WO2024048123A1

WO2024048123A1 - Photoelectric conversion element, ink for producing photoelectric conversion element, method for manufacturing photoelectric conversion element, image sensor, and fingerprint authentication device

Info

Publication number: WO2024048123A1
Application number: PCT/JP2023/026967
Authority: WO
Inventors: 諒一平岡; 裕也鬼塚
Original assignee: 住友化学株式会社
Priority date: 2022-08-31
Filing date: 2023-07-24
Publication date: 2024-03-07
Also published as: JP2024034522A

Abstract

The present invention addresses the problem of providing a photoelectric conversion element in which an increase in dark current after heat treatment is suppressed.　The present invention relates to a photoelectric conversion element having: an anode (12); a cathode (16); an active layer (14) provided between the anode (12) and the cathode (16); and intermediate layers (13, 15) provided between the anode (12) and the active layer (14) and/or between the cathode (16) and the active layer (14). The intermediate layers (13, 15) contain a non-ionic insulating polymer.

Description

Photoelectric conversion element, ink for producing photoelectric conversion element, method for producing photoelectric conversion element, image sensor, and fingerprint authentication device

The present disclosure relates to a photoelectric conversion element, an ink for producing a photoelectric conversion element, a method for producing a photoelectric conversion element, an image sensor, and a fingerprint authentication device.

Photoelectric conversion elements are extremely useful devices from the viewpoint of energy saving and reduction of carbon dioxide emissions, for example, and are attracting attention.

A photoelectric conversion element is an element that has an anode, a cathode, and an active layer provided between the anode and the cathode. In a photoelectric conversion element, one of the electrodes is made of a transparent or semitransparent material, and light is incident on the active layer from the transparent or semitransparent electrode side. Charges (holes and electrons) are generated in the active layer by the energy (hv) of the light incident on the active layer, and the generated holes move toward the anode and electrons move toward the cathode. The charges that have reached the anode and cathode are extracted to the outside of the device.

In the production of photoelectric conversion elements, if electrodes (i.e., anodes and cathodes) are provided directly on the surface of the active layer, the active layer may be damaged. Therefore, in the photoelectric conversion element, an intermediate layer or the like is sometimes provided between the electrode and the active layer.

Non-Patent Document 1 and Non-Patent Document 2 disclose that zinc oxide and PFN (poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2 , 7-(9,9-dioctyl)fluorene]) or PEI (polyethyleneimine).

A photoelectric conversion element is used, for example, as a photodetection element. A photoelectric conversion element used as a photodetection element is used in a state where a voltage is applied, and light incident on the element is converted and detected as an electric current. However, even when no light is incident, a weak current flows through the photoelectric conversion element. This current is known as dark current, and is a factor that reduces the accuracy of photodetection.

Conventionally, when a photoelectric conversion element is mounted on an image sensor or the like, dark current may increase after heat treatment (180 to 230°C) in the soldering or sealing process. From the viewpoint of improving versatility, there is a demand for the development of photoelectric conversion elements with high heat resistance.

Therefore, an object of an embodiment of the present disclosure is to provide a photoelectric conversion element in which an increase in dark current after heat treatment is suppressed.
A problem to be solved by another embodiment of the present disclosure is to provide an ink for producing a photoelectric conversion element containing a nonionic insulating polymer.
A problem to be solved by another embodiment of the present disclosure is to provide a method for manufacturing a photoelectric conversion element that can obtain a photoelectric conversion element in which an increase in dark current after heat treatment is suppressed.
A problem to be solved by another embodiment of the present disclosure is to provide a photodetection element in which an increase in dark current after heat treatment is suppressed.
A problem to be solved by another embodiment of the present disclosure is to provide an image sensor including a photoelectric conversion element in which an increase in dark current after heat treatment is suppressed.
A problem to be solved by another embodiment of the present disclosure is to provide a fingerprint authentication device including a photoelectric conversion element in which an increase in dark current after heat treatment is suppressed.

Means for solving the above problems include the following means.
<1> An anode,
a cathode;
an active layer provided between the anode and the cathode;
an intermediate layer provided between the anode and the active layer and at least one between the cathode and the active layer,
A photoelectric conversion element in which the intermediate layer includes a nonionic insulating polymer.
<2> The photoelectric conversion element according to <1>, wherein the nonionic insulating polymer has a glass transition temperature of 100° C. or higher.
<3> The photoelectric conversion element according to <1> or <2>, wherein the nonionic insulating polymer has a melting point of 150° C. or higher.
<4> Any one of <1> to <3>, wherein the nonionic insulating polymer is at least one selected from the group consisting of poly(meth)acrylic, polycarbonate, polyimide, and fluorine-containing polymer. The photoelectric conversion element described in .
<5> The photoelectric conversion element according to any one of <1> to <4>, wherein the nonionic insulating polymer is polyimide.
<6> The photoelectric conversion element according to any one of <1> to <5>, comprising an intermediate layer between the cathode and the active layer.
<7> The photoelectric conversion element according to <6>, wherein the cathode is a transparent or semitransparent electrode.
<8> The photoelectric conversion element according to any one of <1> to <7>, wherein the active layer contains a p-type semiconductor material.
<9> The p-type semiconductor material is a polymer compound containing at least one selected from the group consisting of a structural unit represented by the following formula (I) and a structural unit represented by the following formula (II). 8>.

In formula (I), Z represents a group represented by any one of formulas (Z-1) to (Z-7), and Ar ¹ and Ar ² may be the same or different. Represents a good trivalent aromatic heterocyclic group. In formula (II), Ar ³ represents a divalent aromatic heterocyclic group. In formulas (Z-1) to (Z-7), R is each independently a hydrogen atom, a halogen atom, an alkyl group that may have a substituent, or a cycloalkyl that may have a substituent. group, alkenyl group that may have a substituent, cycloalkenyl group that may have a substituent, alkynyl group that may have a substituent, cycloalkynyl that may have a substituent group, an aryl group which may have a substituent, an alkyloxy group which may have a substituent, a cycloalkyloxy group which may have a substituent, a cycloalkyloxy group which may have a substituent Aryloxy group, optionally substituted alkylthio group, optionally substituted cycloalkylthio group, optionally substituted arylthio group, optionally substituted arylthio group Monovalent heterocyclic group, substituted amino group that may have a substituent, imine residue that may have a substituent, amide group that may have a substituent, an acid imide group which may have a substituent, a substituted oxycarbonyl group which may have a substituent, a cyano group, a nitro group, a group represented by -C(=O)-R ^c , or -SO ₂ -R ^d R ^c and R ^d each independently represent a hydrogen atom, an alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, or a substituent. an aryl group which may have a substituent, an alkyloxy group which may have a substituent, a cycloalkyloxy group which may have a substituent, an aryloxy group which may have a substituent, Or represents a monovalent heterocyclic group which may have a substituent. When a plurality of R's exist, the plurality of R's may be the same or different.
<10> The photoelectric conversion element according to <1>, wherein the intermediate layer has a thickness of 1 nm or more and 20 nm or less.
<11> An ink for producing a photoelectric conversion element containing a nonionic insulating polymer.
<12> A method for manufacturing a photoelectric conversion element, including the steps of forming a coating film by applying an ink containing a nonionic insulating polymer, and drying the coating film.
<13> The photoelectric conversion element according to any one of <1> to <10>, which is a photodetection element. <14> An image sensor including the photoelectric conversion element according to <13>.
<15> A fingerprint authentication device including the photoelectric conversion element according to <13>.

According to an embodiment of the present disclosure, a photoelectric conversion element is provided in which increase in dark current after heat treatment is suppressed.
According to another embodiment of the present disclosure, an ink for producing a photoelectric conversion element containing a nonionic insulating polymer is provided.
According to another embodiment of the present disclosure, there is provided a method for manufacturing a photoelectric conversion element that can obtain a photoelectric conversion element in which an increase in dark current after heat treatment is suppressed.
According to another embodiment of the present disclosure, a photodetection element is provided in which increase in dark current after heat treatment is suppressed.
According to another embodiment of the present disclosure, an image sensor including a photoelectric conversion element in which increase in dark current after heat treatment is suppressed is provided.
According to another embodiment of the present disclosure, a fingerprint authentication device including a photoelectric conversion element in which increase in dark current after heat treatment is suppressed is provided.

FIG. 1 is a schematic cross-sectional view of a photoelectric conversion element according to an embodiment of the present disclosure. 1 is a schematic cross-sectional view of an image detection section for a solid-state imaging device according to an embodiment of the present disclosure. FIG. 2 is a schematic cross-sectional view of a fingerprint detection unit according to an embodiment of the present disclosure.

An embodiment that is an example of the present disclosure will be described below. These descriptions and examples are illustrative of embodiments and are not intended to limit the scope of the invention.
In the numerical ranges described step by step in this specification, the upper limit value or lower limit value described in one numerical range may be replaced with the upper limit value or lower limit value of another numerical range described step by step. good. Further, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with the value shown in the Examples.

Each component may contain multiple types of applicable substances.
When referring to the amount of each component in a composition, if there are multiple types of substances corresponding to each component in the composition, unless otherwise specified, the total amount of the multiple types of substances present in the composition means quantity.

"P-valent aromatic heterocyclic group" refers to an aromatic heterocyclic compound which may have a substituent, in which P atoms of the hydrogen atoms directly bonded to the carbon atoms or heteroatoms constituting the ring are means the remaining atomic group excluding the hydrogen atom.
"P-valent heterocyclic group" (P represents an integer of 1 or more) means a direct bond from a heterocyclic compound that may have a substituent to a carbon atom or heteroatom constituting the ring. It means the remaining atomic group after removing P hydrogen atoms from among the hydrogen atoms shown in the figure.

<Photoelectric conversion element>
The photoelectric conversion element according to the present disclosure includes an anode, a cathode, an active layer provided between the anode and the cathode, and at least one of between the anode and the active layer and between the cathode and the active layer. an intermediate layer provided, the intermediate layer comprising a nonionic insulating polymer.

The present inventors conducted extensive research and discovered that by applying a layer containing a nonionic insulating polymer as an intermediate layer, the generation of dark current after heat is applied can be suppressed. A photoelectric conversion element according to the present disclosure has been completed.

