Dispersion liquid, photoelectric conversion film, method for producing photoelectric conversion film, photodetection element, and image sensor

Abstract

This dispersion liquid comprises: quantum dots having a band gap of 1.35 eV or less; a ligand; a solvent; and a compound A having a ClogP value of 2.5 or more. The amount of the quantum dots contained in components excluding the ligand and the solvent from the dispersion liquid is 50 mass% or more, and the amount of the compound A having a ClogP value of 2.5 or more contained in the dispersion liquid is 0.01-3.00 mass%. The present invention also pertains to: a photoelectric conversion film obtained by using the dispersion liquid; a method for producing a photoelectric conversion film; a photodetection element; and an image sensor.

Description

Dispersion liquid, photoelectric conversion film, method for producing photoelectric conversion film, photodetector element, and image sensor

[0001] The present invention relates to a dispersion liquid containing quantum dots, a photoelectric conversion film, a method for producing a photoelectric conversion film, a photodetector element, and an image sensor.

[0002] In recent years, photodetectors capable of detecting light in the infrared region have been attracting attention in the fields of smartphones, surveillance cameras, in-vehicle cameras, and the like.

[0003] Conventionally, silicon photodiodes, which use silicon wafers as the material for the photoelectric conversion film, have been used as light detection elements for image sensors, etc. However, silicon photodiodes have low sensitivity in the infrared region with wavelengths of 900 nm or more.

[0004] Furthermore, InGaAs-based semiconductor materials, which are known as near-infrared light receiving elements, have the problem of requiring very costly processes, such as epitaxial growth and substrate bonding processes, to achieve high quantum efficiency, and have therefore not become widely used.

[0005] In addition, in recent years, the use of quantum dots in photoelectric conversion elements has been studied. For example, Patent Document 1 describes quantum dots having inorganic particles, the quantum dots having organic ligands and inorganic ligands on their surfaces, and the molar ratio of the inorganic ligands to the total of the inorganic ligands and the organic ligands being 25% or more and 99.8% or less, being used in a photoelectric conversion film of a photoelectric conversion element.

[0006] Japanese Patent Application Laid-Open No. 2020-150251

[0007] In recent years, along with the demand for improved performance of image sensors and the like, further improvements are being demanded in the properties required of the photodetector elements used in these devices, such as high external quantum efficiency for light of the target wavelength to be detected by the photodetector element and low dark current.

[0008] Therefore, an object of the present invention is to provide a dispersion liquid that can produce a quantum dot film with excellent dispersibility, high external quantum efficiency, and suppressed dark current with high yield. Another object of the present invention is to provide a photoelectric conversion film, a method for producing a photoelectric conversion film, a photodetector, and an image sensor.

[0009] The present invention provides the following: <1> A dispersion comprising quantum dots having a band gap of 1.35 eV or less, a ligand, a solvent, and a compound A having a Clog P value of 2.5 or more, wherein the content of the quantum dots in the components excluding the ligand and the solvent from the dispersion is 50% by mass or more, and the content of the compound A having a Clog P value of 2.5 or more in the dispersion is 0.01 to 3.00% by mass. <2> The dispersion according to <1>, in which the Clog P value of the compound A is 2.5 to 5.8. <3> The dispersion according to <1> or <2>, in which the compound A is at least one compound selected from a hydrocarbon compound and a silane compound. <4> The dispersion according to any one of <1> to <3>, in which the molecular weight of the compound A is 85 to 160. <5> The dispersion according to any one of <1> to <4>, in which the Clog P value of the solvent is 2.0 or less. <6> The dispersion according to any one of <1> to <5>, wherein the difference between the ClogP value of the compound A and the ClogP value of the solvent is 1.0 to 10.0. <7> The dispersion according to any one of <1> to <6>, wherein the ligand includes at least one selected from an inorganic halide and an organic ligand. <8> The dispersion according to any one of <1> to <7>, wherein the quantum dots include at least one element selected from the group consisting of P, As, Sb, and In. <9> The dispersion according to any one of <1> to <8>, wherein the quantum dots have an absorbance maximum in a wavelength range of 900 to 1700 nm. <10> A photoelectric conversion film obtained using the dispersion according to any one of <1> to <9>. <11> A method for producing a photoelectric conversion film, comprising: applying the dispersion according to any one of <1> to <9> onto a support to form a composition layer; and drying the composition layer. <12> A photodetector having the photoelectric conversion film according to <10>. <13> An image sensor having the photoelectric conversion film according to <10>.

[0010] According to the present invention, a dispersion liquid capable of producing a quantum dot film having excellent dispersibility, high external quantum efficiency, and suppressed dark current with high yield can be provided. The present invention also provides a photoelectric conversion film, a method for producing a photoelectric conversion film, a photodetector, and an image sensor.

[0011] FIG. 2 illustrates an embodiment of a photodetector element.

[0012] The present invention will be described in detail below. In this specification, the term "to" is used to mean that the numerical values ​​before and after it are included as the lower and upper limits. In the description of groups (atomic groups) in this specification, a notation that does not specify whether they are substituted or unsubstituted includes both groups (atomic groups) that have no substituents and groups (atomic groups) that have substituents. For example, the term "alkyl group" includes not only alkyl groups that have no substituents (unsubstituted alkyl groups) but also alkyl groups that have substituents (substituted alkyl groups).

[0013] <Dispersion> The dispersion of the present invention is a dispersion containing quantum dots having a band gap of 1.35 eV or less, a ligand, a solvent, and a compound A having a ClogP value of 2.5 or more, characterized in that the content of the quantum dots in the components excluding the ligand and the solvent from the dispersion is 50 mass% or more, and the content of the compound A having a ClogP value of 2.5 or more in the dispersion is 0.01 to 3.00 mass%.

[0014] It is presumed that the dispersion of the present invention contains a predetermined amount of compound A having a ClogP value of 2.5 or more, thereby improving wettability to the support and allowing the dispersion to be applied substantially uniformly onto the support during film formation. Therefore, it is presumed that the use of the dispersion of the present invention makes it possible to form a quantum dot film in which quantum dots are neatly arranged and have little thickness unevenness. It is presumed that the neat arrangement of quantum dots enhances carrier transport ability and improves external quantum efficiency. It is also presumed that the improved wettability to the support prevents the quantum dots from aggregating and further suppresses dark current. Therefore, by using the dispersion of the present invention, quantum dot films with high external quantum efficiency and suppressed dark current can be produced with good yield. Furthermore, since the dispersion of the present invention contains 0.01 to 3.00 mass % of compound A having a ClogP value of 2.5 or more, the quantum dots are well dispersed in the dispersion and have excellent dispersibility.

[0015] Here, the CLogP value is a calculated value of LogP, which is the common logarithm of the 1-octanol / water partition coefficient P. In this specification, the CLogP value is a value obtained by predictive calculation using ChemDraw Professional ver. 20.1.1.125 (manufactured by PerkinElmer).

[0016] The quantum dot film obtained using the dispersion of the present invention can be used in a photodetector element or an image sensor. More specifically, the quantum dot film can be used as a photoelectric conversion film in a photodetector element or an image sensor. Therefore, the dispersion of the present invention is preferably used for the photoelectric conversion film in a photodetector element or an image sensor. Furthermore, the quantum dot film obtained using the dispersion of the present invention has excellent sensitivity to light with wavelengths in the infrared region. Therefore, an image sensor using the quantum dot film obtained using the dispersion of the present invention as a photoelectric conversion film can be particularly preferably used as an infrared sensor. Therefore, the dispersion of the present invention is preferably used for the photoelectric conversion film in an infrared sensor.

[0017] The dispersion of the present invention will be described in more detail below.

[0018] (Quantum dots) The dispersion of the present invention contains quantum dots. The quantum dots are preferably semiconductor particles containing metal atoms. In this specification, the term "metal atoms" also includes semi-metal atoms, such as Si atoms. In addition, the term "semiconductor" in this specification refers to a semiconductor having a specific resistance of 10 －２ Ωcm or more 10 ８ It means a substance with a resistivity of Ωcm or less.

[0019] The quantum dots preferably contain at least one element selected from the group consisting of Ga, Ge, P, As, Se, In, Sn, Sb, Te, Pb, Bi, Ag, Cu, and Hg, more preferably contain at least one element selected from the group consisting of Ga, P, As, Se, In, Sb, Te, and Bi, and even more preferably contain at least one element selected from the group consisting of P, As, Sb, and In.

[0020] The quantum dots are preferably group III-V quantum dots or group IV-VI quantum dots, and are more preferably group III-V quantum dots because the effects of the present invention are more pronounced.

[0021] Group III-V quantum dots are quantum dots containing group III elements (group 13 elements) and group V elements (group 15 elements). Examples of group III-V quantum dots include quantum dots made of compound semiconductors containing group III elements and group V elements. Group IV-VI quantum dots are quantum dots made of group IV elements (group 14 elements) and group VI elements (group 16 elements). Examples of group IV-VI quantum dots include quantum dots made of compound semiconductors containing group IV elements and group VI elements.

[0022] Examples of group III elements contained in III-V quantum dots include boron (B), aluminum (Al), gallium (Ga), and indium (In), with In being preferred. Examples of group V elements contained in III-V quantum dots include nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi), with at least one element selected from As and Sb being preferred. III-V quantum dots may further contain elements other than group III and V elements. Examples of other elements include magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), zinc (Zn), cadmium (Cd), and mercury (Hg).

