Photoelectric conversion element, imaging element, optical sensor, and solid-state imaging device

Abstract

Provided is a photoelectric conversion element comprising a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) that includes a compound α, and a second electrode film (D), wherein a change rate rd3 represented by formula (i) is 0.020-50.0. Formula (i): rd3=d3a / d3b. In the formula, d3a is a dark current (external bias 3V) after heat treatment under the following conditions, and d3b is a dark current (external bias 3V) without heat treatment. The conditions are that heating is performed for 1-3000 minutes at not lower than 450°C below a reference temperature and not higher than 10°C below the reference temperature, the reference temperature being a 5% mass reduction temperature of the compound α as measured at a pressure of 0.10 MPa, with nitrogen at 200 mL / min, a temperature of 20-550°C, and a temperature increase rate of 10°C / min.

Description

Photoelectric conversion element, image sensor, light sensor, and solid-state imaging device

[0001] This disclosure relates to a photoelectric conversion element, an image sensor, a light sensor, and a solid-state imaging device.

[0002] Conventionally, a technology for converting visible light into electrical signals via photoelectric conversion has been known and is used, for example, in image sensors. Such image sensors are provided in solid-state imaging devices such as CCD (Charge Coupled Device) image sensors and CMOS (Complementary Metal Oxide Semiconductor) image sensors. In recent years, there has been a trend towards reducing the pixel size in solid-state imaging devices, and organic photoelectric conversion films are being investigated to address this. For example, Patent Documents 1 and 2 disclose organic photoelectric conversion films composed of subphthalocyanines and imides.

[0003] Furthermore, solid-state imaging devices are required to achieve both high spectral selectivity and a high signal-to-noise ratio. Therefore, it is desirable for solid-state imaging devices to have high external quantum efficiency (EQE) and low dark current characteristics. To achieve such a balance, a method is known in which an electron transport layer and a hole blocking layer, and / or a hole transport layer and an electron blocking layer, are placed between the photoelectric conversion unit and the electrode unit. Here, electron transport layers, hole blocking layers, and electron blocking layers, which are widely used in the field of organic electronic devices, are placed at the interface between an electrode or conductive film and other films in the film constituting the device. These layers play a role in controlling the reverse movement of holes or electrons, respectively, and adjusting unnecessary leakage of holes or electrons. As a material used for such layers, for example, Patent Document 3 shows an example using 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA).

[0004] Japanese Patent Publication No. 2018-32754, Japanese Patent Publication No. 2018-512423, Japanese Patent Publication No. 2014-506736

[0005] Heat treatment may be used when manufacturing a solid-state imaging device. For example, in the manufacture of a solid-state imaging device, in order to make a solid organic film and an electrode adhere closely, the photoelectric conversion element may be heated by an annealing process. The above heat treatment may cause the photoelectric conversion element in the solid-state imaging device to deteriorate, resulting in a decrease in the performance of the solid-state imaging device. Therefore, excellent heat resistance is required for the photoelectric conversion element.

[0006] The problem to be solved by the present invention is to provide a photoelectric conversion element, an imaging element, an optical sensor, and a solid-state imaging device having excellent heat resistance.

[0007] The present invention includes the following aspects. [1] A photoelectric conversion element including a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a second electrode film (D), and the change rate r represented by the following formula (i) ｄ３ is 0.020 or more and 50.0 or less. r ｄ３ = d ３ａ / d ３ｂ ... (i) (In the formula, d ３ａ is the dark current (external bias 3V) after heat treatment under the following conditions, and d ３ｂ is the dark current (external bias 3V) without heat treatment. Conditions: Based on the 5% mass reduction temperature of the compound α measured under the conditions of a pressure of 0.10 MPa, nitrogen of 200 mL / min, a temperature of 20°C to 550°C, and a heating rate of 10°C / min, heat at a temperature of the reference temperature - 450°C or higher and the reference temperature - 10°C or lower for 1 minute or more and 3000 minutes or less.) [2] A photoelectric conversion element including a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a second electrode film (D), and the change rate r represented by the following formula (ii) ｌ３ is 0.50 or more and 2.0 or less. r ｌ３ = l ３ａ / l ３ｂ ... (ii) (In the formula, l ３ａ is the bright current (external bias 3V) after heat treatment under the following conditions, and l ３ｂThis is a non-heating bright current (external bias 3V). Conditions: Using the 5% mass loss temperature of compound α measured under the conditions of pressure 0.10 MPa, nitrogen 200 mL / min, temperature 20°C to 550°C, and heating rate 10°C / min as the reference temperature, the device is heated at a temperature of reference temperature - 450°C or higher and reference temperature - 10°C or lower for 1 minute to 3000 minutes.) [3] A first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a second electrode film (D) comprising a rate of change r represented by the following formula (iii) ｌｄ３ A photoelectric conversion element in which r is between 0.033 and 30. ｌｄ３ =ld ３ａ / ld ３ｂ ...(iii) (In the formula, ld ３ａ The following is the light-dark ratio (external bias 3V) after heat treatment under the conditions below, ld ３ｂ is the light-dark ratio of the non-heat treatment (external bias 3V). Conditions: Using the 5% mass loss temperature of compound α measured under the conditions of pressure 0.10 MPa, nitrogen 200 mL / min, temperature 20 to 550°C, and heating rate 10°C / min as the reference temperature, the mixture is heated at a temperature of reference temperature - 450°C or higher and reference temperature - 10°C or lower for 1 minute to 3000 minutes.) [4] A first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a second electrode film (D), wherein the rate of change r is expressed by formula (iv). ｄ０ A photoelectric conversion element in which r is between 0.20 and 5.0. ｄ０ = d ０ａ / d ０ｂ ...(iv) (in the formula, d ０ａ This is the dark current (external bias 0V) after heat treatment under the following conditions, and d ０ｂ) is a dark current (external bias 0V) for non-heating treatment. Conditions: Using the 5% mass loss temperature of compound α measured under the conditions of pressure 0.10 MPa, nitrogen 200 mL / min, temperature 20 to 550°C, and heating rate 10°C / min as the reference temperature, the device is heated for 1 minute to 3000 minutes at a temperature of reference temperature - 450°C or higher and reference temperature - 10°C or lower.) [5] A photoelectric conversion element according to any one of [1] to [4] in which compound α comprises an aromatic compound. [6] A photoelectric conversion element according to any one of [1] to [5] in which compound α comprises an aromatic imide compound. [7] A photoelectric conversion element according to any one of [1] to [6] in which compound α comprises at least one selected from the group consisting of pyromellitrimide compounds, naphthaleneimide compounds and peryleneimide compounds. [8] A photoelectric conversion element according to any one of [1] to [7] in which compound α comprises a compound represented by the following formula (I).

[0008]

[0009] (X is independently selected from the group consisting of methine groups and nitrogen atoms, n is an integer between 0 and 3, R １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７ Each is independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a thiol group, an amino group, a cyano group, a carboxyl group, a nitro group, and optionally substituted linear, branched or cyclic alkyl groups, thioalkyl groups, thioaryl groups, arylsulfonyl groups, aryloxy groups, alkylsulfonyl groups, alkylamino groups, arylamino groups, alkoxy groups, acylamino groups, acyloxy groups, aryl groups, carboxyamide groups, carboalkoxy groups, carboaryloxy groups, acyl groups, and monovalent heterocyclic groups, and any adjacent R １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７R may be part of a fused ring. The fused ring may contain one or more atoms other than carbon.) [9] In formula (I), R ６ and R ７ [8] A photoelectric element according to [8], wherein at least one of the substituents has a Hammett substituent constant σp of 0.50 or more and 0.90 or less.

[10] A photoelectric element according to [8] or [9], wherein n in formula (I) is 0 or 1.

[11] A photoelectric element according to any one of [8] to

[10] , wherein X in formula (I) is a nitrogen atom.

[12] In formula (I), R １ , R ２ , R ３ , R ４ and R ５

[13] A photoelectric conversion element according to any one of [8] to

[11] , wherein the sum of Hammett substituent constants σp is 0.50 or more and 1.80 or less.

[14] A photoelectric conversion element according to any one of [1] to

[12] , wherein the thickness of the auxiliary layer (C) is 1 nm or more and 1000 nm or less.

[15] An image sensor comprising a photoelectric conversion element according to any one of [1] to

[13] .

[16] An image sensor according to

[14] or

[15] , wherein the photoelectric conversion elements are arranged in an array.

[17] A light sensor comprising an image sensor according to any one of

[14] to

[16] .

[18] A solid-state imaging device comprising an image sensor according to any one of

[14] to

[16] .

[0010] According to the present invention, it is possible to provide a photoelectric conversion element, an image sensor, a light sensor, and a solid-state imaging device that have excellent heat resistance.

[0011] This is a schematic cross-sectional view partially showing an example of the photoelectric conversion element of this embodiment. This is a schematic cross-sectional view partially showing another example of the photoelectric conversion element of this embodiment.

[0012] The following describes in detail embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment"), with reference to the drawings as necessary. However, the present invention is not limited to the embodiments described below. The present invention can be modified in various ways without departing from its essence. In the drawings, the same elements are denoted by the same reference numerals, and redundant explanations are omitted. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Moreover, the dimensional ratios in the drawings are not limited to those shown.

[0013] In this specification, Hammett's substituent constant σp is defined as log(K / K). ０ ) is expressed as, where K and K ０ σp is the dissociation constant of para-substituted and unsubstituted benzoic acid at 25°C in water. The Hammett substituent constants σp for each atom and organic group are described, for example, in the Journal of Synthetic Organic Chemistry, Japan, Vol. 23, No. 8 (1965). In this embodiment, the atoms and organic groups identified by the Hammett substituent constant σp are not limited to atoms and organic groups whose substituent constant σp is known as described in the above-mentioned literature, but also include atoms and organic groups whose substituent constant σp is not known, but whose substituent constant σp measured based on Hammett's rule falls within the range shown in this embodiment. The Hammett substituent constants σp for typical atoms and organic groups are as follows.

[0014]

[0015] In this specification, an organic group is a group comprising at least one element selected from the group consisting of C, N, O, and S.

[0016] In this specification, examples of halogen atoms include fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).

[0017] In this specification, the linear alkyl group which may have substituents may be a linear alkyl group having 1 to 12 carbon atoms in the alkyl group, for example, a methyl group (Me), an ethyl group (Et), an n-propyl group (n-Pr), an n-butyl group (n-Bu), an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, and an n-dodecyl group.

[0018] In this specification, branched alkyl groups which may have substituents may be branched alkyl groups having 1 to 12 carbon atoms in the alkyl group, and examples include isopropyl group (i-Pr), sec-butyl group (s-Bu), tert-butyl group (t-Bu), isopentyl group, sec-pentyl group, 3-pentyl group, neopentyl group, isohexyl group, isooctyl group, isononyl group, isodecyl group and isododecyl group. Linear or branched alkyl groups may also have substituents. Examples of substituents include halogen atoms such as fluorine atoms, monovalent groups having aromatic rings such as benzyl groups, naphthyl groups and phenoxy groups, alkoxy groups, monovalent groups having heteroatoms such as aminoalkyl and thioalkyl groups, monovalent groups having heterocycles such as pyridyl groups, hydroxyl groups, carboxyl groups, amino groups and thiol groups.

[0019] In this specification, a cyclic alkyl group which may have substituents may be a cyclic alkyl group having 3 to 10 carbon atoms in the alkyl group, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Furthermore, the cyclic alkyl group may have heteroatoms such as a nitrogen atom, an oxygen atom, and a sulfur atom in its ring. For example, such cyclic alkyl groups include a pyrrolidinyl group, an oxazolidinyl group, a pyrazolidinyl group, a thiazolidinyl group, an imidazolidinyl group, a dioxofuranyl group, a tetrahydrofuranyl group, a tetrahydrothiophenyl group, a piperazinyl group, a dioxanyl group, and a morphonyl group. In addition, a monovalent group such as a hydroxyl group, a carboxyl group, an amino group, and a thiol group may be bonded to the cyclic alkyl group.

[0020] In this specification, optionally substituted thioalkyl groups (-SR; R represents an alkyl group (hereinafter the same)) and thioaryl groups (-SAr; Ar represents an aryl group (hereinafter the same)) may be thioalkyl groups having 1 to 12 carbon atoms in the alkyl group and thioaryl groups having 6 to 16 carbon atoms in the aryl group. Furthermore, thioalkyl groups and thioaryl groups may have substituents such as an amino group, a hydroxyl group, a halogen atom, an alkoxy group, or a thioalkyl group. Examples of such thioalkyl groups and thioaryl groups include methylthio, ethylthio, phenylthio, toluylthio, aminophenylthio, hydroxyphenylthio, fluorophenylthio, dimethylphenylthio, and methylthiophenylthio.

[0021] In this specification, an arylsulfonyl group which may have a substituent (-SO ２ The -Ar) group may be an arylsulfonyl group having 6 to 16 carbon atoms in the aryl group, for example, a phenylsulfonyl group, a toluenesulfonyl group, a dimethylbenzenesulfonyl group, a mesitylenesulfonyl group, an octylbenzenesulfonyl group, and a naphthalenesulfonyl group.

[0022] In this specification, the optionally substituted aryloxy group (-O-Ar) may be an aryloxy group having 6 to 16 carbon atoms in the aryl group. Furthermore, the aryloxy group may have further substituents such as a cyano group, a halogen atom such as a fluorine atom, a hydroxyl group, an alkoxy group such as a methoxy group, an amino group, an alkylamino group, a thiol group, and an aryloxy group. Examples of such aryloxy groups include a phenoxy group, a cyanophenoxy group, a methylcyanophenoxy group, a dimethylcyanophenoxy group, a fluorocyanophenoxy group, a dicyanophenoxy group, a methoxycyanophenoxy group, a tricyanophenoxy group, a cyanonaphthoxy group, a dicyanonaphthoxy group, a 2-methylphenoxy group, a 3-methylphenoxy group, a 4-methylphenoxy group, a fluoromethylphenoxy group, a dimethylphenoxy group, a 3-hydroxyphenoxy group, Examples include fluoro-3-hydroxyphenoxy group, 2-hydroxyphenoxy group, fluoro-2-hydroxyphenoxy group, methoxyphenoxy group, ethoxyphenoxy group, fluorophenoxy group, perfluorophenoxy group, dimethoxyphenoxy group, aminophenoxy group, N,N-dimethylaminophenoxy group, thiophenoxy group, (trifluoromethyl)phenoxy group, naphthoxy group, methoxynaphthoxy group, fluoronaphthoxy group, and phenoxyphenoxy group.

