoelectric conversion element according to the present invention, the anode, the organic active layer, the electron donating compound and the electron accepting compound constituting the organic active layer, the cathode, and other components formed as necessary, This will be explained in detail.

(Basic form of photoelectric conversion element)
As a basic form of the photoelectric conversion element of the present invention, a pair of electrodes, at least one of which is transparent or translucent, an electron donating compound (p-type organic semiconductor) and an electron-accepting compound (n-type organic semiconductor, etc.) And a bulk hetero-type organic active layer formed from an organic composition.

(Basic operation of photoelectric conversion element)
Light energy incident from a transparent or translucent electrode is absorbed by the electron-accepting compound and / or electron-donating compound, and excitons formed by Coulomb bonds between electrons and holes are generated. When the generated excitons move and reach the heterojunction interface where the electron-accepting compound and the electron-donating compound are adjacent to each other, the respective highest occupied molecular orbital (HOMO) energy and the lowest unoccupied molecular orbital ( LUMO) Due to the difference in energy, electrons and holes are separated, and charges (electrons and holes) that can move independently are generated.
Each generated electric charge can be taken out as electric energy (current) to the outside by moving to the electrode.
Since the photoelectric conversion element of the present invention has an organic active layer that efficiently generates photocharge separation and charge transport, the photoelectric conversion efficiency is increased.

(substrate)
The photoelectric conversion element of the present invention is usually formed on a substrate. The substrate may be any substrate that does not chemically change when the electrodes are formed and the organic layer is formed. Examples of the material for the substrate include glass, plastic, polymer film, and silicon. In the case of an opaque substrate, the opposite electrode (that is, the electrode far from the substrate) is preferably transparent or translucent.

(electrode)
Examples of the transparent or translucent electrode material include a conductive metal oxide film, a translucent metal thin film, and the like. Specifically, it is formed using indium oxide, zinc oxide, tin oxide, and conductive materials such as indium tin oxide (ITO), indium zinc oxide (IZO), and NESA that are composites thereof. And metal thin films formed using gold, platinum, silver, copper, etc., and films formed using ITO, IZO, tin oxide are preferred. Examples of the electrode forming method include a vacuum deposition method, a sputtering method, an ion plating method, and a plating method. Moreover, you may use organic transparent conductive films, such as polyaniline and its derivative (s), polythiophene, and its derivative (s) as an electrode material. The transparent or translucent electrode may be an anode or a cathode.

The other electrode may not be transparent, and as the electrode material of the electrode, a metal, a conductive polymer, or the like can be used. Specific examples of the electrode material include metals such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and the like. And one or more alloys selected from the group consisting of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, and tin. Examples include alloys with metals, graphite, graphite intercalation compounds, polyaniline and derivatives thereof, and polythiophene and derivatives thereof. Examples of the alloy include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, and calcium-aluminum alloy.

(Buffer layer)
In order to improve the photoelectric conversion efficiency, an additional intermediate layer (such as a charge transport layer) other than the organic active layer may be provided. Examples of the material used for the intermediate layer include alkali metal or alkaline earth metal halides or oxides such as lithium fluoride, and specifically lithium fluoride.
Further, as a material used for the intermediate layer, fine particles of inorganic semiconductor such as titanium oxide, a mixture of PEDOT (poly (3,4-ethylenedioxythiophene)) and PSS (poly (4-styrenesulfonate)) (PEDOT: PSS) or the like may be used.

(Organic active layer)
The organic active layer contained in the photoelectric conversion element of the present invention contains an electron donating compound and an electron accepting compound.
Note that the electron-donating compound and the electron-accepting compound are relatively determined from the HOMO or LUMO energy level of the compound.

At least one of the electron donating compound and the electron accepting compound is preferably a polymer compound, and both the electron donating compound and the electron accepting compound are more preferably polymer compounds.

(Electron donating compound)
The electron-donating compound is not limited as long as it has absorption in the solar radiation wavelength region. The electron donating compound is preferably a polymer compound having an energy level of the highest occupied molecular orbital of −4.7 eV or lower and an energy level of the lowest unoccupied molecular orbital of −4.0 eV or higher. The electron donating compound may be a low molecular compound or a high molecular compound. As the electron donating compound, a polymer compound is preferable. Examples of the electron donating compound include pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, oligothiophene and derivatives thereof, polyvinylcarbazole and derivatives thereof, polysilane and derivatives thereof, and aromatic amines in side chains or main chains. And polysiloxane derivatives, polyaniline and derivatives thereof, polythiophene and derivatives thereof, polypyrrole and derivatives thereof, polyphenylene vinylene and derivatives thereof, polythienylene vinylene and derivatives thereof, among which polymer compounds are preferred.
Examples of the polymer compound which is a p-type semiconductor include polythiophene and derivatives thereof, a structure including dimers to pentamers in which thiophenes are bonded to each other, or a structure including dimers to pentamers in which thiophene derivatives are bonded to each other. The polymer compound is preferably polythiophene and derivatives thereof. Here, the polythiophene derivative is a polymer compound having a thiophenediyl group having a substituent.
Polythiophene and its derivatives are preferably homopolymers. A homopolymer is a polymer formed by bonding only a plurality of groups selected from the group consisting of a thiophenediyl group and a substituted thiophenediyl group. The thiophene diyl group is preferably a thiophene-2,5-diyl group, and the thiophene diyl group having a substituent is preferably an alkylthiophene-2, 5-diyl group. Specific examples of the homopolymer polythiophene and derivatives thereof include poly (3-hexylthiophene-2,5-diyl) (P3HT), poly (3-octylthiophene-2,5-diyl), poly (3-dodecyl) Thiophene-2,5-diyl) and poly (3-octadecylthiophene-2,5-diyl). Among the polythiophenes and derivatives thereof which are homopolymers, polythiophene homopolymers comprising thiophene diyl groups substituted with alkyl groups having 6 to 30 carbon atoms are preferred.

Examples of the polymer compound that is an electron donating compound include polymer compound A represented by the following structural formula (4).