[0023] Examples of the group IV elements contained in the group IV-VI quantum dots include silicon (Si), germanium (Ge), tin (Sn), and lead (Pb), with Pb being preferred. Examples of the group VI elements contained in the group IV-VI quantum dots include oxygen (O), sulfur (S), selenium (Se), and tellurium (Te), with at least one element selected from S and Se being preferred, and S being more preferred. The group IV-VI quantum dots may further contain elements other than the group IV and VI elements. Examples of other elements include Mg, Ca, Sr, Ba, Zn, Cd, and Hg.

[0024] Specific examples of quantum dots include PbS, PbSe, PbSeS, InN, Ge, InAs, InGaAs, CuInS, CuInSe, CuInGaSe, InSb, InPAs, InAsSb, InPSb, HgTe, HgCdTe, and Ag ２ S, Ag ２ Se, Ag ２ Te, SnS, SnSe, SnTe, Si, InP, AgBiS ２and AgBiSTe, and at least one selected from InAs, InSb, InPAs, InAsSb, InPSb, PbS and PbSe is preferred, and at least one selected from InAs, InSb, InPAs and InAsSb is more preferred.

[0025] The band gap of the quantum dots is 1.35 eV or less, preferably 1.1 eV or less, and more preferably 1.0 eV or less. The lower limit of the band gap of the quantum dots is not particularly limited, but can be 0.5 eV or more. If the band gap of the quantum dots is 1.35 eV, a quantum dot film having a high external quantum efficiency for light with wavelengths in the infrared region can be formed. The band gap of the quantum dots can be calculated from the energy at the maximum absorption wavelength of the absorption spectrum obtained by measuring optical absorption in the visible to infrared region using a UV-Vis-NIR spectrophotometer. Furthermore, in the case of quantum dots that do not have a maximum absorption wavelength, it can be determined from a Tauc plot, as described in Japanese Patent No. 5,949,567.

[0026] The quantum dots preferably have a maximum absorption in the wavelength range of 900 to 1700 nm, and more preferably have a maximum absorption in the wavelength range of 1300 to 1600 nm. By using such quantum dots, a quantum dot film can be formed that has a high external quantum efficiency for light with wavelengths in the infrared region.

[0027] It is also preferable that the quantum dots have high absorption for light having a wavelength in the range of 900 to 1700 nm (preferably, 1300 to 1600 nm). By using such quantum dots, it is possible to form a quantum dot film having a high external quantum efficiency for light having a wavelength in the infrared region.

[0028] The average primary particle diameter of the quantum dots is preferably 0.5 nm or more and less than 100 nm. The lower limit of the average primary particle diameter of the quantum dots is preferably 1 nm or more, more preferably 2 nm or more, and even more preferably 3 nm or more. The upper limit of the average primary particle diameter of the quantum dots is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 15 nm or less. If the average primary particle diameter of the quantum dots is within the above range, a quantum dot film having high external quantum efficiency for light with wavelengths in the infrared region can be formed. Note that, in this specification, the average primary particle diameter of the quantum dots is the average value of the primary particle diameters of 10 arbitrarily selected quantum dots. The primary particle diameter of the quantum dots can be measured using a transmission electron microscope.

[0029] The content of quantum dots in the dispersion is preferably 1 to 25% by mass. The lower limit is preferably 2% by mass or more, and more preferably 3% by mass or more. The upper limit is preferably 20% by mass or less. The content of quantum dots in the dispersion is preferably 10 to 250 mg / mL. The lower limit is preferably 20 mg / mL or more, and more preferably 30 mg / mL or more. The upper limit is preferably 200 mg / mL or less.

[0030] The content of quantum dots in the dispersion liquid excluding the ligand and the solvent is 50% by mass or more, preferably 55% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Furthermore, the total content of quantum dots and ligands in the dispersion liquid excluding the solvent is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0031] (Ligand) The dispersion of the present invention contains a ligand. Examples of the ligand include inorganic ligands and organic ligands. The ligand preferably contains an inorganic ligand.

[0032] The inorganic ligand is preferably an inorganic halide. Examples of halogen atoms contained in the inorganic halide include fluorine, chlorine, bromine, and iodine atoms, and bromine or iodine atoms are preferred. The inorganic halide is also preferably a compound containing at least one atom selected from the group consisting of Zn, Cd, Ga, Ge, As, Se, In, Sn, Sb, Te, Tl, Pb, Bi, and Po.

[0033] Specific examples of inorganic ligands include zinc iodide, zinc bromide, zinc chloride, indium iodide, indium bromide, indium chloride, cadmium iodide, lead chloride, lead bromide, lead iodide, cadmium bromide, cadmium chloride, gallium iodide, gallium bromide, gallium chloride, potassium sulfide, and sodium sulfide.

[0034] The organic ligand is preferably a compound having at least one functional group selected from a carboxy group, a mercapto group, an amino group, a hydroxy group, a phospho group, a phosphonic acid group, and a sulfo group, more preferably a compound having at least one functional group selected from a carboxy group, a mercapto group, an amino group, and a hydroxy group, and even more preferably a compound having a mercapto group. The organic ligand may be a monodentate ligand having only one of the above functional groups, or a multidentate ligand having two or more of the above ligands.

[0035] The organic ligand is also preferably a compound having a pKa of 3 or less. The pKa of the compound is more preferably 2.5 or less, because this allows the formation of a quantum dot film with high external quantum efficiency and further suppressed dark current. The lower limit of the pKa of the compound is preferably -2.0 or more, more preferably -1.0 or more, and even more preferably 0.5 or more.

[0036] Specific examples of monodentate ligands include 2-naphthylamine, 4-methylthioaniline, 4-methylbenzenethiol, 3,5-dimethylbenzenethiol, 4-chlorobenzenethiol, 4-methoxybenzenethiol, benzoic acid, phenylphosphonic acid, methanesulfonic acid, trifluoroacetic acid, bromoacetic acid, 3-phosphorylpropionic acid, glycine-N,N-bis(methylenephosphonic acid), 2-chloroethylphosphonic acid, phenyl phosphate, dimethyl phosphate, and trifluoromethanesulfonic acid. Of the above compounds, phenylphosphonic acid, methanesulfonic acid, trifluoroacetic acid, bromoacetic acid, 3-phosphorylpropionic acid, glycine-N,N-bis(methylenephosphonic acid), 2-chloroethylphosphonic acid, phenyl phosphate, dimethyl phosphate, and trifluoromethanesulfonic acid are compounds with a pKa of 3 or less.

[0037] The polydentate ligand may be a ligand represented by any one of formulas (A) to (C).

[0038] In formula (A), X Ａ１ and X Ａ２ each independently represents a carboxy group, a mercapto group, an amino group, a hydroxy group, a phospho group, a phosphonic acid group, or a sulfo group; L Ａ１ represents a hydrocarbon group.

[0039] In formula (B), X Ｂ１ and X Ｂ２ each independently represents a carboxy group, a mercapto group, an amino group, a hydroxy group, a phospho group, a phosphonic acid group, or a sulfo group; Ｂ３ represents S, O or NH; L Ｂ１ and L Ｂ２ each independently represents a hydrocarbon group.

[0040] In formula (C), X Ｃ１ ~X Ｃ３ each independently represents a carboxy group, a mercapto group, an amino group, a hydroxy group, a phospho group, a phosphonic acid group, or a sulfo group; Ｃ４ represents N, and L Ｃ１ ~L Ｃ３ each independently represents a hydrocarbon group.

[0041] X Ａ１ , X Ａ２ , X Ｂ１ , X Ｂ２ , X Ｃ１ , X Ｃ２ and X Ｃ３ The amino group represented by is -NH ２ The amino group is not limited to the above, and also includes a substituted amino group and a cyclic amino group. Examples of the substituted amino group include a monoalkylamino group, a dialkylamino group, a monoarylamino group, a diarylamino group, and an alkylarylamino group. The amino group represented by these groups includes -NH ２ , a monoalkylamino group, or a dialkylamino group is preferred, and —NH ２ It is more preferable that:

[0042] L Ａ１ , L Ｂ１ , L Ｂ２ , L Ｃ１ , L Ｃ２ and L Ｃ３ The hydrocarbon group represented by is preferably an aliphatic hydrocarbon group or a group containing an aromatic ring, and more preferably an aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The hydrocarbon group preferably has 1 to 20 carbon atoms. The upper limit of the carbon number is preferably 10 or less, more preferably 6 or less, and even more preferably 3 or less. Specific examples of the hydrocarbon group include an alkylene group, an alkenylene group, an alkynylene group, and an arylene group.

