Light detection element and fingerprint recognition device

Abstract

The present invention provides a light detection element with low dark current. A light detection element, comprising: a first electrode and a second electrode; an active layer disposed between the first electrode and the second electrode; and a hole transport layer disposed between the second electrode and the active layer, wherein the active layer comprises an organic compound, the thickness of the active layer is greater than 600 nm, and the hole transport layer comprises nanoparticles of metal oxide. In addition, the metal oxide comprises at least one selected from the group consisting of molybdenum atoms, tungsten atoms, and nickel atoms.

Description

Technical Field

[0001] The invention relates to a light detection element and a fingerprint recognition device. Background Art

[0002] Photoelectric conversion elements are extremely useful devices from the perspectives of, for example, saving energy and reducing carbon dioxide emissions, and have attracted attention.

[0003] In order to improve the photoelectric conversion efficiency of a photoelectric conversion element, a technique of making a buffer layer of a photoelectric conversion element contain predetermined metal oxide nanoparticles is disclosed (Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2016 / 128133 Summary of the invention

[0007] Problems to be solved by the invention

[0008] A light detection element, which is one of the photoelectric conversion elements, is required to have a low dark current, that is, a current generated when no light is irradiated, in order to improve detection sensitivity.

[0009] On the other hand, in recent years, research and development of light detection elements using organic materials as materials for active layers (organic light detection elements) have been underway. However, conventional organic light detection elements cannot sufficiently reduce dark current.

[0010] Therefore, a light detection element with low dark current is required.

[0011] Means for solving problems

[0012] The inventors of the present invention have conducted intensive research to solve the above problems. As a result, they found that the above problems can be solved by using a light detection element in which the active layer has a predetermined thickness and the hole transport layer contains nanoparticles of metal oxide, thereby completing the present invention. That is, the present invention provides the following solution.

[0013] [1] A light detection element comprising:

[0014] a first electrode and a second electrode;

[0015] an active layer disposed between the first electrode and the second electrode; and

[0016] a hole transport layer disposed between the second electrode and the active layer,

[0017] The active layer contains an organic compound, and the thickness of the active layer is greater than 600 nm.

[0018] The hole transport layer contains nanoparticles of metal oxide.

[0019] [2] The light detection element according to [1], wherein the metal oxide contains one or more atoms selected from the group consisting of molybdenum atoms, tungsten atoms, and nickel atoms.

[0020] [3] The photodetection element according to [2], wherein the metal oxide is one or more selected from the group consisting of molybdenum oxide, tungsten oxide, and nickel oxide.

[0021] [4] The photodetection element according to any one of [1] to [3], wherein the active layer contains a conjugated polymer compound.

[0022] [5] The light detection element according to any one of [1] to [4], wherein the active layer contains a fullerene derivative.

[0023] [6] A fingerprint recognition device comprising the light detection element according to any one of [1] to [5].

[0024] Effects of the Invention

[0025] According to the present invention, a light detection element with low dark current and a fingerprint recognition device including the light detection element can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a diagram schematically showing a light detection element according to one embodiment of the present invention.

[0027] Figure 2 It is a diagram schematically showing a configuration example of an image detection unit.

[0028] Figure 3 It is a diagram schematically showing a configuration example of a fingerprint detection unit. DETAILED DESCRIPTION

[0029] Hereinafter, the light detection element of the embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that the accompanying drawings are merely schematic illustrations of the shapes, sizes, and configurations of the components to the extent that the invention can be understood. The present invention is not limited to the following description, and each component can be appropriately changed without departing from the gist of the present invention. In addition, the structure of the embodiment of the present invention is not necessarily limited to being manufactured or used in the configuration shown in the accompanying drawings. In the various figures described below, the same component is sometimes assigned the same figure mark, and its description is omitted.

[0030] [1. Explanation of common terms]

[0031] The term "polymer compound" refers to a polymer having a molecular weight distribution and a polystyrene-equivalent number average molecular weight of 1×10 3 Above 1×10 8 The following polymers: The total amount of the structural units contained in the polymer compound is 100 mol%.

[0032] The term "structural unit" refers to a unit existing in one or more units in a polymer compound.

[0033] The "hydrogen atom" may be a protium atom or a deuterium atom.

[0034] The "halogen atom" includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0035] The term “having or not having a substituent” includes two aspects: the case where all hydrogen atoms constituting the compound or group are unsubstituted, and the case where part or all of one or more hydrogen atoms are substituted with a substituent.

[0036] Unless otherwise specified, "alkyl" may be any of linear, branched, and cyclic. The number of carbon atoms in a linear alkyl group, excluding the number of carbon atoms in the substituent, is usually 1 to 50, preferably 1 to 30, and more preferably 1 to 20. The number of carbon atoms in a branched or cyclic alkyl group, excluding the number of carbon atoms in the substituent, is usually 3 to 50, preferably 3 to 30, and more preferably 4 to 20.

[0037] The alkyl group may or may not have a substituent. Specific examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, 2-ethylbutyl, n-hexyl, cyclohexyl, n-heptyl, cyclohexylmethyl, cyclohexylethyl, n-octyl, 2-ethylhexyl, 3-n-propylheptyl, adamantyl, n-decyl, 3,7-dimethyloctyl, 2-ethyloctyl, 2-n-hexyldecyl, n-dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl and other alkyl groups, trifluoromethyl, pentafluoroethyl, perfluorobutyl, perfluorohexyl, perfluorooctyl, 3-phenylpropyl, 3-(4-methylphenyl)propyl, 3-(3,5-di-n-hexylphenyl)propyl, 6-ethoxyhexyl and other alkyl groups having substituents.