(Electron-accepting compound)
As the electron-accepting compound, a polymer compound having an energy level of the highest occupied molecular orbital of −5.0 eV or lower and an energy level of the lowest unoccupied molecular orbital of −4.3 eV or higher is preferable.
Examples of the electron-accepting compound include oxadiazole derivatives, anthraquinodimethane and its derivatives, benzoquinone and its derivatives, naphthoquinone and its derivatives, anthraquinone and its derivatives, tetracyanoanthraquinodimethane and its derivatives, fluorenone derivatives, diphenyldicyanoethylene and derivatives thereof, diphenoquinone derivatives, metal complexes of 8-hydroxyquinoline and its derivatives, polyquinoline and its derivatives, polyquinoxaline and its derivatives, polyfluorene and its derivatives, fullerene and derivatives thereof such as C ₆₀ fullerene, bathocuproine etc. Phenanthrene derivatives, metal oxides such as titanium oxide, and carbon nanotubes. The electron accepting compound is preferably a compound containing a benzothiadiazole structure, a polymer compound containing a benzothiadiazole structure in a repeating unit, a compound containing a quinoxaline structure, a polymer compound containing a quinoxaline structure in a repeating unit, titanium oxide, carbon Nanotubes, fullerenes, fullerene derivatives, more preferably fullerenes, fullerene derivatives, compounds containing a benzothiadiazole structure, polymer compounds containing a benzothiadiazole structure in a repeating unit, compounds containing a quinoxaline structure, and a quinoxaline structure in a repeating unit More preferably, it is a compound containing a benzothiadiazole structure, a polymer compound containing a benzothiadiazole structure in a repeating unit, a compound containing a quinoxaline structure, a repeating unit To a polymer compound containing a quinoxaline structure, particularly preferably a polymer compound containing a benzothiadiazole structure in the repeating unit, a polymer compound containing a quinoxaline structure repeating units.
The electron accepting compound is preferably a conjugated polymer compound.

Examples of the polymer compound containing a benzothiadiazole structure in the repeating unit include a polymer compound represented by the following structural formula (4).

Examples of _{fullerene, C 60} _{fullerene, C 70} _{fullerene, C 76} _{fullerene, C 78} fullerene _{include C 84} fullerene.
Examples of fullerene derivatives include C ₆₀ fullerene derivatives, C ₇₀ fullerene derivatives, C ₇₆ fullerene derivatives, C ₇₈ fullerene derivatives, and C ₈₄ fullerene derivatives.

Specific examples of the C ₆₀ fullerene derivative include the following.

Specific examples of C70 fullerene derivatives include the following.

Examples of fullerene derivatives include [6,6] phenyl-C ₆₁ butyric acid methyl ester (C ₆₀ PCBM, [6,6] -Phenyl C ₆₁ butyric acid methyl ester), and [6,6] phenyl-C _71. Butyric acid methyl ester (C ₇₀ PCBM, [6,6] -Phenyl C ₇₁ butyric acid methyl ester), [6,6] Phenyl-C ₈₅ butyric acid methyl ester (C ₈₄ PCBM, [6,6] -Phenyl C ₈₅ butyric acid methyl ester), [6,6] thienyl _{-C 61} butyric acid methyl ester _{([6,6] -Thienyl C 61 butyric} acid methyl ester) and the like.

In the organic active layer, the ratio of the electron accepting compound to the electron donating compound is preferably 10 parts by weight to 1000 parts by weight with respect to 100 parts by weight of the electron donating compound, and 20 parts by weight to 500 parts by weight. It is more preferable that

The thickness of the organic active layer is usually preferably 1 nm to 100 μm, more preferably 2 nm to 1000 nm, still more preferably 5 nm to 500 nm, and particularly preferably 20 nm to 200 nm.

The photoelectric conversion device of the present invention is a polymer compound in which at least one of an electron donating compound and an electron accepting compound includes a repeating unit represented by the following formula (I), Among all the repeating units contained, a polymer compound having the largest ratio of repeating units represented by the following formula (I) is preferable.

In formula (I), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each independently represent a hydrogen atom or a substituent. R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ may be connected to each other to form a cyclic structure. X ₁ , X ₂ and X ₃ each independently represents a sulfur atom, an oxygen atom, a selenium atom, —N (R ₇ ) — or —C (R ₈ ) ═C (R ₉ ) —. R _7, R ₈ and R ₉ each independently represents a hydrogen atom or a substituent. n and m each independently represents an integer of 0 to 5. When there are a plurality of R ₁ , R ₂ , R ₅ , R ₆ , X ₁ , and X ₃ , they may be the same or different.

In formula (I), n and m each independently represents an integer of 0 to 5. n and m are preferably an integer of 1 to 3, and more preferably 1.
R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each independently represent a hydrogen atom or a substituent. When R ₁ to R ₆ are substituents, groups having 1 to 30 carbon atoms are preferred. Examples of the substituent include an alkyl group having 1 to 30 carbon atoms such as a methyl group, an ethyl group, a butyl group, a hexyl group, an octyl group, and a dodecyl group, a methoxy group, an ethoxy group, a butoxy group, a hexyloxy group, and an octyloxy group. Group, an alkoxy group having 1 to 30 carbon atoms such as dodecyloxy group, and an aryl group having 1 to 30 carbon atoms such as phenyl group and naphthyl group.
R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ may be connected to each other to form a cyclic structure. Specific examples of the cyclic structure formed by connecting R ₁ and R ₂ and the cyclic structure formed by connecting R ₅ and R ₆ include the following cyclic structures.

Specific examples of the cyclic structure formed by connecting R ₃ and R ₄ include the following cyclic structures.

In the formula, R ₁₂ and R ₁₃ each independently represent a hydrogen atom or a substituent.

Examples of the substituent represented by R ₁₂ and R ₁₃ include the same groups as the substituents represented by R ₁ to R ₆ described above.

R ₁ to R ₆ are preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom.

X ₁ , X ₂ and X ₃ each independently represents a sulfur atom, an oxygen atom, a selenium atom, —N (R ₇ ) — or —C (R ₈ ) ═C (R ₉ ) —. R _7, R ₈ and R ₉ each independently represents a hydrogen atom or a substituent. When R _7, R ₈ and R ₉ are substituents, examples of the substituent include alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, butyl, hexyl, octyl and dodecyl groups; Examples thereof include aryl groups having 1 to 30 carbon atoms such as a phenyl group and a naphthyl group.
X ₁ , X ₂ and X ₃ are preferably sulfur atoms.

The repeating unit represented by the formula (I) is preferably a repeating unit represented by the following formula (I-1).