(electrode)
The photoelectric conversion element according to the present disclosure has an anode and a cathode (hereinafter, the anode and the cathode are also collectively referred to as electrodes).
Examples of the electrode include transparent or translucent electrodes. Examples of the transparent or semitransparent electrode include a conductive metal oxide film and a semitransparent metal thin film.
Specifically, the electrode material includes conductive materials such as indium oxide, zinc oxide, tin oxide, and their composites such as indium tin oxide (ITO), indium zinc oxide (IZO), and NESA; gold; Examples include platinum; silver; copper; and the like. The material of the electrode is preferably ITO, IZO or tin oxide.
Further, as the material of the electrode, organic compounds such as polyaniline and its derivatives, polythiophene and its derivatives, etc. may be used.

The electrode may be an electrode with low light transmittance. Examples of materials for the electrode with low light transmittance include metals and conductive polymers. Specific examples of electrode materials with low optical transparency include:
Metals such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium; two or more of these alloys of one or more of these metals and one or more metals selected from the group consisting of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten and tin; graphite; Graphite intercalation compounds; polyaniline and its derivatives; polythiophene and its derivatives; and the like. The alloys include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, and calcium-aluminum alloy.

It is preferable that at least one of the electrodes of the photoelectric conversion element according to the present disclosure is a transparent or semitransparent electrode.
Moreover, when the photoelectric conversion element according to the present disclosure has an intermediate layer between the cathode and the active layer, it is preferable that the cathode is a transparent or translucent electrode.

The thickness of the electrode is not particularly limited, but may be, for example, 1 nm or more and 1000 nm or less, or 100 nm or more and 500 nm or less, and when the photoelectric conversion element according to the present disclosure is used as a photodetecting element, high transmittance can be obtained. is required, so it is preferably 5 nm or more and 200 nm or less.

As a method for forming the electrode, any conventionally known suitable forming method can be used. Examples of methods for forming the electrode include vacuum evaporation, sputtering, ion plating, coating methods such as slit coating and spin coating, and plating.

(active layer)
A photoelectric conversion element according to the present disclosure includes an active layer provided between an anode and a cathode.
The active layer preferably contains a p-type semiconductor material (electron-donating compound), and contains a p-type semiconductor material (electron-donating compound) and an n-type semiconductor material (electron-accepting compound) (a suitable p-type semiconductor The details of the material and the n-type semiconductor material will be described later.) is more preferable. Which of the p-type semiconductor material and the n-type semiconductor material is used can be relatively determined from the HOMO energy level or LUMO energy level of the selected compound.

The thickness of the active layer is preferably 150 nm or more and 10000 nm or less, more preferably 200 nm or more and 1000 nm or less.

The active layer can be formed by a coating method. Details of the p-type semiconductor material and n-type semiconductor material that can be included in the active layer and the method for forming the active layer will be described later.

(middle class)
A photoelectric conversion element according to the present disclosure includes an intermediate layer provided between an anode and an active layer and at least one between a cathode and an active layer.
The intermediate layer includes a nonionic insulating polymer.
From the viewpoint of suppressing the generation of dark current, the photoelectric conversion element according to the present disclosure preferably has an intermediate layer between the cathode and the active layer.

Nonionic means that it does not have a salt structure and does not have a Brønsted acid or Brønsted basicity.
The presence or absence of Brønsted acid or Brønsted basicity is determined using a pH meter. Specifically, the judgment is as follows.
A polymer solution is obtained by dissolving 5 g of the target polymer in 100 g of water. The temperature of the polymer solution is set to 25° C., and the pH of the polymer solution is measured using a pH meter. If the pH is 5 or less or 8 or more, it is considered to have Brønsted acid or Brønsted basicity.

An insulating polymer is a polymer having a band gap of 3 eV or more at room temperature. The insulating polymer is preferably a polymer with a voltage of 3.5 eV or more.
Room temperature is a temperature of 25°C±5°C.
The band gap (Eg) can be calculated by the following formula using the optical absorption edge wavelength of the polymer material to be measured. In the formula, h represents Planck's constant (6.626×10 ⁻³⁴ Js) and c represents the speed of light (3×10 ⁸ m/s).
Formula: Eg=hc/absorption edge wavelength

In the above formula, the absorption edge wavelength can be measured with a spectrophotometer that can measure in the wavelength range of ultraviolet light, visible light, and near-infrared light. Photometer JASCO-V670 can be used. In the absorption spectrum obtained by a spectrophotometer, that is, the absorbance (absorption intensity) of the (polymer) compound is plotted on the vertical axis and the wavelength is plotted on the horizontal axis, the absorption edge wavelength is The value of the wavelength at the intersection of the line and the straight line fitted at the shoulder of the absorption peak (on the high wavelength side) can be taken as the absorption edge wavelength (nm).

From the viewpoint of suppressing an increase in dark current, the glass transition temperature of the nonionic insulating polymer is preferably 100° C. or higher. The glass transition temperature is more preferably 150°C or higher, and even more preferably 200°C or higher. Further, the upper limit of the glass transition temperature is not particularly limited, but may be, for example, 400° C. or lower.
Therefore, the glass transition temperature of the nonionic insulating polymer is preferably 100°C or more and 400°C or less, more preferably 150°C or more and 400°C or less, and even more preferably 200°C or more and 400°C or less. preferable.

From the viewpoint of suppressing an increase in dark current, the melting point of the nonionic insulating polymer is preferably 150° C. or higher. The melting point of the nonionic insulating polymer is more preferably 200°C or higher, and even more preferably 300°C or higher. The upper limit of the melting point of the nonionic insulating polymer is not particularly limited, but may be, for example, 600° C. or lower.
Therefore, the melting point of the nonionic insulating polymer is preferably 150°C or more and 600°C or less, more preferably 200°C or more and 600°C or less, and even more preferably 300°C or more and 600°C or less. A more preferable range of the melting point of the nonionic insulating polymer is 150°C or more and 500°C or less, more preferably 200°C or more and 500°C or less, and still more preferably 300°C or more and 500°C or less.

For the glass transition temperature and melting point, values described in known documents including commercial catalogs may be referred to, but in accordance with JIS-K7121:2012, "4.1 Differential Thermal Analysis (DTA)" or "4. 2. It may be measured by differential scanning calorimetry (DSC). In either measurement method, the glass transition temperature and melting point of the nonionic insulating polymer are preferably within the above ranges.

The glass transition temperature and melting point are measured using a differential thermal analyzer or a differential scanning calorimeter. As the differential thermal analysis device, DTA-50 manufactured by Shimadzu Corporation can be used, and as the differential scanning calorimetry device, DSC-60A Plus manufactured by Shimadzu Corporation can be used.

The procedure for measuring the glass transition temperature and melting point using a differential thermal analyzer is, for example, as follows.
The melting point is defined as the endothermic peak temperature observed when measuring 2 to 10 mg of sample under heating conditions of 10°C/min from room temperature to 400°C. The glass transition temperature can be determined by the method described in "9.3 How to determine the glass transition temperature" of JIS-K7121:2012.

The nonionic insulating polymer is preferably a nonconjugated polymer.
A non-conjugated polymer is a polymer other than a conjugated polymer.
A conjugated polymer is a polymer in which a conjugated structure exists throughout the polymer.

Nonionic insulating polymers include poly(meth)acrylic (e.g., polyacrylate, polymethacrylate, polyacrylonitrile, etc.); polyvinyl alcohol; polyester (e.g., polyethylene terephthalate, polyester naphthalate, polycarbonate, etc.); polyamide; vinyl Polymers (e.g., polystyrene, polyvinyltoluene, polyvinylxylene, etc.); polyimide-based polymers; polysulfides; polysulfones; polyphenylene; (e.g., polysilsesquioxane, polysilane, etc.); polyvinyl chloride; polyacetate; polynorbornene; synthetic rubber (e.g., ethylene propylene rubber, styrene butadiene rubber, ethylene propylene diene rubber, etc.); fluorine-containing polymers (e.g., polyvinylidene fluoride rubber, etc.); Acrylonitrile-butadiene-styrene copolymer ( ABS); phenolic resins (e.g., novolak, etc.), etc.

From the viewpoint of suppressing increase in dark current, the nonionic insulating polymer is preferably at least one selected from the group consisting of poly(meth)acrylic, polycarbonate, polyimide polymer, and fluorine-containing polymer, More preferably, it is a polyimide polymer.

The polyimide polymer can be produced using the tetracarboxylic acid compound and diamine described below as raw materials. Moreover, diisocyanate can be used as a raw material instead of diamine.

Polyimide represents a polymer containing a structural unit containing an imide group, and polyamide-imide represents a polymer containing both a structural unit containing an imide group and a structural unit containing an amide group. The polyimide polymer represents any polymer selected from polyimide and polyamideimide.

The polyimide polymer has a structural unit represented by formula (10). Here, in formula (10), G represents a tetravalent organic group, and A represents a divalent organic group.
The polyimide polymer may contain two or more different types of structural units represented by formula (10). Furthermore, the polyimide polymer according to the present disclosure may include any one or more of the structural units represented by any one of formula (11), formula (12), and formula (13).

In formulas (10) and (11), G and G ¹ each independently represent a tetravalent organic group, preferably a tetravalent organic group having 4 or more and 40 or less carbon atoms. The organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, and in that case, the number of carbon atoms in the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1 or more and 8 or less. . As G and ^G1 , formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28 ) or a group represented by formula (29); a tetravalent chain hydrocarbon group having 6 or less carbon atoms; and the like. * in formulas (20) to (29) represents a bond, and Z represents a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, - C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -Ar-, -SO ₂ -, -CO-, -O-Ar-O-, -Ar-O-Ar-, -Ar-CH ₂ -Ar-, -Ar-C(CH ₃ ) ₂ -Ar- or -Ar-SO ₂ -Ar-. Ar represents an arylene group having 6 or more and 20 or less carbon atoms which may be substituted with a fluorine atom, and a specific example thereof is a phenylene group. Since it is easy to suppress the yellowness of the intermediate layer, G and ^G1 are expressed by formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula A group represented by either (26) or formula (27) is preferable.

In formula (12), G ² represents a trivalent organic group, and is preferably a trivalent organic group having 4 or more and 40 or less carbon atoms. The organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, and in that case, the number of carbon atoms in the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1 or more and 8 or less. . As ^G2 , formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) or Examples include a group in which any one of the bonds of the group represented by formula (29) is replaced with a hydrogen atom; a trivalent chain hydrocarbon group having 6 or less carbon atoms; and the like. The example of Z in the formula is the same as the example of Z in the description regarding G.