[0038] The "aryl group" refers to an atomic group remaining after removing one hydrogen atom directly bonded to a carbon atom constituting a ring from an aromatic hydrocarbon which may have a substituent.

[0039] The aryl group may have a substituent. Specific examples of the aryl group include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-pyrenyl, 2-pyrenyl, 4-pyrenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl, 2-phenylphenyl, 3-phenylphenyl, 4-phenylphenyl, and groups having substituents such as alkyl, alkoxy, aryl, and fluorine atoms.

[0040] The "alkoxy group" may be any of linear, branched, and cyclic. The number of carbon atoms in a linear alkoxy group is usually 1 to 40, preferably 1 to 10, excluding the number of carbon atoms in the substituent. The number of carbon atoms in a branched or cyclic alkoxy group is usually 3 to 40, preferably 4 to 10, excluding the number of carbon atoms in the substituent.

[0041] The alkoxy group may be substituted. Specific examples of the alkoxy group include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, n-pentyloxy, n-hexyloxy, cyclohexyloxy, n-heptyloxy, n-octyloxy, 2-ethylhexyloxy, n-nonyloxy, n-decyloxy, 3,7-dimethyloctyloxy and lauryloxy.

[0042] The number of carbon atoms in the "aryloxy group" is usually 6 to 60, preferably 6 to 48, not including the number of carbon atoms in the substituent.

[0043] The aryloxy group may be substituted. Specific examples of the aryloxy group include phenoxy, 1-naphthyloxy, 2-naphthyloxy, 1-anthryloxy, 9-anthryloxy, 1-pyreneoxy, and groups having a substituent such as an alkyl group, an alkoxy group, or a fluorine atom.

[0044] The "alkylthio group" may be any of linear, branched, and cyclic. The number of carbon atoms in a linear alkylthio group excluding the number of carbon atoms in the substituent is usually 1 to 40, preferably 1 to 10. The number of carbon atoms in a branched or cyclic alkylthio group excluding the number of carbon atoms in the substituent is usually 3 to 40, preferably 4 to 10.

[0045] The alkylthio group may be substituted. Specific examples of the alkylthio group include methylthio, ethylthio, propylthio, isopropylthio, butylthio, isobutylthio, tert-butylthio, pentylthio, hexylthio, cyclohexylthio, heptylthio, octylthio, 2-ethylhexylthio, nonylthio, decylthio, 3,7-dimethyloctylthio, laurylthio and trifluoromethylthio.

[0046] The carbon number of the "arylthio group" is usually 6 to 60, preferably 6 to 48, not including the carbon number of the substituent.

[0047] The arylthio group may have a substituent. Examples of the arylthio group include a phenylthio group, a C1-C12 alkoxyphenylthio group (here, "C1-C12" means that the carbon number of the group recorded immediately thereafter is 1-12. The same applies hereinafter), a C1-C12 alkylphenylthio group, a 1-naphthylthio group, a 2-naphthylthio group, and a pentafluorophenylthio group.

[0048] "p-valent heterocyclic group" (p represents an integer greater than 1) refers to an atomic group remaining after removing p hydrogen atoms directly bonded to carbon atoms or heteroatoms constituting the ring from a heterocyclic compound which may or may not have a substituent. Among the p-valent heterocyclic groups, "p-valent aromatic heterocyclic group" is preferred. "p-valent aromatic heterocyclic group" refers to an atomic group remaining after removing p hydrogen atoms directly bonded to carbon atoms or heteroatoms constituting the ring from an aromatic heterocyclic compound which may or may not have a substituent.

[0049] Examples of the substituent which the heterocyclic compound may have include a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, a monovalent heterocyclic group, a substituted amino group, an acyl group, an imide residue, an amide group, an imide group, a substituted oxycarbonyl group, an alkenyl group, an alkynyl group, a cyano group, and a nitro group.

[0050] The aromatic heterocyclic compound includes compounds in which the heterocycle itself exhibits aromaticity and compounds in which the heterocycle itself does not exhibit aromaticity but an aromatic ring is fused to the heterocycle.

[0051] Among the aromatic heterocyclic compounds, specific examples of compounds in which the heterocycle itself exhibits aromaticity include oxadiazole, thiadiazole, thiazole, oxazole, thiophene, pyrrole, phosphole, furan, pyridine, pyrazine, pyrimidine, triazine, pyridazine, quinoline, isoquinoline, carbazole and dibenzophosphole.

[0052] Among the aromatic heterocyclic compounds, specific examples of compounds in which the aromatic heterocyclic ring itself does not exhibit aromaticity but an aromatic ring is condensed on the heterocyclic ring include phenoxazine, phenothiazine, dibenzoborole, dibenzosilole and benzopyran.

[0053] The monovalent heterocyclic group has usually 2 to 60 carbon atoms, preferably 4 to 20 carbon atoms, excluding the carbon atoms of the substituent.

[0054] The monovalent heterocyclic group may have a substituent. Specific examples of the monovalent heterocyclic group include a thienyl group, a pyrrolyl group, a furyl group, a pyridyl group, a piperidyl group, a quinolyl group, an isoquinolyl group, a pyrimidyl group, a triazine group, and a group having a substituent such as an alkyl group or an alkoxy group.

[0055] "Substituted amino group" refers to an amino group having a substituent. Examples of the substituent of the amino group include an alkyl group, an aryl group, and a monovalent heterocyclic group. As the substituent, an alkyl group, an aryl group, or a monovalent heterocyclic group is preferred. The number of carbon atoms in the substituted amino group is usually 2 to 30.