The polymer compound used in the present invention is a polymer compound containing a repeating unit represented by the formula (I), and among all the repeating units contained in the polymer compound, the compound represented by the formula (I) The content (number of moles) of the repeating unit represented is the largest.
In the polymer compound used in the present invention, it is preferable that the repeating unit represented by the formula (I) exceeds 50% with respect to the total of all repeating units in the polymer compound. A polymer in which the repeating unit represented by the formula (I) does not exceed 50% by using a polymer compound that exceeds 50% in the photoelectric conversion element with respect to the total of all the repeating units in the polymer compound. Photoelectric conversion efficiency is higher than that of a photoelectric conversion element using a compound. More preferably, the repeating unit represented by the formula (I) is 52% or more based on the total of all repeating units in the polymer compound. More preferably, the repeating unit represented by the formula (I) is 55% or more with respect to the total of all repeating units in the polymer compound.
Moreover, it is preferable that the repeating unit represented by a formula (I) is less than 100% with respect to the sum total of all the repeating units in a high molecular compound. More preferably, the repeating unit represented by the formula (I) is preferably 98% or less with respect to the total of all repeating units in the polymer compound. More preferably, the repeating unit represented by the formula (I) is 70% or less with respect to the total of all repeating units in the polymer compound. The polymer compound used in the present invention preferably contains a repeating unit other than the repeating unit represented by the formula (I).

The polymer compound may further contain a repeating unit represented by the following formula (II).

In formula (II), ring A and ring B each independently represent an aromatic ring. R ₁₀ and R ₁₁ each independently represents a hydrogen atom or a substituent. R ₁₀ and R ₁₁ may be linked to form a cyclic structure.

When R ₁₀ and R ₁₁ are substituents, examples of the substituent include methyl, ethyl, butyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, Alkyl groups having 1 to 30 carbon atoms such as tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group and the like, and aryl groups having 1 to 30 carbon atoms such as phenyl group and naphthyl group Etc. R ₁₀ and R ₁₁ are preferably hydrocarbon groups such as alkyl groups and aryl groups, and more preferably alkyl groups. Moreover, when R < ₁₀ >, R < ₁₁ > is a substituent, it is preferable that a carbon atom number is 12 or more.

Examples of ring A and ring B include aromatic carbocycles such as benzene ring and naphthalene ring, and aromatic heterocycles such as thiophene. Ring A and ring B are preferably 5- to 10-membered rings, and more preferably benzene rings or naphthalene rings.

The repeating unit represented by the formula (II) is preferably a repeating unit represented by the following formula (II-1).

In formula (II-1), R ₁₀ and R ₁₁ represent the same meaning as described above.

When the polymer compound used in the present invention contains a repeating unit represented by the formula (II) in addition to the repeating unit represented by the formula (I), the compound of the formula (II) It is preferable that the ratio of the repeating unit represented by the formula (I) is next to the ratio of the repeating unit represented by the formula (I). The case where the repeating unit of the polymer compound is only the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) is more preferable.

The method for producing the polymer compound used in the present invention is not particularly limited. Since the synthesis of the polymer compound is easy, a method using a Suzuki coupling reaction is preferable. Moreover, the manufacturing method of the high molecular compound used for this invention can be implemented with reference to international publication 2010/016613.

(Other ingredients)
In order to express various functions, the organic active layer may contain other components as necessary. Other components include, for example, ultraviolet absorbers, antioxidants, sensitizers for sensitizing the function of generating charges by absorbed light, light stabilizers for increasing stability from ultraviolet rays, etc. Is mentioned.

Components other than the electron-donating compound and the electron-accepting compound constituting the organic active layer are 5 parts by weight or less, particularly 0.01 parts by weight with respect to 100 parts by weight of the total amount of the electron-donating compound and the electron-accepting compound. It is effective to add in a proportion of 3 parts by weight.
Further, the organic active layer may contain a polymer compound other than the electron donating compound and the electron accepting compound as a polymer binder in order to improve mechanical properties. As the polymer binder, those that do not inhibit the electron transport property or hole transport property are preferable, and those that do not strongly absorb visible light are preferably used. Polymer binders include poly (N-vinylcarbazole), polyaniline and derivatives thereof, polythiophene and derivatives thereof, poly (p-phenylene vinylene) and derivatives thereof, poly (2,5-thienylene vinylene) and derivatives thereof, poly Examples include carbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, and polysiloxane.

The organic active layer of the photoelectric conversion element of the present invention is an image of the organic active layer observed with a transmission electron microscope, and the image of the organic active layer in which light and dark are binarized. Is 100 μm or more per 1 μm ² of the image area of the organic active layer.

Examples of the method for measuring the junction length between the electron donating compound and the electron accepting compound include a method of observing the active layer using a transmission electron microscope (TEM) and obtaining the length. The electron-donating compound and the electron-accepting compound can be separated and observed from an image characteristic of the element contained in the electron-donating compound and the electron-accepting compound. An image characteristic of the element includes an element mapping image by an energy filter TEM, an energy loss image using an energy value giving the same contrast as the element mapping image, and an energy dispersive X-ray analysis (STEM) using a scanning transmission electron microscope. Element mapping image by -EDX). By comparing the electron-donating compound phase with the electron-accepting compound phase, and performing binarization processing of the image in which the bright phase is white and the dark phase is black, the electron-donating compound and the electron-accepting compound are The joining length of can be calculated.

The bonding length between the electron donating compound and the electron accepting compound is preferably 100 μm or more and 300 μm or less, more preferably 115 μm or more and 250 μm or less, per 1 μm ² of the image area of the organic active layer.

In the photoelectric conversion element of the present invention, the phase separation structure of the electron donating compound material and the electron accepting compound material in the organic active layer is appropriately controlled, so that photocharge separation and charge transport are efficiently generated. And exhibit high photoelectric conversion efficiency.

Another aspect of the photoelectric conversion device of the present invention includes an anode, a cathode, and an organic active layer provided between the anode and the cathode, and an electron donating compound and an electron accepting property in the organic active layer. 9 sections of an image of an organic active layer having a compound and having an area of 900 nm × 900 nm, in which white and black portions are formed by binarizing light and dark, and having an equal area It is a photoelectric conversion element whose standard deviation calculated from the area fraction of the black part of each section is 0.09 or less.

When at least one of the electron-donating compound material and the electron-accepting compound material contains a sulfur atom, examples of the method for binarizing the brightness of the organic active layer include the following methods. An image showing phase separation between the electron-donating compound material and the electron-accepting compound material in the layer is obtained as a mapping image of sulfur atoms by a three-window method of electron energy loss spectroscopy (TEM-EELS) using a transmission electron microscope. . Then, a histogram of the mapping image of the obtained sulfur atom is calculated, and the phase containing the compound having a high sulfur atom (S) composition is white with the peak top of the obtained histogram as a threshold, and the polymer compound having a low S composition Binarization is performed by setting the phase including the black as black.