[0043] Examples of the alkylene group include a linear alkylene group, a branched alkylene group, and a cyclic alkylene group, and are preferably a linear alkylene group or a branched alkylene group, and more preferably a linear alkylene group. Examples of the alkenylene group include a linear alkenylene group, a branched alkenylene group, and a cyclic alkenylene group, and are preferably a linear alkenylene group or a branched alkenylene group, and more preferably a linear alkenylene group. Examples of the alkynylene group include a linear alkynylene group and a branched alkynylene group, and are preferably a linear alkynylene group. The arylene group may be monocyclic or polycyclic. A monocyclic arylene group is preferred. Specific examples of the arylene group include a phenylene group and a naphthylene group, and are preferably a phenylene group. The alkylene group, alkenylene group, alkynylene group, and arylene group may further have a substituent. The substituent is preferably a group having 1 to 10 atoms. Specific preferred examples of the group having 1 to 10 atoms include alkyl groups having 1 to 3 carbon atoms (methyl, ethyl, propyl, and isopropyl groups), alkenyl groups having 2 to 3 carbon atoms (ethenyl and propenyl groups), alkynyl groups having 2 to 4 carbon atoms (ethynyl, propynyl, etc.), cyclopropyl groups, alkoxy groups having 1 to 2 carbon atoms (methoxy and ethoxy groups), acyl groups having 2 to 3 carbon atoms (acetyl and propionyl groups), alkoxycarbonyl groups having 2 to 3 carbon atoms (methoxycarbonyl and ethoxycarbonyl groups), acyloxy groups having 2 carbon atoms (acetyloxy group), and alkyl groups having 2 to 3 carbon atoms (ethynyl, propynyl, etc.). acylamino group [acetylamino group], hydroxyalkyl group having 1 to 3 carbon atoms [hydroxymethyl group, hydroxyethyl group, hydroxypropyl group], aldehyde group, hydroxy group, carboxy group, sulfo group, phospho group, carbamoyl group, cyano group, isocyanate group, mercapto group, nitro group, nitroxy group, isothiocyanate group, cyanate group, thiocyanate group, acetoxy group, acetamido group, formyl group, formyloxy group, formamido group, sulfamino group, sulfino group, sulfamoyl group, phosphono group, acetyl group, halogen atom, alkali metal atom, etc.

[0044] In formula (A), XＡ１ and X Ａ２ Is L Ａ１ Preferably, they are separated by 1 to 10 atoms, more preferably by 1 to 6 atoms, even more preferably by 1 to 4 atoms, even more preferably by 1 to 3 atoms, and particularly preferably by 1 or 2 atoms.

[0045] In formula (B), X Ｂ１ and X Ｂ３ Is L Ｂ１ Preferably, they are separated by 1 to 10 atoms, more preferably 1 to 6 atoms, even more preferably 1 to 4 atoms, still more preferably 1 to 3 atoms, and particularly preferably 1 or 2 atoms. Ｂ２ and X Ｂ３ Is L Ｂ２ Preferably, they are separated by 1 to 10 atoms, more preferably by 1 to 6 atoms, even more preferably by 1 to 4 atoms, even more preferably by 1 to 3 atoms, and particularly preferably by 1 or 2 atoms.

[0046] In formula (C), X Ｃ１ and X Ｃ４ Is L Ｃ１ Preferably, they are separated by 1 to 10 atoms, more preferably 1 to 6 atoms, even more preferably 1 to 4 atoms, still more preferably 1 to 3 atoms, and particularly preferably 1 or 2 atoms. Ｃ２ and X Ｃ４ Is L Ｃ２ Preferably, they are separated by 1 to 10 atoms, more preferably 1 to 6 atoms, even more preferably 1 to 4 atoms, still more preferably 1 to 3 atoms, and particularly preferably 1 or 2 atoms. Ｃ３ and X Ｃ４ Is L Ｃ３Preferably, they are separated by 1 to 10 atoms, more preferably by 1 to 6 atoms, even more preferably by 1 to 4 atoms, even more preferably by 1 to 3 atoms, and particularly preferably by 1 or 2 atoms.

[0047] In addition, X Ａ１ and X Ａ２ Is L Ａ１ The term "separated by 1 to 10 atoms" means that X Ａ１ and X Ａ２ This means that the number of atoms constituting the molecular chain with the shortest distance connecting X is 1 to 10. For example, in the case of the following formula (A1), X Ａ１ and X Ａ２ and are separated by two atoms, and in the case of the following formula (A2) and formula (A3), X Ａ１ and X Ａ２ The numbers in the following structural formulas represent X Ａ１ and X Ａ２ It represents the order of the arrangement of atoms that make up the shortest molecular chain connecting the

[0048] Specific examples of polydentate ligands include ethanedithiol, 3-mercaptopropionic acid, thiosalicylic acid, thioglycolic acid, 2-aminoethanol, 2-aminoethanethiol, 2-mercaptoethanol, glycolic acid, ethylenediamine, glycine, guanidine, diethylenetriamine, tris(2-aminoethyl)amine, 4-mercaptobutanoic acid, 3-aminopropanol, 3-mercaptopropanol, N-(3-aminopropyl)-1,3-propanediamine, 3-(bis(3- (aminopropyl)amino)propan-1-ol, 3-aminopropan-1-ol, 3-mercapto-2,2-bis(mercaptomethyl)-1-propanol, 1-thioglycerol, dimercaprol, 1-mercapto-2-butanol, 1-mercapto-2-pentanol, 3-mercapto-1-propanol, 2,3-dimercapto-1-propanol, diethanolamine, 2-(2-aminoethyl)aminoethanol, dimethylenetriamine, 1,1-oxybismethylamine amine, 1,1-thiobismethylamine, 2-[(2-aminoethyl)amino]ethanethiol, bis(2-mercaptoethyl)amine, 2-aminoethane-1-thiol, 1-amino-2-butanol, 1-amino-2-pentanol, L-cysteine, D-cysteine, 3-amino-1-propanol, L-homoserine, D-homoserine, aminohydroxyacetic acid, L-lactic acid, D-lactic acid, L-malic acid, D-malic acid, glyceric acid, 2-hydroxybutyric acid, L-tartaric acid, D-tartaric acid, 1,2 mercaptobenzoic acid, 3-mercaptobenzoic acid, 4-mercaptobenzoic acid, 3-mercapto-2,2-bismercaptomethyl-1-propanol, trimethylolpropane tris(thioglycolate), pentaerythritol tetrakis(mercaptoacetate), dipentaerythritol hexakis(3-mercaptopropionate), dithioerythritol, and derivatives thereof.

[0049] The organic ligand may be a salt of a compound having at least one functional group selected from a carboxy group, a phospho group, a phosphonic acid group, and a sulfo group. The atom or atomic group constituting the salt with the compound having the functional group may be a metal ion (Li ＋ , Na ＋ , K. ＋ , Ca ２＋ , Mg ２＋ , Zn ２＋ , Cu ２＋ , Ga ３＋ , In ３＋ , Zr ４＋ , Hf ４＋ and the like), ammonium ions, etc. That is, examples of the salts of the compounds having the above functional groups include metal salts of the compounds having the above functional groups, ammonium salts of the compounds having the above functional groups, etc.

[0050] The compound having the functional group is preferably a compound having a pKa of 3 or less, more preferably a compound having a pKa of 2.5 or less. The lower limit of the pKa of the compound having the functional group is preferably -2.0 or more, more preferably -1.0 or more, and even more preferably 0.5 or more.

[0051] The molecular weight of the compound having the functional group is preferably 50 to 500. The upper limit of the molecular weight is preferably 450 or less, and more preferably 400 or less.

[0052] Specific examples of salts of compounds having the above functional group include metal salts and ammonium salts of compounds selected from phenylphosphonic acid, methanesulfonic acid, trifluoroacetic acid, bromoacetic acid, 3-phosphorylpropionic acid, glycine-N,N-bis(methylenephosphonic acid), 2-chloroethylphosphonic acid, methylphosphonic acid, methyl phosphate, phenyl phosphate, dimethyl phosphate, trifluoromethanesulfonic acid, and acetic acid.

[0053] The content of the ligand in the dispersion is preferably 0.1 to 15% by mass. The lower limit is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more. The upper limit is preferably 10% by mass or less, and more preferably 7% by mass or less. The content of the ligand in the dispersion is preferably 10 to 150 mg / mL. The lower limit is preferably 20 mg / mL or more, and more preferably 25 mg / mL or more. The upper limit is preferably 100 mg / mL or less, and more preferably 70 mg / mL or less. The ratio of the quantum dots to the ligand is preferably 10 to 100 parts by mass of the ligand per 100 parts by mass of the quantum dots. The lower limit is preferably 20 parts by mass or more, and more preferably 30 parts by mass or more. The upper limit is preferably 80 parts by mass or less, and more preferably 70 parts by mass or less.

[0054] (Solvent) The dispersion of the present invention contains a solvent. The solvent is not particularly limited, but is preferably a solvent that hardly dissolves quantum dots and easily dissolves ligands. The solvent is preferably an organic solvent. The organic solvent may be either a polar solvent or a non-polar solvent, but is preferably a polar solvent, and more preferably a polar solvent having an amide group, for the reason of the dispersibility of quantum dots.

[0055] The boiling point of the organic solvent is preferably 60 to 250° C. The lower limit is preferably 70° C. or higher, more preferably 80° C. or higher. The upper limit is preferably 200° C. or lower, more preferably 190° C. or lower.

[0056] The ClogP value of the organic solvent is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.3 or less.