[0023] In this specification, alkylsulfonyl groups which may have substituents (-SO ２ -R) may be an alkylsulfonyl group having 1 to 12 carbon atoms in the alkyl group, for example, a mesyl group, an ethylsulfonyl group, and an n-butylsulfonyl group.

[0024] In this specification, alkylamino groups which may have substituents (-NHR or -NR ２The two Rs may be the same or different from each other.) The alkyl group may be an alkylamino group having 1 to 12 carbon atoms, for example, methylamino group, ethylamino group, n-propylamino group, n-butylamino group, n-pentylamino group, n-hexylamino group, n-heptylamino group, n-octylamino group, n-nonylamino group, n-decylamino group, n-dodecylamino group, isopropylamino group, sec-butylamino group, tert-butylamino group, isopentylamino group, sec-pentylamino group, 3-pentylamino group, neopentylamino group, isohexylamino group, isoheptylamino group, isooctylamino group, isononylamino group, isodecylamino group and isododecylamino group, dimethylamino group, diethylamino group, diisopropylamino group and isopropylethylamino group.

[0025] In this specification, an arylamino group which may have a substituent (-NHAr or -NAr) ２ The two Ar groups may be the same or different. The aryl group may be an arylamino group having 6 to 16 carbon atoms, for example, anyl group, toluidinyl group, dimethylanilyl group, isopropylarilinyl group, t-butylanilyl group, fluoroanilyl group, trifluoromethylanilyl group, bis(trifluoromethyl)anilyl group, pyridylamino group, methylpyridylamino group, fluoropyridylamino group, pyrimidylamino group, and biphenylamino group.

[0026] In this specification, the alkoxy group (-OR), which may have substituents, may be an alkoxy group having 1 to 12 carbon atoms, and examples include a methoxy group, an ethoxy group, an n-propoxy group, an n-butyroxy group, an n-pentoxy group, an n-hexoxy group, an n-heptoxy group, an n-octoxy group, an n-nonoxy group, an n-decoxy group and an n-dodecoxy group, an isopropoxy group, a sec-butyroxy group, a tert-butyroxy group, an isopentoxy group, a sec-pentoxy group, a 3-pentoxy group, a neopentoxy group, an isohexoxy group, an isooctoxy group, an isononoxy group, an isodecoxoxy group and an isododecoxy group.

[0027] In this specification, the optionally substituted acylamino group (-NH-COR or -NH-COAr) may have 1 to 12 carbon atoms in the alkyl group or 6 to 16 carbon atoms in the aryl group, and may have substituents such as halogen atoms like fluorine, alkoxy groups, and cyano groups. Examples of such acylamino groups include acetylamino group, propionylamino group, benzoylamino group, methylbenzoylamino group, dimethylbenzoylamino group, methoxybenzoylamino group, cyanobenzoylamino group, and bis(trifluoromethyl)benzoylamino group.

[0028] In this specification, the optionally substituted acyloxy group (-O-COR or -O-COAr) may have 1 to 12 carbon atoms in the alkyl group or 6 to 16 carbon atoms in the aryl group. The acyloxy group may further have substituents such as a halogen atom such as a fluorine atom, a cyano group, and an optionally substituted alkyl group, and may have a heteroatom such as a nitrogen atom in the aromatic ring. Examples of such acyloxy groups include benzoyloxy group, toluyloxy group, dimethylbenzoyloxy group, cyanobenzoyloxy group, fluorobenzoyloxy group, bis(trifluoromethyl)benzoyloxy group, pyridinecarboxyl group, and methylpyridinecarboxyl group.

[0029] In this specification, the optionally substituted aryl group (-Ar) may be an aryl group having 6 to 16 carbon atoms. The aryl group may further have substituents such as an amino group, a hydroxyl group, a thiol group, a halogen atom such as a fluorine atom, a nitro group, a cyano group, and an optionally substituted alkyl group, and may also have a heteroatom such as a nitrogen atom in the aromatic ring. Examples of such aryl groups include phenyl group, methylphenyl group, ethylphenyl group, dimethylphenyl group, trimethylphenyl group, methoxyphenyl group, dimethoxyphenyl group, trimethoxyphenyl group, methoxymethylphenyl group, aminophenyl group, diaminophenyl group, aminomethylphenyl group, hydroxyphenyl group, dihydroxyphenyl group, hydroxymethylphenyl group, hydroxyethylphenyl group, thiophenyl group, methylthiophenyl group, dithiophenyl group, fluorophenyl group, fluoromethylphenyl group, trifluoromethylphenyl group, perfluorophenyl group, fluoro(trifluoromethyl)phenyl group, bis(trifluoromethyl)phenyl group, cyanophenyl group, methylcyanophenyl group, dimethylcyanophenyl group, dicyanophenyl group, methoxycyanophenyl group, tricyanophenyl group, and dicyanophenyl group. Examples include methylcyanopyridyl group, (trifluoromethyl)cyanopyridyl group, dimethylcyanopyridyl group, dicyanopyridyl group, methoxycyanopyridyl group, tricyanopyridyl group, cyanopyridyl group, naphthyl group, nitrophenyl group, dinitrophenyl group, nitrofluorophenyl group, methylnaphthyl group, ethylnaphthyl group, dimethylnaphthyl group, trimethylnaphthyl group, methoxynaphthyl group, dimethoxynaphthyl group, trimethoxynaphthyl group, aminonaphthyl group, diaminonaphthyl group, aminomethylnaphthyl group, hydroxynaphthyl group, dihydroxynaphthyl group, hydroxymethylnaphthyl group, hydroxyethylnaphthyl group, thionaphthyl group, methylthionaphthyl group, dithionaphthyl group, fluoronaphthyl group, trifluoromethylnaphthyl group, perfluoronaphthyl group, di(trifluoromethyl)naphthyl group, biphenyl group, and cyanobiphenyl group.

[0030] In this specification, a carboxyamide group (-CO-NH) which may have a substituent ２ , -CO-NHR, -CONR ２ The two Rs may be the same or different, and can be -CONHAr or -CONAR. ２ The two Ar groups may be the same or different. The alkyl group may be a carboxyamide group having 1 to 12 carbon atoms or an aryl group having 6 to 16 carbon atoms, for example, a dimethylcarboxyamide group and a diphenylcarboxyamide group.

[0031] In this specification, the optionally substituted carboalkoxy group and optionally substituted carboaryloxy group (-COOR or -COOAr) may be a carboalkoxy group having 1 to 12 carbon atoms in the alkyl group or 6 to 16 carbon atoms in the aryl group, for example, a carbomethoxy group and a carbophenoxy group.

[0032] In this specification, the optionally substituted monovalent heterocyclic group may be a heteroaryl group or a monovalent heterocyclic group having 3 to 14 carbon atoms, for example, a furanyl group, a thienyl group, a pyrrolyl group, a pyrazolyl group, an imidazolyl group, a triazolyl group, an oxazolyl group, a dioxazolyl group, an isoxazolyl group, an oxadiazolyl group, a thiazolyl group, an isothiazolyl group, a thiadiazolyl group, a triazolyl group, an indolyl group, an indolinyl group, an indolidinyl group, an indazolinyl group, an indoleninyl group, a benzofuranyl group, or a benzothienyl group. Examples include carbazolyl group, dibenzofuranyl group, dibenzothienyl group, pyridinyl group, diazinyl group, oxazinyl group, thiadinyl group, dioxynyl group, dithienyl group, triazinyl group, pyrimidinyl group, pyrazinyl group, pyridadinyl group, quinolinyl group, isoquinolinyl group, cinnonyl group, phthalazinyl group, quinazolinyl group, naphthilidinyl group, prinyl group, pteridinyl group, acridinyl group, phenanthridine group, phenanthrolinyl group, xanthenyl group, phenoxadinyl group, thianthrenyl group, morpholinyl group, and phenadinyl group.

[0033] <Photoelectric Conversion Element> The photoelectric conversion element of this embodiment includes the following first to fourth embodiments. <First Embodiment> The photoelectric conversion element of the first embodiment includes a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a rate of change r represented by the following formula (i) ｄ３ The value is between 0.020 and 50.0. ｄ３ = d ３ａ / d ３ｂ ...(i) (in the formula, d ３ａ This is the dark current (external bias 3V) after heat treatment under the following conditions, and d ３ｂ This is the dark current (external bias 3V) for non-heating treatment. Conditions: The 5% mass loss temperature of compound α, measured under conditions of pressure 0.10 MPa, nitrogen 200 mL / min, temperature 20°C to 550°C, and heating rate 10°C / min, is used as the reference temperature. The compound is then heated at a temperature of reference temperature - 450°C or higher and reference temperature - 10°C or lower for 1 minute to 3000 minutes.

[0034] In this embodiment, for example, the notation "reference temperature - 450°C" means the temperature obtained by subtracting 450°C from the reference temperature, and the notation "reference temperature - 10°C or less" means the temperature obtained by subtracting 10°C from the reference temperature. In this embodiment, for example, the notation "dark current (external bias 3V)" means the dark current at an external bias of 3V.

[0035] In the first embodiment, the rate of change r is represented by formula (i). ｄ３ The value is between 0.020 and 50.0. The photoelectric conversion element of the first embodiment has excellent heat resistance, as it suppresses fluctuations in dark current (external bias 3V) due to heating. The rate of change r is expressed by formula (i) ｄ３ The rate of change r, expressed by formula (i), is preferably 0.025 or higher, more preferably 0.030 or higher, even more preferably 0.10 or higher, and particularly preferably 0.20 or higher. ｄ３ It is preferably 30.0 or less, more preferably 20.0 or less, and even more preferably 10.0 or less.

[0036] The conditions for the heat treatment will now be explained. The heating temperature can be appropriately selected from the reference temperature of the 5% mass loss temperature, with the reference temperature being 450°C or higher and 10°C or lower. Preferably, the heating temperature is 440°C or higher and 200°C or lower, and more preferably 430°C or higher and 300°C or lower. There are no particular restrictions on the method for detecting the heating temperature, but examples include using a thermocouple, a resistance thermometer, a thermistor, or infrared radiation.

[0037] The heating time is 1 minute or more and 3000 minutes or less. The heating time is preferably 5 minutes or more, more preferably 10 minutes or more. The heating time is preferably 2000 minutes or less, more preferably 1000 minutes or less, even more preferably 500 minutes or less, and particularly preferably 150 minutes or less. The heating time is the holding time after the start of heating, when the temperature exceeds the above-mentioned heating temperature of -5°C, is maintained within ±5°C, and then falls below -5°C.

[0038] The reference temperature for the heat treatment is the 5% mass loss temperature of compound α measured under the conditions of a pressure of 0.10 MPa, nitrogen at 200 mL / min, a temperature of 20°C to 550°C, and a heating rate of 10°C / min. The 5% mass loss temperature is measured using a thermogravimetric differential thermal analyzer (TG-DTA), for example, a STA-7200 (manufactured by Hitachi High-Tech Science Corporation). There are no particular restrictions on the heating method in the heat treatment, but examples include heating in a chamber using a hot plate under a vacuum or inert gas atmosphere, heating using a heater, heating using an infrared lamp, or heating using a laser.

[0039] <Second Embodiment> The photoelectric conversion element of the second embodiment includes a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a rate of change r represented by the following formula (ii) ｌ３ r is between 0.50 and 2.0. ｌ３ = l ３ａ / l ３ｂ ...(ii) (in the formula, l ３ａThis is the bright current (external bias 3V) after heat treatment under the following conditions, l ３ｂ This is a non-heating treatment with bright current (external bias 3V). Conditions: The 5% mass loss temperature of compound α, measured under conditions of pressure 0.10 MPa, nitrogen 200 mL / min, temperature 20°C to 550°C, and heating rate 10°C / min, is used as the reference temperature. The compound α is then heated at a temperature of reference temperature - 450°C or higher and reference temperature - 10°C or lower for 1 minute to 3000 minutes.

[0040] In the second embodiment, the rate of change r is represented by formula (ii). ｌ３ The value is 0.50 or more and 2.0 or less. The photoelectric conversion element of the second embodiment has suppressed fluctuations in the bright current due to heating and has excellent heat resistance. The rate of change r is expressed by formula (ii) ｌ３ It is preferable that r be 0.55 or higher, and more preferably 0.60 or higher. The rate of change r is expressed by formula (ii). ｌ３ It is preferably 1.5 or less, more preferably 1.3 or less, and even more preferably 1.2 or less.

[0041] Details regarding the specific and preferred modes of heat treatment are the same as those in the first embodiment.

[0042] <Third Embodiment> The photoelectric conversion element of the third embodiment includes a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a rate of change r represented by the following formula (iii) ｌｄ３ A photoelectric conversion element in which r is between 0.033 and 30. ｌｄ３ =ld ３ａ / ld ３ｂ ...(iii) (In the formula, ld ３ａ The following is the light-dark ratio (external bias 3V) after heat treatment under the conditions below, ld ３ｂThis is the light-dark ratio for non-heating treatment (external bias 3V). Conditions: The 5% mass loss temperature of compound α, measured under conditions of pressure 0.10 MPa, nitrogen 200 mL / min, temperature 20 to 550°C, and heating rate 10°C / min, is used as the reference temperature. The compound is heated at a temperature of reference temperature - 450°C or higher and reference temperature - 10°C or lower for 1 minute to 3000 minutes. The light-dark ratio is the value obtained by dividing the light current value by the dark current value.

[0043] In the third embodiment, the rate of change r is represented by formula (iii). ｌｄ３ The value is 0.033 or more and 30 or less. The photoelectric conversion element of the third embodiment has suppressed fluctuations in the light-dark ratio due to heating and has excellent heat resistance. The rate of change r is expressed by formula (iii). ｌｄ３ The rate of change r is preferably 0.035 or higher, more preferably 0.30 or higher, and even more preferably 0.40 or higher. ｌｄ３ It is preferable that the value is 20 or less, and more preferably 15 or less.

[0044] Details regarding the specific and preferred modes of heat treatment are the same as those in the first embodiment.