[0056] Examples of the substituted amino group include dialkylamino groups such as dimethylamino and diethylamino groups, and diarylamino groups such as diphenylamino groups, bis(4-methylphenyl)amino groups, bis(4-tert-butylphenyl)amino groups, and bis(3,5-di-tert-butylphenyl)amino groups.

[0057] The carbon number of the "acyl group" is usually about 2 to 20, preferably 2 to 18. Specific examples of the acyl group include acetyl, propionyl, butyryl, isobutyryl, pivaloyl, benzoyl, trifluoroacetyl and pentafluorobenzoyl.

[0058] "Imine residue" refers to an atomic group remaining after removing a hydrogen atom directly bonded to a carbon atom or a nitrogen atom constituting a carbon-nitrogen double bond from an imine compound. "Imine compound" refers to an organic compound having a carbon-nitrogen double bond in a molecule. Examples of imine compounds include aldimine, ketimines, and compounds in which the hydrogen atom bonded to the nitrogen atom constituting a carbon-nitrogen double bond in aldimine is substituted with an alkyl group or the like.

[0059] The imine residue generally has about 2 to 20 carbon atoms, and preferably has 2 to 18 carbon atoms. Examples of the imine residue include groups represented by the following structural formulas.

[0060] [Chemistry 1]

[0061]

[0062] "Acylamide" refers to an atomic group remaining after removing one hydrogen atom bonded to a nitrogen atom from an amide. The number of carbon atoms in an amide is usually about 1 to 20, preferably 1 to 18. Specific examples of amide include formamide, acetamide, propionamide, butyramide, benzamide, trifluoroacetamide, pentafluorobenzamide, diformamide, diacetamide, dipropionamide, dibutyramide, dibenzamide, di(trifluoroacetamide) and di(pentafluorobenzamide).

[0063] The "acylimido group" refers to an atomic group remaining after removing one hydrogen atom bonded to a nitrogen atom from an imide. The number of carbon atoms in the acylimido group is usually about 4 to 20. Specific examples of the acylimido group include groups represented by the following structural formulas.

[0064] [Chemistry 2]

[0065]

[0066] The "substituted oxycarbonyl group" refers to a group represented by R'-O-(C=O)-.

[0067] Here, R' represents an alkyl group, an aryl group, an aralkyl group or a monovalent heterocyclic group.

[0068] The substituted oxycarbonyl group usually has about 2 to 60 carbon atoms, preferably 2 to 48 carbon atoms.

[0069] Specific examples of the substituted oxycarbonyl group include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, tert-butoxycarbonyl, pentyloxycarbonyl, hexyloxycarbonyl, cyclohexyloxycarbonyl, heptyloxycarbonyl, octyloxycarbonyl, 2-ethylhexyloxycarbonyl, nonyloxycarbonyl, decyloxycarbonyl, 3,7-dimethyloctyloxycarbonyl, dodecyloxycarbonyl, trifluoromethoxycarbonyl, pentafluoroethoxycarbonyl, perfluorobutoxycarbonyl, perfluorohexyloxycarbonyl, perfluorooctyloxycarbonyl, phenoxycarbonyl, naphthoxycarbonyl and pyridyloxycarbonyl.

[0070] The "alkenyl group" may be any of linear, branched, and cyclic. The number of carbon atoms in a linear alkenyl group is usually 2 to 30, preferably 3 to 20, excluding the number of carbon atoms in the substituent. The number of carbon atoms in a branched or cyclic alkenyl group is usually 3 to 30, preferably 4 to 20, excluding the number of carbon atoms in the substituent.

[0071] The alkenyl group may have a substituent. Specific examples of the alkenyl group include vinyl, 1-propenyl, 2-propenyl, 2-butenyl, 3-butenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 5-hexenyl, 7-octenyl, and groups having substituents such as alkyl and alkoxy groups.

[0072] The "alkynyl group" may be any of linear, branched, and cyclic. The number of carbon atoms in a linear alkynyl group, excluding the number of carbon atoms in the substituent, is usually 2 to 20, preferably 3 to 20. The number of carbon atoms in a branched or cyclic alkynyl group, excluding the number of carbon atoms in the substituent, is usually 4 to 30, preferably 4 to 20.

[0073] The alkynyl group may have a substituent. Specific examples of the alkynyl group include ethynyl, 1-propynyl, 2-propynyl, 2-butynyl, 3-butynyl, 3-pentynyl, 4-pentynyl, 1-hexynyl, 5-hexynyl, and groups having substituents such as alkyl and alkoxy groups.

[0074] [2. Light detection element]

[0075] [2.1. Overview of Photodetection Element]

[0076] A light detection element according to one embodiment of the present invention includes: a first electrode and a second electrode; an active layer disposed between the first electrode and the second electrode; and a hole transport layer disposed between the second electrode and the active layer, wherein the active layer includes an organic compound, the thickness of the active layer is greater than 600 nm, and the hole transport layer includes nanoparticles of metal oxide.

[0077] Figure 1 Schematically shows a cross-sectional view of the light detection element of this embodiment. Figure 1 As shown, the light detection element 10 is provided on a supporting substrate 11, for example. The light detection element 10 includes a first electrode 12, an electron transport layer 13, an active layer 14, a hole transport layer 15, and a second electrode 16 in this order. Therefore, the active layer 14 is provided between the first electrode 12 and the second electrode 16, and the hole transport layer 15 is provided between the second electrode 16 and the active layer 14. In this configuration example, a sealing substrate 17 is further provided.

[0078] The first electrode 12 is provided so as to be in contact with the support substrate 11. The electron transport layer 13 is provided so as to be in contact with the first electrode 12. The active layer 14 is provided so as to be in contact with the electron transport layer 13. The hole transport layer 15 is provided so as to be in contact with the active layer 14.