In formula (13), G ³ represents a divalent organic group, and is preferably a divalent organic group having 4 or more and 40 or less carbon atoms. The organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group, and in that case, the number of carbon atoms in the hydrocarbon group and the fluorine-substituted hydrocarbon group is preferably 1 or more and 8 or less. . As ^G3 , formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) or Examples include a group in which two non-adjacent bonds of the group represented by any of formula (29) are replaced with hydrogen atoms; a divalent chain hydrocarbon group having 6 or less carbon atoms; and the like. The example of Z in the formula is the same as the example of Z in the description regarding G.

In formulas (10) to (13), A, A ¹ , A ² and A ³ all represent a divalent organic group, preferably a divalent organic group having 4 or more and 40 or less carbon atoms. The organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group having 1 to 8 carbon atoms; in that case, the hydrocarbon group and the fluorine-substituted hydrocarbon group have 1 or more carbon atoms. It is preferably 8 or less. A, A ¹ , A ² and A ³ are respectively formula (30), formula (31), formula (32), formula (33), formula (34), formula (35), formula (36), and formula A group represented by either (37) or formula (38); a group in which any of them is substituted with one or more of methyl group, fluoro group, chloro group, or trifluoromethyl group; carbon number 6 Examples include the following chain hydrocarbon groups.
In formulas (30) to (38), * represents a bond, and Z ¹ , Z ² and Z ³ each independently represent a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ - or -CO-. One example is Z ¹
and Z ³ is -O-, and Z ² is -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ - or -SO ₂ -.
Z ¹ and Z ² and Z ² and Z ³ are each preferably located at the meta or para position with respect to each ring.

Polyimide polymers are obtained, for example, by polycondensation of diamines and tetracarboxylic acid compounds (tetracarboxylic dianhydrides, etc.), and are described in, for example, JP-A No. 2006-199945 or JP-A No. 2008-163107. It can be synthesized according to the method described. Examples of polyimide polymers include Neoprim manufactured by Mitsubishi Gas Chemical Co., Ltd. and KPI-MX300F manufactured by Kawamura Sangyo Co., Ltd.

Examples of tetracarboxylic acid compounds used in the synthesis of polyimide polymers include aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic dianhydride, and aliphatic tetracarboxylic acid compounds such as aliphatic tetracarboxylic dianhydride. can be mentioned. Tetracarboxylic acid compounds may be used alone or in combination of two or more. The tetracarboxylic acid compound may be a tetracarboxylic acid compound analog such as a tetracarboxylic acid chloride compound in addition to a tetracarboxylic dianhydride.

Examples of the aromatic tetracarboxylic dianhydride include non-fused polycyclic aromatic tetracarboxylic dianhydride, monocyclic aromatic tetracarboxylic dianhydride, and fused polycyclic aromatic tetracarboxylic dianhydride. Examples include anhydrides. Examples of the non-fused polycyclic aromatic tetracarboxylic dianhydride include 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2' , 3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxylic dianhydride) phenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (can be written as 6FDA) ), 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,2-bis(3,4 -dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3- dicarboxyphenyl)methane dianhydride, 4,4'-(p-phenylenedioxy)diphthalic dianhydride, and 4,4'-(m-phenylenedioxy)diphthalic dianhydride. In addition, as the monocyclic aromatic tetracarboxylic dianhydride, 1,2,4,5-benzenetetracarboxylic dianhydride is used, and as the fused polycyclic aromatic tetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride is mentioned.

Among these, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, and 2,2',3,3'-benzophenonetetracarboxylic dianhydride are preferable. Anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyl Sulfone tetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2- Bis(3,4-dicarboxyphenoxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), 1,2-bis(2,3-dicarboxyphenyl) Ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3 ,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(p- Examples include phenylenedioxy)diphthalic dianhydride and 4,4'-(m-phenylenedioxy)diphthalic dianhydride, more preferably 4,4'-oxydiphthalic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) , bis(3,4-dicarboxyphenyl)methane dianhydride and 4,4′-(p-phenylenedioxy)diphthalic dianhydride. These can be used alone or in combination of two or more.

Examples of the aliphatic tetracarboxylic dianhydride include cyclic or acyclic aliphatic tetracarboxylic dianhydride. Cycloaliphatic tetracarboxylic dianhydride is a tetracarboxylic dianhydride having an alicyclic hydrocarbon structure, and specific examples include 1,2,4,5-cyclohexanetetracarboxylic dianhydride. , cycloalkane tetracarboxylic dianhydride such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, bicyclo[2.2. 2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl 3,3'-4,4'-tetracarboxylic dianhydride, and positional isomers thereof. These can be used alone or in combination of two or more. Specific examples of the acyclic aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-pentanetetracarboxylic dianhydride, etc. These can be used alone or in combination of two or more.

From the viewpoint of transparency of the intermediate layer and suppression of coloration, the tetracarboxylic acid compound is preferably the alicyclic tetracarboxylic dianhydride or the non-fused polycyclic aromatic tetracarboxylic dianhydride. It will be done. More preferred specific examples include 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, and 2,2-bis(3 , 4-dicarboxyphenyl)propane dianhydride, and 4,4'-(hexafluoroisopropylidene) diphthalic dianhydride (6FDA). These can be used alone or in combination of two or more.

Polyimide polymers are made by further reacting tetracarboxylic acids, tricarboxylic acid compounds, dicarboxylic acid compounds, their anhydrides, and their derivatives in addition to the tetracarboxylic acid anhydrides used in the polyimide synthesis described above. There may be.

Examples of the tricarboxylic acid compound include aromatic tricarboxylic acids, aliphatic tricarboxylic acids, their acid chloride compounds, and acid anhydrides, and two or more of these may be used in combination.
Specific examples of tricarboxylic acid compounds include 1,2,4-benzenetricarboxylic anhydride; 2,3,6-naphthalenetricarboxylic acid-2,3-anhydride; phthalic anhydride and benzoic acid forming a single bond , -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ - or a phenylene group; and the like.

Examples of dicarboxylic acid compounds include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and their analogous acid chloride compounds, acid anhydrides, and the like, and two or more of these may be used in combination. Specific examples include dicarboxylic acid compounds of terephthalic acid; isophthalic acid; naphthalenedicarboxylic acid; 4,4'-biphenyldicarboxylic acid; 3,3'-biphenyldicarboxylic acid; chain hydrocarbons having 8 or less carbon atoms; The two benzoic acid skeletons are -CH ₂ -, -S-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -O-, -NR ⁹ -, -C(=O)-, Examples include compounds linked with either -SO ₂ - or a phenylene group. These can be used alone or in combination of two or more.

The dicarboxylic acid compound is preferably terephthalic acid; isophthalic acid; 4,4'-biphenyldicarboxylic acid; 3,3'-biphenyldicarboxylic acid; and two benzoic acid skeletons having -CH ₂ -, -C(=O) -, -O-, -NR ⁹ -, -SO ₂ - or a compound linked with a phenylene group, more preferably terephthalic acid; 4,4'-biphenyldicarboxylic acid; and two benzoic acids It is a compound whose skeletons are connected by either -O-, -NR ⁹ -, -C(=O)- or -SO ₂ -. These can be used alone or in combination of two or more.
R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom.

The ratio of the tetracarboxylic acid compound to the total of the tetracarboxylic acid compound, tricarboxylic acid compound, and dicarboxylic acid compound is preferably 40 mol% or more, more preferably 50 mol% or more, and even more preferably 70 mol%. The content is more preferably 90 mol% or more, particularly preferably 98 mol% or more.

Diamines used in the synthesis of polyimide polymers include aliphatic diamines, aromatic diamines, and mixtures thereof. In this specification, the term "aromatic diamine" refers to a diamine in which an amino group is directly bonded to an aromatic ring, and may include an aliphatic group or other substituent as part of its structure. The aromatic ring may be a single ring or a condensed ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, a fluorene ring, etc., but are not limited thereto. Among these, a benzene ring is preferred. Moreover, "aliphatic diamine" refers to a diamine in which an amino group is directly bonded to an aliphatic group, and may include an aromatic ring or other substituents as part of its structure.

Examples of aliphatic diamines include acyclic aliphatic diamines such as hexamethylene diamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, norbornanediamine, and 4,4'-diaminodicyclohexyl. Examples include cycloaliphatic diamines such as methane, and these can be used alone or in combination of two or more.

Examples of aromatic diamines include p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, etc. Aromatic diamine having one aromatic ring; 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether , 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-amino phenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl (written as TFMB) ), 4,4'-bis(4-aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, 9 , 9-bis(4-amino-3-chlorophenyl)fluorene, 9,9-bis(4-amino-3-fluorophenyl)fluorene, and other aromatic diamines having two or more aromatic rings. These can be used alone or in combination of two or more.

The aromatic diamine is preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenylsulfone, 1,4-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis (trifluoromethyl)-4,4'-diaminodiphenyl (TFMB), 4,4'-bis(4-aminophenoxy)biphenyl, more preferably 4,4'-diaminodiphenylmethane, 4,4'-diamino Diphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 1,4-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2 -Bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl (TFMB), 4,4' -bis(4-aminophenoxy)biphenyl. These can be used alone or in combination of two or more.

The diamine can also have a fluorine substituent. Examples of the fluorine-based substituent include a perfluoroalkyl group having 1 to 5 carbon atoms, such as a trifluoromethyl group, and a fluoro group.

Among the diamines, from the viewpoint of high transparency and low coloration, it is preferable to use one or more selected from the group consisting of aromatic diamines having a biphenyl structure, specifically 2,2'-dimethylbenzidine, It is preferable to use one or more selected from the group consisting of 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl (TFMB) and 4,4'-bis(4-aminophenoxy)biphenyl. . It is more preferable to use a diamine having a biphenyl structure and a fluorine substituent, and specifically, it is more preferable to use 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl (TFMB).

The polyimide polymer is formed by polycondensation of a diamine and a tetracarboxylic acid compound (including tetracarboxylic acid compound analogs such as acid chloride compounds and tetracarboxylic dianhydride), and is represented by formula (10). It is a condensation type polymer containing structural units of In addition to these, as starting materials, tricarboxylic acid compounds (including tricarboxylic acid compound analogs such as acid chloride compounds and tricarboxylic acid anhydrides) and dicarboxylic acid compounds (including analogs such as acid chloride compounds) are used. Sometimes.
The structural units represented by formulas (10) and (11) are usually derived from diamines and tetracarboxylic acid compounds. The structural unit represented by formula (12) is usually derived from a diamine and a tricarboxylic acid compound. The structural unit represented by formula (13) is usually derived from a diamine and a dicarboxylic acid compound. Specific examples of the diamine, tetracarboxylic acid compound, tricarboxylic acid compound, and dicarboxylic acid compound are as described above.