The image of the obtained organic active layer in a range of 900 nm × 900 nm, in which the white portion and the black portion, in which the brightness is binarized, is divided into nine sections having an equal area. The standard deviation calculated from the area fraction of the black part is preferably 0.03 to 0.09, and more preferably 0.04 to 0.08.

The material of the electrode included in the photoelectric conversion element of this embodiment, the electron donating compound, the electron accepting compound, and the other constituent material formed as necessary include the material of the electrode included in the photoelectric conversion element of the above embodiment. , Electron-donating compound, electron-accepting compound, and the same materials as those of other components formed as necessary.
In the photoelectric conversion device of this embodiment, at least one of the electron donating compound and the electron accepting compound is a polymer compound containing a repeating unit represented by the formula (I), and the polymer compound Among all the repeating units contained therein, a polymer compound having the largest ratio of repeating units represented by formula (I) is preferable.

Another aspect of the photoelectric conversion device of the present invention includes an anode, a cathode, and an organic active layer provided between the anode and the cathode, and an electron donating compound and an electron accepting property in the organic active layer. And a lifetime of an excited state of at least one of an electron donating compound in the organic active layer and an electron accepting compound in the organic active layer is 1 ns or less.

Here, the excited state means an excited singlet or an excited triplet generated as a result of absorbing light, and the excited state lifetime is the number of excited states or the concentration of the first excited state generated. Mean time to decrease to 1 / e of number or concentration.
Here, the lifetime of the excited singlet or triplet of the compound is evaluated from the time when the initial absorption intensity of the excited state decreases to 1 / e by pump probe transient absorption spectroscopy using a femtosecond laser as the excitation light source. be able to. E means the base of natural logarithm.
A method for measuring transient absorption will be described using an organic thin film solar cell as an example. A bulk hetero type organic active layer composed of an electron donating compound and an electron accepting compound is formed on a glass substrate by the same operation as in the production of the organic thin film solar cell. Here, the absorbance of the active layer measured when not photoexcited is A0. A0 is defined as A0 = log (Ip / I0), where Ip is the intensity of the probe light incident on the active layer, and I0 is the intensity of the probe light transmitted through the active layer. Further, the absorbance of the active layer measured after the active layer is photoexcited with pump light and the time t has elapsed is defined as A (t). A (t) is A (t) = log (Ip, where I is the intensity of the probe light that has passed through the active layer out of the probe light that has entered the active layer after time t has elapsed after photoexcitation with pump light. / I). Here, the absorption intensity (ΔA) of a chemical species newly generated (increased) or extinguished (decreased) in the active layer by photoexcitation is defined as ΔA = A (t) −A0. That is, it is defined by ΔA = log (Ip / I) −log (Ip / I0) = log (I0 / I). Here, by measuring the value of ΔA at different delay times t, it is possible to evaluate the temporal change in absorption intensity at the wavelength of the probe light used. Furthermore, by changing the wavelength of the probe light to be used, an absorption spectrum of a chemical species newly generated (increased) or extinguished (decreased) in the active layer can be obtained at a certain delay time t as compared to before photoexcitation. Furthermore, a time resolution of 100 fs can be achieved by using pulsed light with a femtosecond laser as a light source for both the probe light and the pump light.

The lifetime of the excited state is preferably 1 ns or less, more preferably 100 ps or less, and even more preferably 10 ps or less.

Since the lifetime of the excited state of at least one of the electron donating compound in the organic active layer and the electron accepting compound in the organic active layer is 1 ns or less, the charge separation efficiency is high in the organic active layer. The photoelectric conversion efficiency of the photoelectric conversion element is increased.

The material of the electrode included in the photoelectric conversion element of this embodiment, the electron donating compound, the electron accepting compound, and the other constituent material formed as necessary include the material of the electrode included in the photoelectric conversion element of the above embodiment. , Electron-donating compound, electron-accepting compound, and the same materials as those of other components formed as necessary.
In the photoelectric conversion element of this embodiment, at least one of the electron-donating compound and the electron-accepting compound is a polymer compound containing a repeating unit represented by the formula (I), and is included in the polymer compound Among all the repeating units, a polymer compound having the largest ratio of the repeating units represented by the formula (I) is preferable.

Another aspect of the photoelectric conversion device of the present invention includes an anode, a cathode, and an organic active layer provided between the anode and the cathode, and an electron-donating compound and an electron-accepting compound are included in the organic active layer. And a fluorescence quenching rate of at least one of the electron donating compound in the organic active layer and the electron accepting compound in the organic active layer is 60% or more.

A method for measuring the fluorescence quenching rate will be described by taking an organic thin-film solar cell having a bulk hetero type organic active layer composed of an electron donating compound and an electron accepting compound as an example. A bulk hetero-type organic active layer is formed on the glass substrate by the same operation as the production of the organic thin film solar cell. Using a spectrofluorometer, at least one of the electron-donating compound and the electron-accepting compound forming this active layer is photoexcited, and the observed fluorescence intensity from the electron-donating compound or the electron-accepting compound is Φ1 And The absorbance of the electron donating compound or electron accepting compound at this photoexcitation wavelength is A1. An electron-donating property when an active layer consisting only of an electron-donating compound or an electron-accepting compound is formed on a glass substrate by the same operation and photoexcitation is performed under the same conditions as in the case of a bulk hetero-type organic active layer except that the active layer is different. The fluorescence intensity from the compound or electron accepting compound is Φ2, and the absorbance of the electron donating compound or electron accepting compound at the photoexcitation wavelength is A2. Here, the fluorescence quenching rate of the electron-donating compound or electron-accepting compound in the bulk-type organic active layer (.PHI.q) is, Φq = (1-Φ1 / (1-10 -A1) / Φ2 / (1-10 - ^A2 )) x 100.
The fluorescence quenching rate (Φq) of the active layer of the photoelectric conversion element of the present invention is preferably 60% or more, and more preferably 70% or more. Since Φq is 60% or more, the charge separation efficiency is high in the organic active layer, and the photoelectric conversion efficiency of the photoelectric conversion element is high.