[0079] The second electrode 16 is provided so as to be in contact with the hole transport layer 15. The sealing substrate 17 is provided so as to be in contact with the second electrode 16.

[0080] [2.2. Support base plate]

[0081] The material of the support substrate 11 is not particularly limited as long as it is a material that does not undergo chemical changes when a layer containing a particularly organic compound is formed. Examples of the material of the support substrate 11 include glass, plastic, polymer film, and silicon.

[0082] When the support substrate 11 is opaque, the electrode on the opposite side to the electrode provided on the opaque support substrate side (that is, the electrode on the side away from the opaque support substrate) is preferably a transparent or semi-transparent electrode.

[0083] [2.3. Electrode]

[0084] The first electrode 12 functions as a cathode that allows electrons to flow out of the light detection element 10 to an external circuit. The second electrode 16 functions as an anode that allows electrons to flow from an external circuit into the light detection element 10. At least one of the first electrode 12 and the second electrode 16 is preferably transparent or translucent for light to be incident.

[0085] As the material of the transparent or semi-transparent electrode, for example, a conductive metal oxide film, a semi-transparent metal film, etc. can be cited. Specifically, conductive materials such as indium oxide, zinc oxide, tin oxide, and indium tin oxide (ITO), indium zinc oxide (IZO), NESA, gold, platinum, silver, and copper can be cited. As the material of the transparent or semi-transparent electrode, ITO, IZO, and tin oxide are preferred. In addition, as the electrode, a transparent conductive film using organic compounds such as polyaniline and its derivatives, polythiophene and its derivatives as the material can be adopted.

[0086] If one of the first electrode 12 and the second electrode 16 is transparent or translucent, the other electrode may be an electrode with low light transmittance. As materials for electrodes with low light transmittance, for example, metals and conductive polymers may be cited. Specific examples of materials for electrodes with low light transmittance include metals such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, and ytterbium, and alloys of two or more of these metals; or alloys of one or more of these metals and one or more of the 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. As alloys, magnesium-silver alloys, magnesium-indium alloys, magnesium-aluminum alloys, indium-silver alloys, lithium-aluminum alloys, lithium-magnesium alloys, lithium-indium alloys, and calcium-aluminum alloys may be cited.

[0087] As described above, when the support substrate 11 is opaque, the electrode on the opposite side to the electrode provided on the opaque support substrate 11 side (ie, the electrode on the side away from the support substrate) is preferably a transparent or semi-transparent electrode.

[0088] That is, in the present embodiment, when the support substrate 11 is opaque, the second electrode 16 is preferably a transparent or semi-transparent electrode.

[0089] [2.4. Electron transport layer]

[0090] The electron transport layer 13 has a function of transporting electrons generated in the active layer 14 to the first electrode 12. The electron transport layer 13 may also have a function of serving as a hole blocking layer to prevent holes generated in the active layer 14 from being transported to the first electrode 12.

[0091] The electron transport layer 13 generally contains an electron transport material. Examples of the electron transport material include polyalkylene imine and its derivatives, polymer compounds containing a fluorene structure, and metal oxides.

[0092] Examples of polyalkyleneimines and their derivatives include polymers obtained by polymerizing one or more of alkyleneimines having 2 to 8 carbon atoms, particularly alkyleneimines having 2 to 4 carbon atoms, such as ethyleneimine, propyleneimine, butyleneimine, dimethylethyleneimine, pentyleneimine, hexyleneimine, heptyleneimine, and octyleneimine by conventional methods, and polymers chemically modified by reacting these with various compounds, more specifically, polyethyleneimine (PEI) and polyethyleneimine ethoxylate (PEIE: ethoxylated polyethyleneimine). Polyethyleneimine ethoxylate is a modified product containing polyalkyleneimine as the main chain and having ethylene oxide added to the nitrogen atom in the main chain.

[0093] Examples of the polymer compound containing a fluorene structure include poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-o-2,7-(9,9′-dioctylfluorene)] (PFN).

[0094] As examples of the metal oxide, zinc oxide, gallium-doped zinc oxide, aluminum-doped zinc oxide, titanium oxide, and niobium oxide can be cited.

[0095] Examples of other electron transporting materials include poly(4-vinylphenol) and perylene diimide.

[0096] [2.5. Active layer]

[0097] [Constitution of active layer]

[0098] The active layer 14 includes an organic compound, preferably a polymer compound, and more preferably a conjugated polymer compound, and generally includes a p-type semiconductor material (electron-donating compound) and an n-type semiconductor material (electron-accepting compound). Examples and preferred examples of p-type semiconductor materials and n-type semiconductor materials are described below. The material included can be relatively determined to be a p-type semiconductor material or an n-type semiconductor material according to the energy level of the HOMO or LUMO of the selected compound.

[0099] Here, the conjugated polymer compound refers to a polymer compound having a structure in which π electrons are delocalized due to p orbital overlap in the main chain, and examples thereof include: (1) a polymer compound having a structure in which double bonds and single bonds are alternately arranged; (2) a polymer compound having a structure in which double bonds and single bonds are arranged via nitrogen atoms; and (3) a polymer compound having a structure in which double bonds and single bonds are alternately arranged and a structure in which double bonds and single bonds are arranged via nitrogen atoms.

[0100] The active layer 14 preferably has a structure in which a phase of a p-type semiconductor material and a phase of an n-type semiconductor material exist separately, that is, a so-called bulk heterojunction structure.

[0101] [Thickness of active layer]

[0102] From the perspective of reducing dark current, the thickness of the active layer 14 is usually greater than 600nm, preferably greater than 700nm, more preferably greater than 800nm, and further preferably greater than 1000nm. From the perspective of improving external quantum efficiency, the thickness is preferably less than 5000nm, more preferably less than 3000nm, and further preferably less than 1500nm.