The molar ratio between the diamine and the carboxylic acid compound such as the tetracarboxylic acid compound can be appropriately adjusted in the range of preferably 0.9 mol or more and 1.1 mol or less of the tetracarboxylic acid per 1.00 mol of the diamine. In order to exhibit high bending durability, it is preferable that the obtained polyimide polymer has a high molecular weight, so it is more preferable that the amount of tetracarboxylic acid is 0.98 mol or more and 1.02 mol per 1.00 mol of diamine. , more preferably 0.99 mol% or more and 1.01 mol% or less.
In addition, from the viewpoint of suppressing the yellowness of the obtained intermediate layer, it is preferable that the proportion of amino groups occupying the terminals of the obtained polymer is low, and the ratio of carboxylic acid compounds such as tetracarboxylic acid compounds to 1.00 mol of diamine is 1. It is preferable that it is .00 mol or more.

By adjusting the number of fluorine in the molecule of diamine and carboxylic acid compound (for example, tetracarboxylic acid compound), the amount of fluorine in the resulting polyimide polymer is 1% by mass or more based on the mass of the polyimide polymer. , 5% by mass or more, 10% by mass or more, or 20% by mass or more. Since raw material costs tend to increase as the proportion of fluorine increases, the upper limit of the amount of fluorine is preferably 40% by mass or less. The fluorine substituent may be present in either the diamine or the carboxylic acid compound, or in both.

The polyimide polymer may be a copolymer containing a plurality of different types of the above structural units. The weight average molecular weight of the polyimide polymer in terms of standard polystyrene is usually 100,000 to 800,000, preferably 200,000 to 700,000, and 300,000 to 600,000. is more preferable, and even more preferably 350,000 or more and 500,000 or less.

From the viewpoint of light transparency, the polyimide polymer preferably has a fluorine-containing substituent. Specific examples of the fluorine-containing substituent include a fluoro group and a trifluoromethyl group.

The intermediate layer may or may not contain components other than the nonionic insulating polymer.
Examples of other components include components included in the second intermediate layer described below, such as a hole transporting material, an electron transporting material, and the like.

From the viewpoint of suppressing the increase in dark current, the content of the nonionic insulating polymer in the intermediate layer is preferably 80% by mass or more and 100% by mass or less, and 90% by mass or less, based on the mass of the entire intermediate layer. % or more and 100% by mass or less, and more preferably 95% by mass or more and 100% by mass or less.

From the viewpoint of ease of charge movement, the thickness of the intermediate layer is preferably 1 nm or more and 100 nm or less, more preferably 1 nm or more and 20 nm or less, and even more preferably 1 nm or more and 15 nm or less.

The intermediate layer can be formed by a coating method. Details of the method for forming the intermediate layer will be described later.

(Second middle layer)
The photoelectric conversion element according to the present disclosure may have a second intermediate layer that does not contain the nonionic insulating polymer, if necessary.
The second intermediate layer is also referred to as a hole transport layer, an electron transport layer, a hole injection layer, an electron injection layer, etc. depending on its function.
The hole transport layer is a layer that has the function of transporting holes from the active layer to the electrode.
The hole injection layer is a hole transport layer provided in contact with the anode.
The electron transport layer is a layer that has the function of transporting electrons from the active layer to the electrode.
The electron injection layer is an electron transport layer provided in contact with the cathode.

As the material used for the second intermediate layer, any conventionally known suitable material can be used. Examples of the material for the second intermediate layer include halides and oxides of alkali metals or alkaline earth metals such as lithium fluoride.
Examples of materials used for the second intermediate layer include fine particles of inorganic semiconductor materials such as titanium oxide, PEDOT (poly(3,4-ethylenedioxythiophene)) and PSS (poly(4-styrene sulfonate)). ) (PEDOT:PSS).

When the second intermediate layer is a hole transport layer, the photoelectric conversion element preferably includes a hole transport layer (hole injection layer) between the anode and the active layer.
The hole transport layer may be a single layer or a stack of two or more layers. The hole transport layer (hole injection layer) may be in contact with the active layer.

The hole transport layer contains a hole transport material. Examples of hole-transporting materials include polythiophene and its derivatives, aromatic amine compounds, polymer compounds containing structural units having aromatic amine residues, CuSCN, CuI, NiO, and molybdenum oxide (MoO ₃ ). It will be done.

When the second intermediate layer is an electron transport layer, the photoelectric conversion element preferably includes an electron transport layer (or an electron injection layer; the same shall apply hereinafter) between the cathode and the active layer.
The electron transport layer may be a single layer or a stack of two or more layers. The electron transport layer may be in contact with the active layer.

The electron transport layer contains an electron transport material. Examples of the electron transporting material include any suitable material that contributes to the movement of electrons in the layers constituting the photoelectric conversion element. Examples of the electron transporting material include metal compounds and compounds having an alkylene structure.

Examples of metal compounds include metal oxides, metal hydroxides and metal alkoxides. The metal compound is preferably a metal oxide containing a divalent or higher valent metal; a metal hydroxide; or a metal alkoxide; more preferably a metal oxide containing zinc or titanium; a metal hydroxide; or a metal alkoxide; Good too.
Examples of metal alkoxides include metal methoxide, metal ethoxide, metal propoxide, metal isopropoxide, metal n-butoxide, metal sec-butoxide, metal isobutoxide, metal tert-butoxide.
Examples of metal oxides include zinc oxide, gallium-doped zinc oxide, aluminum-doped zinc oxide, titanium oxide, and niobium oxide. As the metal oxide, metal oxides containing zinc are preferred, and zinc oxide is particularly preferred.

As the metal alkoxide, metal alkoxides containing titanium are preferred, and titanium (IV) isopropoxide is particularly preferred.

Examples of compounds having an alkylene structure include polyalkylene imines and derivatives thereof. Examples of polyalkyleneimines and derivatives thereof include alkyleneimines having 2 to 8 carbon atoms, especially those having 2 to 8 carbon atoms, such as ethyleneimine, propyleneimine, butyleneimine, dimethylethyleneimine, pentyleneimine, hexyleneimine, heptyleneimine, octyleneimine. Examples include polymers obtained by polymerizing one or more of 2 to 4 alkylene imines by a conventional method, and polymers chemically modified by reacting them with various compounds. Polyalkyleneimine and its derivatives include polyethyleneimine ethoxylate (PEIE: ethoxylated polyethyleneimine), which is a modified product containing polyethyleneimine (PEI) and polyalkyleneimine as the main chain, with ethylene oxide added to the nitrogen atom in the main chain. ) is preferred.

The second intermediate layer can be formed by a coating method. Details of the method for forming the second intermediate layer will be described later.

(substrate)
The photoelectric conversion element according to the present disclosure may have a substrate.
A photoelectric conversion element is usually formed on a substrate. Electrodes are usually formed on this substrate. The material of the substrate is not particularly limited. Examples of the material for the substrate include glass, plastic, polymer film, and silicon. When the substrate is opaque, it is preferable that the electrode on the opposite side of the electrode provided on the opaque substrate (ie, the electrode on the side far from the substrate) be a transparent or semitransparent electrode.

(Example of configuration of photoelectric conversion element)
Examples of configurations that can be taken by the photoelectric conversion element according to the present disclosure will be described. FIG. 1 is a schematic cross-sectional view of a photoelectric conversion element according to an embodiment of the present disclosure.
As shown in FIG. 1, a photoelectric conversion element 10 according to the present disclosure is provided on, for example, a substrate (support substrate) 11. The photoelectric conversion element 10 includes an electrode 12 provided in contact with a substrate 11, a second intermediate layer or layer 13 provided in contact with the electrode 12, and a second intermediate layer or intermediate layer. an active layer 14 provided in contact with active layer 13; a second intermediate layer or layer 15 provided in contact with active layer 14; and layer 15, which is a second intermediate layer or intermediate layer. The electrode 16 is provided so as to be in contact with the electrode 16.
This configuration example further includes a substrate 17 provided in contact with the electrode 16.

Here, in the photoelectric conversion element 10 according to the present disclosure, it is preferable that the electrode 12 is an anode, the layer 13 is a second intermediate layer, the layer 15 is an intermediate layer, and the electrode 16 is a cathode.

(Applications of photoelectric conversion elements)
The photoelectric conversion element according to the present disclosure can generate photovoltaic force between electrodes when irradiated with light, and can be operated as a solar cell. Furthermore, a thin film solar cell module can be formed by integrating a plurality of solar cells.

The photoelectric conversion element according to the present disclosure can cause a photocurrent to flow by irradiating light from the transparent or semi-transparent electrode side with a voltage applied between the electrodes, and can be used as a photodetection element (photosensor). It can be made to work. Furthermore, by integrating a plurality of optical sensors, it can also be used as an image sensor.

The photoelectric conversion element according to the present disclosure can be suitably applied to detection units included in various electronic devices such as workstations, personal computers, personal digital assistants, room access control systems, digital cameras, and medical equipment.

The photoelectric conversion element according to the present disclosure includes, for example, an image detection unit (image sensor) for a solid-state imaging device such as an X-ray imaging device and a CMOS image sensor, a fingerprint detection unit, a face detection unit, It can be suitably applied to a detection unit that detects a predetermined characteristic of a part of a living body, such as a vein detection unit and an iris detection unit, and a detection unit of an optical biosensor such as a pulse oximeter.

Hereinafter, configuration examples of an image detection section for a solid-state imaging device and a fingerprint detection section for a biometric information authentication device (fingerprint authentication device) among the detection sections to which the photoelectric conversion element according to the present disclosure can be suitably applied will be explained in drawings. Explain with reference to.

-Image detection section-
FIG. 2 is a schematic cross-sectional view of an image detection section for a solid-state imaging device.
The image detection unit 1 includes a CMOS transistor substrate 20, an interlayer insulating film 30 provided to cover the CMOS transistor substrate 20, and a photoelectric conversion element 10 according to the present disclosure provided on the interlayer insulating film 30. , an interlayer wiring section 32 that is provided to penetrate the interlayer insulating film 30 and electrically connect the CMOS transistor substrate 20 and the photoelectric conversion element 10, and a sealing section that is provided to cover the photoelectric conversion element 10. It includes a sealing layer 40 and a color filter 50 provided on the sealing layer 40.
The CMOS transistor substrate 20 is provided with any conventionally known suitable configuration in accordance with the design.