[0045] <Fourth Embodiment> The photoelectric conversion element of the fourth embodiment includes a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a rate of change r represented by formula (iv). ｄ０ r is between 0.20 and 5.0. ｄ０ = d ０ａ / d ０ｂ ...(iv) (in the formula, d ０ａ This is the dark current (external bias 0V) after heat treatment under the following conditions, and d ０ｂ This represents the dark current (external bias 0V) for non-heating treatment. Conditions: The 5% mass loss temperature of compound α, measured under conditions of pressure 0.10 MPa, nitrogen 200 mL / min, temperature 20-550°C, and heating rate 10°C / min, is used as the reference temperature. The compound is then heated at a temperature of reference temperature - 450°C or higher and reference temperature - 10°C or lower for 1 minute to 3000 minutes.

[0046] In the fourth embodiment, the change rate r represented by the formula (iv) ｄ０ is 0.20 or more and 5.0 or less. The photoelectric conversion element of the fourth embodiment has suppressed fluctuations in the dark current (external bias: 0 V) due to heating and is excellent in heat resistance. The change rate r represented by the formula (iv) ｄ０ is preferably 0.50 or more, more preferably 0.70 or more. The change rate r represented by the formula (iv) ｄ０ is preferably 4.0 or less, more preferably 3.5 or less.

[0047] Details such as the specific mode and preferred mode of the heat treatment are the same as those of the specific mode and preferred mode of the heat treatment in the first embodiment.

[0048] The photoelectric conversion elements of the first to fourth embodiments are excellent in heat resistance by including the above configuration. Therefore, the photoelectric conversion element of the first embodiment is suitably used, for example, when heating the photoelectric conversion element by an annealing process in the manufacture of a solid-state imaging device.

[0049] The photoelectric conversion element of this embodiment generates an electric charge corresponding to the amount of incident light and outputs it to the outside of the photoelectric conversion element via a capacitor for storing the generated charge (hereinafter also referred to as the "storage unit") and a transistor circuit for reading out the charge (hereinafter also referred to as the "readout unit"). Here, the photoelectric conversion element is defined as having a photoelectric conversion layer that absorbs at least a portion of the incident light placed between a pair of opposing electrodes, and light is incident on the photoelectric conversion element from above the electrodes. The photoelectric conversion layer may also be a photosensitive thin film containing a material that absorbs at least a portion of the incident light in the infrared region, and generates holes and electrons as a result of the incident light. Furthermore, the photoelectric conversion element of this embodiment may also include a photoelectric conversion element that generates an electric charge corresponding to the amount of incident light in the infrared region (hereinafter also referred to as the "infrared photoelectric conversion element"). Here, the infrared photoelectric conversion element is defined as having a photoelectric conversion layer that absorbs infrared light (hereinafter also referred to as the "infrared photoelectric conversion layer") placed between a pair of opposing electrodes, and light is incident on the infrared photoelectric conversion element from above the electrodes. The infrared photoelectric conversion layer may also be a photosensitive thin film containing a material that absorbs at least a portion of the incident light in the infrared region (hereinafter also referred to as the "infrared absorbing material"), and generates holes and electrons as a result of the incident light. The details of the photoelectric conversion element of this embodiment and each of the components that may be included in the photoelectric conversion element of this embodiment will be described below.

[0050] The photoelectric conversion element of this embodiment is not particularly limited in its specific form, as long as it includes a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a second electrode film (D). For example, it may include multiple photoelectric conversion layers (B), auxiliary layers (C) containing compound α, etc., and there are no particular restrictions on the stacking order of the multiple photoelectric conversion layers (B) and auxiliary layers (C) containing compound α. The photoelectric conversion element of this embodiment may be a laminate containing the first electrode film (A), photoelectric conversion layer (B), auxiliary layer (C) containing compound α, and second electrode film (D) in this order, or it may be a laminate containing the first electrode film (A), auxiliary layer (C) containing compound α, photoelectric conversion layer (B), and second electrode film (D) in this order, and the same or different films, etc. may be included between the films and layers (also called films, etc.) of these laminates. For example, the photoelectric conversion element of this embodiment may be a laminate comprising a first electrode film (A), an auxiliary layer not containing compound α, a photoelectric conversion layer (B), an auxiliary layer containing compound α (C), and a second electrode film (D) in this order, or it may be a laminate comprising a first electrode film (A), an auxiliary layer not containing compound α, a photoelectric conversion layer (B), an auxiliary layer not containing compound α, an auxiliary layer containing compound α (C), and a second electrode film (D) in this order.

[0051] Figure 1 is a schematic cross-sectional view partially showing an example of a photoelectric conversion element of this embodiment. In Figure 1, the photoelectric conversion element 100 comprises a lower electrode 102 which is a first electrode film, an upper electrode 106 which is a second electrode film, and a photoelectric conversion layer 104 located between the lower electrode 102 and the upper electrode 106. The photoelectric conversion element 100 may also have a substrate 101, which is normally insulating, on the side of the upper electrode 106 opposite to the photoelectric conversion layer 104. The photoelectric conversion element 100 shown in Figure 1 includes a photoelectric conversion layer 104, a first auxiliary layer 103, and a second auxiliary layer 105. The photoelectric conversion element 100 shown in Figure 1 includes the first auxiliary layer 103 and the second auxiliary layer 105, but the photoelectric conversion element may also include only one of these auxiliary layers.

[0052] Figure 2 is a schematic cross-sectional view partially showing another example of the photoelectric conversion element of this embodiment. In Figure 2, the photoelectric conversion element 200 comprises a lower electrode 102 which is a first electrode film, an upper electrode 106 which is a second electrode film, and a photoelectric conversion layer 104 located between the lower electrode 102 and the upper electrode 106. The photoelectric conversion element 200 may also have a substrate 101, which is normally insulating, on the side of the upper electrode 106 opposite to the photoelectric conversion layer 104. The photoelectric conversion element 200 shown in Figure 2 includes the photoelectric conversion layer 104, a first auxiliary layer 103, a second auxiliary layer 105, and a third auxiliary layer 107. The photoelectric conversion element 200 shown in Figure 2 includes the first auxiliary layer 103, the second auxiliary layer 105, and the third auxiliary layer 107, but an auxiliary layer is not required between the lower electrode 102 and the photoelectric conversion layer 104. The photoelectric conversion element of this embodiment will be described with reference to Figures 1 and 2 as appropriate.

[0053] (Electrode Film) The photoelectric conversion element of this embodiment includes a first electrode film (A) and a second electrode film (D). In Figure 1, the lower electrode 102 may be the first electrode film, and the upper electrode 106 may be the second electrode film. The lower electrode 102 and the upper electrode 106 play a role in extracting and collecting holes from each auxiliary layer, or extracting and ejecting electrons, when each auxiliary layer has hole transport properties or electron transport properties. The materials that can be used as these electrodes are not particularly limited as long as they have a certain degree of conductivity, but it is preferable to select them considering adhesion to adjacent layers and films, electron affinity, ionization potential, and stability.

[0054] Examples of materials that can be used as electrodes include conductive metal oxides such as tin oxide (NESA), indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); metals such as gold, silver, platinum, chromium, aluminum, iron, cobalt, nickel, and tungsten; inorganic conductive substances such as copper iodide and copper sulfide; conductive polymers such as polythiophene, polypyrrole, and polyaniline; and carbon. These materials may be used individually or in combination.

[0055] The lower electrode 102, which is the first electrode film, is made of a light-transmitting conductive film, for example, indium tin oxide (ITO). The material constituting the lower electrode 102 is not limited to ITO, but for example, dopant-doped tin oxide (SnO ２ Examples of zinc oxide-based materials include zinc oxide (ZnO) with added dopants, and zinc oxide-based materials obtained by adding dopants to zinc oxide (ZnO). Examples of zinc oxide-based materials include aluminum zinc oxide (AZO) with added aluminum (Al) as a dopant, gallium zinc oxide (GZO) with added gallium (Ga), and indium zinc oxide (IZO) with added indium (In). Alternatively, examples of materials constituting the lower electrode 102 include CuI, InSbO ４ , ZnMgO, CuInO ２ MgIN ２ O ４ , CdO, and ZnSnO ３ This can also be mentioned.

[0056] The thickness of the lower electrode 102 is, for example, 5 nm to 3000 nm, and may be 5 nm to 500 nm, or 10 nm to 300 nm.

[0057] The upper electrode 106, which is the second electrode film, may be made of a conductive film having the same light-transmitting properties as the lower electrode 102, or it may be made of a conductive film having different light-transmitting properties than the lower electrode 102. For example, the upper electrode 106 may be made of a metal commonly used for electrodes of photoelectric conversion elements, such as aluminum. In a solid-state imaging device that uses a solid-state image sensor as a single pixel, this upper electrode 106 may be separated for each pixel, or it may be formed as a common electrode for each pixel. The material that constitutes the upper electrode 106 can be appropriately selected from the materials that constitute the lower electrode 102 as described above.

[0058] The thickness of the upper electrode 106 is, for example, 5 nm to 3000 nm, and may be 5 nm to 500 nm, or 10 nm to 300 nm.

[0059] The conductivity of the materials used for electrodes, such as the first and second electrode films, is not particularly limited as long as it does not unnecessarily hinder the light reception of the photoelectric conversion element. However, from the viewpoint of signal strength and power consumption of the photoelectric conversion element, it is preferable to have the highest possible conductivity. For example, as a transparent electrode, an ITO film with a sheet resistance of 300 Ω / sq or less is sufficient for functioning as an electrode. However, commercially available substrates equipped with ITO films having conductivity of several Ω / sq (for example, 5 to 9 Ω / sq) are also available, and substrates with such high conductivity are desirable.

[0060] When using an ITO film, the electrode thickness can be arbitrarily selected considering conductivity, but is usually 5 nm to 3000 nm, preferably 10 nm to 300 nm. Methods for forming ITO films include conventionally known methods such as vapor deposition, electron beam method, sputtering, chemical reaction method, and coating method. The ITO film provided on the substrate may be subjected to UV-ozone treatment or plasma treatment as needed.

[0061] Furthermore, when stacking multiple photoelectric conversion layers with different wavelengths to be detected, the electrode films used between each photoelectric conversion layer must transmit light of wavelengths other than those detected by each respective photoelectric conversion layer. From this viewpoint, it is preferable to use a material that transmits 90% or more of the incident light for the electrode film, and more preferably a material that transmits 95% or more of the light. Note that the electrode film mentioned above refers to the electrode film other than the pair of electrodes described above.

[0062] Furthermore, if a visible light photoelectric conversion unit that senses infrared light or light in a different visible light range is provided below the photoelectric conversion element in this embodiment, the electrodes used in the photoelectric conversion element preferably have a transmittance of 90% or more for visible light and infrared light, and more preferably 95% or more.

[0063] As a material for the electrode that satisfies such conditions, a transparent conductive oxide (TCO; Transparent Conducting Oxide) with high transmittance to visible light and infrared light and a small resistance value is preferable. Although a metal thin film such as gold can also be used as the electrode, when trying to make the transmittance 90% or more, the resistance value extremely increases. Therefore, TCO is preferable as the electrode. As TCO, in particular, ITO, IZO, AZO, FTO, SnO ２ , TiO ２ and ZnO ２ are preferable.

[0064] The method for forming the electrode is not particularly limited and can be appropriately selected in consideration of its suitability with the electrode material. When using a transparent electrode, specific examples of the forming method include wet methods such as printing and coating methods, physical methods such as vacuum evaporation, sputtering, and ion plating methods, and chemical methods such as CVD and plasma CVD methods. Further, when the electrode material is a transparent conductive metal oxide such as ITO, examples of the forming method include an electron beam method, a sputtering method, a resistance heating evaporation method, a chemical reaction method (e.g., sol-gel method, etc.), and a method of applying a dispersion of the metal oxide. Furthermore, UV-ozone treatment and plasma treatment can also be applied to a film of a transparent conductive metal oxide such as ITO.

[0065] The photoelectric conversion element of this embodiment includes a photoelectric conversion layer (B) and an auxiliary layer (C) containing compound α. The photoelectric conversion layer and the auxiliary layer may each contain only a single compound or may contain a plurality of types of compounds.

[0066] The exact factors that enable such photoelectric conversion elements to suppress leakage current in the dark are unclear, but the inventors believe the following. The photoelectric conversion element of this embodiment includes at least one auxiliary layer containing compound α between the photoelectric conversion layer and the first or second electrode film. This provides a rectifying effect that suppresses holes flowing in from the first or second electrode film due to the relatively low HOMO level of compound α, and as a result, it is thought that leakage current in the dark (hereinafter also referred to as "dark current") can be suppressed. However, the factors are not limited to this. Furthermore, the photoelectric conversion element of this embodiment can also have high photoelectric conversion efficiency. This is thought to be because the relatively low LUMO level of compound α allows electrons generated in the photoelectric conversion layer to move smoothly to the first or second electrode film. However, the factors are not limited to this.

[0067] In one embodiment of this design, the photoelectric conversion element 100 includes, for example, a photoelectric conversion layer 104, a first auxiliary layer 103 located on the lower electrode film 102 side of the photoelectric conversion layer 104, and a second auxiliary layer 105 located on the upper electrode film 106 side of the photoelectric conversion layer 104. Although the photoelectric conversion element 100 shown in Figure 1 includes the first auxiliary layer 103 and the second auxiliary layer 105, it may also include only one of these auxiliary layers.

[0068] In one embodiment of this design, for example, the photoelectric conversion element 200 comprises a photoelectric conversion layer 104 and a second auxiliary layer 105 and a third auxiliary layer 107 located between the photoelectric conversion layer 104 and the upper electrode 106. Of these auxiliary layers 105 and 107, the third auxiliary layer 107, which is closer to the upper electrode 106, is adjacent to the upper electrode 106, and the second auxiliary layer 105 is located on the photoelectric conversion layer 104 side of the third auxiliary layer 107. Although the photoelectric conversion element 200 shown in Figure 2 comprises a first auxiliary layer 103, a second auxiliary layer 105, and a third auxiliary layer 107, an auxiliary layer may not be provided between the lower electrode 102 and the photoelectric conversion layer 104.