[0103] The thickness of the active layer 14 can be adjusted by a conventionally known method. For example, when the active layer 14 is formed by a coating method, the thickness of the active layer 14 can be adjusted by adjusting the concentration of components other than the solvent contained in the coating liquid used (solid content concentration), the coating conditions, etc.

[0104] Specifically, for example, when the coating method is a blade coating method, the thickness of the active layer 14 can be adjusted by adjusting the coating speed and / or adjusting the gap between the coating surface and the blade.

[0105] In addition, for example, by increasing the solid content concentration of the coating liquid, the thickness of the active layer 14 can be increased, and by decreasing the solid content concentration, the thickness of the active layer 14 can be decreased.

[0106] The thickness of the active layer can be measured using a stylus-type film thickness meter (“Surfcorder ET-200” manufactured by Kosaka Laboratory Co., Ltd.).

[0107] [Material of active layer]

[0108] (p-type semiconductor material)

[0109] The p-type semiconductor material that can be included in the active layer can be a low molecular compound or a high molecular compound. The p-type semiconductor material is preferably a high molecular compound, more preferably a conjugated high molecular compound.

[0110] Examples of the p-type semiconductor material that is a low molecular weight compound include phthalocyanine, metallophthalocyanine, porphyrin, metalloporphyrin, oligothiophene, tetracene, pentacene, and rubrene.

[0111] When the p-type semiconductor material is a polymer compound, the polymer compound preferably has a predetermined weight average molecular weight in terms of polystyrene.

[0112] Here, the polystyrene-equivalent weight average molecular weight refers to a weight average molecular weight calculated using a standard sample of polystyrene by gel permeation chromatography (GPC).

[0113] From the viewpoint of solubility in a solvent, the polystyrene-equivalent weight average molecular weight of the p-type semiconductor material is preferably 20,000 to 200,000, more preferably 30,000 to 180,000, and even more preferably 40,000 to 150,000.

[0114] As p-type semiconductor materials belonging to conjugated polymer compounds, for example, polyvinylcarbazole and its derivatives, polysilane and its derivatives, polysiloxane derivatives containing an aromatic amine structure in the side chain or the main chain, polyaniline and its derivatives, polythiophene and its derivatives, polypyrrole and its derivatives, polyphenylene vinylene and its derivatives, polythiophenylene vinylene and its derivatives, polyfluorene and its derivatives, etc. can be cited.

[0115] As the p-type semiconductor material which is a conjugated polymer compound, a polymer compound including a structural unit having a thiophene skeleton is preferable.

[0116] The p-type semiconductor material is preferably a polymer compound comprising a structural unit represented by the following formula (I) and / or a structural unit represented by the following formula (II), and more preferably a conjugated polymer compound comprising a structural unit represented by the following formula (I) and / or a structural unit represented by the following formula (II).

[0117] [Chemistry 3]

[0118]

[0119] In formula (I), Ar 1 and Ar 2 represents a trivalent aromatic heterocyclic group, and Z represents a group represented by the following formula (Z-1) to formula (Z-7).

[0120] [Chemistry 4]

[0121] -Ar 3 - (II)

[0122] In formula (II), Ar 3 It represents a divalent aromatic heterocyclic group.

[0123] [Chemistry 5]

[0124]

[0125] In formulas (Z-1) to (Z-7), R represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, a monovalent heterocyclic group, a substituted amino group, an acyl group, an imide residue, an amide group, an imide group, a substituted oxycarbonyl group, an alkenyl group, an alkynyl group, a cyano group, or a nitro group. In each of formulas (Z-1) to (Z-7), when there are two Rs, the two Rs may be the same or different from each other.

[0126] The structural unit represented by formula (I) is preferably a structural unit represented by the following formula (I-1).

[0127] [Chemistry 6]

[0128]

[0129] In the formula (I-1), Z has the same meaning as described above.

[0130] Examples of the structural unit represented by formula (I-1) include structural units represented by the following formulae (501) to (505).

[0131] [Chemistry 7]

[0132]

[0133] In the above formulae (501) to (505), R has the same meaning as above. When there are two Rs, the two Rs may be the same as or different from each other.

[0134] Ar 3 The divalent aromatic heterocyclic group represented by is usually 2 to 60 carbon atoms, preferably 4 to 60 carbon atoms, and more preferably 4 to 20 carbon atoms. 3 The divalent aromatic heterocyclic group represented by may have a substituent. 3 Examples of substituents that the divalent aromatic heterocyclic group represented may have include a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, a monovalent heterocyclic group, a substituted amino group, an acyl group, an imide residue, an amide group, an imide group, a substituted oxycarbonyl group, an alkenyl group, an alkynyl group, a cyano group, and a nitro group.

[0135] As Ar 3 Examples of the divalent aromatic heterocyclic group represented by include groups represented by the following formulae (101) to (185).

[0136] [Chemistry 8]

[0137]

[0138] [Chemistry 9]

[0139]

[0140] [Chemistry 10]

[0141]

[0142] [Chemistry 11]

[0143]

[0144] In formulae (101) to (185), R has the same meaning as above. When there are two or more Rs, the two or more Rs may be the same or different from each other.

[0145] As the structural unit represented by the above formula (II), structural units represented by the following formulae (II-1) to (II-6) are preferred.

[0146] [Chemistry 12]

[0147]

[0148] In formula (II-1) to formula (II-6), X 1 and X 2 Each independently represents an oxygen atom or a sulfur atom, and R has the same meaning as above. When there are two or more Rs, the two or more Rs may be the same or different from each other.