The CMOS transistor substrate 20 includes transistors, capacitors, etc. formed within the thickness of the substrate, and is equipped with functional elements such as CMOS transistor circuits (MOS transistor circuits) for realizing various functions.
Examples of the functional element include a floating diffusion, a reset transistor, an output transistor, and a selection transistor.
A signal readout circuit and the like are built into the CMOS transistor substrate 20 using such functional elements, wiring, and the like.

The interlayer insulating film 30 can be made of any suitable insulating material known in the art, such as silicon oxide or insulating resin. The interlayer wiring section 32 can be made of any conventionally known suitable conductive material (wiring material), such as copper or tungsten. The interlayer wiring section 32 may be, for example, an in-hole wiring formed simultaneously with the formation of the wiring layer, or a buried plug formed separately from the wiring layer.

The sealing layer 40 may be made of any conventionally known suitable material, provided that it can prevent or suppress the penetration of harmful substances such as oxygen and water that may functionally deteriorate the photoelectric conversion element 10. Can be done. The sealing layer 40 may be constituted by the sealing substrate 17 described above.

As the color filter 50, for example, a primary color filter that is made of any suitable conventionally known material and that corresponds to the design of the image detection section 1 can be used. Further, as the color filter 50, a complementary color filter that can be made thinner than a primary color filter can also be used. Examples of complementary color filters include three types (yellow, cyan, magenta), three types (yellow, cyan, transparent), three types (yellow, transparent, magenta), and three types (transparent, cyan, magenta). Color filters having a combination of types can be used. These can be arranged in any suitable manner depending on the design of the photoelectric conversion element 10 and the CMOS transistor substrate 20, provided that color image data can be generated.

The light received by the photoelectric conversion element 10 via the color filter 50 is converted by the photoelectric conversion element 10 into an electric signal according to the amount of received light, and the received light signal, that is, the imaged object, is transmitted to the outside of the photoelectric conversion element 10 via the electrode. is output as an electrical signal corresponding to

Next, the light reception signal outputted from the photoelectric conversion element 10 is inputted to the CMOS transistor substrate 20 via the interlayer wiring section 32, and is read out by a signal readout circuit built in the CMOS transistor substrate 20. Image information based on the imaging target is generated by signal processing by any suitable conventionally known functional unit.

-Fingerprint detection part-
FIG. 3 is a schematic cross-sectional view of a fingerprint detection unit that is integrated with the display device.
The display device 2 of the mobile information terminal includes a fingerprint detection section 100 that includes the photoelectric conversion element 10 according to the present disclosure as a main component, and a display panel section 200 that is provided on the fingerprint detection section 100 and displays a predetermined image. It is equipped with

In this configuration example, the fingerprint detection section 100 is provided in an area that substantially coincides with the display area 200a of the display panel section 200. In other words, the display panel section 200 is integrally stacked above the fingerprint detection section 100.
If fingerprint detection is to be performed only in a part of the display area 200a, the fingerprint detection section 100 may be provided corresponding to only the part of the area.

The fingerprint detection unit 100 includes the photoelectric conversion element 10 according to the present disclosure as a functional unit that performs essential functions. The fingerprint detection unit 100 is equipped with a protective film (not shown).
Any suitable conventionally known members such as a supporting substrate, a sealing substrate, a sealing member, a barrier film, a bandpass filter, an infrared cut film, etc. can be provided in a manner corresponding to the design so that desired characteristics can be obtained. . The fingerprint detection unit 100 may also employ the configuration of the image detection unit described above.

The photoelectric conversion element 10 may be included in the display area 200a in any manner. For example, a plurality of photoelectric conversion elements 10 may be arranged in a matrix.
As already explained, the photoelectric conversion element 10 is provided on the support substrate 11 or the sealing substrate, and the support substrate 11 is provided with electrodes (anodes or cathodes), for example, in a matrix.
The light received by the photoelectric conversion element 10 is converted by the photoelectric conversion element 10 into an electric signal according to the amount of received light, and the light reception signal, that is, the electric signal corresponding to the imaged fingerprint is transmitted outside the photoelectric conversion element 10 via the electrode. Output as a signal.

In this configuration example, the display panel section 200 is configured as an organic electroluminescence display panel (organic EL display panel) including a touch sensor panel. For example, instead of the organic EL display panel, the display panel section 200 may be configured with a display panel having any suitable conventionally known configuration, such as a liquid crystal display panel including a light source such as a backlight.
The display panel section 200 is provided on the already described fingerprint detection section 100. The display panel section 200 includes an organic electroluminescent element (organic EL element) 220 as a functional section that performs an essential function. The display panel section 200 may further include any suitable conventionally known substrate such as a glass substrate (support substrate 210 or sealing substrate 240), a sealing member, a barrier film, a polarizing plate such as a circularly polarizing plate, a touch sensor panel 230, etc. Suitable conventionally known members may be provided in a manner corresponding to desired characteristics.

In the configuration example described above, the organic EL element 220 is used as a light source for pixels in the display area 200a, and is also used as a light source for imaging a fingerprint in the fingerprint detection unit 100.

Here, the operation of the fingerprint detection section 100 will be briefly explained.
When performing fingerprint authentication, the fingerprint detection section 100 detects a fingerprint using light emitted from the organic EL element 220 of the display panel section 200. Specifically, the light emitted from the organic EL element 220 passes through the components present between the organic EL element 220 and the photoelectric conversion element 10 of the fingerprint detection unit 100, and displays a certain display within the display area 200a. The light is reflected by the skin of the fingertip (finger surface) of the finger placed so as to be in contact with the surface of the panel section 200. At least a portion of the light reflected by the finger surface is transmitted through the intervening components, is received by the photoelectric conversion element 10, and is converted into an electrical signal according to the amount of light received by the photoelectric conversion element 10. Then, image information about the fingerprint on the finger surface is constructed from the converted electrical signal.

The portable information terminal equipped with the display device 2 performs fingerprint authentication by comparing the obtained image information with pre-recorded fingerprint data for fingerprint authentication using any suitable conventionally known steps.

<Method for manufacturing photoelectric conversion element>
A method for manufacturing a photoelectric conversion element according to the present disclosure includes the steps of forming a coating film by applying an ink containing a nonionic insulating polymer, and drying the coating film.
Hereinafter, as an example of a method for manufacturing a photoelectric conversion element, a substrate (supporting substrate), an electrode, a second intermediate layer or intermediate layer, an active layer, a second intermediate layer or intermediate layer, and an electrode are prepared in this order. A method for manufacturing a photoelectric conversion element having a stacked structure will be described.

(Process of forming electrodes on the substrate)
In this step, a support substrate provided with electrodes is prepared.
The method of forming electrodes on the support substrate is not particularly limited. The electrode can be formed on the support substrate using, for example, a vacuum evaporation method, a sputtering method, an ion plating method, a plating method, or the like using an electrode material.
Examples of the material for the electrode include the compounds exemplified as the material for the electrode described above.

Furthermore, a support substrate provided with electrodes can be prepared by obtaining a substrate provided with electrodes from the market and forming electrodes by patterning a conductive thin film as necessary.

(Step-1 of forming the second intermediate layer or intermediate layer)
In this step, a second intermediate layer or an intermediate layer is formed on the electrode of the substrate provided with the electrode.
First, the procedure for forming the intermediate layer in this step will be explained.

-Process of forming the intermediate layer-
This step is a step of forming a coating film by applying an ink containing a nonionic insulating polymer (hereinafter also referred to as "specific ink"), and drying the coating film.

Preferably, the specific ink contains a nonionic insulating polymer and a solvent.
As the nonionic insulating polymer contained in the specific ink, the nonionic insulating polymer according to the present disclosure is applied.
Examples of solvents include water, alcohols, ketones, and hydrocarbons. The specific ink may contain only one type of solvent, or may contain two or more types of solvents.

From the viewpoint of suppressing the influence on the active layer adjacent to the intermediate layer, the alcohol is preferably an alcohol having 1 or more and 6 or less carbon atoms.
Specific examples of alcohols include ethanol, 1-propanol, 2-propanol, 2-butanol, 2-pentanol, 3-pentanol, ethylene glycol, propylene glycol, butoxyethanol and methoxybutanol.

Specific examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, and cyclohexanone.

The specific ink may contain components other than the nonionic insulating polymer and the solvent. Examples of other components include components contained in the second intermediate layer, such as hole transporting materials, electron transporting materials, and the like.

The content of the solvent in the specific ink may be 1 part by mass or more and 10,000 parts by mass or less, when the total mass of the nonionic insulating polymer and other components contained in the specific ink is 1 part by mass. It is preferably 10 parts by mass or more and 1000 parts by mass or less.

The specific ink may be a solution, or a dispersion such as a dispersion, an emulsion, or a suspension.

In this step, a specific ink is applied onto the electrode of the substrate provided with the electrode to form a coating film.
Any coating method can be used to apply the specific ink.
The coating method is preferably a slit coating method, a knife coating method, a spin coating method, a microgravure coating method, a gravure coating method, a bar coating method, an inkjet printing method, a nozzle coating method, or a capillary coating method. A coating method or a bar coating method is more preferred, and a spin coating method is even more preferred.

Next, in this step, the coating film is dried.
Any suitable method can be used to form the intermediate layer by drying the coating film. Examples of the drying method include drying methods such as direct heating using a hot plate, hot air drying, infrared heat drying, flash lamp annealing drying, and vacuum drying.

-Process of forming the second intermediate layer-
Next, the step of forming the second intermediate layer in this step will be explained.
This step is a step of forming a coating film by applying the second intermediate layer forming ink and drying the coating film.

When forming a hole transport layer, the second intermediate layer forming ink preferably contains a hole transport material and a solvent.
When forming an electron transport layer, the second intermediate layer forming ink preferably contains an electron transport material and a solvent.