[0069] (Photoelectric Conversion Layer) The photoelectric conversion element of this embodiment includes a photoelectric conversion layer (B). The photoelectric conversion layer may be an organic thin film, or it may be an organic semiconductor film commonly used as a photoelectric conversion layer. The photoelectric conversion element of this embodiment may also include one or more photoelectric conversion layers. If there is one layer, a p-type organic semiconductor film, an n-type organic semiconductor film, or a mixed film thereof (hereinafter referred to as a "bulk heterostructure") may be used. On the other hand, if there are multiple layers, the number of layers may be about 2 to 10, and the structure is made by stacking any of the p-type organic semiconductor films, n-type organic semiconductor films, or mixed films thereof (hereinafter referred to as a "bulk heterostructure"), and buffer layers may be inserted between the layers.

[0070] In this embodiment, the photoelectric conversion layer preferably includes at least one of an organic p-type semiconductor, an organic n-type semiconductor, and a light-absorbing material, from the viewpoint of being able to more efficiently convert incident light energy of a desired wavelength into an electrical signal. From the viewpoint of being able to convert incident light energy into an electrical signal even more efficiently, the organic p-type semiconductor is preferably one that readily donates electrons to the light-absorbing material and has a small ionization potential, and the organic n-type semiconductor is preferably one that readily accepts electrons and has a large electron affinity. Here, the ionization potential (HOMO level) refers to the value measured by photoelectron yield spectroscopy or photoelectron spectroscopy. The electron affinity (LUMO level) refers to the value obtained by calculating the energy band gap value from the longest wavelength absorption edge of the near-infrared spectroscopic spectrum and subtracting it from the HOMO level, or the value measured by inverse photoelectron spectroscopy.

[0071] When an organic semiconductor film is used as the photoelectric conversion layer, the film may consist of one layer or two or more layers. The organic semiconductor film may be an organic p-type semiconductor film, an organic n-type semiconductor film, a light-absorbing material film, or a mixed film (bulk heterostructure) thereof. In particular, it is preferable that the organic semiconductor film has a bulk heterojunction structure layer. In such a case, by incorporating a bulk heterojunction structure into the photoelectric conversion layer, the disadvantage of a short carrier diffusion length in the photoelectric conversion layer can be compensated for, and the photoelectric conversion efficiency can be improved.

[0072] The thickness of the photoelectric conversion layer may be, for example, 0.5 nm to 5000 nm, 1 nm to 1000 nm, or 5 nm to 500 nm.

[0073] The following provides a detailed explanation of organic semiconductors. Organic p-type semiconductors are donor organic semiconductors (hereinafter also called "donor organic compounds"), and are mainly represented by hole-transporting organic compounds, which are organic compounds that readily donate electrons. More specifically, they are organic compounds that have a lower ionization potential when two organic materials are brought into contact. Therefore, any organic compound that is electron-donating can be used as a donor organic compound.

[0074] Examples of such donor organic compounds include triarylamine compounds, benzidine compounds, pyrazoline compounds, styrylamine compounds, hydrazone compounds, triphenylmethane compounds, carbazole compounds, polysilane compounds, thiophene compounds, phthalocyanine compounds, cyanine compounds, merocyanine compounds, oxonol compounds, polyamine compounds, indole compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbocyclic compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluorantene derivatives), and metal complexes having nitrogen-containing heterocyclic compounds as ligands. However, as mentioned above, any organic compound with a lower ionization potential than the organic compound used as the acceptor organic compound can be used as a donor organic semiconductor.

[0075] Organic n-type semiconductors are acceptor organic semiconductors (hereinafter also referred to as "acceptor organic compounds"), mainly represented by electron-transporting organic compounds, and refer to organic compounds that have a property of readily accepting electrons. More specifically, they refer to the organic compound with the greater electron affinity when two organic compounds are used in contact. Therefore, any organic compound that has electron-accepting properties can be used as an acceptor organic compound.

[0076] Examples of such acceptor organic compounds include condensed aromatic carbocyclic compounds (e.g., naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluorantene derivatives, fullerene derivatives), and 5-7 membered heterocyclic compounds containing nitrogen, oxygen, and sulfur atoms (e.g., pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, Examples include metal complexes having pyrazoles, imidazoles, thiazoles, oxazoles, indazoles, benzimidazoles, benzotriazoles, benzoxazoles, benzothiazoles, carbazoles, purines, triazolopyridazines, triazolopyrimidines, tetrazaidene, oxadiazoles, imidazopyridines, pyrridines, pyrrolopyridines, thiadiazolopyridines, dibenzazepines, and tripenzazepines), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, and nitrogen-containing heterocyclic compounds as ligands. However, as mentioned above, any organic compound with a greater electron affinity than the organic compound used as the donor organic compound can be used as an acceptor organic semiconductor.

[0077] The light-absorbing material is a compound having a maximum light absorption wavelength in the visible light range, particularly in the range of 450 nm to 650 nm. It is desirable that the absorption intensity of the light-absorbing material at its maximum light absorption wavelength is greater than the absorption intensity of the donor organic compound or the acceptor organic compound at its maximum light absorption wavelength. Having such an absorption intensity allows for selective absorption of incident light at the light-absorbing material's maximum light absorption wavelength. After the incident light is absorbed by the light-absorbing material and the photons become excitons, exciton separation occurs at the interface between the donor organic compound and the acceptor organic compound, efficiently generating hole and electron carriers.

[0078] As such light-absorbing materials, compounds generally called dyes can be used. For example, phthalocyanine derivatives, subphthalocyanine derivatives, quinacridone derivatives, porphyrin derivatives, naphthalene or perylene derivatives, phthaloperylene derivatives, styryl derivatives, cyanine derivatives, hemicyanine derivatives, merocyanine derivatives, rhodacyanine derivatives, oxonol derivatives, hemioxonol derivatives, croconium derivatives, squarylium derivatives, azametine derivatives, allylidene derivatives, azo derivatives, azomethine derivatives, metallocene derivatives, fulgide derivatives, phenazine derivatives, phenothiazine derivatives, polyene derivatives, acridine derivatives, acridinone derivatives, diphenylamine derivatives, triarylamine derivatives such as triphenylamine, naphthylamine and styrylamine, quinophthalone derivatives, phenoxazine derivatives, chlorophyll derivatives, rhodamine derivatives, diphenylmethane or triphenylmethane derivatives, xanthene derivatives, acridine derivatives, phenoxazine derivatives, quinoline derivatives, oxazine Examples of derivatives include thiazine derivatives, quinone derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, indigo or thioindigo derivatives, pyrrole derivatives, pyridine derivatives, dipyrine derivatives, indole derivatives, diketopyrrolopyrrole derivatives, coumarin derivatives, fluorene derivatives, fluorenone derivatives, fluorantene derivatives, anthracene derivatives, pyrene derivatives, carbazole derivatives, phenylenediamine derivatives, benzidine derivatives, phenanthroline derivatives, imidazole derivatives, oxazoline derivatives, thiazoline derivatives, triazole derivatives, thiadiazole derivatives, oxazole derivatives, thiazoline derivatives, oxazole derivatives, thiazoline derivatives, oxadiazole derivatives, thiophene derivatives, selenofen derivatives, silole derivatives, germole derivatives, stilbene derivatives, phenylenevinylene derivatives, pentacene derivatives, rubrene derivatives, thienothiophene derivatives, benzodithiophene derivatives, xanthenoxanthene derivatives, and fullerene derivatives. Furthermore, as mentioned above, any compound whose absorption intensity is greater than that of the donor organic compound or acceptor organic compound at the maximum light absorption wavelength can be used as a light-absorbing material.Furthermore, light-absorbing materials can also function as either donor or acceptor organic compounds.

[0079] (Auxiliary Layer) The photoelectric conversion element of this embodiment includes an auxiliary layer (C) containing compound α. The photoelectric conversion element of this embodiment may include a plurality of auxiliary layers (C) containing compound α, or may further include an auxiliary layer that does not contain compound α. The auxiliary layer may include a hole blocking layer, an electron blocking layer, a hole transport layer, an electron transport layer, a hole injection layer, an electron injection layer, and the like.

[0080] [Compound α] The auxiliary layer (C) contains compound α. Compound α is a heat-resistant compound. As a result, the photoelectric conversion element of this embodiment has excellent heat resistance.

[0081] The compound α preferably contains an aromatic compound, and more preferably contains an aromatic imide compound.

[0082] Specifically, compound α preferably contains at least one selected from the group consisting of pyromellimide compounds, naphthaleneimide compounds, and peryleneimide compounds.

[0083] [Compound (I)] Compound α preferably contains the compound represented by the following formula (I) (also referred to as compound (I)).

[0084]

[0085] X is independently selected from the group consisting of a methine group (i.e., a CH group) and a nitrogen atom, n is an integer between 0 and 3, and R １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７Each is independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a thiol group, an amino group, a cyano group, a carboxyl group, a nitro group, and optionally substituted linear, branched or cyclic alkyl groups, thioalkyl groups, thioaryl groups, arylsulfonyl groups, aryloxy groups, alkylsulfonyl groups, alkylamino groups, arylamino groups, alkoxy groups, acylamino groups, acyloxy groups, aryl groups, carboxyamide groups, carboalkoxy groups, carboaryloxy groups, acyl groups, and monovalent heterocyclic groups, and any adjacent R １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７ This may be part of a fused ring. The fused ring may contain one or more atoms other than carbon.

[0086] Compound α, by containing compound (I), can suppress leakage current in the dark and exhibit excellent wavelength selectivity, making it particularly excellent as a photoelectric conversion element material. The reason for this is not clear, but it is speculated, however, that it may be due to the following, although the reason is not limited to this. Specifically, compound (I) has a structure in which the π-conjugated system is extended, which lowers the energy level of the lowest unoccupied orbital, suppressing leakage current in the dark and exhibiting excellent wavelength selectivity.

[0087] In formula (I), n is not particularly limited, but is preferably an integer between 0 and 2, and more preferably 0 or 1.

[0088] In formula (I), from the viewpoint of achieving the effects of this embodiment more effectively and reliably, it is preferable that each X is an independent nitrogen atom. Furthermore, in compound (I), the two Xs may be the same or different, and are not particularly limited, but it is preferable that they be the same.

[0089] In formula (I), R １ , R ２ , R ３ , R ４ and R ５While not particularly limited, from the viewpoint of more effectively and reliably achieving the effects of this embodiment, it is preferable that each be independently selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a nitro group, and a linear, branched, or cyclic alkyl group which may have a substituent; more preferably, each be independently selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a nitro group, and an alkyl group having a halogen atom as a substituent; and even more preferably, each be independently selected from the group consisting of a hydrogen atom and a cyano group.

[0090] In formula (I), R １ , R ２ , R ３ , R ４ and R ５ They may be the same or different. From the viewpoint of achieving the effects of this embodiment more effectively and reliably, R is not particularly limited, but １ , R ２ , R ３ , R ４ and R ５ Preferably, at least two selected from are the same, R １ , R ２ , R ３ , R ４ and R ５ It is more preferable that at least three of those selected are identical.

[0091] In formula (I), although not particularly limited, R is used in order to more effectively and reliably achieve the effects of this embodiment. １ , R ２ , R ３ , R ４ and R ５ Preferably, at least one of them is not a hydrogen atom, R １ , R ２ , R ３ , R ４ and R ５ It is more preferable that at least one of is selected from the group consisting of halogen atoms, nitro groups, cyano groups, and linear, branched, or cyclic alkyl groups which may have substituents, R １ , R ２ , R ３ , R４ and R ５ It is more preferable that at least one of is selected from the group consisting of a halogen atom, a nitro group, a cyano group, and an alkyl group having a halogen atom as a substituent, R １ , R ２ , R ３ , R ４ and R ５ It is particularly preferable that at least one of them is a cyano group.

[0092] In formula (I), although not particularly limited, R is used in order to more effectively and reliably achieve the effects of this embodiment. １ , R ２ , R ３ , R ４ and R ５ Preferably, at least two of them are hydrogen atoms, R １ , R ２ , R ３ , R ４ and R ５ It is more preferable that at least three of them are hydrogen atoms.

[0093] In formula (I), R ６ and R ７ While not particularly limited, it is preferably selected independently from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a nitro group, and a linear, branched, or cyclic alkyl group which may have a substituent; more preferably selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a nitro group, and an alkyl group having a halogen atom as a substituent; and even more preferably selected from the group consisting of a hydrogen atom and a cyano group.

[0094] In formula (I), R ６ and R ７ They may be the same or different.

[0095] Compound (I), having the structure described above, can further suppress leakage current in the dark and tends to exhibit superior wavelength selectivity. Furthermore, having the structure described above allows for a higher 5% mass loss temperature, as described later, and tends to improve manufacturability.

[0096] From the above perspective, in equation (I), R １ , R ２ , R ３ , R ４ , and R ５ It is preferable that one or two of these have a Hammett substituent constant σp of 0.10 or more. Also, from a similar viewpoint, R １ , R ２ , R ３ , R ４ , and R ５ One or two of these have a Hammett substituent constant σp which is more preferably 0.30 or greater, and even more preferably 0.50 or greater. １ , R ２ , R ３ , R ４ , and R ５ In one or two of these, the Hammett substituent constant σp is not particularly limited, but may be 4.0 or less, 3.0 or less, 2.0 or less, 1.0 or less, or 0.90 or less.

[0097] In formula (I), R １ , R ２ , R ３ , R ４ and R ５ The sum of Hammett substituent constants σp is preferably 0.5 or more and 1.80 or less. In formula (I), R １ , R ２ , R ３ , R ４ and R ５ The sum of Hammett substituent constants σp is more preferably 0.70 or higher, and even more preferably 0.90 or higher. In formula (I), R １ , R ２ , R ３ , R ４ and R ５ The sum of Hammett substituent constants σp is more preferably 1.60 or less, and even more preferably 1.40 or less.

[0098] From the same viewpoint as above, in equation (I), R ６ and R ７At least one of them preferably has a Hammett substituent constant σp of 0.10 or higher, more preferably 0.30 or higher, and even more preferably 0.50 or higher. ６ and R ７ At least one of these is such that the Hammett substituent constant σp is not particularly limited, but may be 2.0 or less, 1.0 or less, or 0.90 or less.

[0099] Examples of halogen atoms and monovalent groups with Hammett substituent constant σp of 0.10 or higher include chlorine atom (σp: 0.227), bromine atom (σp: 0.232), iodine atom (σp: 0.180), cyano group (σp: 0.660), nitro group (σp: 0.778), trifluoromethyl group (σp: 0.540), sulfonylmethyl group (σp: 0.728), sulfonylamino group (σp: 0.570), and carboxyl group (σp: 0.450).