[0149] From the viewpoint of the availability of the raw material compounds, X in Formula (II-1) to Formula (II-6) 1 and X 2 Preferably, they are all sulfur atoms.

[0150] The polymer compound as a p-type semiconductor material may contain two or more structural units of the formula (I), or may contain two or more structural units of the formula (II).

[0151] In order to improve solubility in a solvent, the polymer compound as a p-type semiconductor material may contain a structural unit represented by the following formula (III).

[0152] [Chemistry 13]

[0153] -Ar 4 - (III)

[0154] In formula (III), Ar 4 It represents an arylene group.

[0155] Ar 4The arylene group represented here refers to the atomic group remaining after removing two hydrogen atoms from an aromatic hydrocarbon with or without a substituent. Aromatic hydrocarbons also include compounds having condensed rings, and compounds in which two or more selected from the group consisting of independent benzene rings and condensed rings are bonded directly or through a divalent group such as vinylene.

[0156] Examples of the substituent which the aromatic hydrocarbon may have include the same substituents as those exemplified as the substituent which the heterocyclic compound may have.

[0157] The carbon number of the part excluding the substituent in the arylene group is usually 6 to 60, preferably 6 to 20. The carbon number of the arylene group including the substituent is usually about 6 to 100.

[0158] Examples of arylene groups include phenylene groups (for example, formulas 1 to 3 below), naphthalene diyl groups (for example, formulas 4 to 13 below), anthracene diyl groups (for example, formulas 14 to 19 below), biphenyl diyl groups (for example, formulas 20 to 25 below), terphenyl diyl groups (for example, formulas 26 to 28 below), condensed ring compound groups (for example, formulas 29 to 35 below), fluorene diyl groups (for example, formulas 36 to 38 below), and benzofluorene diyl groups (for example, formulas 39 to 46 below).

[0159] [Chemistry 14]

[0160]

[0161] [Chemistry 15]

[0162]

[0163] [Chemistry 16]

[0164]

[0165] [Chemistry 17]

[0166]

[0167] [Chemistry 18]

[0168]

[0169] [Chemistry 19]

[0170]

[0171] [Chemistry 20]

[0172]

[0173] [Chemistry 21]

[0174]

[0175] The structural unit constituting the polymer compound serving as a p-type semiconductor material may be a structural unit formed by combining and linking two or more structural units selected from the structural unit represented by formula (I), the structural unit represented by formula (II) and the structural unit represented by formula (III).

[0176] In the case where a polymer compound serving as a p-type semiconductor material contains a structural unit represented by formula (I) and / or a structural unit represented by formula (II), when the amount of all structural units contained in the polymer compound is 100 mol %, the total amount of the structural units represented by formula (I) and the structural units represented by formula (II) is generally 20 mol % to 100 mol %, and is preferably 40 mol % to 100 mol %, and more preferably 50 mol % to 100 mol % for the purpose of improving the charge transport properties as a p-type semiconductor material.

[0177] Specific examples of the polymer compound as the p-type semiconductor material include polymer compounds represented by the following formulae P-1 to P-6.

[0178] [Chemistry 22]

[0179]

[0180] [Chemistry 23]

[0181]

[0182] The active layer may include only one p-type semiconductor material, or may include two or more p-type semiconductor materials in combination in any ratio.

[0183] (n-type semiconductor material)

[0184] As examples of n-type semiconductor materials that may be included in the active layer, there can be cited polyvinylcarbazole and its derivatives, polysilane and its derivatives, polysiloxane derivatives having an aromatic amine structure in the side chain or the main chain, polyaniline and its derivatives, polythiophene and its derivatives, polypyrrole and its derivatives, polyphenylene vinylene and its derivatives, polythiophenylene vinylene and its derivatives, polyquinoline and its derivatives, polyquinoxaline and its derivatives, and polyfluorene and its derivatives.

[0185] The n-type semiconductor material is preferably at least one selected from the group consisting of fullerenes and fullerene derivatives, and more preferably a fullerene derivative.

[0186] Examples of fullerene include C60 fullerene, C 70 Fullerene, C 76 Fullerene, C 78Fullerenes and C 84 Fullerene. Examples of fullerene derivatives include derivatives of these fullerenes. Fullerene derivatives refer to compounds in which at least a part of fullerene is modified.

[0187] Examples of the fullerene derivative include compounds represented by the following formula (N-1) to formula (N-4).

[0188] [Chemistry 24]

[0189]

[0190] In formula (N-1) to formula (N-4), R a represents an alkyl group, an aryl group, a monovalent heterocyclic group or a group having an ester structure. a They may be the same as or different from each other.

[0191] R b represents an alkyl group or an aryl group. b They may be the same as or different from each other.

[0192] As R a Examples of the group having an ester structure include a group represented by the following formula (19).

[0193] [Chemistry 25]

[0194]

[0195] In formula (19), u1 represents an integer of 1 to 6. u2 represents an integer of 0 to 6. R c represents an alkyl group, an aryl group or a monovalent heterocyclic group.

[0196] As C 60 Examples of fullerene derivatives include the following compounds.

[0197] [Chemistry 26]

[0198]

[0199] As C 60 Specific examples of the fullerene derivative include [6,6]-phenyl-C61 butyric acid methyl ester (C60PCBM, [6,6]-Phenyl C61 butyric acid methyl ester) and [6,6]-thienyl-C61 butyric acid methyl ester ([6,6]-Thienyl C61 butyric acid methyl ester).

[0200] The active layer may include only one n-type semiconductor material, or may include two or more n-type semiconductor materials in combination in any ratio.