The material of the electrode included in the photoelectric conversion element of this embodiment, the electron donating compound, the electron accepting compound, and the other constituent material formed as necessary include the material of the electrode included in the photoelectric conversion element of the above embodiment. , Electron-donating compound, electron-accepting compound, and the same materials as those of other components formed as necessary.
In the photoelectric conversion device of this embodiment, at least one of the electron donating compound and the electron accepting compound is a polymer compound containing a repeating unit represented by the formula (I), It is preferable that the polymer compound has the largest ratio of the repeating units represented by the formula (I) among all the repeating units contained in.

(Method for producing organic active layer)
The organic active layer of the photoelectric conversion element of the present invention is a bulk hetero type, and is formed by coating using a solution containing the electron donating compound, the electron accepting compound, and other components blended as necessary. It can be formed by forming a film. For example, the solution can be applied on the anode or cathode to form an organic active layer. Then, another electrode can be formed on an organic active layer, and a photoelectric conversion element can be manufactured.

The solvent used for the coating film formation using a solution is a solvent having a boiling point of 100 ° C. or lower capable of dissolving the electron donating compound and the electron accepting compound used in the present invention. Moreover, as a solvent, you may mix a some solvent, The boiling point of at least 1 type of solvent is 100 degrees C or less.
Examples of the solvent having a boiling point of 100 ° C. or less used for controlling the junction length between the electron donating compound and the electron accepting compound to increase the photoelectric conversion efficiency of the photoelectric conversion element include carbon tetrachloride, chloroform, Examples thereof include halogenated saturated hydrocarbon solvents such as dichloromethane, dichloroethane, dichloropropane and chlorobutane, and ether solvents such as tetrahydrofuran and tetrahydropyran. The organic material constituting the organic active layer can be usually dissolved in a solvent in an amount of 0.1% by weight or more.
A more preferred solvent is chloroform.

For film formation, spin coating method, casting method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, dip coating method, spray coating method, screen printing method, gravure printing method, Application methods such as flexographic printing method, offset printing method, ink jet printing method, dispenser printing method, nozzle coating method, capillary coating method can be used, spin coating method, flexographic printing method, gravure printing method, ink jet printing method, dispenser A printing method is preferred.

A preferred embodiment of the method for producing a photoelectric conversion element is a step of producing an organic active layer by applying a solution containing an electron donating compound, an electron accepting compound, and a solvent having a boiling point of 100 ° C. or less on an anode or a cathode. Wherein at least one of the electron-donating compound and the electron-accepting compound is a polymer compound containing a repeating unit represented by the formula (I), and is contained in all repeating units contained in the polymer compound This is a method for producing a photoelectric conversion element which is a polymer compound having the largest ratio of repeating units represented by formula (I).

In formula (I), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each independently represent a hydrogen atom or a substituent. R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ may be connected to each other to form a cyclic structure. X ₁ , X ₂ and X ₃ each independently represents a sulfur atom, an oxygen atom, a selenium atom, —N (R ₇ ) — or —C (R ₈ ) ═C (R ₉ ) —. R _7, R ₈ and R ₉ each independently represents a hydrogen atom or a substituent. n and m each independently represents an integer of 0 to 5. When there are a plurality of R ₁ , R ₂ , R ₅ , R ₆ , X ₁ , and X ₃ , they may be the same or different.
By using a solution containing a polymer compound containing a repeating unit represented by the formula (I) and a solvent having a boiling point of 100 ° C. or less to form an organic active layer by a coating electron microscope, In the image of the organic active layer observed and the image of the organic active layer binarized in light and dark, the bonding length between the electron donating compound and the electron accepting compound is expressed as follows per 1 μm ² of the area of the organic active layer image. It can be set to 100 μm or more, and further can be set to 100 μm or more and 300 μm or less.
Further, a transmission electron is formed by coating and forming an organic active layer using a solution containing a polymer compound containing a repeating unit represented by formula (I) and a solvent having a boiling point of 100 ° C. or less. It is an image of an organic active layer in the range of 900 nm × 900 nm observed with a microscope, and the image obtained by binarizing the brightness and forming the white portion and the black portion is divided into nine sections having an equal area, The standard deviation calculated from the area fraction of the black portion of the compartment can be 0.09 or less, and can be 0.03 or more and 0.09 or less.

(Application of the device)
The photoelectric conversion element of the present invention can be operated as an organic thin film solar cell by generating a photovoltaic force between the electrodes by irradiating light such as sunlight from a transparent or translucent electrode. It can also be used as an organic thin film solar cell module by integrating a plurality of organic thin film solar cells.

Also, by applying light from a transparent or translucent electrode in a state where a voltage is applied between the electrodes or in a state where no voltage is applied, a photocurrent flows and it can be operated as an organic photosensor. It can also be used as an organic image sensor by integrating a plurality of organic photosensors.

(Solar cell module)
The organic thin film solar cell can basically have the same module structure as a conventional solar cell module. A solar cell module generally has a structure in which cells are formed on a support substrate made of metal, ceramic, etc., which is covered with a filling resin, protective glass, etc., and light is incident from the opposite side of the support substrate. Further, a transparent material such as tempered glass can be used for the support substrate, and a cell can be formed thereon so that light can enter from the transparent support substrate side. Specifically, a module structure called a super straight type, a substrate type, and a potting type, a substrate integrated module structure used in an amorphous silicon solar cell, and the like are known. Even in an organic thin-film solar cell to which the organic photoelectric conversion element of the present invention is applied, these module structures can be appropriately selected depending on the purpose of use, the place of use and the environment.

In a typical super straight type or substrate type module, cells are arranged at regular intervals between support substrates that are transparent on one or both sides and subjected to antireflection treatment, and adjacent cells are connected by metal leads or flexible wiring. It is connected, and the collector electrode is arrange | positioned in the outer edge part, It has the structure which takes out generated electric power outside. Various types of plastic materials such as ethylene vinyl acetate (EVA) may be used between the substrate and the cell in the form of a film or a filling resin depending on the purpose in order to protect the cell and improve the current collection efficiency. In addition, when used in a place where it is not necessary to cover the surface with a hard material such as a place where there is little impact from the outside, the surface protection layer is made of a transparent plastic film, or the protective function is achieved by curing the filling resin It is possible to eliminate the supporting substrate on one side. The periphery of the support substrate is fixed in a sandwich shape with a metal frame in order to ensure internal sealing and module rigidity, and the support substrate and the frame are hermetically sealed with a sealing material. In addition, if a flexible material is used for the cell itself, the support substrate, the filling material, and the sealing material, a solar cell can be formed on the curved surface.