[0057] Specific examples of the organic solvent include N,N-dimethylformamide (ClogP value -1.0), dimethyl sulfoxide (ClogP value -1.5), N-methylformamide (ClogP value -0.8), N,N-dimethylacetamide (ClogP value -0.5), propylene carbonate (ClogP value 0.6), and ethylene glycol (ClogP value -0.8), and N,N-dimethylformamide, dimethyl sulfoxide, or N-methylformamide is preferred.

[0058] The content of the solvent in the dispersion is preferably 50 to 99% by mass, more preferably 70 to 99% by mass, and even more preferably 85 to 98% by mass. The solvent contained in the dispersion may be a single solvent or a mixed solvent containing two or more solvents. When two or more solvents are contained, the total amount thereof is preferably in the above range.

[0059] (Specific Compound (Compound A having a ClogP value of 2.5 or more)) The dispersion of the present invention contains a compound A (hereinafter also referred to as specific compound) having a ClogP value of 2.5 or more.

[0060] The ClogP value of the specific compound is preferably 2.5 to 8.0, more preferably 2.5 to 5.8. The lower limit of the ClogP value is preferably 2.7 or more, more preferably 3.0 or more.

[0061] The molecular weight of the specific compound is preferably 65 to 200, more preferably 75 to 180, and even more preferably 85 to 160.

[0062] The specific compound is preferably a hydrocarbon compound or a silane compound.

[0063] Specific examples of the specific compound include heptane (ClogP value: 4.4), nonane (ClogP value: 5.5), toluene (ClogP value: 2.6), tetramethylsilane (ClogP value: 3.2), tetraethylsilane (ClogP value: 5.0), and tripropylsilane (ClogP value: 3.8).

[0064] The difference between the ClogP value of the specific compound contained in the dispersion and the ClogP value of the solvent (hereinafter also referred to as ΔClogP value) is preferably 1.0 to 10.0. When the ΔClogP value is within the above range, the effects of the present invention are more significantly exhibited. The upper limit of the ΔClogP value is preferably 9.0 or less, more preferably 8.0 or less. The lower limit of the ΔClogP value is preferably 1.5 or more, more preferably 2.0 or more. Furthermore, the ClogP value of the specific compound is preferably higher than the ClogP value of the solvent.

[0065] The content of the specific compound in the dispersion is 0.01 to 3.00% by mass. The upper limit is preferably 2.50% by mass or less, and more preferably 2.00% by mass or less. The lower limit is preferably 0.05% by mass or more, and more preferably 0.50% by mass or more. The specific compound contained in the dispersion may be one type only, or may contain two or more types. When two or more types of specific compounds are contained, the total amount thereof is within the above range.

[0066] <Photoelectric conversion film> The photoelectric conversion film of the present invention is obtained using the dispersion liquid of the present invention described above. Since the photoelectric conversion film of the present invention has excellent sensitivity to light with a wavelength in the infrared region, a photodetector using this photoelectric conversion film is preferably used as a photodetector for detecting light with a wavelength in the infrared region. Therefore, the photoelectric conversion film of the present invention is preferably used as a photoelectric conversion film for an infrared light detection element.

[0067] The infrared light preferably has a wavelength of more than 700 nm, more preferably has a wavelength of 800 nm or more, and even more preferably has a wavelength of 900 nm or more. The infrared light preferably has a wavelength of 2000 nm or less, and more preferably has a wavelength of 1600 nm or less.

[0068] The total content of the quantum dots and ligands in the photoelectric conversion film is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0069] <Method for producing photoelectric conversion film> The method for producing a photoelectric conversion film of the present invention includes the steps of applying the dispersion of the present invention described above onto a support to form a composition layer, and drying the composition layer.

[0070] There are no particular limitations on the shape, structure, size, etc. of the support to which the dispersion is applied, and these can be appropriately selected depending on the purpose. The support may have a single-layer structure or a laminated structure. As the support, for example, a support made of an inorganic material such as silicon, glass, or YSZ (Yttrium-Stabilized Zirconia), a resin, a resin composite material, etc. can be used. Furthermore, an electrode, an insulating film, etc. may be formed on the support. In this case, the dispersion is also applied to the electrode and insulating film on the support.

[0071] The method for applying the dispersion is not particularly limited, and examples thereof include coating methods such as spin coating, dipping, inkjet printing, dispenser printing, screen printing, letterpress printing, intaglio printing, and spray coating.

[0072] After the composition layer is formed, it is dried. By drying, the solvent remaining in the composition layer can be removed. The drying temperature is preferably 50 to 150°C. The upper limit of the drying temperature is preferably 120°C or less, and more preferably 100°C or less. The lower limit of the drying temperature is preferably 55°C or more, and more preferably 60°C or more. The drying time is preferably 1 to 300 minutes. The upper limit of the drying time is preferably 200 minutes or less, and more preferably 100 minutes or less. The lower limit of the drying time is preferably 2 minutes or more, and more preferably 5 minutes or more.

[0073] In the method for producing a photoelectric conversion film of the present invention, the step of forming a composition layer and the step of drying the composition layer may be alternately repeated multiple times.

[0074] In the method for producing a photoelectric conversion film of the present invention, after the step of drying the composition layer, a step of applying a ligand solution onto the dried composition layer may be performed. By performing this step, the ligands coordinated to the quantum dots can be exchanged for the ligands contained in the ligand solution, or the ligands contained in the ligand solution can be coordinated to the quantum dots, thereby suppressing the occurrence of surface defects on the quantum dots.

[0075] The ligand contained in the ligand solution may be the ligand described as being used in the dispersion of the present invention. The ligand contained in the ligand solution may be the same as or different from the ligand contained in the dispersion. The ligand solution may contain only one type of ligand, or may contain two or more types. Furthermore, two or more types of ligand solutions may be used in the step of applying the ligand solution.

[0076] The solvent contained in the ligand solution is preferably selected appropriately depending on the type of ligand contained in the ligand solution, and is preferably a solvent that easily dissolves the ligand. Furthermore, the solvent contained in the ligand solution is preferably an organic solvent with a high dielectric constant. Specific examples include ethanol, acetone, methanol, acetonitrile, dimethylformamide, dimethyl sulfoxide, butanol, and propanol. Furthermore, the solvent contained in the ligand solution is preferably a solvent that is unlikely to remain in the photoelectric conversion film that is formed. From the viewpoint of ease of drying and ease of removal by washing, a low-boiling alcohol, ketone, or nitrile is preferred, and methanol, ethanol, acetone, or acetonitrile is more preferred.

[0077] The method for applying the ligand solution is the same as the method for applying the dispersion onto the support, and the preferred embodiments are also the same.

[0078] When performing the step of applying a ligand solution, a step of rinsing the film after applying the ligand solution by contacting it with a rinse liquid (rinsing step) may be performed. By performing the rinsing step, excess ligands contained in the film and ligands detached from the quantum dots can be removed. Furthermore, remaining solvent and other impurities can be removed. The rinse liquid is preferably an aprotic solvent because it can more effectively remove excess ligands contained in the film and ligands detached from the quantum dots and easily maintain a uniform film surface by rearranging the quantum dot surface. Specific examples of aprotic solvents include acetonitrile, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, diethyl ether, tetrahydrofuran, cyclopentyl methyl ether, dioxane, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, hexane, octane, cyclohexane, benzene, toluene, chloroform, carbon tetrachloride, and dimethylformamide. Acetonitrile or tetrahydrofuran is preferred, and acetonitrile is more preferred.

[0079] The rinsing step may be performed multiple times using two or more rinse solutions with different polarities (dielectric constants). For example, it is preferable to first rinse using a rinse solution with a high dielectric constant (also referred to as a first rinse solution), and then rinse using a rinse solution with a lower dielectric constant than the first rinse solution (also referred to as a second rinse solution). The dielectric constant of the first rinse solution is preferably 15 to 50, more preferably 20 to 45, and even more preferably 25 to 40. The dielectric constant of the second rinse solution is preferably 1 to 15, more preferably 1 to 10, and even more preferably 1 to 5.

[0080] A photoelectric conversion film can be produced through such steps. The obtained photoelectric conversion film can be used in a photodetector or an image sensor. The photoelectric conversion film obtained using the dispersion of the present invention has excellent sensitivity to light with wavelengths in the infrared region, so that a photodetector using this photoelectric conversion film is preferably used as a photodetector that detects light with wavelengths in the infrared region. Therefore, the photoelectric conversion film is preferably used as a photoelectric conversion film for an infrared light detection element.

[0081] The infrared light preferably has a wavelength of more than 700 nm, more preferably has a wavelength of 800 nm or more, and even more preferably has a wavelength of 900 nm or more. The infrared light preferably has a wavelength of 2000 nm or less, and more preferably has a wavelength of 1600 nm or less.

[0082] The total amount of quantum dots and ligands in the photoelectric conversion film is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0083] <Photodetector> The photodetector of the present invention has the photoelectric conversion film of the present invention described above. Types of photodetector include photoconductor-type photodetector elements and photodiode-type photodetector elements. Among these, photodiode-type photodetector elements are preferred because they tend to provide a high signal-to-noise ratio (SN ratio).

[0084] Since the photoelectric conversion film of the present invention has excellent sensitivity to light with wavelengths in the infrared region, the photodetector of the present invention is preferably used as a photodetector for detecting light with wavelengths in the infrared region, i.e., the photodetector of the present invention is preferably used as an infrared light detection element.