[0201] [2.6. Hole transport layer]

[0202] The hole transport layer 15 has a function of transporting holes generated in the active layer 14 to the second electrode 16. The hole transport layer 15 may also have a function of serving as an electron blocking layer to prevent electrons generated in the active layer 14 from being transported to the second electrode 16.

[0203] The hole transport layer 15 contains nanoparticles of metal oxide.

[0204] (Nanoparticles)

[0205] In this specification, "nanoparticles" refer to particles having an average particle diameter of less than 1 μm.

[0206] The average particle size of the nanoparticles is usually greater than 0 nm. The hole transport layer 15 can reduce dark current by including metal oxide nanoparticles.

[0207] From the viewpoint of making the hole transport layer smooth, the average particle size of the metal oxide nanoparticles is preferably 50 nm or less, more preferably 30 nm or less. The lower limit of the average particle size of the metal oxide nanoparticles is preferably 5 nm or more.

[0208] From the viewpoint of making the hole transport layer thin and dense and improving the hole transport property, the average particle diameter of the metal oxide nanoparticles is preferably 5 nm or more and 30 nm or less.

[0209] Here, the average particle size of the nanoparticles is a value measured by a dynamic light scattering (DLS) method.

[0210] (Metal Oxide)

[0211] The metal oxide may be an oxide of a single metal element or a composite oxide composed of oxides of a plurality of metal elements. Preferably, the metal oxide contains one or more selected from the group consisting of molybdenum atoms, tungsten atoms, and nickel atoms.

[0212] Examples of metal oxides include molybdenum oxide (MoO3, etc.), vanadium oxide (V2O5, etc.), tungsten oxide (WO3, etc.) and nickel oxide (NiO, etc.), preferably one or more selected from the group consisting of molybdenum oxide, tungsten oxide and nickel oxide, more preferably molybdenum oxide, tungsten oxide or nickel oxide.

[0213] As molybdenum oxide, MoO 3 is preferred. As tungsten oxide, WO 3 is preferred. As nickel oxide, NiO is preferred.

[0214] The hole transport layer 15 may include only one metal oxide in the form of nanoparticles, or may include two or more metal oxides in the form of nanoparticles. When the hole transport layer 15 includes two or more metal oxides, the average particle diameters of the nanoparticles of the metal oxides may be different from each other.

[0215] In order to improve dispersibility in a solvent, the metal oxide nanoparticles may be treated with a surface treatment agent.

[0216] Examples of the surface treatment agent include silane coupling agents.

[0217] The hole transport layer 15 may contain a hole transport material other than the metal oxide nanoparticles.

[0218] Examples of hole transporting materials other than metal oxide nanoparticles include polythiophene and derivatives thereof, aromatic amine compounds, and polymer compounds containing a structural unit having an aromatic amine residue.

[0219] The hole transport material other than the metal oxide nanoparticles that may be contained in the hole transport layer 15 is, for example, preferably 5 wt % or less, more preferably 1 wt % or less, and is usually 0 wt % or more, and may be 0 wt %.

[0220] The thickness of the hole transport layer can be arbitrarily set, and may be, for example, 5 nm or more, 10 nm or more, or 50 nm or less, or 200 nm or less, 100 nm or less, or 80 nm or less.

[0221] [2.7. Sealing substrate]

[0222] The light detection element 10 may be sealed by a sealing substrate 17. As an example of the sealing substrate, for example, a combination of a cover glass having a recessed portion and a sealing material can be cited.

[0223] The sealing substrate may have a layer structure of one or more layers. Therefore, examples of the sealing substrate include layer structures such as a gas barrier layer and a gas barrier film.

[0224] The layer structure of the sealing substrate is preferably formed of a material having a property of blocking moisture (water vapor barrier property) or a property of blocking oxygen (oxygen barrier property). Examples of preferred materials for the layer structure include organic materials such as trifluoroethylene, polychlorotrifluoroethylene (PCTFE), polyimide, polycarbonate, polyethylene terephthalate, alicyclic polyolefin, ethylene-vinyl alcohol copolymer and other resins, and inorganic materials such as silicon oxide, silicon nitride, aluminum oxide, and diamond-like carbon.

[0225] [2.8. Other embodiments of light detection element]

[0226] The light detection element of the above-mentioned embodiment includes a supporting substrate, a first electrode, an electron transport layer, an active layer, a hole transport layer, a second electrode and a sealing substrate in sequence, but the light detection element may also include a supporting substrate, a second electrode, a hole transport layer, an active layer, an electron transport layer, a first electrode and a sealing substrate in sequence. In addition, the light detection element may not include an electron transport layer, and the active layer and the first electrode may be in contact. In addition, the light detection element may not include a supporting substrate, and may not include a sealing substrate.

[0227] [3. Method for manufacturing light detection element]

[0228] The method for manufacturing the light detecting element of the present invention is not particularly limited. The light detecting element of the present invention can be manufactured by an appropriate forming method using materials selected when forming each component.

[0229] For example, a photodetection element according to one embodiment of the present invention including a supporting substrate, a first electrode, an electron transport layer, an active layer, a hole transport layer, and a second electrode in this order can be manufactured by a manufacturing method including the following steps in this order.

[0230] Step (I) Step of preparing a supporting substrate provided with a first electrode

[0231] Step (II) Step of forming an electron transport layer

[0232] Step (III) Step of forming an active layer

[0233] Step (VI) Step of forming a hole transport layer containing metal oxide nanoparticles

[0234] Step (V) Step of forming the second electrode

[0235] Next, each process will be described in sequence.