In the case of a solar cell using a flexible support such as a polymer film, cells are sequentially formed while feeding out a roll-shaped support, cut to a desired size, and then the periphery is sealed with a flexible and moisture-proof material. Thus, the battery body can be produced. Moreover, it can also have a module structure called “SCAF” described in Solar Energy Materials and Solar Cells, 48, p383-391. Furthermore, a solar cell using a flexible support can be used by being bonded and fixed to a curved glass or the like.

Hereinafter, examples of the present invention will be described. The following examples are preferred examples for explaining the present invention, and do not limit the present invention.

Synthesis example 1
(Production of polymer compound A)

A reaction vessel was charged with 0.945 g (1.60 mmol) of monomer (1), 0.918 g of monomer (2) (2.00 mmol) and 25 mg of tetrakis (triphenylphosphine) palladium (0), and the reaction was performed. The inside of the container was sufficiently replaced with argon gas. To this reaction vessel, 50 g of toluene deaerated previously by bubbling with argon gas was added. The resulting solution was stirred at 100 ° C. for about 10 minutes. Next, 5 mL of a tetraethylammonium hydroxide solution (20% aqueous solution) previously deaerated by bubbling with an argon gas was dropped into the obtained solution, and then refluxed for 3.5 hours. Next, after adding 0.55 g of phenylboric acid to the obtained reaction solution, it was refluxed for 8.5 hours. The reaction was performed in an argon gas atmosphere.

After completion of the reaction, the reaction solution was cooled at room temperature (25 ° C.), and then the obtained reaction solution was allowed to stand and a separated toluene layer was recovered. Next, the obtained toluene layer was poured into methanol and re-precipitated, and the generated precipitate was collected. This precipitate was dried under reduced pressure and then dissolved in chloroform. Next, the obtained chloroform solution was filtered to remove insoluble matters, and then passed through an alumina column for purification. Next, the obtained chloroform solution was concentrated under reduced pressure, poured into methanol, re-precipitated, and the generated precipitate was collected. This precipitate was washed with methanol and then dried under reduced pressure to obtain 0.93 g of a polymer. Hereinafter, this polymer is referred to as polymer compound A. The polymer compound A had a polystyrene equivalent weight average molecular weight of 2.0 × 10 ⁴ and a polystyrene equivalent number average molecular weight of 4.7 × 10 ³ .
The ratio of the repeating unit represented by the formula (2 ′) calculated from the charging ratio among all the repeating units of the polymer compound A was 55.6%.

Example 1
(Production and evaluation of organic thin-film solar cells)
A glass substrate on which an ITO film having a thickness of 300 nm was formed by vacuum evaporation was subjected to ultrasonic cleaning in this order for 15 minutes in toluene, acetone, and ethanol, respectively, followed by surface treatment by ozone UV treatment. A mixture of PEDOT (poly (3,4-ethylenedioxythiophene)) and PSS (poly (4-styrenesulfonate)) (PEDOT: PSS) (manufactured by HCStarck, PH500) on a surface-treated ITO substrate Was spin-coated to a thickness of about 40 nm, and heated in the air on a hot plate at 140 ° C. for 10 minutes. Next, a chloroform solution containing a polymer compound A which is an electron-accepting compound and poly (3-hexylthiophene-2,5-diyl) (P3HT) (Resiregular, manufactured by Aldrich Co.) which is an electron-donating compound (high The weight ratio of molecular compound A / P3HT = 1/1, and the total concentration of polymer compound A and P3HT was 1% by weight) was applied onto this PEDOT: PSS film by spin coating to produce an organic active layer. The thickness of the organic active layer was about 70 nm. Then, lithium fluoride was vapor-deposited with a thickness of 1 nm by a vacuum vapor deposition machine, and then Al was vapor-deposited with a thickness of 80 nm. Thereafter, the organic thin film solar cell was heated at 140 ° C. for 10 minutes in the glove box. The shape of the obtained organic thin film solar cell was a circle having a radius of 1.5 mm. The obtained organic thin-film solar cell is irradiated with a constant light using a solar simulator (manufactured by Eagle Engineering, 500 W xenon light source device LHX-500E3: AM1.5G filter, irradiance 100 mW / cm ² ), The voltage was measured to determine photoelectric conversion efficiency, short circuit current density, open circuit voltage, and fill factor. Jsc (short circuit current density) is 3.94 mA / cm ² , Voc (open circuit voltage) is 1.19 V, ff (fill factor) is 0.42, and photoelectric conversion efficiency (η) is 1. 95%.

(Measurement of HOMO energy level and LUMO energy level)
The energy level of HOMO was measured with a photoelectron spectrometer AC-2 (manufactured by Riken Keiki Co., Ltd.). The LUMO energy level was calculated from the end of the absorption wavelength (λth (nm)) using the following equation.
(LUMO energy level) = (HOMO energy level) + 1240 / λth
The HOMO energy level of the polymer compound A was −5.5 eV, and the LUMO energy level was −3.6 eV. The energy level of HOMO of P3HT was -4.9 eV, and the energy level of LUMO was -3.0 eV.

(Measurement of fluorescence quenching rate)
The blend film formed on the glass substrate by the same operation as the production of the organic thin film solar cell was excited at 392 nm, and the fluorescence quenching rate (Φq) of the polymer compound A was estimated. As a result, Φq was 71%.

(Observation of phase separation structure)
After forming the organic active layer on the substrate by the method of Example 1, observation of phase separation between the phase containing the electron-donating compound and the phase containing the electron-accepting compound was conducted using a transmission electron microscope (TEM). This was performed by obtaining a mapping image of sulfur atoms by the three-window method of spectroscopy (TEM-EELS). A sample for TEM observation was obtained by floating a film formed by spin casting on water and scoring with a TEM grid. For TEM, JEM2200FS (manufactured by JEOL Ltd.) was used at an acceleration voltage of 200 kV, and a layer in the range of 900 nm × 900 nm at 20000 times was observed with 512 × 512 pixels. A histogram of the mapping image of the obtained sulfur atom is calculated, and the phase containing the polymer compound having a high sulfur atom (S) composition is white with the peak top of the obtained histogram as a threshold, and the polymer compound having a low S composition Binarization was performed by setting the phase containing the black as black. The binarized image obtained as described above was divided into nine sections having an equal area, and the area fraction of the black portion of each section was determined. The above image analysis was performed using image analysis software image-J. The average value and standard deviation of the area fractions of the nine black sections obtained were calculated. As a result, the average value of the area fraction of the black portion was 0.454, and the standard deviation of the area fraction of the black portion was 0.074.