The hole-transporting material and electron-transporting material contained in the ink for forming the second intermediate layer are the same as the hole-transporting material and electron-transporting material that can be contained in the second intermediate layer described above. be done.
Examples of the solvent include water, alcohol, ketone, and hydrocarbon. Specific examples of alcohol include methanol, ethanol, isopropanol, butanol, ethylene glycol, propylene glycol, butoxyethanol, and methoxybutanol. Specific examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, and cyclohexanone. Specific examples of hydrocarbons include n-pentane, cyclohexane, n-hexane, benzene, toluene, xylene, tetralin, chlorobenzene, and orthodichlorobenzene. The second intermediate layer forming ink may contain one type of solvent alone, or may contain two or more types of solvents. The amount of the solvent in the second intermediate layer forming ink is 1 part by mass or more when the total mass of the hole transporting material and electron transporting material contained in the second intermediate layer forming ink is 1 part by mass. It is preferably 10,000 parts by mass or less, and more preferably 10 parts by mass or more and 1,000 parts by mass or less.

As the method (coating method) for applying the second intermediate layer forming ink, the coating method explained in the above-mentioned - step of forming the intermediate layer - can be applied.

Any suitable method can be used to form the second intermediate layer by drying the coating film. As an example of the drying method, the same drying method as explained in the above-mentioned step of forming the intermediate layer can be applied.

(Step of forming active layer)
This step is a step of forming a coating film by applying an active layer forming ink and drying the coating film.
The active layer forming ink contains a p-type semiconductor material, an n-type semiconductor material, and a solvent.

-p-type semiconductor material-
Examples of p-type semiconductor materials include polyvinylcarbazole and its derivatives; polysilane and its derivatives; polysiloxane derivatives containing an aromatic amine structure in the side chain or main chain; polyaniline and its derivatives; polythiophene and its derivatives; polypyrrole and its derivatives ; polyphenylene vinylene and its derivatives; polythienylene vinylene and its derivatives; polyfluorene and its derivatives; and the like.

It is preferable that the p-type semiconductor material is a polymer compound containing at least one member selected from the group consisting of a structural unit represented by the following formula (I) and a structural unit represented by the following formula (II).

In formula (I), Z represents a group represented by any one of the following formulas (Z-1) to (Z-7). Ar ¹ and Ar ² represent trivalent aromatic heterocyclic groups which may be the same or different.

In formula (II), Ar ³ represents a divalent aromatic heterocyclic group.

In formulas (Z-1) to (Z-7), R is each independently a hydrogen atom, a halogen atom, an alkyl group that may have a substituent, or a cyclo that may have a substituent. Alkyl group, alkenyl group that may have a substituent, cycloalkenyl group that may have a substituent, alkynyl group that may have a substituent, cycloalkenyl group that may have a substituent Alkynyl group, aryl group that may have a substituent, alkyloxy group that may have a substituent, cycloalkyloxy group that may have a substituent, Good aryloxy group, optionally substituted alkylthio group, optionally substituted cycloalkylthio group, optionally substituted arylthio group, optionally substituted arylthio group, optionally substituted arylthio group, optionally substituted cycloalkylthio group, optionally substituted arylthio group A good monovalent heterocyclic group, a substituted amino group that may have a substituent, an imine residue that may have a substituent, an amide group that may have a substituent, a substituted amino group that may have a substituent, an amide group that may have a substituent, an optionally substituted oxycarbonyl group, a cyano group, a nitro group, a group represented by -C(=O)-R ^c , or -SO ₂ -R represents a group represented by ^d , and R ^c and R ^d each independently represent a hydrogen atom, an alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, or a substituent. Aryl group which may have a group, alkyloxy group which may have a substituent, cycloalkyloxy group which may have a substituent, aryloxy group which may have a substituent , or a monovalent heterocyclic group which may have a substituent. When a plurality of R's exist, the plurality of R's may be the same or different.

The structural unit represented by formula (I) is preferably a structural unit represented by formula (I-1) below.

In formula (I-1), Z has the same meaning as Z in formula (I).
In formula (I-1), Z is preferably a group selected from the group consisting of groups represented by formulas (Z-4) to (Z-7).

Examples of the structural unit represented by formula (I-1) include structural units represented by formulas (501) to (505) below, and the structural unit is represented by formula (501). is preferred.

In formulas (501) to (505), R each independently has the same meaning as R in formulas (Z-1) to (Z-7). When a plurality of R's exist, the plurality of R's may be the same or different.

In formula (II), the number of carbon atoms in the divalent aromatic heterocyclic group represented by Ar ³ is usually 2 to 60, preferably 4 to 60, and more preferably 4 to 20. . The divalent aromatic heterocyclic group represented by Ar ³ may have a substituent.

Examples of the divalent aromatic heterocyclic group represented by Ar ³ include groups represented by the following formulas (101) to (185).

In formulas (101) to (185), R has the same meaning as R in formulas (Z-1) to (Z-7). When a plurality of R's exist, the plurality of R's may be the same or different.

As the structural unit represented by the above formula (II), structural units represented by the following formulas (II-1) to (II-6) are preferable.

In formulas (II-1) to (II-6), X ¹ and X ² each independently represent an oxygen atom or a sulfur atom, and R each independently represents a formula (Z-1) to (Z It has the same meaning as R in -7). When a plurality of R's exist, the plurality of R's may be the same or different.

From the viewpoint of availability of raw material compounds, it is preferable that X ¹ and X ² in formulas (II-1) to (II-6) are both sulfur atoms.

The p-type semiconductor material is preferably a polymer compound containing a structural unit containing a thiophene skeleton.

The polymer compound that is a p-type semiconductor material may contain two or more types of structural units of formula (I), or may contain two or more types of structural units of formula (II).

In order to improve solubility in a solvent, the polymer compound that is a p-type semiconductor material may contain a structural unit represented by the following formula (III).

In formula (III), Ar ⁴ represents an arylene group.
The arylene group represented by Ar ⁴ means an atomic group remaining after two hydrogen atoms are removed from an aromatic hydrocarbon which may have a substituent. Aromatic hydrocarbons also include compounds with fused rings, and compounds in which two or more rings selected from the group consisting of independent benzene rings and fused rings are bonded directly or via a divalent group such as a vinylene group. .

The number of carbon atoms in the arylene group excluding substituents is usually 6 to 60, preferably 6 to 20.
Examples of arylene groups include phenylene groups (e.g., formulas 1 to 3 below), naphthalene-diyl groups (e.g., formulas 4 to 13 below), anthracene-diyl groups (e.g., formulas 14 to 19 below), Biphenyl-diyl group (e.g., formulas 20 to 25 below), terphenyl-diyl group (e.g., formulas 26 to 28 below), fused ring compound groups (e.g., formulas 29 to 35 below), fluorene-diyl groups (for example, the following formulas 36 to 38), and benzofluorene-diyl groups (for example, the following formulas 39 to 46).

In formulas 1 to 46, R each independently has the same meaning as R in formulas (Z-1) to (Z-7). A plurality of R's may be the same or different.

The structural units constituting the polymer compound that is a p-type semiconductor material are selected from the structural units represented by formula (I), the structural units represented by formula (II), and the structural units represented by formula (III). It may be a structural unit in which two or more types of structural units are combined and connected.

When the polymer compound as a p-type semiconductor material contains at least one selected from the group consisting of a structural unit represented by formula (I) and a structural unit represented by formula (II), formula (I) The total amount of the structural unit represented by and the structural unit represented by formula (II) is usually 20 to 100 mol% of all the structural units (100 mol%) contained in the polymer compound, and the p-type The content is preferably 40 to 100 mol%, more preferably 50 to 100 mol%, since it can improve the charge transport properties as a semiconductor material.

Specific examples of polymer compounds that are p-type semiconductor materials include polymer compounds represented by the following formulas P-1 to P-8. In the following formulas P-1 to P-8, n is a number of 1 or more and is arbitrarily selected within the weight average molecular weight range described below.

The active layer forming ink may contain only one type of p-type semiconductor material, or may contain two or more types in any combination of p-type semiconductor materials.

The weight average molecular weight of the p-type semiconductor material in terms of polystyrene is preferably 40,000 or more and 200,000 or less, more preferably 40,000 or more and 150,000 or less, especially from the viewpoint of reducing the dark current ratio, and particularly from the viewpoint of reducing the dark current ratio. From the viewpoint of improvement, it is more preferably 45,000 or more and 150,000 or less.

Here, the weight average molecular weight in terms of polystyrene means the weight average molecular weight calculated using a standard sample of polystyrene using gel permeation chromatography (GPC).

-N-type semiconductor material-
The n-type semiconductor material may be a low-molecular compound or a high-molecular compound.

Examples of n-type semiconductor materials that are low molecular weight compounds include oxadiazole derivatives; anthraquinodimethane and its derivatives; benzoquinone and its derivatives; naphthoquinone and its derivatives; anthraquinone and its derivatives; tetracyanoanthraquinodimethane and its derivatives. Derivatives; fluorenone derivatives; diphenyldicyanoethylene and its derivatives; diphenoquinone derivatives; metal complexes of 8-hydroxyquinoline and its derivatives; fullerenes such as C ₆₀ fullerene and derivatives thereof; and phenanthrene derivatives such as bathocuproine;

As another example of the n-type semiconductor material, a low molecular compound having an acceptor-donor-acceptor (ADA) type structure as described in Non-Patent Document 3 can also be suitably used.
Non-patent document 3: Advanced Energy Materials, 2021, Volume 11, Issue 15, Article Number 2003570

Examples of n-type semiconductor materials that are polymeric compounds include polyvinylcarbazole and its derivatives; polysilane and its derivatives; polysiloxane derivatives having an aromatic amine structure in the side chain or main chain; polyaniline and its derivatives; polythiophene and its derivatives ; polypyrrole and its derivatives; polyphenylene vinylene and its derivatives; polythienylene vinylene and its derivatives; polyquinoline and its derivatives; polyquinoxaline and its derivatives; and polyfluorene and its derivatives.

The n-type semiconductor material is preferably one or more selected from fullerene and fullerene derivatives, and fullerene derivatives are more preferred.

Examples of fullerenes include C ₆₀ fullerene, C ₇₀ fullerene, C ₇₆ fullerene, C ₇₈ fullerene, and C ₈₄ fullerene. Examples of fullerene derivatives include these fullerene derivatives. Fullerene derivative means a compound in which at least a portion of fullerene is modified.

Examples of fullerene derivatives include compounds represented by the following formulas (N-1) to (N-4).

In formulas (N-1) to (N-4), R ^a each independently represents an alkyl group, an aryl group, a monovalent heterocyclic group, or a group having an ester structure. A plurality of R ^a 's may be the same or different.
R ^b each independently represents an alkyl group or an aryl group. A plurality of R ^b 's may be the same or different.