[0100] In equation (I) below, R １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７ Here are some examples of combinations.

[0101]

[0102]

[0103]

[0104]

[0105]

[0106] Specific examples of compound (I) are given below. However, compound (I) is not limited to these examples.

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114] (Compound (V)) Compound α may also preferably contain a compound represented by the following formula (V) (also referred to as compound (V)).

[0115]

[0116] R １ , R ２ , R ３ , R ４ , and R ５ Each is independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a thiol group, an amino group, a cyano group, a carboxyl group, a nitro group, and optionally substituted linear, branched or cyclic alkyl groups, thioalkyl groups, thioaryl groups, arylsulfonyl groups, aryloxy groups, alkylsulfonyl groups, alkylamino groups, arylamino groups, alkoxy groups, acylamino groups, acyloxy groups, aryl groups, carboxyamide groups, carboalkoxy groups, carboaryloxy groups, acyl groups, and monovalent heterocyclic groups, R １ , R ２ , R ３ , R ４ and R ５ One or more of these are halogen atoms or monovalent organic groups with a Hammett substituent constant σp of 0.10 or greater. ６ and R ７ Each of these is independently a hydrogen atom, a halogen atom, or a monovalent organic group, and R ６ and R ７ One or more of them are a halogen atom or a monovalent organic group with a Hammett substituent constant σp of 0.10 or greater, and any adjacent R １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７This may be part of a fused ring, and the fused ring may contain one or more atoms other than carbon atoms.

[0117] From the viewpoint of achieving the effects of this embodiment more effectively and reliably, R ６ and R ７ Preferably, each of these is independently selected from the group consisting of a hydrogen atom, a fluorine atom, a hydroxyl group, a thiol group, an amino group, a cyano group, a carboxyl group, a nitro group, and a linear, branched, or cyclic alkyl group, thioalkyl group, thioaryl group, arylsulfonyl group, aryloxy group, alkylsulfonyl group, alkylamino group, arylamino group, alkoxy group, acylamino group, acyloxy group, aryl group, carboxyamide group, carboalkoxy group, carboaryloxy group, acyl group, and a monovalent heterocyclic group, which may have substituents.

[0118] Compound (V) can suppress leakage current in the dark and has excellent wavelength selectivity, exhibiting particularly excellent properties as a photoelectric conversion element material. The reason for this is not clear, but the inventors believe it to be as follows. However, the reason is not limited to the following. In other words, compound (V) contains substituents having the above-mentioned Hammett substituent constant σp, and has a structure with an extended π-conjugated system, which lowers the energy level of the lowest unoccupied orbital, suppresses leakage current in the dark, and exhibits excellent wavelength selectivity.

[0119] In compound (V), R １ , R ２ , R ３ , R ４ , and R ５ While not particularly limited, it is more preferable to select from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group, and a linear, branched, or cyclic alkyl group which may each have a substituent, and even more preferable to select from the group consisting of a hydrogen atom, a halogen atom, a nitro group, a cyano group, and an alkyl group substituted with a halogen atom.

[0120] In compound (V), R １ , R ２ , R ３ , R ４and R ５ They may be the same or different. From the viewpoint of achieving the effects of this embodiment more effectively and reliably, R is not particularly limited, but １ , R ２ , R ３ , R ４ and R ５ Preferably, at least two selected from are the same, R １ , R ２ , R ３ , R ４ and R ５ It is more preferable that at least three of those selected are identical.

[0121] Compound (V) is not particularly limited, but from the viewpoint of achieving the effects of this embodiment more effectively and reliably, R １ , R ２ , R ３ , R ４ and R ５ Preferably, at least one of them is not a hydrogen atom, R １ , R ２ , R ３ , R ４ and R ５ It is more preferable that at least one of is selected from the group consisting of halogen atoms, nitro groups, cyano groups, and linear, branched, or cyclic alkyl groups which may have substituents, R １ , R ２ , R ３ , R ４ and R ５ It is even more preferable that at least one of is selected from the group consisting of halogen atoms, nitro groups, cyano groups, and alkyl groups substituted with halogen atoms. Also, at least R １ However, it is preferable that the group be selected from the group consisting of halogen atoms, nitro groups, cyano groups, and alkyl groups substituted with halogen atoms, and more preferably a cyano group.

[0122] In compound (V), R ６ and R ７While not particularly limited, each is preferably independently selected from the group consisting of a hydrogen atom, a fluorine atom, a hydroxyl group, a thiol group, an amino group, a cyano group, a carboxyl group, a nitro group, and optionally substituted linear, branched, or cyclic alkyl groups, thioalkyl groups, thioaryl groups, arylsulfonyl groups, aryloxy groups, alkylsulfonyl groups, alkylamino groups, arylamino groups, alkoxy groups, acylamino groups, acyloxy groups, aryl groups, carboxyamide groups, carboalkoxy groups, carboaryloxy groups, acyl groups, and monovalent heterocyclic groups; more preferably selected from the group consisting of a hydrogen atom, a fluorine atom, a nitro group, a cyano group, and optionally substituted linear, branched, or cyclic alkyl groups; and even more preferably selected from the group consisting of a hydrogen atom, a fluorine atom, a nitro group, a cyano group, and alkyl groups substituted with halogen atoms.

[0123] In compound (V), R １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７ The preferred Hammett substituent constant σp is the same as that for compound (I).

[0124] In compound (V) of this embodiment, R ６ and R ７ They may be the same or different.

[0125] Below, in compound (V), R １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７ This shows the preferred combination.

[0126]

[0127] Specific examples of compound (V) are shown below. However, compound (V) is not limited to these examples.

[0128]

[0129] (Compound (VI)) Compound α may also preferably contain a compound represented by the following formula (VI) (also referred to as compound (VI)).

[0130]

[0131] X is independently selected from the group consisting of methine groups and nitrogen atoms, and m is an integer between 0 and 3. ８ , R ９ , R １０ , R １１ and R １２ Each of these is independently a hydrogen atom, a halogen atom with a Hammett substituent constant σp less than 0.10, or a monovalent organic group with a Hammett substituent constant σp less than 0.10. １３ and R １４ Each of these is independently a hydrogen atom, a halogen atom, or a monovalent organic group, and R １３ and R １４ One or more of these are halogen atoms or monovalent organic groups with Hammett substituent constant σp of 0.10 or greater. Any adjacent R ８ , R ９ , R １０ , R １１ , R １２ , R １３ and R １４ This may be part of a fused ring, and the fused ring may contain one or more atoms other than carbon atoms.

[0132] Compound (VI) is particularly useful when used in image sensors because it can suppress leakage current in the dark and has excellent wavelength selectivity. The reason for this is not clear, but the inventors believe it to be as follows. However, the reason is not limited to the following. In other words, compound (VI) contains substituents having the above-mentioned Hammett substituent constant σp and has a structure with an extended π-conjugated system, which lowers the energy level of the lowest unoccupied orbital, suppresses leakage current in the dark, and has excellent wavelength selectivity.

[0133] Compound (VI) is R ８ , R ９ , R １０ , R １１ and R１２ However, each is independently a hydrogen atom, a halogen atom with a Hammett substituent constant σp less than 0.10, or a monovalent organic group with a Hammett substituent constant σp less than 0.10, R １３ and R １４ Except that R may be a fluorine atom, the specific embodiments and preferred embodiments are the same as those of compound (I). That is, in formula (VI) R １３ and R １４ R in equation (1) is ６ and R ７ It corresponds to.

[0134] Examples of monovalent groups with Hammett substituent constant σp less than 0.1 include fluorine atoms (σp: 0.062), methyl groups (σp: -0.170), methoxy groups (σp: -0.268), amino groups (σp: -0.660), and hydroxyl groups (σp: -0.370).

[0135] The energy levels of the lowest unoccupied molecular orbitals (LUMOs) obtained by density functional theory for compounds (I), (V), and (VI) (hereinafter also simply referred to as "compounds (I), (V), and (VI)") are preferably between -6.00 eV and -3.60 eV, and more preferably between -5.50 eV and -3.65 eV, from the viewpoint of more effectively and reliably achieving the effects of this embodiment. For compounds (I), (V), and (VI) of this embodiment, structural optimization can be performed by molecular simulation using density functional theory (for example, molecular simulation using the quantum chemistry calculation program Gaussian from Gaussian, Inc.) to determine the energy levels of the lowest unoccupied orbitals. Furthermore, the energy levels of the lowest unoccupied orbitals obtained by density functional theory for compounds (I), (V), and (VI) are not particularly limited, however R １ ~R ７ Ya R ８ ~R １４ This may be adjusted by changing R. With respect to the energy levels of the lowest unoccupied orbitals of each of the above compounds being within the above range, compounds (I), (V), and (VI) may have R, although this is not particularly limited. １ , R２ , R ３ , R ４ , R ５ , R ６ and R ７ , or R ８ , R ９ , R １０ , R １１ , R １２ , R １３ and R １４ Preferably, at least one of them is an electron-withdrawing group, R １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７ , or R ８ , R ９ , R １０ , R １１ , R １２ , R １３ and R １４ At least one of the members is more preferably a cyano group or an alkyl group substituted with a halogen atom.

[0136] The difference (eV) between the energy level of the lowest unoccupied orbital and the energy level of the highest occupied molecular orbital (HOMO) obtained by density functional theory of compounds (I), (V), and (VI) is preferably 2.85 eV to 4.00 eV. By keeping the energy level difference within the above range, it tends to reduce leakage current in the dark when used as a photoelectric conversion element material.

[0137] Compounds (I), (V), and (VI) preferably have a molecular weight of 350 or more, more preferably 370 or more, and even more preferably 390 or more. A molecular weight of 350 or more can further suppress changes in physical properties caused by thermal motion of molecules that may occur during heating operations in the manufacturing process of organic thin films using compounds (I), (V), and (VI) or in high-temperature operating environments. In particular, when compounds (I), (V), and (VI) are formed by vacuum deposition, the molecular weight of compounds (I), (V), and (VI) is preferably 1000 or less, more preferably 950 or less, and even more preferably 900 or less. A molecular weight of 1000 or less can further reduce the thermal energy required for sublimation when forming organic thin films of compounds (I), (V), and (VI) by vacuum deposition. As a result, compounds (I), (V), and (VI) do not degrade due to heat, and good thin films can be formed. However, when thin films are formed by solution coating, such problems are unlikely to occur, so the molecular weights of compounds (I), (V), and (VI) may be greater than 1000.

[0138] It is preferable that compounds (I), (V), and (VI) have a temperature at which their mass decreases by 5% from their mass before heating (hereinafter also referred to as the "5% mass loss temperature"), measured under the following condition 1, that is between 430°C and 550°C. When the 5% mass loss temperature is within the above range, changes in physical properties caused by thermal motion of molecules that may occur during heating operations in the manufacturing process of organic thin films using compounds (I), (V), and (VI) or in high-temperature operating environments can be further suppressed. (Condition 1) Pressure: 0.10 MPa Nitrogen: 200 mL / min Heating conditions: Heating from 20°C to 550°C at a rate of 10°C / min

[0139] Compounds (I), (V), and (VI) can be synthesized, for example, by the following scheme. Note that compound (VI) is R in the following scheme. １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７ R ８ , R ９ , R １０ , R １１ , R１２ , R １３ and R １４ You can replace it with this.

[0140]

[0141] More specifically, compound (C) can be obtained by an imide reaction using compound (B) from a commercially available (A), for example. Furthermore, compound (E) can be obtained by an addition reaction of compound (D). More specifically, it can be synthesized by referring to the method described in Japanese Patent Publication No. 2014-520394, for example. Also, R １ ~R ７ The imide reaction and addition reaction may be carried out using the compound into which R has been introduced, and after the imide reaction and addition reaction, R may be used. １ ~R ７ It may be introduced.

[0142] Compounds (I), (II), (III), (IV), (V), and (VI) of this embodiment are obtained, for example, by synthesis as described above. In the product obtained by synthesis (100% by mass), the content of compounds (I) to (VI) is preferably 90% by mass or more, more preferably 93% by mass, and even more preferably 97% by mass or more. By having a content of 90% by mass or more of the above compounds, when the above compounds are used in a photoelectric conversion element or image sensor, the trapping of carriers to impurity levels caused by unintended impurities can be more effectively and reliably avoided. As a result, carrier recombination can be suppressed, and a photoelectric conversion element or image sensor with superior performance can be obtained. The content can be measured by liquid chromatography, gas chromatography, elemental analysis, etc., but any known method is acceptable.

[0143] Compound α is suitably used as a photoelectric conversion element material and is included in the auxiliary layer (C). Furthermore, compound α only needs to be included in the auxiliary layer (C); it can also be included in other layers. It is preferable that compound α is included in the auxiliary layer and in at least one of the electron transport layer and the hole blocking layer.

[0144] Furthermore, compound α can be used as is as a photosensitive material, or it can be mixed with other materials to form a photosensitive composition. The content of compound α in the photosensitive composition may be 50% by mass or more based on the total amount of the composition. The content of compound α in the photosensitive composition may be 95% by mass or less, 90% by mass or less, or 80% by mass or less based on the total amount of the composition. The materials other than compound α in the above photosensitive composition are not particularly limited as long as they are included in a normal photosensitive composition. Examples of such materials include n-type semiconductor materials, p-type semiconductor materials, and light-absorbing materials, which will be described later. These can be used individually or in combination of two or more.

[0145] In this embodiment, the thickness of the auxiliary layer (C) of the photoelectric conversion element is preferably 1 nm to 1000 nm, preferably 3 nm to 300 nm, and preferably 5 nm to 150 nm. When the photoelectric conversion element of this embodiment includes a plurality of auxiliary layers (C), "thickness of the auxiliary layer (C)" refers to the thickness of each auxiliary layer (C) unless otherwise specified. When the photoelectric conversion element includes a plurality of auxiliary layers (C), "the thickness of the auxiliary layer (C) is 1 nm to 1000 nm" means that the thickness of all auxiliary layers (C) is 1 nm to 1000 nm. When the photoelectric conversion element of this embodiment includes a plurality of auxiliary layers (C), the thickness of each auxiliary layer (C) may be the same or different, and can be set independently depending on the position in which each auxiliary layer (C) is arranged.