[0085] The photodetector may be a photodetector that simultaneously detects light with a wavelength in the infrared region and light with a wavelength in the visible region (preferably light with a wavelength in the range of 400 to 700 nm).

[0086] FIG. 1 shows one embodiment of a photodetector element. FIG. 1 is a diagram illustrating one embodiment of a photodiode-type photodetector element. The arrows in the figure indicate incident light on the photodetector element. The photodetector element 1 shown in FIG. 1 includes a second electrode 12, a first electrode 11 disposed opposite the second electrode 12, a photoelectric conversion film 13 disposed between the second electrode 12 and the first electrode 11, an electron transport layer 21 disposed between the first electrode 11 and the photoelectric conversion film 13, and a hole transport layer 22 disposed between the second electrode 12 and the photoelectric conversion film 13. The photodetector element 1 shown in FIG. 1 is used so that light is incident from above the first electrode 11. Although not shown, a transparent substrate may be disposed on the light-incident surface of the first electrode 11. Examples of transparent substrates include glass substrates, resin substrates, and ceramic substrates.

[0087] (First Electrode) The first electrode 11 is preferably a transparent electrode formed of a conductive material that is substantially transparent to the wavelength of light to be detected by the photodetector. In this specification, "substantially transparent" means that the light transmittance is 50% or more, preferably 60% or more, and more preferably 80% or more. Examples of materials for the first electrode 11 include conductive metal oxides. Specific examples include tin oxide, zinc oxide, indium oxide, indium tungsten oxide, indium zinc oxide (IZO), indium tin oxide (ITO), and fluorine-doped tin oxide (FTO).

[0088] The film thickness of the first electrode 11 is not particularly limited, but is preferably 0.01 to 100 μm, more preferably 0.01 to 10 μm, and even more preferably 0.01 to 1 μm. The film thickness of each layer can be measured by observing a cross section of the photodetector element 1 using a scanning electron microscope (SEM) or the like.

[0089] (Electron Transport Layer) The electron transport layer 21 is a layer having a function of transporting electrons generated in the photoelectric conversion film 13 to the electrode. The electron transport layer is also called a hole blocking layer. The electron transport layer is formed of an electron transport material that can exhibit this function.

[0090] Examples of electron transport materials include fullerene compounds such as [6,6]-phenyl-C61-butylic acid methyl ester (PC61BM), perylene compounds such as perylene tetracarboxydiimide, tetracyanoquinodimethane, titanium oxide, tin oxide, zinc oxide, indium oxide, indium tungsten oxide, indium zinc oxide, indium tin oxide, and fluorine-doped tin oxide. The electron transport material may be in the form of particles. The electron transport material is preferably zinc oxide. Furthermore, the zinc oxide is preferably in the form of particles (zinc oxide particles) from the viewpoints of reducing residual organic components and increasing the contact area with the photoelectric conversion film.

[0091] The zinc oxide may be zinc oxide doped with metal atoms other than Zn. Hereinafter, zinc oxide doped with metal atoms other than Zn will also be referred to as doped zinc oxide.

[0092] The metal atoms other than Zn in the doped zinc oxide are preferably monovalent to trivalent metal atoms, more preferably at least one selected from Li, Mg, Al, and Ga, further preferably Li, Mg, Al, or Ga, and particularly preferably Li or Mg.

[0093] In the doped zinc oxide, the ratio of metal atoms other than Zn to the total of Zn and metal atoms other than Zn is preferably 1 atomic % or more, more preferably 2 atomic % or more, and even more preferably 4 atomic % or more. From the viewpoint of suppressing an increase in crystal defects, the upper limit is preferably 20 atomic % or less, more preferably 15 atomic % or less, and even more preferably 12 atomic % or less. The ratio of metal atoms other than Zn in the doped zinc oxide can be measured by a high-frequency inductively coupled plasma (ICP) method.

[0094] The average particle size of the zinc oxide particles is preferably 2 to 30 nm. The upper limit of the average particle size of the zinc oxide particles is preferably 20 nm or less, and more preferably 15 nm or less. When the average particle size of the zinc oxide particles is within the above range, the contact area with the photoelectric conversion film is large, and a film with high flatness is likely to be obtained. In this specification, the average particle size of the zinc oxide particles is the average value of the particle sizes of 10 arbitrarily selected particles. The particle size of the zinc oxide particles can be measured using a transmission electron microscope.

[0095] The electron transport layer may be a single layer film or a laminated film of two or more layers. The thickness of the electron transport layer is preferably 10 to 1000 nm. The upper limit is preferably 800 nm or less. The lower limit is preferably 20 nm or more, and more preferably 50 nm or more. The thickness of the electron transport layer is preferably 0.05 to 10 times, more preferably 0.1 to 5 times, and even more preferably 0.2 to 2 times the thickness of the photoelectric conversion film 13.

[0096] The electron transport layer may be subjected to ultraviolet ozone treatment. In particular, when the electron transport layer is a layer made of nanoparticles, ultraviolet ozone treatment is desirable. By performing ultraviolet ozone treatment, the wettability of the quantum dot dispersion liquid to the electron transport layer can be improved, and residual organic matter in the electron transport layer can be decomposed or removed, resulting in high device performance. The wavelength of the ultraviolet light to be irradiated can be selected between 100 and 400 nm. In particular, because the above-mentioned effects can be easily obtained and excessive damage to the film can be avoided, it is preferable for the peak intensity to be between 200 and 300 nm, and more preferably between 240 and 270 nm. There are no particular restrictions on the ultraviolet light irradiation intensity, but because the above-mentioned effects can be easily obtained and excessive damage to the film can be avoided, it is preferable for the peak intensity to be between 1 and 100 mW / cm. ２ is preferably 10 to 50 mW / cm ２ There is no particular limitation on the treatment time, but for the same reason, it is preferably 1 to 60 minutes, more preferably 1 to 20 minutes, and even more preferably 3 to 15 minutes.

[0097] (Photoelectric Conversion Film) The photoelectric conversion film 13 is composed of a quantum dot film formed using the dispersion liquid of the present invention described above. The photoelectric conversion film 13 can be formed by the method described above.

[0098] The thickness of the photoelectric conversion film 13 is preferably 10 to 1000 nm. The lower limit of the thickness is preferably 20 nm or more, and more preferably 30 nm or more. The upper limit of the thickness is preferably 600 nm or less, more preferably 550 nm or less, even more preferably 500 nm or less, and particularly preferably 450 nm or less. The refractive index of the photoelectric conversion film 13 for light of the target wavelength to be detected by the photodetector element can be 1.5 to 5.0.

[0099] (Hole Transport Layer) The hole transport layer 22 is a layer having a function of transporting holes generated in the photoelectric conversion film 13 to the electrode. The hole transport layer is also called an electron blocking layer.

[0100] The hole transport layer 22 is formed of a hole transport material that can perform this function. Examples of hole transport materials include PEDOT:PSS (a composite of poly(3,4-ethylenedioxythiophene) and poly(4-styrenesulfonic acid)), PTB7 (poly{4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-lt-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno) and thieno[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-lt-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno)). [3,4-b]thiophene-4,6-diyl}), PTB7-Th (poly([2,6'-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,3-b]dithiophene]{3-fluoro-2[(2-ethylhexyl-1)carbonyl]thieno[3,4-b]thiophenediyl})), poly(3-hexylthiophene-2,5-diyl), poly(3-n-octyl oxythiophene), poly(9,9'-dioctyl-fluorene-co-bithiophene), poly(3,3'''-didodecyl-quaterthiophene), poly(3,6-dioctylthieno[3,2-b]thiophene), poly(2,5-bis(3-decylthiophen-2-yl)thieno[3,2-b]thiophene), poly(3,4-didecylthiophene-co-thieno[3,2-b]thiophene), poly(3,6-dioctylthieno[3,2-b]thiophene-co-thieno[3,2-b]thiophene), poly(3,6-dioctylthieno[3,2-b]thiophene-co-thiophene), poly(3,6-dioctylthieno[3,2-b]thiophene-co-bithiophene), PC71BM ([6,6]-phenyl-C71-methyl butyrate). Alternatively, organic hole transport materials such as those described in paragraphs 0209 to 0212 of JP-A-2001-291534 can be used. Quantum dots can also be used as the hole transport material. Examples of quantum dot materials that constitute quantum dots include nanoparticles (particles with a size of 0.5 nm or more and less than 100 nm) of common semiconductor crystals (a) Group IV semiconductors, b) Group IV-IV, III-V, or II-VI compound semiconductors, and c) compound semiconductors formed from a combination of three or more of Group II, III, IV, V, and VI elements).Specifically, PbS, PbSe, PbSeS, InN, Ge, InAs, InGaAs, CuInS, CuInSe, CuInGaSe, InSb, HgTe, HgCdTe, and Ag. ２ S, Ag ２ Se, Ag ２ Examples of such semiconductor materials include Te, SnS, SnSe, SnTe, Si, InP, etc. Ligands may be coordinated to the surface of the quantum dots.

[0101] The thickness of the hole transport layer 22 is preferably 5 to 100 nm. The lower limit is preferably 10 nm or more. The upper limit is preferably 50 nm or less, and more preferably 30 nm or less.