Examples of the group having an ester structure represented by R ^a include a group represented by the following formula (19).

In formula (19), u1 represents an integer from 1 to 6. u2 represents an integer from 0 to 6. R ^c represents an alkyl group, an aryl group, or a monovalent heterocyclic group.

Examples of C ₆₀ fullerene derivatives include the following compounds.

Examples of C70 fullerene derivatives include the following compounds.

Specific examples of fullerene derivatives include [6,6]-phenyl-C61 butyric acid methyl ester (C60PCBM, [6,6]-Phenyl C61 butyric acid methyl ester), [6,6]-phenyl-C71 butyric acid methyl ester ( C70PCBM, [6,6]-Phenyl C71 butyric acid meth
[6,6]-Phenyl C85 butyric acid methyl ester), [6,6]-Phenyl C85 butyric acid methyl ester (C84PCBM, [6,6]-Phenyl C85 butyric acid methyl ester), 6]-Thienyl C61 butyric acid methyl ester).

The active layer forming ink may contain only one type of n-type semiconductor material, or may contain two or more types in any combination of n-type semiconductor materials.

-solvent-
The active layer forming ink preferably contains a solvent.
Preferably, the solvent includes a first solvent and, if necessary, a second solvent.

・First solvent The first solvent should be selected taking into consideration the solubility of the selected p-type semiconductor material and n-type semiconductor material, and the characteristics (boiling point, etc.) that correspond to the drying conditions when forming the active layer. Bye.
The first solvent is an aromatic hydrocarbon (hereinafter simply referred to as aromatic hydrocarbon) that may have a substituent (eg, an alkyl group, a halogen atom). The first solvent is preferably selected in consideration of the solubility of the selected p-type semiconductor material and n-type semiconductor material.

Examples of aromatic hydrocarbons include toluene, xylene (e.g. o-xylene, m-xylene, p-xylene), trimethylbenzene (e.g. mesitylene, 1,2,4-trimethylbenzene (pseudocumene)), butylbenzene. (eg n-butylbenzene, sec-butylbenzene, tert-butylbenzene), methylnaphthalene (eg 1-methylnaphthalene), tetralin, indane, chlorobenzene and dichlorobenzene (eg o-dichlorobenzene).

The first solvent is preferably toluene, o-xylene, m-xylene, p-xylene, mesitylene, pseudocumene, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, methylnaphthalene, tetralin, indane, chlorobenzene and It contains one or more selected from the group consisting of o-dichlorobenzene, more preferably o-xylene, pseudocumene, tetralin, chlorobenzene or o-dichlorobenzene.

The first solvent may be composed of only one type of aromatic hydrocarbon, or may be composed of two or more types of aromatic hydrocarbons. Preferably, the first solvent is composed of only one type of aromatic hydrocarbon.

-Second Solvent The second solvent is a solvent selected from the viewpoint of particularly improving the solubility of the n-type semiconductor material. Examples of the second solvent include ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, acetophenone, and propiophenone, ethyl acetate, butyl acetate, phenyl acetate, ethyl cellosolve acetate, methyl benzoate, butyl benzoate, benzyl benzoate, etc. and ether solvents such as anisole and o-dimethoxybenzene.
The second solvent is preferably acetophenone, propiophenone, or benzyl benzoate.

- Combination of the first solvent and the second solvent Examples of the combination of the first solvent and the second solvent include the combinations shown in Table 1 below.

・Weight ratio of the first solvent and the second solvent The mass ratio of the first solvent to the second solvent (first solvent/second solvent) is determined from the viewpoint of further improving the solubility of the p-type semiconductor material and the n-type semiconductor material. , preferably in the range of 85/15 to 97/3.

・The total mass percentage of the first solvent and the second solvent in the active layer forming ink The total mass of the first solvent and the second solvent contained in the active layer forming ink is calculated by dividing the total weight of the active layer forming ink by 100 mass. %, it is preferably 90% by mass or more and 97.5% by mass or less from the viewpoint of further improving the solubility of the p-type semiconductor material and the n-type semiconductor material.

-Other ingredients-
The active layer forming ink may contain components other than the p-type semiconductor material, the n-type semiconductor material, and the solvent.
Other components include ultraviolet absorbers, antioxidants, sensitizers for sensitizing the function of generating charges from absorbed light, and photostabilizers for increasing stability against ultraviolet light.

(Step-2 of forming the second intermediate layer or intermediate layer)
In this step, a second intermediate layer or an intermediate layer is formed on the active layer.
When forming the second intermediate layer in this step, the procedure for forming the second intermediate layer includes forming the second intermediate layer in the above-mentioned (step-1 of forming the second intermediate layer or intermediate layer). Follow the same procedure as step -.
When forming the intermediate layer in this step, the procedure for forming the intermediate layer is the same as the step of forming the intermediate layer in (Step-1 of forming the second intermediate layer or intermediate layer) described above. Do it with

(Step of forming an electrode on the second intermediate layer or the intermediate layer)
The method of forming the second intermediate layer or the electrodes on the intermediate layer is not particularly limited. The electrode can be formed on the support substrate using, for example, a vacuum evaporation method, a sputtering method, an ion plating method, a plating method, or the like using an electrode material.
Examples of the material for the electrode include the compounds exemplified as the material for the electrode described above.

Examples will be described below, but the present invention is not limited to these examples in any way. In the following description, all "parts" and "%" are based on mass unless otherwise specified.

<Materials>
The p-type semiconductor material, n-type semiconductor material, nonionic insulating polymer, ionic polymer, and inorganic buffer material used in the following Examples and Comparative Examples are as follows.

(p-type semiconductor material)
As the p-type semiconductor material, polymer compounds represented by the aforementioned formulas P-7 and P-8 were used.
The polymer compound represented by formula P-7 was synthesized and used with reference to the method described in International Publication No. 2013/051676.
The polymer compound represented by formula P-8 was synthesized and used with reference to the method described in International Publication No. 2011/052709.

(n-type semiconductor material)
As the n-type semiconductor material N-1, Guard Surf NC-1010 manufactured by Harbes Co., Ltd. was used.

(Nonionic insulating polymer)
The following Z-1 to Z-8 were used as nonionic insulating polymers.
The glass transition temperature and melting point of the nonionic insulating polymers are listed in Table 4.
・Z-1: Polyimide, manufactured by Kawamura Sangyo Co., Ltd., product name: KPI-MX300F
・Z-2: Polycarbonate, manufactured by Scientific Polymer Products ・Z-3: Polymethyl methacrylate, manufactured by Scientific Polymer Products ・Z-5: Cellulose acetate, manufactured by Scientific Polymer Products ・Z-6: Polyphenylene ether sulfone, Scientific Polymer Products
・Z-7: Polytetrafluoroethylene, manufactured by Scientific Polymer Products ・Z-8: Fluorine-containing polymer, manufactured by AGC, product name: CYTOP CTL-809M

(ionic polymer)
The following I-1 to I-3 were used as ionic polymers.
・I-1: Polyethyleneimine derivative, manufactured by Sigma-Aldrich, trade name: Polyethyleneimine, 80% ethoxylated solution ・I-2: PFN-Br, manufactured by Ossila ・I-3: Polyvinylpyrrolidone, Scientific Polymer Products

The structural formulas of Z-2 to Z-3, Z-5 to Z-8, and I-1 to I-3 are shown below.

(Inorganic material)
The following M-1 was used as the inorganic material.
・M-1: Manufactured by Teika, zinc oxide nanoparticle dispersion (HTD-711Z)

<Band gap calculation>
The band gap can be calculated by the following formula using the optical absorption edge wavelength of the nonionic insulating polymer. In the formula, Eg is the band gap, h is Planck's constant (6.626×10 ⁻³⁴ Js), and c is the speed of light (3×10 ⁸ m/s).
Formula: Eg=hc/absorption edge wavelength

In the above equation, the absorption edge wavelength can be measured using a spectrophotometer that can measure in the wavelength range of ultraviolet light, visible light, and near-infrared light (an ultraviolet-visible-near-infrared spectrophotometer manufactured by JASCO Corporation). JASCO-V670) was used. In the absorption spectrum obtained by a spectrophotometer, that is, the absorbance (absorption intensity) of the (polymer) compound is plotted on the vertical axis and the wavelength is plotted on the horizontal axis, the absorption edge wavelength is The value of the wavelength at the intersection of the line and the straight line fitted at the shoulder of the absorption peak (on the high wavelength side) was defined as the absorption edge wavelength (nm).
The band gaps of Z-1, Z-2, Z-3, Z-5, Z-6, Z-7, and Z-8 were all within the range of 3.5 to 3.8 eV.

<Preparation of specific ink>
Specific inks BI-1 to BI-3 and BI-5 to BI-11 were prepared by mixing nonionic insulating polymers or ionic polymers and solvents at the blending ratios shown in Table 2.
The amounts of Z-8 and I-1 shown in Table 2 are the polymer solution in which Z-8 is diluted with a solvent (the solvent is the same as the solvent contained in the specific ink) and the amount of I-1 diluted with a solvent. This is the amount of polymer solution added.
The concentration of the polymer solution of BI-8 using Z-8 is 0.45% by mass, and the concentration of the polymer solution of BI-9 using I-1 is 3% from the standard value of the product of I-1. .5 to 4% by mass.

In Table 2, BS-1 to BS-5 are as follows.
・BS-1: 2,2,3,3,4,4,5,5-octafluoro-1-pentanol ・BS-2: γ-butyrolactone ・BS-3: 3-pentanol ・BS-4 :2-Methoxyethanol/BS-5: Fluorine solvent, manufactured by AGC, product name: CT-SOLV180

<Preparation of ink for forming active layer>
A p-type semiconductor material, an n-type semiconductor material, a first solvent, and a second solvent were mixed at the blending ratio shown in Table 3 to prepare active layer forming inks AI-1 and AI-2.