[0146] In one embodiment of this design, the first auxiliary layer 103 may be a single layer or two or more layers. The first auxiliary layer 103 may comprise at least one of a hole blocking layer and an electron transport layer. When the first auxiliary layer 103 comprises two of these, they are usually stacked in the order of electron transport layer and hole blocking layer, starting from the photoelectric conversion layer 104 side. The electron transport layer plays the role of transporting electrons generated in the photoelectric conversion layer 104 to the first electrode 102 and blocking the movement of holes from the first electrode 102 to the photoelectric conversion layer 104. The hole blocking layer prevents the movement of holes from the first electrode 102 to the photoelectric conversion layer 104, prevents recombination within the photoelectric conversion layer 104, reduces dark current, reduces noise, and expands the dynamic range. Alternatively, one layer may have both the functions of a hole blocking layer and an electron transport layer.

[0147] The thickness of the first auxiliary layer 103 is preferably 5 nm to 300 nm, more preferably 7 nm to 250 nm, and even more preferably 10 nm to 200 nm, from the viewpoint of suppressing dark current and improving photoelectric conversion efficiency.

[0148] In one embodiment of this design, the second auxiliary layer 105 may be a single layer or two or more layers. The second auxiliary layer 105 may comprise at least one of an electron blocking layer and a hole transport layer. When the second auxiliary layer 105 comprises two of these, they are usually stacked in the order of a hole transport layer and an electron blocking layer, starting from the photoelectric conversion layer 104 side. The hole transport layer plays the role of transporting generated holes from the photoelectric conversion layer 104 to the second electrode 106 and blocking the movement of electrons from the second electrode 106 to the photoelectric conversion layer 104. The electron blocking layer prevents the movement of electrons from the second electrode 106 to the photoelectric conversion layer 104, prevents recombination within the photoelectric conversion layer 104, reduces dark current, reduces noise, and expands the dynamic range. Alternatively, one layer may have both the functions of an electron blocking layer and a hole transport layer.

[0149] The thickness of the second auxiliary layer 105 is preferably 5 nm to 200 nm, more preferably 7 nm to 130 nm, and even more preferably 10 nm to 100 nm, from the viewpoint of suppressing dark current and improving photoelectric conversion efficiency.

[0150] In one embodiment of this design, the third auxiliary layer 107 is an auxiliary layer closer to the upper electrode 106 than the second auxiliary layer 105, and may be, for example, a hole blocking layer. The hole blocking layer prevents the movement of holes from the second electrode 106 to the photoelectric conversion layer 104, prevents recombination within the photoelectric conversion layer 104, reduces dark current, reduces noise, and expands the dynamic range. At least one of the layers located between the photoelectric conversion layer 104 and the upper electrode 106 may have the functions of both a hole blocking layer and an electron transport layer.

[0151] The thickness of the third auxiliary layer 107 is preferably 5 nm to 200 nm, more preferably 7 nm to 130 nm, and even more preferably 10 nm to 100 nm, from the viewpoint of suppressing dark current and improving photoelectric conversion efficiency.

[0152] The material for the photoelectric conversion element of this embodiment may be included in any of the first auxiliary layer 103, the second auxiliary layer 105, and the third auxiliary layer 107, but it is preferable that it be included in the first auxiliary layer 103 and / or the third auxiliary layer 107. In the photoelectric conversion element of this embodiment, it is preferable that the first auxiliary layer 103 and / or the third auxiliary layer 107 contain the above-mentioned organic thin film. Furthermore, it is even more preferable that the material for the photoelectric conversion element of this embodiment is included in at least one of the hole blocking layer and the electron transport layer in the first auxiliary layer 103 and / or the third auxiliary layer 107. In the photoelectric conversion element of this embodiment, it is preferable that at least one of the hole blocking layer and the electron transport layer is the above-mentioned organic thin film. These features allow the effects of this embodiment to be achieved more effectively and reliably.

[0153] In one aspect of this embodiment, compound α of this embodiment may be included in at least the third auxiliary layer 107 among these auxiliary layers. The third auxiliary layer 107 may contain materials other than compound α. The content of compound α in the third auxiliary layer 107 is not particularly limited as long as it exhibits the performance necessary for use as an auxiliary layer close to the upper electrode 106. For example, its content may be 50% by mass or more of the total amount of the third auxiliary layer 107, but from the viewpoint of more effectively and reliably achieving the effect of suppressing leakage current in the dark according to this embodiment, it is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The upper limit of its content may be 100% by mass.

[0154] The material for the hole transport layer is not particularly limited as long as it is known as a hole transport layer in photoelectric conversion elements such as solid-state image sensors. Examples include polyaniline and its doping materials, and cyanide compounds described in International Publication No. 2006 / 019270.

[0155] More specifically, the materials that constitute the hole transport layer include selenium, iodides such as copper iodide (CuI), cobalt complexes such as layered cobalt oxide, CuSCN, and molybdenum oxide (MoO ３ (etc.), nickel oxide (NiO etc.), 4CuBr・3S (C ４ H ９ Examples include iodides and organic hole transporters. Among these, copper iodide (CuI) is an example of an iodide. Examples of layered cobalt oxides include AxCoO ２(Here, A represents Li, Na, K, Ca, Sr, or Ba, and 0 ≤ X ≤ 1.) Examples of organic hole transporters include polythiophene derivatives such as poly-3-hexylthiophene (P3HT), poly(3,4-ethylenedioxythiophene), (PEDOT; for example, the trade name "Baytron P" from Starck Vitek), fluorene derivatives such as 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-MeO-TAD), carbazole derivatives such as polyvinylcarbazole, triphenylamine derivatives, diphenylamine derivatives, polysilane derivatives, and polyaniline derivatives. Furthermore, as a material for the hole transport layer, for example, CuInSe ２ and compound semiconductors having monovalent copper such as copper sulfide (CuS), gallium phosphide (GaP), nickel oxide (NiO), cobalt oxide (CoO), iron oxide (FeO), bismuth oxide (Bi ２ O ３ ), molybdenum oxide (MoO ２ ), and chromium oxide (Cr ２ O ３ ) are some examples.

[0156] Furthermore, it is preferable that the hole transport layer has a LUMO level higher than the LUMO level of the photoelectric conversion layer, as this provides an electron blocking function that has a rectifying effect, suppressing the movement of electrons generated in the photoelectric conversion layer toward the electrodes. Such a hole transport layer is also called an electron blocking layer.

[0157] Among the materials constituting the electron blocking layer, low molecular weight organic compounds include, for example, aromatic diamine compounds such as N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD) and 4,4'-bis[N-(naphthyl)-N-phenyl-amino]biphenyl (α-NPD), oxazole, oxadiazole, triazole, imidazole, imidazolon, stilbene derivatives, pyrazoline derivatives, tetrahydroimidazole, polyarylalkane, butadiene, and 4,4',4''tris(N-(3-methylphenyl)N-phenyl Examples of porphyrin compounds include porphyrin (m-MTDATA), tetraphenylporphyrin copper, phthalocyanine, copper phthalocyanine, and titanium phthalocyanine oxide; triazole derivatives, oxadizaazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, and silazane derivatives. Examples of polymeric organic compounds include polymers such as phenylenevinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, as well as their derivatives. Even if a compound is not electron-donating, if it has sufficient hole transport properties, it can be used as a material to constitute the electron blocking layer. Furthermore, examples of inorganic compounds among the materials constituting the electron blocking layer include metal oxides such as calcium oxide, chromium oxide, chromium copper oxide, manganese oxide, cobalt oxide, nickel oxide, copper oxide, gallium copper oxide, strontium copper oxide, niobium oxide, molybdenum oxide, indium copper oxide, indium silver oxide, and iridium oxide, as well as selenium, tellurium, and antimony sulfide. These can be used individually or in combination of two or more.

[0158] From the viewpoint of suppressing dark current and improving photoelectric conversion efficiency, the thickness of the hole transport layer is preferably 10 nm to 300 nm, more preferably 30 nm to 250 nm, and even more preferably 50 nm to 200 nm.

[0159] The method for forming the hole transport layer and electron blocking layer may be any conventionally known method, and may be either a dry film formation method such as vacuum deposition or a wet film formation method such as solution coating. However, from the viewpoint of being able to level the coated surface, a wet film formation method is preferred. Examples of dry film formation methods include vapor deposition methods such as vacuum deposition and sputtering. Vacuum deposition may be either physical vapor deposition (PVD) or chemical vapor deposition (CVD), but physical vapor deposition such as vacuum deposition is preferred. Examples of wet film formation methods include inkjet, spray, nozzle print, spin coat, dip coat, cast, die coat, roll coat, bar coat, and gravure coat.

[0160] The materials constituting the electron transport layer are not particularly limited as long as they are known as electron transport layers in photoelectric conversion elements such as solid-state image sensors, and include, for example, octa-azaporphyrin, perfluoro compounds of p-type semiconductors (e.g., perfluoropentacene and perfluorophthalocyanine), fullerenes, fullerene derivatives (e.g., [6,6]-Phenyl-C61-Butyric Acid Methyl Ester; PCBM, etc.), perylene, organic compounds such as indenoindene and indenoindene derivatives, and titanium dioxide (TiO2). ２ (etc.), nickel oxide (NiO), tin oxide (SnO) ２ ), tungsten oxide (WO ２ WO ３ , W ２ O ３ (etc.), zinc oxide (ZnO), niobium oxide (Nb ２ O ５ (e.g.), tantalum oxide (Ta ２ O ５ (etc.), yttrium oxide (Y ２ O ３ (etc.), and strontium titanate (SrTiO) ３Examples of inorganic oxides include those such as (etc.). The electron transport layer may be porous or dense, and when stacking them, it is preferable to stack the porous electron transport layer and the dense electron transport layer in that order from the photoelectric conversion layer side.

[0161] Furthermore, it is preferable that the electron transport layer has a HOMO level lower than the HOMO level of the photoelectric conversion layer, as this provides a hole blocking function that has a rectifying effect that suppresses the movement of holes generated in the photoelectric conversion layer toward the opposing electrode. Such an electron transport layer is also called a hole blocking layer.

[0162] Materials that constitute the hole blocking layer include, for example, oxadiazole derivatives such as 1,3-bis(4-tert-butylphenyl-1,3,4-oxadiazolyl)phenylene (OXD-7), anthraquinodimethane derivatives, diphenylquinone derivatives, vasocuproin, vasophenanthroline, and their derivatives, triazine compounds, triazole compounds, tris(8-hydroxyquinolinate)aluminum complexes, bis(4-methyl-8-quinolinate)aluminum complexes, silole compounds, and porphyrins. Examples include styrene compounds, styryl compounds such as DCM (4-dicyanomethylene-2-methyl-6-(4-(dimethylaminostyryl))-4Hpyran), n-type semiconductor materials such as naphthalenetetracarboxylic anhydride (NTCDA), naphthalenetetracarboxylic diimide, perylenetetracarboxylic anhydride (PTCDA), and perylenetetracarboxylic diimide, n-type inorganic oxides such as titanium dioxide, zinc oxide, and gallium oxide, and alkali metal fluorides such as lithium fluoride, sodium fluoride, and cesium fluoride. Furthermore, alkali metal compounds doped into organic semiconductor molecules are also preferred because they have the function of improving the electrical junction with the counter electrode. These can be used individually or in combination of two or more.

[0163] From the viewpoint of suppressing dark current and improving photoelectric conversion efficiency, the thickness of the electron transport layer is preferably 10 nm to 300 nm, more preferably 30 nm to 250 nm, and even more preferably 50 nm to 200 nm.

[0164] The method for forming the electron transport layer and hole blocking layer may be any conventionally known method, and may be either a dry film formation method such as vacuum deposition or a wet film formation method such as solution coating. However, from the viewpoint of being able to level the coated surface, a wet film formation method is preferred. Examples of dry film formation methods include vapor deposition methods such as vacuum deposition and sputtering. Vacuum deposition may be either physical vapor deposition (PVD) or chemical vapor deposition (CVD), but physical vapor deposition such as vacuum deposition is preferred. Examples of wet film formation methods include inkjet, spray, nozzle print, spin coat, dip coat, cast, die coat, roll coat, bar coat, and gravure coat.

[0165] The photoelectric conversion element of this embodiment may include a single or two or more auxiliary layers between the first auxiliary layer 103 and the lower electrode 102, separate from the first auxiliary layer 103. Examples of such auxiliary layers include hole injection layers that improve hole injection from the lower electrode 102 to the first auxiliary layer 103. Examples of materials constituting the hole injection layer include phthalocyanine derivatives, starburst amines such as m-MTDATA (4,4',4''-tris[phenyl(m-tolyl)amino]triphenylamine), polythiophenes such as PEDOT (poly(3,4-ethylenedioxythiophene)), and polymeric materials such as polyvinylcarbazole derivatives. The thickness of this auxiliary layer may be the same as that of the first auxiliary layer 103.

[0166] In this embodiment, the photoelectric conversion element may include a single or multi-layer auxiliary layer between the second auxiliary layer 105 and the upper electrode 106, separate from the second auxiliary layer 105. Examples of such auxiliary layers include an electron injection layer that improves electron injection from the upper electrode 106 to the second auxiliary layer 105, and an electron transport layer. Examples of materials constituting the electron injection layer include metals such as cesium, lithium, and strontium, as well as lithium fluoride. The materials constituting the electron transport layer may be the same as those described above. Furthermore, the thickness of this auxiliary layer may be the same as that of the second auxiliary layer 105.

[0167] In this embodiment, the photoelectric conversion element may include a single or two or more auxiliary layers between the third auxiliary layer 107 and the upper electrode 106, separate from the second auxiliary layer 105 and the third auxiliary layer 107. Examples of such auxiliary layers include an electron injection layer that improves the electron injection from the upper electrode 106 to the third auxiliary layer 107, and an electron transport layer. Examples of materials constituting the electron injection layer include metals such as cesium, lithium, and strontium, as well as lithium fluoride. The material constituting the electron transport layer may be the same as described above. Furthermore, the thickness of this auxiliary layer may be the same as that of the second auxiliary layer 105.