Comparative Example 1
(Production and evaluation of organic thin-film solar cells)
An organic thin film solar cell was prepared and evaluated in the same manner as in Example 1 except that chlorobenzene was used instead of chloroform. As a result, Jsc was 0.91 mA / cm ² , Voc was 1.06 V, ff was 0.48, and the photoelectric conversion efficiency (η) was 0.46%.
Under this condition, the fluorescence quenching rate (Φq) of the polymer compound A was estimated. As a result, Φq was 50%.
Moreover, the average value of the area fraction of the black part observed by TEM was 0.581, and the standard deviation of the area fraction of the black part was 0.171.

Comparative Example 2
(Production and evaluation of organic thin-film solar cells)
An organic thin film solar cell was prepared and evaluated in the same manner as in Example 1 except that o-dichlorobenzene was used instead of chloroform. As a result, Jsc was 0.84 mA / cm ² , Voc was 0.80 V, ff was 0.36, and the photoelectric conversion efficiency (η) was 0.24%.
Moreover, the average value of the area fraction of the black part observed by TEM was 0.535, and the standard deviation of the area fraction of the black part was 0.221.

Comparative Example 3
(Production and evaluation of organic thin-film solar cells)
An organic thin film solar cell was prepared and evaluated in the same manner as in Example 1 except that xylene was used instead of chloroform. Consequently, Jsc is 1.37mA / cm ^2, Voc is 0.91 V, ff is 0.54, the photoelectric conversion efficiency (eta) was 0.67%.
Moreover, the average value of the area fraction of the black part observed by TEM was 0.476, and the standard deviation of the area fraction of the black part was 0.099.

Claims

Organic having an anode, a cathode, and an organic active layer provided between the anode and the cathode, having an electron donating compound and an electron accepting compound in the organic active layer, and being observed with a transmission electron microscope In the image of the active layer and the image of the organic active layer in which the brightness is binarized, the bonding length between the electron donating compound and the electron accepting compound is 100 μm or more per 1 μm 2 of the area of the organic active layer image. There is a photoelectric conversion element.
2. The photoelectric conversion device according to claim 1, wherein the bonding length between the electron donating compound and the electron accepting compound is 300 μm or less per 1 μm 2 of the area of the image of the organic active layer.
The photoelectric conversion element according to claim 1, wherein the lifetime of at least one of the electron donating compound in the organic active layer and the electron accepting compound in the organic active layer is 1 ns or less.
The photoelectric conversion element according to claim 1, wherein at least one of the electron donating compound and the electron accepting compound is a polymer compound.
The photoelectric conversion element according to claim 4, wherein both the electron donating compound and the electron accepting compound are polymer compounds.
The electron donating compound is a polymer compound having an energy level of its highest occupied molecular orbital of −4.7 eV or lower and an energy level of its lowest unoccupied molecular orbital of −4.0 eV or higher. Item 5. The photoelectric conversion element according to Item 4.
The photoelectric conversion element according to claim 1, wherein the electron donating compound is polythiophene or a derivative thereof.
The electron-accepting compound is a polymer compound having an energy level of its highest occupied molecular orbital of −5.0 eV or lower and an energy level of its lowest unoccupied molecular orbital of −4.3 eV or higher. Item 5. The photoelectric conversion element according to Item 4.
The photoelectric conversion element according to claim 4, wherein the electron-accepting compound is a polymer compound having a benzothiadiazole structure or a quinoxaline structure.
At least one of the electron-donating compound and the electron-accepting compound is a polymer compound containing a repeating unit represented by the formula (I), wherein all the repeating units contained in the polymer compound are represented by the formula ( The photoelectric conversion element according to claim 4, which is a polymer compound having the largest ratio of the repeating unit represented by I).

(In the formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each independently represents a hydrogen atom or a substituent. Also, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may be linked to each other to form a cyclic structure, and X 1 , X 2 and X 3 are each independently a sulfur atom, an oxygen atom, a selenium atom, —N ( R 7 ) — or —C (R 8 ) ═C (R 9 ) — R 7, R 8 and R 9 each independently represents a hydrogen atom or a substituent, n and m each independently Represents an integer of 0 to 5. When there are a plurality of R 1 , R 2 , R 5 , R 6 , X 1 and X 3 , they may be the same or different.
Organic having an anode, a cathode, and an organic active layer provided between the anode and the cathode, having an electron donating compound and an electron accepting compound in the organic active layer, and being observed with a transmission electron microscope An image of the active layer in a range of 900 nm × 900 nm, in which brightness and darkness are binarized to form a white portion and a black portion, is divided into nine sections having an equal area, and the black portion of each section is The photoelectric conversion element whose standard deviation computed from the area fraction is 0.09 or less.
The photoelectric conversion element according to claim 11, wherein the standard deviation calculated from the area fraction of the black portion of each section is 0.03 or more.
The photoelectric conversion device according to claim 11, wherein the lifetime of at least one of the electron donating compound in the organic active layer and the electron accepting compound in the organic active layer is 1 ns or less.
The photoelectric conversion element according to claim 11, wherein at least one of the electron donating compound and the electron accepting compound is a polymer compound.
The photoelectric conversion element according to claim 14, wherein both the electron donating compound and the electron accepting compound are polymer compounds.
The electron donating compound is a polymer compound having an energy level of its highest occupied molecular orbital of −4.7 eV or lower and an energy level of its lowest unoccupied molecular orbital of −4.0 eV or higher. Item 15. The photoelectric conversion element according to Item 14.
The photoelectric conversion element according to claim 11, wherein the electron donating compound is polythiophene or a derivative thereof.
The electron-accepting compound is a polymer compound having an energy level of its highest occupied molecular orbital of −5.0 eV or lower and an energy level of its lowest unoccupied molecular orbital of −4.3 eV or higher. Item 15. The photoelectric conversion element according to Item 14.
The photoelectric conversion element according to claim 14, wherein the electron-accepting compound is a polymer compound having a benzothiadiazole structure or a quinoxaline structure.
At least one of the electron-donating compound and the electron-accepting compound is a polymer compound containing a repeating unit represented by the formula (I), wherein all the repeating units contained in the polymer compound are represented by the formula ( The photoelectric conversion element according to claim 14, which is a polymer compound having the largest ratio of the repeating unit represented by I).