[0102] (Second Electrode) The second electrode 12 is preferably composed of a metal material containing at least one metal atom selected from Ag, Au, Pt, Ir, Pd, Cu, Pb, Sn, Zn, Ti, W, Mo, Ta, Ge, Ni, Al, Cr, and In. By using such a metal material for the second electrode 12, a photodetector element with high external quantum efficiency and low dark current can be obtained. The second electrode 12 can also be made of the above-mentioned conductive metal oxides, carbon materials, conductive polymers, and the like. The carbon material may be any conductive material, such as fullerene, carbon nanotube, graphite, and graphene.

[0103] The work function of the second electrode 12 is preferably 4.6 eV or more, more preferably 4.8 to 5.7 eV, and even more preferably 4.9 to 5.3 eV, for the reasons that this enhances the electron blocking property of the hole transport layer and makes it easy to collect holes generated in the device.

[0104] The film thickness of the second electrode 12 is not particularly limited, but is preferably 0.01 to 100 μm, more preferably 0.01 to 10 μm, and even more preferably 0.01 to 1 μm.

[0105] (Charge Extraction Layer) Although not shown, the photodetector element may have a charge extraction layer between the second electrode 12 and the hole transport layer 22. By having the charge extraction layer, high external quantum efficiency can be obtained at a low applied voltage.

[0106] Materials for forming the charge extraction layer include metal oxides and organic semiconductors, with metal oxides being preferred. Metal oxides include molybdenum oxide, titanium oxide, vanadium oxide, chromium oxide, cobalt oxide, nickel oxide, copper oxide, zirconium oxide, molybdenum oxide, silver oxide, tantalum oxide, and tungsten oxide, with molybdenum oxide being preferred. Organic semiconductors include polythiophene compounds, with the materials mentioned above being specific examples of polythiophene compounds. The charge extraction layer may be a single-layer film or a laminated film of two or more layers.

[0107] The thickness of the charge extraction layer is preferably 1 to 100 nm, with the lower limit being preferably 5 nm or more and the upper limit being preferably 50 nm or less.

[0108] (Blocking Layer) Although not shown, the photodetector element may have a blocking layer between the first electrode 11 and the electron transport layer 21. The blocking layer has the function of preventing reverse current. The blocking layer is also called a short-circuit prevention layer. Examples of materials that form the blocking layer include silicon oxide, magnesium oxide, aluminum oxide, calcium carbonate, cesium carbonate, polyvinyl alcohol, polyurethane, titanium oxide, tin oxide, zinc oxide, niobium oxide, and tungsten oxide. The blocking layer may be a single-layer film or a laminated film of two or more layers. The blocking layer may be a single-layer film or a laminated film of two or more layers. The film thickness of the blocking layer is preferably 5 to 100 nm. The lower limit is preferably 10 nm or more. The upper limit is preferably 50 nm or less, and more preferably 30 nm or less.

[0109] In the photodetector element, the wavelength λ of the light to be detected by the photodetector element and the optical path length L of the light of the wavelength λ from the surface of the second electrode 12 on the photoelectric conversion film 13 side to the surface of the photoelectric conversion film 13 on the first electrode 11 side are λ and preferably satisfy the relationship of the following formula (1-1), and more preferably satisfy the relationship of the following formula (1-2): λWhen these satisfy this relationship, the phases of the light incident from the first electrode 11 side (incident light) and the light reflected from the surface of the second electrode 12 (reflected light) can be aligned in the photoelectric conversion film 13, and as a result, the light is reinforced by the optical interference effect, thereby achieving a higher external quantum efficiency.

[0110] 0.05+m / 2≦L λ / λ≦0.35+m / 2 ... (1-1) 0.10+m / 2≦L λ / λ≦0.30+m / 2 ... (1-2)

[0111] In the above formula, λ is the wavelength of the light to be detected by the light detection element, and L λ is the optical path length of light of wavelength λ from the surface of the second electrode 12 on the photoelectric conversion film 13 side to the surface of the photoelectric conversion film 13 on the first electrode 11 side, and m is an integer of 0 or more.

[0112] m is preferably an integer of 0 to 4, more preferably an integer of 0 to 3, and even more preferably an integer of 0 to 2. According to this embodiment, the transport properties of charges such as holes and electrons are good, and the external quantum efficiency of the photodetector can be further increased.

[0113] Here, the optical path length means the product of the physical thickness of the material through which light passes and the refractive index. Taking the photoelectric conversion film 13 as an example, the thickness of the photoelectric conversion film is d １ , the wavelength λ of the photoelectric conversion film １ The refractive index of the light is N １ When the wavelength λ transmitted through the photoelectric conversion film 13 is １ The optical path length of the light is N １ ×d １ When the photoelectric conversion film 13 or the hole transport layer 22 is configured by a laminated film of two or more layers, or when an intermediate layer is present between the hole transport layer 22 and the second electrode 12, the integrated value of the optical path lengths of the respective layers is the above-mentioned optical path length L λ is.

[0114] <Image Sensor> The image sensor of the present invention has the photoelectric conversion film of the present invention described above. The configuration of the image sensor is not particularly limited as long as it has a photodetection element and functions as an image sensor. Examples of the photodetection element include those described above.

[0115] The image sensor may include an infrared-transmitting filter layer, which preferably has low transmittance for light in the visible wavelength range, and more preferably has an average transmittance of 10% or less, even more preferably 7.5% or less, and particularly preferably 5% or less for light in the wavelength range of 400 to 650 nm.

[0116] The infrared transmission filter layer may be formed of a resin film containing a colorant. Examples of the colorant include chromatic colorants such as red, green, blue, yellow, purple, and orange, as well as black colorants. The colorant contained in the infrared transmission filter layer preferably comprises a combination of two or more chromatic colorants to form a black color, or a black colorant. Examples of combinations of chromatic colorants when a black color is formed by combining two or more chromatic colorants include the following (C1) to (C7): (C1) A configuration containing a red colorant and a blue colorant; (C2) A configuration containing a red colorant, a blue colorant, and a yellow colorant; (C3) A configuration containing a red colorant, a blue colorant, a yellow colorant, and a purple colorant; (C4) A configuration containing a red colorant, a blue colorant, a yellow colorant, a purple colorant, and a green colorant; and (C5) A configuration containing a red colorant, a blue colorant, a yellow colorant, and a green colorant. (C6) An embodiment containing a red color material, a blue color material, and a green color material. (C7) An embodiment containing a yellow color material and a purple color material.

[0117] The chromatic colorant may be a pigment or a dye. It may contain both a pigment and a dye. The black colorant is preferably an organic black colorant. Examples of organic black colorants include bisbenzofuranone compounds, azomethine compounds, perylene compounds, and azo compounds.

[0118] The infrared transmission filter layer may further contain an infrared absorber. By incorporating an infrared absorber into the infrared transmission filter layer, the wavelength of light to be transmitted can be shifted to a longer wavelength side. Examples of the infrared absorber include pyrrolopyrrole compounds, cyanine compounds, squarylium compounds, phthalocyanine compounds, naphthalocyanine compounds, quaterrylene compounds, merocyanine compounds, croconium compounds, oxonol compounds, iminium compounds, dithiol compounds, triarylmethane compounds, pyrromethene compounds, azomethine compounds, anthraquinone compounds, dibenzofuranone compounds, dithiolene metal complexes, metal oxides, and metal borides.

[0119] The spectral characteristics of the infrared transmission filter layer can be appropriately selected depending on the application of the image sensor. Examples include filter layers satisfying any one of the following spectral characteristics (1) to (5): (1): A filter layer in which the maximum light transmittance in the thickness direction of the film in the wavelength range of 400 to 750 nm is 20% or less (preferably 15% or less, more preferably 10% or less), and the minimum light transmittance in the thickness direction of the film in the wavelength range of 900 to 1500 nm is 70% or more (preferably 75% or more, more preferably 80% or more). (2): A filter layer in which the maximum light transmittance in the thickness direction of the film in the wavelength range of 400 to 830 nm is 20% or less (preferably 15% or less, more preferably 10% or less), and the minimum light transmittance in the thickness direction of the film in the wavelength range of 1000 to 1500 nm is 70% or more (preferably 75% or more, more preferably 80% or more). (3): A filter layer in which the maximum light transmittance in the thickness direction of the film in the wavelength range of 400 to 950 nm is 20% or less (preferably 15% or less, more preferably 10% or less), and the minimum light transmittance in the thickness direction of the film in the wavelength range of 1100 to 1500 nm is 70% or more (preferably 75% or more, more preferably 80% or more). (4): A filter layer in which the maximum light transmittance in the thickness direction of the film in the wavelength range of 400 to 1100 nm is 20% or less (preferably 15% or less, more preferably 10% or less), and the minimum light transmittance in the wavelength range of 1400 to 1500 nm is 70% or more (preferably 75% or more, more preferably 80% or more). (5) A filter layer having a maximum light transmittance in the thickness direction of the film in the wavelength range of 400 to 1300 nm of 20% or less (preferably 15% or less, more preferably 10% or less), and a minimum light transmittance in the wavelength range of 1600 to 2000 nm of 70% or more (preferably 75% or more, more preferably 80% or more).Further, as the infrared transmission filter, films described in JP 2013-077009 A, JP 2014-130173 A, JP 2014-130338 A, WO 2015 / 166779 A, ​​WO 2016 / 178346 A, WO 2016 / 190162 A, WO 2018 / 016232 A, JP 2016-177079 A, ​​JP 2014-130332 A, and WO 2016 / 027798 can be used. The infrared transmission filter may be a combination of two or more filters, or a dual bandpass filter that transmits two or more specific wavelength regions with one filter may be used.