[0168] Each layer and film included in the photoelectric conversion element of this embodiment may be an organic thin film. Organic thin films can be fabricated by general dry or wet deposition methods. Specifically, examples include vacuum processes such as resistance heating evaporation, electron beam evaporation, sputtering, and molecular stacking; solution processes such as casting, spin coating, dip coating, blade coating, wire bar coating, and spray coating; printing methods such as inkjet printing, screen printing, offset printing, and letterpress printing; and soft lithography methods such as microcontact printing. Generally, from the viewpoint of ease of processing, it is desirable that materials for photoelectric conversion elements be used in processes that involve coating compounds in a solution state. However, in the case of photoelectric conversion elements in which organic thin films are stacked, dry deposition methods such as resistance heating evaporation are preferred because the coating solution may damage the underlying film.

[0169] For example, in a dry deposition method, an organic thin film can be obtained by mixing a material for photoelectric conversion elements (for example, compound α in this embodiment) and, if necessary, other materials depending on the application of the photoelectric conversion element to form a composition, and then depositing the composition onto a substrate or other film under vacuum. Alternatively, in a wet deposition method, an organic thin film can be obtained by coating the above composition onto a substrate or other film, printing it, and then drying it.

[0170] The organic thin film of this embodiment may contain materials other than compound α, which is a material for photoelectric conversion elements. The content of compound α in the organic thin film of this embodiment is not particularly limited as long as it exhibits the performance necessary for use as a material for photoelectric conversion elements. For example, the content of compound α may be 50% by mass or more of the total amount of the organic thin film, but from the viewpoint of more effectively and reliably achieving the effects of this embodiment, it is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The upper limit of the content of compound α may be 100% by mass.

[0171] If the organic thin film of this embodiment contains materials other than compound α, those materials are not particularly limited as long as they are commonly used as materials for photoelectric conversion elements. Examples of such materials include n-type semiconductor materials, p-type semiconductor materials, and light-absorbing materials, as well as molybdenum oxide, alkali metals, and alkali metal compounds, which are called doping materials. These can be used individually or in combination of two or more.

[0172] The thickness of the organic thin film cannot be limited as it depends on the resistance and charge mobility of each material, but it is usually between 0.5 nm and 5000 nm, and may also be between 1 nm and 1000 nm, or between 5 nm and 500 nm.

[0173] In addition to the layers described above, the photoelectric conversion element of this embodiment may also include at least one of the interlayer contact improvement layer and crystallization prevention layer located between those layers.

[0174] The interlayer contact improvement layer serves to reduce damage to the immediately below the upper electrode 106, such as the photoelectric conversion layer 104, during film formation of the upper electrode 106. In particular, high-energy particles present in the apparatus used for film formation of the upper electrode 106, such as sputtered particles, secondary electrons, Ar particles, and oxygen negative ions in the sputtering method, can collide with the immediately below film, causing alteration and potentially leading to performance degradation such as increased leakage current and decreased sensitivity. One way to prevent this is to provide an interlayer contact improvement layer on top of the immediately below film. Preferably, the interlayer contact improvement layer is made of organic substances such as copper phthalocyanine, NTCDA, PTCDA, [dipyradino[2,3-F:2',3'-H]quinoxaline-2,3,6,7,10,11-hexacarbonitride] (HATCN), acetylacetonate complexes, BCP, organometallic compounds, or inorganic substances such as MgAg and MgO. The appropriate thickness of the interlayer contact improvement layer varies depending on the composition of each layer and the thickness of the electrodes, but it is preferable that it be between 2 nm and 500 nm, particularly from the viewpoint of selecting a material that does not absorb in the visible range or from the viewpoint of using a thin thickness.

[0175] As described above, the photoelectric conversion element of this embodiment is connected to a storage unit, which is a capacitor for storing the generated charge, and a readout unit, which is a transistor circuit for reading the charge, via a connection part made of a conductive material. In addition, the photoelectric conversion element may include a protective structure from the outside air, such as a protective film, a substrate for maintaining strength, and microlenses for focusing light, if necessary.

[0176] The readout unit is provided to read out a signal corresponding to the charge generated in the photoelectric conversion layer. The readout unit is composed of, for example, a CCD, CMOS circuit, or TFT circuit, and is preferably shielded from light by a light-shielding layer placed within the insulating layer. The readout circuit is electrically connected to the corresponding electrode via a connector. In addition, to secure the amount of charge necessary for reading, a storage unit composed of a capacitor or the like may be interposed between the electrode and the connector. The connector is embedded in the insulating layer and is a plug or the like for electrically connecting the electrode (for example, a transparent electrode or a counter electrode) and the readout unit. When the component configured in this way is a solid-state image sensor, when light is incident, this light is incident on the photoelectric conversion layer, and charge is generated there. Electrons of the generated charge are collected (and stored) by one electrode, and holes are collected by the other electrode. A voltage signal corresponding to the amount is output to the outside of the solid-state image sensor by the readout unit.

[0177] (Image Sensor) The image sensor of this embodiment is equipped with the photoelectric conversion element of this embodiment. In one aspect of this embodiment, the image sensor of this embodiment may have the same configuration as a conventional image sensor, as long as it is equipped with the photoelectric conversion element of this embodiment. For example, the image sensor of this embodiment may have multiple photoelectric conversion elements arranged in an array. By arranging a large number of photoelectric conversion elements in an array, a solid-state image sensor can be configured that indicates not only the amount of incident light but also the incident position information.

[0178] The image sensor of this embodiment may be a laminate containing one of the photoelectric conversion elements of this embodiment, or a laminate containing two or more of them. When the image sensor of this embodiment is a laminate containing two or more of the photoelectric conversion elements of this embodiment, each photoelectric conversion element may selectively detect light in different wavelength bands and perform photoelectric conversion. For example, when the laminate contains three or more of the photoelectric conversion elements of this embodiment, at least one may acquire a green color signal, another at least one may acquire a blue color signal, another at least one may acquire a red color signal, and yet another at least one may acquire an infrared color signal. As a result, the image sensor can acquire multiple types of color signals in a single pixel without using a color filter. In addition, color signals other than those detected by the photoelectric conversion elements of this embodiment may be sensed by a conventionally known device having a silicon photodiode.

[0179] In an image sensor, if a photoelectric conversion element positioned closer to the light source does not block (i.e., transmit) the absorption wavelength of another photoelectric conversion element positioned behind it as viewed from the light source side, then a device having multiple photoelectric conversion elements or silicon photodiodes may be stacked.

[0180] In an image sensor, from the viewpoint of ease of molding, some of the photoelectric conversion elements may be configured as thin films on the same plane without structural separations between adjacent photoelectric conversion elements.

[0181] The image sensor of this embodiment may further include a substrate. The substrate may be used to manufacture the image sensor by laminating each layer thereon, or to increase the mechanical strength of the image sensor. The type of substrate is not particularly limited, and examples include semiconductor substrates, glass substrates, and plastic substrates.

[0182] (Optical Sensor) The optical sensor of this embodiment includes the image sensor of this embodiment. The optical sensor of this embodiment only needs to include the image sensor of this embodiment, and other configurations may be the same as those of a conventional optical sensor. This optical sensor can receive light with the image sensor of this embodiment and output an electrical signal corresponding to the amount of light received.

[0183] (Solid-State Imaging Device) The solid-state imaging device of this embodiment includes the image sensor of this embodiment. The solid-state imaging device of this embodiment only needs to include the image sensor of this embodiment, and other configurations may be the same as those of a conventional solid-state imaging device. The solid-state imaging device of this embodiment may be, for example, a CMOS image sensor, and may include a pixel section as an imaging area on a semiconductor substrate, and further may include a peripheral circuit section having a row scanning section, a horizontal selection section, a column scanning section, and a system control section in the peripheral region or vertically below the pixel section. The pixel section has the image sensor of this embodiment.

[0184] The photoelectric conversion element of this embodiment has the following advantages by using the photoelectric conversion element material of this embodiment. Specifically, the photoelectric conversion element of this embodiment is less prone to short circuits and pinhole formation, resulting in a lower dark current value. As a result, the photoelectric conversion element of this embodiment has excellent leakage prevention properties (especially in the dark). Furthermore, the photoelectric conversion element of this embodiment tends to exhibit a high light-dark ratio, in which case it has even better leakage prevention properties. In addition, the photoelectric conversion element of this embodiment has excellent hole and electron transport properties despite the photoelectric conversion element material being less prone to aggregation, resulting in higher photoelectric conversion efficiency. Furthermore, by using the photoelectric conversion element material of this embodiment, the photoelectric conversion element of this embodiment also has good heat resistance, improving durability in the manufacturing process and in practical environments.

[0185] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0186] <Synthesis Example 1>

[0187] 6.0 g of 1,4,5,8-naphthalenetetracarboxylic dianhydride (1) (manufactured by Tokyo Chemical Industry Co., Ltd.) and 2.1 g of aniline (manufactured by Tokyo Chemical Industry Co., Ltd.) (1.0 molar equivalent to anhydride (1)) were added to 90 mL of N,N-dimethylformamide (manufactured by Tokyo Chemical Industry Co., Ltd.), and the resulting mixture was stirred at 150°C for 8 hours. After that, it was cooled to room temperature and the solvent was removed by distillation under reduced pressure. Acetone was added to the solid obtained by distillation, and water was gradually added while stirring, and the precipitate was filtered. After dissolving the precipitate with chloroform, sodium sulfate was added and it was allowed to stand for 30 minutes. Next, the sodium sulfate was filtered, and the solvent was removed by distillation under reduced pressure. Compound (2), a pale yellow solid, was obtained by size exclusion chromatography using chloroform as the eluent.

[0188]

[0189] 3.0 g of compound (2), 1.4 g of diaminomaleonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) (1.5 molar equivalents relative to compound (2)), and 1.6 g of benzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) (1.5 molar equivalents relative to compound (2)) were added to 50 mL of N-methylpyrrolidone (manufactured by Tokyo Chemical Industry Co., Ltd.), and the resulting mixture was stirred at 200°C for 8 hours. After cooling to room temperature, methanol was added, and the precipitated mixture was filtered. Compound (3), an orange solid, was obtained by size exclusion chromatography using chloroform as the eluent. The results of its NMR measurement are shown below. １ HNMR (500MHz, DMSO-d6): 8.85 (dd, 2H), 8.76 (dd, 2H), 7.56 (dm, 2H), 7.51 (dm, 1H), 7.45 (d, 2H)

[0190] <Synthesis Example 2>

[0191] Compound (5) was obtained in the same manner as in Synthesis Example 1, except that 4-aminobenzonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of aniline. The results of its NMR measurement are shown below. １ HNMR (500MHz, DMSO-d6): 8.96 (dd, 2H), 8.77 (dd, 2H), 8.04 (d, 2H), 7.63 (d, 2H)

[0192] <Synthesis Example 3>

[0193] Compound (7) was obtained in the same manner as in Synthesis Example 1, except that 4-aminophthalonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of aniline. The results of its NMR measurement are shown below. １ HNMR (500MHz, DMSO-d6): 9.01 (d, 1H), 8.94 (d, 1H), 8.82 (d, 1H), 8.78 (d, 1H), 8.37 (d, 1H), 8.30 (d, 1H), 8.09 (dd, 1H)

[0194] <Synthesis Example 4>

[0195] Compound (8) was obtained in the same manner as in Synthesis Example 1, except that 5,6-diamino-2,3-dicyanopyrazine (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of diaminomaleonitrile. The results of its NMR measurement are shown below. １ HNMR (500MHz, DMSO-d6): 9.22 (d, 1H), 9.02 (d, 1H), 8.82 (d, 2H), 7.58-7.47 (m, 5H)

[0196] <Synthesis Example 5>

[0197] Compound (10) was obtained in the same manner as in Synthesis Example 1, except that 1,2-diamino-4,5-dichlorobenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of diaminomaleonitrile. The results of its NMR measurement are shown below. １ HNMR (500MHz, DMSO-d6): 9.23 (dd, 2H), 9.07 (dd, 2H), 8.95 (s, 1H), 8.12 (s, 1H), 7.60 to 7.54 (m, 3H), 7.45 to 7.30 (m, 2H)

[0198] [Fabrication and Evaluation of Organic Thin Films and Photoelectric Conversion Elements] In each example and comparative example, organic thin films were fabricated and laminated using a vapor deposition machine to create non-heated photoelectric conversion elements. Heat-treated photoelectric conversion elements were also fabricated by subjecting the non-heated photoelectric conversion elements to a heat treatment at 160°C for 90 minutes. The fabricated photoelectric conversion elements were placed in a measurement chamber, and current and voltage measurements were performed under atmospheric conditions. An automatic IV measuring instrument (manufactured by System Giken Co., Ltd.) was used for current and voltage measurements. Light irradiation was performed using a light source device (manufactured by Asahi Spectroscopic Co., Ltd., product name (PVL-3300)), with an irradiation wavelength of 550 nm, an irradiation width at half maximum of 20 nm, and an illumination intensity of 0.25 mW / cm². ２ The experiment was conducted under the following conditions. The light-dark ratio is the value obtained by dividing the current value when irradiated with light (light current) by the current value in the dark (dark current). Each rate of change is the value obtained by dividing the measured value of the heat-treated photoelectric conversion element by the measured value of the unheat-treated photoelectric conversion element. In addition, in each example and comparative example, the 5% mass loss temperature of compound α is the temperature measured under the conditions of a pressure of 0.10 MPa, nitrogen of 200 mL / min, temperature of 20°C to 550°C, and heating rate of 10°C / min. The 5% mass loss temperature was measured using a thermogravimetric differential thermal analyzer (TG-DTA, STA-7200, manufactured by Hitachi High-Tech Science Corporation).

[0199] (Example 1) Compound (5) [Compound α] was deposited as an auxiliary layer to a thickness of 50 nm on ITO transparent conductive glass (ITO manufactured by Geomatec Co., Ltd., thickness 100 nm) by resistance heating vacuum deposition. Subsequently, boron subphthalocyanine chloride (refined product manufactured by Sigma-Aldrich, purity >99%) was vacuum deposited on top of this to a thickness of 100 nm as a photoelectric conversion layer. On top of the photoelectric conversion layer, aluminum was fabricated as an electrode film to a thickness of 100 nm by vacuum deposition. Two batches were prepared, and one of the batches was heat-treated on a hot plate at 100°C for 60 minutes under a nitrogen atmosphere to obtain a heat-treated photoelectric conversion element. The 5% mass loss temperature of compound (5) is shown in Table 2. For both the heat-treated and unheated photoelectric conversion elements, a voltage of 3V was applied from ITO to aluminum using ITO and aluminum as electrodes, and the current value in the dark (dark current: d ３ａ and d ３ｂ ) and the current value during light irradiation (light current: l３ａ and l ３ｂ The dark current change rate r was measured. From the obtained measurement results, the rate of change r ｄ３ , rate of change of the bright current r ｌ３ , and the rate of change r of the light-dark ratio ｌｄ３ The result was calculated and is shown in Table 2.