In Table 3, AS-1 to AS-4 are as follows.
・AS-1: Tetralin ・AS-2: Butyl benzoate ・AS-3: Pseudocumene ・AS-4: o-dimethoxybenzene

<Example 1>
For photoelectric conversion elements having a structure in which a supporting substrate, an electrode, an active layer, an intermediate layer, and an electrode are laminated in this order in the following steps, photoelectric conversion elements that are not heat-treated before sealing, and photoelectric conversion elements that are not heat-treated before sealing, and after heat treatment are Two sealed photoelectric conversion elements were produced.
A photoelectric conversion element that was not heat-treated before sealing was manufactured using the following steps (1) to (5). This element is hereinafter referred to as a photoelectric conversion element without heat treatment.
After the steps (1) to (4) below, the photoelectric conversion element sealed after heat treatment is heat treated on a hot plate heated to 200°C in a nitrogen gas atmosphere for 10 minutes, and then in step (5). It was sealed and produced. This element is hereinafter referred to as a heat-treated photoelectric conversion element.

(1) Step of forming an electrode on a substrate An ITO thin film with a thickness of 45 nm was formed as an electrode on a glass substrate as a supporting substrate by sputtering. The surface of this glass substrate was subjected to ozone UV treatment.

(2) Step of forming active layer Next, after forming a coating film of active layer forming ink AI-1 on the ITO thin film by spin coating method, it was heated at 70°C for 5 minutes on a hot plate in the atmosphere. After this, a heat treatment was performed for 10 minutes using a hot plate heated to 100° C. in a nitrogen gas atmosphere to form an active layer. The thickness of the active layer formed was about 250 nm.

(3) Step-2 of forming the second intermediate layer or intermediate layer
In this step, an intermediate layer was formed on the active layer. A coating film of an intermediate layer was formed on the active layer by a spin coating method using specific ink BI-1. The thickness of the formed intermediate layer was 6 nm.

(4) Step of forming the second intermediate layer or an electrode on the intermediate layer Next, using a sputtering device, an ITO film, which is an electrode, is formed with a thickness of about 50 nm on the intermediate layer, and the photoelectric conversion element is formed. Formed. The planar shape of the obtained photoelectric conversion element when viewed from the thickness direction was a square of 2 mm x 2 mm.

(5) Other steps Next, after applying an ultraviolet (UV) curable sealant to the sealing glass substrate, it is bonded to the glass substrate on which the photoelectric conversion element is formed, and sealed by irradiating it with UV light. A completed photoelectric conversion element was obtained.

<Examples 2 to 7, Comparative Examples 1 to 3>
Example except that the type of ink for forming the active layer in (step of forming the active layer) and the type of specific ink in (step-2 of forming the second intermediate layer or intermediate layer) were changed as shown in Table 4. A sealed photoelectric conversion element was obtained by the same procedure as in Example 1.

<Comparative example 4>
The intermediate layer was formed by performing (step-2 of forming the second intermediate layer or intermediate layer) according to the following procedure.
A solution was prepared by diluting inorganic material M-1 10 times with 3-pentanol. A coating film of an intermediate layer made of inorganic material M-1 was formed on the active layer by a spin coating method. The thickness of the formed intermediate layer was 40 nm.
The subsequent steps were the same as in Example 1 (the step of forming the second intermediate layer or an electrode on the intermediate layer) to obtain a sealed photoelectric conversion element.

<Evaluation>
(Dark current density Jd)
For the photoelectric conversion elements without heat treatment obtained in each example and the photoelectric conversion elements with heat treatment obtained in each example, current-voltage measurements were performed using a source meter (KEITHLEY 2611B Source Meter, Keithley Instruments) in a dark state where no light was irradiated. The dark current density Jd was obtained when the reverse bias voltage was 5V.
Table 4 shows the absolute values of the dark current densities Jd of the photoelectric conversion elements without heat treatment and the photoelectric conversion elements with heat treatment.
Evaluation was performed using the following evaluation criteria based on the absolute value of the dark current density Jd of the photoelectric conversion element subjected to heat treatment.
-Evaluation criteria-
A: The absolute value of the dark current density Jd of the photoelectric conversion element with heat treatment is 200 or less. B: The absolute value of the dark current density Jd of the photoelectric conversion element with heat treatment is more than 200 and 500 or less. C: With heat treatment. The absolute value of the dark current density Jd of the photoelectric conversion element exceeds 500.

(Specific detection ability D ^* )
It is known that the ratio detection ability D ^* can be approximately calculated as shown in the following equation 1.
Formula 1: D ^* = SR/(2 x elementary charge x Jd) ^0.5
Here, SR is spectral sensitivity (unit: A/W, ampere/watt).
SR was obtained as follows. Obtain the value of the photocurrent JL when the reverse bias voltage is 5 V while irradiating light using a spectral sensitivity measuring device CEP-25ML manufactured by Bunko Keiki Co., Ltd. The amount of irradiated light was 1E+14 photons. In the case of the active layer forming ink AI-1, the photocurrent value at a wavelength of 940 nm is used, and in the case of the active layer forming ink AI-2, the photocurrent value at a wavelength of 800 nm is used to calculate as shown in the following equation 2.
Formula 2: SR=(JL-Jd)/(energy of irradiated light)
Here, in Equations 1 and 2, Jd is the absolute value of the dark current density Jd of the photoelectric conversion element without heat treatment or the absolute value of the dark current density Jd of the photoelectric conversion element with heat treatment. When calculating the specific detectability D ^* of the photoelectric conversion element without heat treatment, the absolute value of the dark current density Jd of the photoelectric conversion element without heat treatment is substituted into Equations 1 and 2. Furthermore, when calculating the specific detectability D ^* of the photoelectric conversion element subjected to heat treatment, the absolute value of the dark current density Jd of the photoelectric conversion element subjected to heat treatment is substituted into Equations 1 and 2.
Table 4 shows the absolute values of the specific detectability D ^* of the photoelectric conversion element without heat treatment and the photoelectric conversion element with heat treatment.
Evaluation was performed using the following evaluation criteria based on the absolute value of the specific detectability D ^* of the photoelectric conversion element subjected to heat treatment.
-Evaluation criteria-
A: The exponent part of the numerical value of the photoelectric conversion element D ^* with heat treatment is 13. B: The exponent part of the numerical value of the photoelectric conversion element D ^* with heat treatment is 12. C: With heat treatment. The exponent part of the value of the specific detectability D ^* of the photoelectric conversion element is 11. Here, the "exponent part" is the value written to the right of "E+" in the value of D ^* with heat treatment in Table 4. .

In Table 4, the values of D ^* without heat treatment and D ^* with heat treatment are expressed as an index.
In Table 4, the notation in the column below the glass transition temperature and melting point will be explained as follows.
・“-”: Means not measured.
- ">": Means that the glass transition temperature or melting point is higher than the numerical value written to the right of ">".
- "ND": means not detected.
From the above results, it can be seen that the photoelectric conversion element of this example suppresses the increase in dark current after heat is applied.

1 Image detection unit 2 Display device 10

Photoelectric conversion element

11, 210 Support substrate 12 Electrode 13 Second intermediate layer or layer that is an intermediate layer 14 Active layer 15 Second intermediate layer or layer that is an intermediate layer 16

Electrode

17, 240 Sealing Substrate 20 CMOS transistor substrate 30 Interlayer insulating film 32 Interlayer wiring section 40 Sealing layer 50 Color filter 100 Fingerprint detection section 200 Display panel section 200a Display area 220 Organic EL element 230 Touch sensor panel

Claims

an anode;
a cathode;
an active layer provided between the anode and the cathode;
an intermediate layer provided between the anode and the active layer and at least one between the cathode and the active layer,
A photoelectric conversion element in which the intermediate layer includes a nonionic insulating polymer.
The photoelectric conversion element according to claim 1, wherein the nonionic insulating polymer has a glass transition temperature of 100°C or higher.
The photoelectric conversion element according to claim 1, wherein the nonionic insulating polymer has a melting point of 150°C or higher.
The photoelectric conversion element according to claim 1, wherein the nonionic insulating polymer is at least one selected from the group consisting of poly(meth)acrylic, polycarbonate, polyimide, and fluorine-containing polymer.
The photoelectric conversion element according to claim 1, wherein the nonionic insulating polymer is polyimide.
The photoelectric conversion element according to claim 1, further comprising an intermediate layer between the cathode and the active layer.
The photoelectric conversion element according to claim 6, wherein the cathode is a transparent or semitransparent electrode.
The photoelectric conversion element according to claim 1, wherein the active layer contains a p-type semiconductor material.
9. The p-type semiconductor material is a polymer compound containing at least one selected from the group consisting of a structural unit represented by the following formula (I) and a structural unit represented by the following formula (II). The photoelectric conversion element described.

(In formula (I), Z represents a group represented by any one of formulas (Z-1) to (Z-7),
Ar 1 and Ar 2 represent trivalent aromatic heterocyclic groups which may be the same or different. In formula (II), Ar 3 represents a divalent aromatic heterocyclic group. In formulas (Z-1) to (Z-7), R is each independently a hydrogen atom, a halogen atom, an alkyl group that may have a substituent, or a cycloalkyl that may have a substituent. group, alkenyl group that may have a substituent, cycloalkenyl group that may have a substituent, alkynyl group that may have a substituent, cycloalkynyl that may have a substituent group, an aryl group which may have a substituent, an alkyloxy group which may have a substituent, a cycloalkyloxy group which may have a substituent, a cycloalkyloxy group which may have a substituent Aryloxy group, optionally substituted alkylthio group, optionally substituted cycloalkylthio group, optionally substituted arylthio group, optionally substituted arylthio group Monovalent heterocyclic group, substituted amino group that may have a substituent, imine residue that may have a substituent, amide group that may have a substituent, an acid imide group which may have a substituent, a substituted oxycarbonyl group which may have a substituent, a cyano group, a nitro group, a group represented by -C(=O)-R c , or -SO 2 -R d R c and R d each independently represent a hydrogen atom, an alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, or a substituent. an aryl group which may have a substituent, an alkyloxy group which may have a substituent, a cycloalkyloxy group which may have a substituent, an aryloxy group which may have a substituent, Or represents a monovalent heterocyclic group which may have a substituent. When a plurality of R's exist, the plurality of R's may be the same or different. )
The photoelectric conversion element according to claim 1, wherein the intermediate layer has a thickness of 1 nm or more and 20 nm or less.
Ink for producing photoelectric conversion elements containing nonionic insulating polymer.
A method for manufacturing a photoelectric conversion element, which includes the steps of forming a coating film by applying an ink containing a nonionic insulating polymer, and drying the coating film.
The photoelectric conversion element according to any one of claims 1 to 10, which is a photodetection element.
An image sensor comprising the photoelectric conversion element according to claim 13.
A fingerprint authentication device comprising the photoelectric conversion element according to claim 13.