(In the formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each independently represents a hydrogen atom or a substituent. Also, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may be linked to each other to form a cyclic structure, and X 1 , X 2 and X 3 are each independently a sulfur atom, an oxygen atom, a selenium atom, —N ( R 7 ) — or —C (R 8 ) ═C (R 9 ) — R 7, R 8 and R 9 each independently represents a hydrogen atom or a substituent, n and m each independently Represents an integer of 0 to 5. When there are a plurality of R 1 , R 2 , R 5 , R 6 , X 1 and X 3 , they may be the same or different.
Having an anode, a cathode, and an organic active layer provided between the anode and the cathode, having an electron-donating compound and an electron-accepting compound in the organic active layer, and providing an electron-donating property in the organic active layer The photoelectric conversion element whose lifetime of the excited state of at least one of a compound and the electron-accepting compound in an organic active layer is 1 ns or less.
The photoelectric conversion element according to claim 21, wherein at least one of the electron donating compound and the electron accepting compound is a polymer compound.
23. The photoelectric conversion element according to claim 22, wherein the electron donating compound and the electron accepting compound are both polymer compounds.
The electron donating compound is a polymer compound having an energy level of its highest occupied molecular orbital of −4.7 eV or lower and an energy level of its lowest unoccupied molecular orbital of −4.0 eV or higher. Item 23. The photoelectric conversion element according to Item 22.
The photoelectric conversion element according to claim 21, wherein the electron donating compound is polythiophene or a derivative thereof.
The electron-accepting compound is a polymer compound having an energy level of its highest occupied molecular orbital of −5.0 eV or lower and an energy level of its lowest unoccupied molecular orbital of −4.3 eV or higher. Item 22. The photoelectric conversion element according to Item 21.
The photoelectric conversion element according to claim 21, wherein the electron-accepting compound is a polymer compound having a benzothiadiazole structure or a quinoxaline structure.
At least one of the electron-donating compound and the electron-accepting compound is a polymer compound containing a repeating unit represented by the formula (I), wherein all the repeating units contained in the polymer compound are represented by the formula ( The photoelectric conversion element according to claim 21, which is a polymer compound having the largest ratio of the repeating unit represented by I).

(In the formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each independently represents a hydrogen atom or a substituent. Also, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may be linked to each other to form a cyclic structure, and X 1 , X 2 and X 3 are each independently a sulfur atom, an oxygen atom, a selenium atom, —N ( R 7 ) — or —C (R 8 ) ═C (R 9 ) — R 7, R 8 and R 9 each independently represents a hydrogen atom or a substituent, n and m each independently Represents an integer of 0 to 5. When there are a plurality of R 1 , R 2 , R 5 , R 6 , X 1 and X 3 , they may be the same or different.
Having an anode, a cathode, and an organic active layer provided between the anode and the cathode, having an electron-donating compound and an electron-accepting compound in the organic active layer, and providing an electron-donating property in the organic active layer The photoelectric conversion element whose fluorescence quenching rate of at least one of a compound and the electron-accepting compound in an organic active layer is 60% or more.
30. The photoelectric conversion element according to claim 29, wherein at least one of the electron donating compound and the electron accepting compound is a polymer compound.
The photoelectric conversion element according to claim 30, wherein both the electron donating compound and the electron accepting compound are polymer compounds.
The electron donating compound is a polymer compound having an energy level of its highest occupied molecular orbital of −4.7 eV or lower and an energy level of its lowest unoccupied molecular orbital of −4.0 eV or higher. Item 30. The photoelectric conversion element according to Item 30.
The photoelectric conversion element according to claim 29, wherein the electron donating compound is polythiophene or a derivative thereof.
The electron-accepting compound is a polymer compound having an energy level of its highest occupied molecular orbital of −5.0 eV or lower and an energy level of its lowest unoccupied molecular orbital of −4.3 eV or higher. Item 30. The photoelectric conversion element according to Item 29.
30. The photoelectric conversion element according to claim 29, wherein the electron-accepting compound is a polymer compound having a benzothiadiazole structure or a quinoxaline structure.
At least one of the electron-donating compound and the electron-accepting compound is a polymer compound containing a repeating unit represented by the formula (I), wherein all the repeating units contained in the polymer compound are represented by the formula ( 30. The photoelectric conversion device according to claim 29, which is a polymer compound having the largest ratio of the repeating unit represented by I).

(In the formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each independently represents a hydrogen atom or a substituent. Also, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may be linked to each other to form a cyclic structure, and X 1 , X 2 and X 3 are each independently a sulfur atom, an oxygen atom, a selenium atom, —N ( R 7 ) — or —C (R 8 ) ═C (R 9 ) — R 7, R 8 and R 9 each independently represents a hydrogen atom or a substituent, n and m each independently Represents an integer of 0 to 5. When there are a plurality of R 1 , R 2 , R 5 , R 6 , X 1 and X 3 , they may be the same or different.
The photoelectric conversion device according to claim 1, comprising a step of producing an organic active layer by applying a solution containing an electron donating compound, an electron accepting compound, and a solvent having a boiling point of 100 ° C. or less on the anode or the cathode. Manufacturing method.
A step of producing an organic active layer by applying a solution containing an electron-donating compound, an electron-accepting compound, and a solvent having a boiling point of 100 ° C. or less on an anode or a cathode, the electron-donating compound and the electron-accepting The compound having at least one of the functional compound is a polymer compound containing a repeating unit represented by the formula (I), and the repeating compound represented by the formula (I) among all the repeating units contained in the polymer compound A method for producing a photoelectric conversion element, which is a polymer compound having the largest unit ratio.

(In the formula (I), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each independently represents a hydrogen atom or a substituent. Also, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may be linked to each other to form a cyclic structure, and X 1 , X 2 and X 3 are each independently a sulfur atom, an oxygen atom, a selenium atom, —N ( R 7 ) — or —C (R 8 ) ═C (R 9 ) — R 7, R 8 and R 9 each independently represents a hydrogen atom or a substituent, n and m each independently Represents an integer of 0 to 5. When there are a plurality of R 1 , R 2 , R 5 , R 6 , X 1 and X 3 , they may be the same or different.
A photoelectric conversion element obtainable by the production method according to claim 38.
A solar cell module including the photoelectric conversion element according to claim 1.
An image sensor comprising the photoelectric conversion element according to claim 1.