[0200] (Example 2) A photoelectric conversion element was fabricated in the same manner as in Example 1, except that compound (7) [compound α] was used instead of compound (5). The 5% mass loss temperature of compound (7) is shown in Table 2. The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0201] (Example 3) A photoelectric conversion element was fabricated in the same manner as in Example 1, except that compound (8) [compound α] was used instead of compound (5). The 5% mass loss temperature of compound (8) is shown in Table 2. The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0202] (Comparative Example 1) A photoelectric conversion element was fabricated in the same manner as in Example 1, except that compound (10) [compound α] was used instead of compound (5). The 5% mass loss temperature of compound (10) is shown in Table 2. The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0203] (Example 4) A 100 nm thick film of boron subphthalocyanine chloride (a refined product from Sigma-Aldrich, purity >99%) was vacuum deposited on an ITO transparent conductive glass (ITO manufactured by Geomatec Co., Ltd.) as a photoelectric conversion layer. Compound (7) [compound α] was then deposited on top of this as an auxiliary layer to a thickness of 10 nm by resistance heating vacuum deposition. Next, an electrode made of aluminum was fabricated on top of the auxiliary layer to a thickness of 100 nm by vacuum deposition. Two batches were prepared, and one of the batches was heat-treated on a hot plate at 160°C for 90 minutes under a nitrogen atmosphere to obtain a heat-treated photoelectric conversion element. The 5% mass loss temperature of compound (5) is shown in Table 3. For both the heat-treated and unheated photoelectric conversion elements, a voltage of 3V was applied from ITO to aluminum using ITO and aluminum as electrodes, and the dark current (dark current: d) was measured. ３ａ and d ３ｂ) and the current value during light irradiation (light current: l ３ａ and l ３ｂ The dark current change rate r was measured. From the obtained measurement results, the rate of change r ｄ３ , rate of change of the bright current r ｌ３ , and the rate of change r of the light-dark ratio ｌｄ３ The result was calculated and is shown in Table 3.

[0204] (Example 5) A photoelectric conversion element was fabricated in the same manner as in Example 4, except that compound (7) [compound α] was used instead of compound (5). The 5% mass loss temperature of compound (7) is shown in Table 3. The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0205] (Example 6) A photoelectric conversion element was fabricated in the same manner as in Example 4, except that compound (8) [compound α] was used instead of compound (5). The 5% mass loss temperature of compound (8) is shown in Table 3. The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0206] (Comparative Example 2) A photoelectric conversion element was fabricated in the same manner as in Example 4, except that compound (9), represented by the following structural formula, which is 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitride (HAT-CN, manufactured by JiLin OLED Material Tech Co., LTD), was used instead of compound (5). The 5% mass loss temperature of compound (9) is shown in Table 3. The obtained photoelectric conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0207]

[0208] (Example 7) Compound (5) [Compound α] was deposited as an auxiliary layer to a thickness of 50 nm on ITO transparent conductive glass (ITO manufactured by Geomatec Co., Ltd., thickness 100 nm) by resistance heating vacuum deposition. Subsequently, boron subphthalocyanine chloride (refined product manufactured by Sigma-Aldrich, purity >99%) was vacuum deposited on top of this to a thickness of 100 nm as a photoelectric conversion layer. On top of the photoelectric conversion layer, aluminum was fabricated as an electrode film to a thickness of 100 nm by vacuum deposition. Two batches were prepared, and one of the batches was heat-treated on a hot plate under a nitrogen atmosphere at 160°C for 90 minutes to obtain a heat-treated photoelectric conversion element. The 5% mass loss temperature of compound (7) is shown in Table 4. For both the heat-treated and unheated photoelectric conversion elements, a voltage of 3V was applied from ITO to aluminum using ITO and aluminum as electrodes, and the current value in the dark (dark current: d ３ａ and d ３ｂ ) and the current value during light irradiation (light current: l ３ａ and l ３ｂ The dark current change rate r was measured. From the obtained measurement results, the rate of change r ｄ３ , rate of change of the bright current r ｌ３ , and the rate of change r of the light-dark ratio ｌｄ３ The following was calculated. In addition, for both the heat-treated and non-heat-treated photoelectric conversion elements, the amount of current leakage when the device is OFF was calculated by applying a voltage of 0V to obtain the current value in the dark (dark current: d ０ａ and d ０ｂ The following was measured: The rate of change of dark current r when a voltage of 0V is applied was obtained from the measurement results. ｄ０ The result was calculated and is shown in Table 4.

[0209] (Example 8) A photoelectric conversion element was fabricated in the same manner as in Example 7, except that compound (8) [compound α] was used instead of compound (7). The 5% mass loss temperature of compound (8) is shown in Table 4. The obtained photoelectric conversion element was evaluated in the same manner as in Example 4. The results are shown in Table 4.

[0210] (Comparative Example 3) A photoelectric conversion element was fabricated in the same manner as in Example 7, except that the above-mentioned 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitride (HAT-CN, manufactured by JiLin OLED Material Tech Co., LTD, compound (9)) was used instead of compound (7). The 5% mass loss temperature of compound (9) is shown in Table 4. The obtained photoelectric conversion element was evaluated in the same manner as in Example 4. The results are shown in Table 4.

[0211]

[0212]

[0213]

[0214] The results shown in Tables 2, 3, and 4 indicate that the electrode film includes a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer containing compound α (C), and a second electrode film (D), and the rate of change r ｄ３ The value is between 0.020 and 50.0, and the rate of change r ｌ３ The value is between 0.50 and 2.0, and the rate of change r ｌｄ３ The photoelectric conversion element in the embodiment where r is 0.033 or more and 30 or less exhibited excellent heat resistance because it had small dark current change rates, light current change rates, and light-dark ratio change rates due to heating, and thus had excellent thermal stability. On the other hand, the change rate r ｄ３ The value is less than 0.020, and the rate of change r ｌ３ The value is less than 0.50, and the rate of change r ｌｄ３ The photoelectric conversion elements in Comparative Examples 1 and 2, where the change rate r was greater than 30, had poor thermal stability and therefore poor heat resistance. Furthermore, the elements included a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a second electrode film (D), and the change rate r ｄ３ The value is between 0.020 and 50.0, and the rate of change r ｌ３ The value is between 0.50 and 2.0, and the rate of change r ｌｄ３ The value is between 0.033 and 30, and the rate of change r ｄ０ The photoelectric conversion elements of Examples 4 and 5, where r was between 0.20 and 5.0, exhibited excellent heat resistance because they had small dark current change rates, light current change rates, and light-dark ratio change rates due to heating, and thus had excellent thermal stability. On the other hand, the change rate r ｄ３ The value is greater than 50.0, and the rate of change rｌ３ The value is greater than 2.0, and the rate of change r ｌｄ３ The value is less than 0.033, and the rate of change r ｄ０ The photoelectric conversion element in Comparative Example 3, where the ratio was greater than 5.0, had poor thermal stability and therefore poor heat resistance. From the above, it was found that the compound of the present invention is suitable as a material for photoelectric conversion elements that undergo heat treatment, and in particular as a material to be included in the electron transport layer and hole blocking layer of the photoelectric conversion element.

[0215] The disclosure of Japanese Patent Application No. 2024-208412, filed on 29 November 2024, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

[0216] The photoelectric conversion element and its applications according to this embodiment have industrial applicability. Specifically, as a solid-state image sensor, it has industrial applicability in security cameras, automotive cameras, unmanned aerial vehicle cameras, agricultural cameras, industrial cameras, medical cameras such as endoscope cameras, game console cameras, digital still cameras, digital video cameras, mobile phone cameras, and other mobile device cameras; as an image reading element in facsimile machines, scanners, and copiers; and as a light sensor in bio and chemical sensors. Furthermore, as an electroluminescent display, it has industrial applicability in television monitors, touch monitors, digital signage, wearable displays, electronic paper, and head-up displays for mobility applications.

[0217] 100, 200... Photoelectric conversion element, 101... Substrate, 102... Lower electrode, 103... First auxiliary layer, 104... Photoelectric conversion layer, 105... Second auxiliary layer, 106... Upper electrode, 107... Third auxiliary layer

Claims

1. The device comprises a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a second electrode film (D), wherein the rate of change r is represented by the following formula (i). ｄ３ A photoelectric conversion element in which r is between 0.020 and 50.

0. ｄ３ = d ３ａ / d ３ｂ ...(i) (in the formula, d ３ａ This is the dark current (external bias 3V) after heat treatment under the following conditions, and d ３ｂ This is the dark current (external bias 3V) for non-heating treatment. Conditions: The 5% mass loss temperature of compound α, measured under conditions of pressure 0.10 MPa, nitrogen 200 mL / min, temperature 20°C to 550°C, and heating rate 10°C / min, is used as the reference temperature. The compound is then heated at a temperature of reference temperature - 450°C or higher and reference temperature - 10°C or lower for 1 minute to 3000 minutes.

2. A photoelectric conversion device including a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a second electrode film (D), and a change rate r represented by the following formula (ii) ｌ３ is 0.50 or more and 2.0 or less. r ｌ３ = l ３ａ / l ３ｂ ...(ii) (In the formula, l ３ａ is the photocurrent (external bias 3 V) after heat treatment under the following conditions, and l ３ｂ is the photocurrent (external bias 3 V) without heat treatment. Conditions: Using the 5% mass reduction temperature of the compound α measured under the conditions of a pressure of 0.10 MPa, nitrogen of 200 mL / min, a temperature of 20°C to 550°C, and a heating rate of 10°C / min as the reference temperature, heat at a temperature of the reference temperature - 450°C or more and the reference temperature - 10°C or less for 1 minute or more and 3000 minutes or less.) 3. The device comprises a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a second electrode film (D), wherein the rate of change r is represented by the following formula (iii). ｌｄ３ A photoelectric conversion element in which r is between 0.033 and 30. ｌｄ３ =ld ３ａ / ld ３ｂ ...(iii) (In the formula, ld ３ａ The following is the light-dark ratio (external bias 3V) after heat treatment under the conditions below, ld ３ｂ This is the light-dark ratio for non-heating treatment (external bias 3V). Conditions: The 5% mass loss temperature of compound α, measured under conditions of pressure 0.10 MPa, nitrogen 200 mL / min, temperature 20-550°C, and heating rate 10°C / min, is used as the reference temperature. The compound α is then heated at a temperature of reference temperature - 450°C or higher and reference temperature - 10°C or lower for 1 minute to 3000 minutes.

4. The device comprises a first electrode film (A), a photoelectric conversion layer (B), an auxiliary layer (C) containing compound α, and a second electrode film (D), wherein the rate of change r is represented by the following formula (iv). ｄ０ A photoelectric conversion element in which r is between 0.20 and 5.

0. ｄ０ = d ０ａ / d ０ｂ ...(iv) (in the formula, d ０ａ This is the dark current (external bias 0V) after heat treatment under the following conditions, and d ０ｂ This represents the dark current (external bias 0V) for non-heating treatment. Conditions: The 5% mass loss temperature of compound α, measured under conditions of pressure 0.10 MPa, nitrogen 200 mL / min, temperature 20-550°C, and heating rate 10°C / min, is used as the reference temperature. The compound is then heated at a temperature of reference temperature - 450°C or higher and reference temperature - 10°C or lower for 1 minute to 3000 minutes.

5. The photoelectric conversion element according to any one of claims 1 to 4, wherein the compound α comprises an aromatic compound.

6. The photoelectric conversion element according to any one of claims 1 to 4, wherein the compound α comprises an aromatic imide compound.

7. The photoelectric conversion element according to any one of claims 1 to 4, wherein the compound α comprises at least one selected from the group consisting of pyromellitrimide compounds, naphthaleneimide compounds, and peryleneimide compounds.

8. The photoelectric conversion element according to any one of claims 1 to 4, wherein the compound α comprises a compound represented by the following formula (I). (X is independently selected from the group consisting of methine groups and nitrogen atoms, n is an integer between 0 and 3, R １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７ Each is independently selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a thiol group, an amino group, a cyano group, a carboxyl group, a nitro group, and optionally substituted linear, branched or cyclic alkyl groups, thioalkyl groups, thioaryl groups, arylsulfonyl groups, aryloxy groups, alkylsulfonyl groups, alkylamino groups, arylamino groups, alkoxy groups, acylamino groups, acyloxy groups, aryl groups, carboxyamide groups, carboalkoxy groups, carboaryloxy groups, acyl groups, and monovalent heterocyclic groups, and any adjacent R １ , R ２ , R ３ , R ４ , R ５ , R ６ and R ７ (This may be part of a fused ring. The fused ring may contain one or more atoms other than carbon.) 9. In formula (I), R ６ and R ７ The photoelectric conversion element according to claim 8, wherein at least one of the substituents is a substituent whose Hammett substituent constant σp is 0.50 or more and 0.90 or less.

10. The photoelectric conversion element according to claim 8, wherein n is 0 or 1 in formula (I).

11. The photoelectric conversion element according to claim 8, wherein X is a nitrogen atom in formula (I).

12. In formula (I), R １ , R ２ , R ３ , R ４ and R ５ The photoelectric conversion element according to claim 8, wherein the sum of Hammett substituent constants σp is 0.50 or more and 1.80 or less.

13. The photoelectric conversion element according to any one of claims 1 to 4, wherein the thickness of the auxiliary layer (C) is 1 nm or more and 1000 nm or less.

14. An image sensor comprising a photoelectric conversion element according to any one of claims 1 to 4.

15. The image sensor according to claim 14, which is a laminate containing two or more photoelectric conversion elements.

16. The image sensor according to claim 14, wherein a plurality of photoelectric conversion elements are arranged in an array.

17. An optical sensor comprising the image sensor described in claim 14.

18. A solid-state imaging device comprising the image sensor described in claim 14.

Images