[0120] The image sensor may include an infrared shielding filter for the purpose of improving various performances such as noise reduction, etc. Specific examples of the infrared shielding filter include the filters described in International Publication No. 2016 / 186050, International Publication No. 2016 / 035695, Japanese Patent No. 6248945, International Publication No. 2019 / 021767, Japanese Patent Laid-Open No. 2017-067963, and Japanese Patent No. 6506529.

[0121] The image sensor may include a dielectric multilayer film. Examples of the dielectric multilayer film include a multilayer film in which a high refractive index dielectric thin film (high refractive index material layer) and a low refractive index dielectric thin film (low refractive index material layer) are alternately stacked. The number of dielectric thin films stacked in the dielectric multilayer film is not particularly limited, but is preferably 2 to 100 layers, more preferably 4 to 60 layers, and even more preferably 6 to 40 layers. A material with a refractive index of 1.7 to 2.5 is preferred as a material used to form the high refractive index material layer. Specific examples include Sb ２ O ３ , Sb ２ S ３ , Bi ２ O ３ , CeO ２ , CeF ３ , HfO ２ , La ２ O ３ , Nd ２ O ３ , Pr ６ O １１ , Sc ２ O３ , SiO, Ta ２ O ５ , TiO ２ , TlCl, Y ２ O ３ , ZnSe, ZnS, ZrO ２ The material used to form the low refractive index material layer is preferably a material having a refractive index of 1.2 to 1.6. ２ O ３ , BiF ３ , CaF ２ , LaF ３ , PbCl ２ , PbF ２ , LiF, MgF ２ , MgO, NdF ３ , SiO ２ , Si ２ O ３ , NaF, ThO ２ , ThF ４ , Na ３ AlF ６ and the like. The method for forming the dielectric multilayer film is not particularly limited, and examples thereof include vacuum deposition methods such as ion plating and ion beam, physical vapor deposition methods (PVD methods) such as sputtering, and chemical vapor deposition methods (CVD methods). The thickness of each of the high refractive index material layer and the low refractive index material layer is preferably 0.1λ to 0.5λ, where λ (nm) is the wavelength of the light to be blocked. Specific examples of the dielectric multilayer film that can be used include the films described in JP 2014-130344 A and JP 2018-010296 A.

[0122] The dielectric multilayer film preferably has a transmission wavelength band in the infrared region (preferably a wavelength region exceeding 700 nm, more preferably a wavelength region exceeding 800 nm, and even more preferably a wavelength region exceeding 900 nm). The maximum transmittance in the transmission wavelength band is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. The maximum transmittance in the light-shielding wavelength band is preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less. The average transmittance in the transmission wavelength band is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more. The wavelength range of the transmission wavelength band is determined by dividing the wavelength showing the maximum transmittance by the center wavelength λ ｔ１ In this case, the central wavelength λ ｔ１ ±100 nm, and the central wavelength λ ｔ１ More preferably, the central wavelength λ ｔ１ It is more preferably ±50 nm.

[0123] The dielectric multilayer film may have only one transmission wavelength band (preferably a transmission wavelength band with a maximum transmittance of 90% or more), or may have a plurality of transmission wavelength bands.

[0124] The image sensor may include a color separation filter layer. Examples of the color separation filter layer include a filter layer containing colored pixels. Examples of the colored pixels include red, green, blue, yellow, cyan, and magenta pixels. The color separation filter layer may include colored pixels of two or more colors, or may include only one color. The filter layer may be appropriately selected depending on the application and purpose. For example, the filter described in International Publication No. 2019 / 039172 may be used.

[0125] Furthermore, when the color separation layer includes color pixels of two or more colors, the color pixels of each color may be adjacent to each other, and a partition wall may be provided between each color pixel. The material of the partition wall is not particularly limited. Examples include organic materials such as siloxane resin and fluororesin, and inorganic particles such as silica particles. The partition wall may also be made of a metal such as tungsten or aluminum.

[0126] When the image sensor includes an infrared transmission filter layer and a color separation layer, it is preferable that the color separation layer is provided on a different optical path from the infrared transmission filter layer. It is also preferable that the infrared transmission filter layer and the color separation layer are arranged two-dimensionally. The two-dimensional arrangement of the infrared transmission filter layer and the color separation layer means that at least a portion of each layer exists on the same plane.

[0127] The image sensor may include an intermediate layer such as a planarization layer, a base layer, or an adhesion layer, an anti-reflection film, and a lens. The anti-reflection film may be, for example, a film made from a composition described in International Publication No. 2019 / 017280. The lens may be, for example, a structure described in International Publication No. 2018 / 092600.

[0128] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. The ClogP value of each compound was calculated by predictive calculation using ChemDraw Professional ver. 20.1.1.125 (manufactured by PerkinElmer).

[0129] <Preparation of Dispersion> 1 mL of an octane dispersion of quantum dots (quantum dot concentration: 50 mg / mL, oleic acid concentration: 50 mg / mL) with oleic acid coordinated to the surface, as shown in the table below, 0.5 g of the ligand, and 10 mL of the solvent were weighed into a centrifuge tube and vigorously stirred for 10 minutes. Next, 30 mL of hexane was added, and the mixture was vigorously stirred for 1 minute. The upper hexane layer was then removed. This procedure was repeated twice. An excess amount of toluene was then added, and the mixture was centrifuged at 4000 rpm for 5 minutes. The resulting precipitate was vacuum-dried for 30 minutes, and the solvent and additives listed in the table below were added and stirred for 2 hours to obtain a dispersion. All of the above procedures were carried out under nitrogen. The average primary particle size of the InAs quantum dots was in the range of 3 to 13 nm. The average primary particle size of the PbS quantum dots was in the range of 5 to 8 nm. The quantum dot content in each dispersion was 5 to 7% by mass, and the ligand content was 0.5 to 3% by mass.

[0130] <Evaluation of Dispersibility> The obtained dispersion was left standing under nitrogen at 25°C for one week or one month, and then the presence or absence of aggregates was visually confirmed to evaluate dispersibility. A: No aggregation was observed even after standing for one month. B: Slight aggregation was observed after standing for one month, but no aggregation was observed after standing for one week. C: Slight aggregation was observed after standing for one week. D: The precipitate was not dispersed after centrifugation in the production process of the dispersion.

[0131]

[0132]

[0133] The details of the materials indicated by the abbreviations in the table above are as follows: (Ligand) L1-1: InBr ３ L1-2: InCl ３ L1-3: InI ３ L2-1: 3-mercaptopropionic acid L2-2: mercaptoethanol

[0134] (Solvent) S-1: N,N-dimethylformamide (CloP value -1.0) S-2: Dimethyl sulfoxide (CloP value -1.5)

[0135] (Specific compounds) A-1: ​​Heptane (CloP value 4.4) A-2: Nonane (CloP value 5.5) A-3: Tetramethylsilane (CloP value 3.2) A-4: Tetraethylsilane (CloP value 5.0)

[0136] The values ​​in the λmax column in the table above are the values ​​of the maximum absorption wavelength of the quantum dots. Furthermore, the values ​​listed in the content column in the table above are the values ​​of the content of additives contained in the dispersion. Of the materials contained in the dispersion, the only compounds with a ClogP value of 2.5 or greater are the materials listed in the additive column. Therefore, the additive content value is the content of compounds with a ClogP value of 2.5 or greater in the dispersion. Since Comparative Example 4 does not contain any additives, the content of compounds with a ClogP value of 2.5 or greater in the dispersion is 0% by mass. Furthermore, details of the materials listed in the type column in the table above, denoted by abbreviation, are as follows. In the dispersions of Examples 1 to 13 and 101, the content of quantum dots in the components excluding ligands and solvents is 55% by mass or greater, and the total content of quantum dots and ligands in the components excluding solvents is 60% by mass or greater.

[0137] As shown in the above table, all of the dispersions of the examples were excellent in dispersibility.

[0138] <Preparation of Zinc Oxide Particle Dispersion> (Zinc Oxide Particle Dispersion 1) 1.5 mmol of zinc acetate dihydrate and 15 mL of dimethyl sulfoxide (DMSO) were weighed and stirred in a flask to prepare a zinc acetate solution. A TMACl solution was prepared by dissolving 4 mmol of tetramethylammonium chloride (TMACl) in 4 mL of methanol, and a KOH solution was prepared by dissolving 4 mmol of potassium hydroxide (KOH) in 4 mL of methanol. While vigorously stirring the TMACl solution, the KOH solution was slowly added. After stirring for 30 minutes, the insoluble components were removed through a 0.45 μm pore filter to obtain a tetramethylammonium hydroxide (TMAH) solution. 6 mL of the TMAH solution was added dropwise to the zinc acetate solution in the flask at a rate of 6 mL / min. After holding for 1 hour, the reaction solution was recovered. An excess amount of acetone was added to the reaction solution, and the mixture was centrifuged at 10,000 rpm for 10 minutes. The supernatant was then removed, and the precipitate was dispersed in methanol. The precipitate was then precipitated again with acetone, and 5 ml of ethanol and 80 μl of aminoethanol were added thereto. The mixture was then ultrasonically dispersed to obtain zinc oxide particle dispersion 1 having a concentration of non-doped zinc oxide particles of approximately 30 mg / mL.

[0139] <Production of Photodetector Element> An ITO (Indium Tin Oxide) film having a thickness of about 100 nm was formed on quartz glass by sputtering using a metal mask to form a first electrode. ２ An insulating layer was formed by sputtering through a metal mask so as to fill the gap between the electrodes. Then, a UVO-CLEANER MODEL 144AX-100 manufactured by Jlight was used to apply a 30 mW / cm ２The film was subjected to ultraviolet ozone treatment for 5 minutes under conditions of wavelength peak 254 nm. Next, zinc oxide particle dispersion 1 was dropped onto the ITO film (first electrode), spin-coated at 3000 rpm, and heated at 60°C for 5 minutes. This process was repeated twice to form a zinc oxide particle film with a thickness of approximately 200 nm, thereby forming an electron transport layer. Next, a dispersion liquid shown in the table below was dropped onto the electron transport layer, followed by spin-coating at 1000 rpm and drying at 120°C for 10 minutes to form a quantum dot film. The quantum dot film formation process was repeated twice to form a photoelectric conversion film with a thickness of 200 nm. The photoelectric conversion film was then dried in a glove box for 10 hours.

[0140] Next, a dichlorobenzene solution (concentration: 5 mg / mL) of PTB7 (poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl})) was spin-coated onto the photoelectric conversion film at 2000 rpm, and then dried in a glove box for 10 hours to form a hole transport layer.

[0141] Next, a 100 nm thick Au film (second electrode) was formed on the hole transport layer by vacuum deposition using a metal mask to form six element portions, thereby producing a photodiode-type light-detecting element.

[0142] <Evaluation> (Photodetector elements using the dispersions of Examples 1 to 13 (Production Examples 1 to 13) and photodetector elements using the dispersions of Comparative Examples 1 to 4 (Production Examples R1 to R4)) For each photodetector element, the dark current, external quantum efficiency, and yield were evaluated using a semiconductor parameter analyzer (C4156, manufactured by Agilent). First, the current-voltage characteristics (I-V characteristics) were measured while sweeping the voltage from 0 V to -5 V in a state where no light was irradiated, and the dark current was evaluated based on the following criteria. Here, the dark current value was defined as the value at -1 V. Next, the I-V characteristics were measured while sweeping the voltage from 0 V to -5 V in a state where monochromatic light with a wavelength of 1450 nm was irradiated. The photocurrent value was determined by subtracting the dark current value from the current value in a state where -1 V was applied, and the photoelectric conversion efficiency was calculated from this value. The external quantum efficiency was evaluated based on the following criteria. The dark current value and external quantum efficiency were measured for each element part of the 10 photodetector elements (60 element parts in total). The dark current value and external quantum efficiency values ​​used in the evaluation of the dark current and external quantum efficiency were the values ​​of the element part showing the median value among the measured values ​​for the 60 element parts. Regarding the yield evaluation, if the measured value of the dark current or photoelectric conversion rate for each element part was one digit or more away from the value of the element part showing the median value, the product was deemed defective. Furthermore, each element part of the photodetector element was observed with an optical microscope, and if aggregates were confirmed, the product was deemed defective. The yield rate was calculated using the following formula, and the yield was evaluated according to the following criteria: Yield rate = (60 - number of defective element parts) / 60 x 100

[0143] -Dark current evaluation criteria- A: Dark current value is 5×10 －８ A / cm ２ 5x10 or more －７ A / cm ２ B: The dark current value is less than 5×10 －７ A / cm ２ 5x10 or more －６ A / cm ２ C: The dark current value is less than 5×10 －６ A / cm ２ That's all

[0144] -External quantum efficiency evaluation criteria- A: The external quantum efficiency value is 5% or more. B: The external quantum efficiency value is 2% or more and less than 5%. C: The external quantum efficiency value is less than 2%.

[0145] - Yield evaluation criteria - A: Yield rate is 75% or more. B: Yield rate is 50% or more but less than 75%. C: Yield rate is less than 50%.

[0146] The evaluation results for each Production Example are shown in the evaluation column of the table below. Note that for Production Examples R1 and R2, the dark current and external quantum efficiency could not be measured.

[0147]

[0148] As shown in the table above, the photodetector elements manufactured using the dispersions of the Examples were superior in all evaluations of yield, dark current, and external quantum efficiency to the photodetector elements manufactured using the dispersions of the Comparative Examples.

[0149] (Regarding Photodetector Element Using the Dispersion of Example 101 (Production Example 101)) The photodetector element was evaluated for dark current, external quantum efficiency, and yield using a semiconductor parameter analyzer (C4156, manufactured by Agilent). First, the current-voltage characteristics (IV characteristics) were measured while sweeping the voltage from 0 V to -5 V in a state where no light was irradiated, and the dark current was evaluated based on the following criteria. Here, the dark current value at -1 V was taken as the dark current value. Next, the IV characteristics were measured while sweeping the voltage from 0 V to -5 V in a state where monochrome light with a wavelength of 1450 nm was irradiated. The photocurrent value was determined by subtracting the above dark current value from the current value in a state where -1 V was applied, and the photoelectric conversion efficiency was calculated from this value, and the external quantum efficiency was evaluated based on the following criteria. The dark current value and external quantum efficiency were measured for each element part of 10 photodetector elements (a total of 60 element parts). The dark current and external quantum efficiency values ​​used in the evaluation of dark current and external quantum efficiency were the values ​​of the element part showing the median value among the measured values ​​of 60 element parts. In addition, for the evaluation of yield, if the measured value of the dark current or photoelectric conversion rate of each element part was one digit or more away from the value of the element part showing the median value, it was deemed to be a defective product. In addition, each element part of the photodetector was observed with an optical microscope, and if aggregates were confirmed, it was also deemed to be a defective product. The yield rate was calculated using the following formula and evaluated according to the following criteria. Yield rate = (60 - number of defective element parts) / 60 x 100

[0150] -Dark current evaluation criteria- A: Dark current value is 5×10 －８ A / cm ２ 5x10 or more －７ A / cm ２ B: The dark current value is less than 5×10 －７ A / cm ２ 5x10 or more －６ A / cm ２ C: The dark current value is less than 5×10 －６ A / cm ２ That's all

[0151] -External quantum efficiency evaluation criteria- A: The external quantum efficiency value is 5% or more. B: The external quantum efficiency value is 2% or more and less than 5%. C: The external quantum efficiency value is less than 2%.

[0152] - Yield evaluation criteria - A: Yield rate is 75% or more. B: Yield rate is 50% or more but less than 75%. C: Yield rate is less than 50%.

[0153]

[0154] As shown in the above table, the photodetector elements manufactured using the dispersions of the examples were excellent in the evaluations of yield, dark current, and external quantum efficiency.

[0155] By using the photodetector elements obtained in the examples and optical filters prepared according to the methods described in WO 2016 / 186050 and WO 2016 / 190162 to prepare an image sensor by a known method, an image sensor having good visible-infrared imaging performance can be obtained.

[0156] 1: Photodetector element 11: First electrode 12: Second electrode 13: Photoelectric conversion film 21: Electron transport layer 22: Hole transport layer

Claims

1. A dispersion comprising quantum dots having a band gap of 1.35 eV or less, a ligand, a solvent, and a compound A having a ClogP value of 2.5 or more, wherein the content of the quantum dots in the components excluding the ligand and the solvent from the dispersion is 50% by mass or more, and the content of the compound A having a ClogP value of 2.5 or more in the dispersion is 0.01 to 3.00% by mass.

2. The dispersion of claim 1, wherein the ClogP value of compound A is from 2.5 to 5.

8.

3. The dispersion according to claim 1 or 2, wherein the compound A is at least one selected from the group consisting of hydrocarbon compounds and silane compounds.

4. The dispersion according to claim 1 or 2, wherein the molecular weight of compound A is 85 to 160.

5. The dispersion of claim 1 or 2, wherein the solvent has a ClogP value of 2.0 or less.

6. The dispersion according to claim 1 or 2, wherein the difference between the ClogP value of said compound A and the ClogP value of said solvent is 1.0 to 10.

0.

7. The dispersion according to claim 1 or 2, wherein the ligand comprises at least one selected from inorganic halides and organic ligands.

8. The dispersion according to claim 1 or 2, wherein the quantum dots contain at least one element selected from the group consisting of P, As, Sb, and In.

9. The dispersion according to claim 1 or 2, wherein the quantum dots have a maximum absorption in the wavelength range of 900 to 1700 nm.

10. A photoelectric conversion film obtained using the dispersion liquid according to claim 1 or 2.

11. A method for producing a photoelectric conversion film, comprising the steps of: applying the dispersion liquid according to claim 1 or 2 onto a support to form a composition layer; and drying the composition layer.

12. A photodetector having the photoelectric conversion film according to claim 10.

13. An image sensor having the photoelectric conversion film according to claim 10.