[0236] [Step (I)]

[0237] In this step, a support substrate provided with a first electrode is prepared. The method for providing the first electrode on the support substrate is not particularly limited. For example, the materials exemplified above may be stacked on a support substrate composed of the materials described above by vacuum evaporation, sputtering, ion plating, plating, coating, etc., thereby forming the first electrode.

[0238] Alternatively, the supporting substrate provided with the first electrode can be prepared by obtaining a supporting substrate provided with a thin film formed of the material of the electrode described above from the market, and patterning the conductive thin film as necessary to form the first electrode.

[0239] [Step (II)]

[0240] In this step, an electron transport layer is formed. Since the electron transport layer can be formed simply and at low cost, it is preferable to form the electron transport layer by a coating method using a coating liquid.

[0241] As a coating method for forming an electron transport layer, for example, slit coating, blade coating, spin coating, micro gravure coating, gravure printing, rod coating, inkjet printing, nozzle coating, capillary coating, casting, roller coating, wire rod coating, dip coating, spray coating, screen printing, flexographic printing, offset printing and dispenser printing can be cited. Among them, slit coating, blade coating, spin coating, micro gravure coating, gravure printing, rod coating, inkjet printing, nozzle coating or capillary coating are preferred, slit coating, blade coating, spin coating, rod coating or capillary coating are more preferred, and slit coating, blade coating or spin coating are further preferred.

[0242] The coating liquid for forming the electron transport layer by a coating method generally contains an electron transport material and a solvent. Examples of the electron transport material that can be contained in the coating liquid are the same as the examples described above as the electron transport material that can be contained in the electron transport layer.

[0243] As solvents that can be included in the coating solution for forming the electron transport layer, for example, water, alcohol solvents, ketone solvents, and hydrocarbon solvents can be cited. As specific examples of alcohol solvents, methanol, ethanol, isopropanol, butanol, ethylene glycol, propylene glycol, butoxyethanol, methoxybutanol, etc. can be cited. As specific examples of ketone solvents, acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, cyclohexanone, etc. can be cited. As specific examples of hydrocarbon solvents, n-pentane, cyclohexane, n-hexane, benzene, toluene, xylene, tetralin, chlorobenzene, o-dichlorobenzene, etc. can be cited. The coating solution can contain a single solvent, or it can contain two or more solvents, and it can contain two or more of the above-mentioned solvents.

[0244] The coating liquid used in the coating method for forming the electron transport layer may be a dispersion such as an emulsion (emulsion) or a suspension (suspension).

[0245] After the coating liquid is applied to the coating object to form a coating film, the solvent is usually removed from the coating film. Examples of methods for removing the solvent include a method of directly heating with a hot plate, a hot air drying method, an infrared heating drying method, a flash lamp annealing drying method, a reduced pressure drying method, and the like.

[0246] [Step (III)]

[0247] In this step, an active layer is formed. Since the active layer can be formed simply and at low cost, it is preferable to form the active layer by a coating method using a coating liquid.

[0248] Examples and preferred examples of the coating method for forming the active layer are the same as those described above as the coating method for forming the electron transport layer. As the coating method for forming the active layer, the doctor blade coating method is particularly preferred because the active layer can be easily thickened.

[0249] The coating liquid for forming the active layer by a coating method contains, for example, a p-type semiconductor material (electron donating compound), an n-type semiconductor material (electron accepting compound), and a solvent.

[0250] Examples and preferred examples of the p-type semiconductor material and the n-type semiconductor material (electron accepting compound) that may be contained in the coating liquid are the same as the examples and preferred examples described above as the respective materials that may be contained in the active layer.

[0251] Examples of solvents that may be included in the coating solution for forming the active layer include aromatic hydrocarbon solvents (e.g., toluene, xylene, trimethylbenzene, butylbenzene, methylnaphthalene, tetralin, indane, chlorobenzene, and dichlorobenzene); ketone solvents (e.g., acetone, methyl ethyl ketone, cyclohexanone, acetophenone, and propiophenone); ester solvents (e.g., ethyl acetate, butyl acetate, phenyl acetate, ethyl cellosolve acetate, methyl benzoate, butyl benzoate, and benzyl benzoate); and mixed solvents thereof. As solvents that may be included in the coating solution for forming the active layer, the following solvents are preferred, which include (1) an aromatic hydrocarbon solvent as a main solvent (hereinafter also referred to as the first solvent); and (2) one or more solvents selected from the group consisting of ketone solvents and ester solvents as other additional solvents (referred to as the second solvent).

[0252] As a preferred combination of the first solvent and the second solvent, for example, a combination of o-xylene and acetophenone can be mentioned.

[0253] The coating liquid used in the coating method for forming the active layer may be a dispersion such as an emulsion (emulsion) or a suspension (suspension).

[0254] After the coating liquid is applied to the coating object to form a coating film, the solvent is usually removed from the coating film. Examples of the method for removing the solvent are the same as the examples of the method for removing the solvent described above in the step of forming the electron transport layer.

[0255] The thickness of the active layer can be adjusted, for example, by appropriately adjusting the solid content concentration in the coating liquid, the conditions of the above-mentioned coating method, etc. More specifically, when the active layer is formed by coating using a doctor blade coating method, the thickness of the active layer can be adjusted by adjusting the gap between the coating surface and the doctor blade.

[0256] [Step (VI)]

[0257] In this step, a hole transport layer containing nanoparticles of a metal oxide is formed.

[0258] Since the hole transport layer can be formed easily and at low cost, it is preferred to form the hole transport layer by a coating method using a coating liquid.

[0259] An example of a coating method for forming the hole transport layer is the same as the example explained above as the coating method for forming the electron transport layer.

[0260] As a coating method for forming the hole transport layer, a spin coating method, a slit coating method, a flexographic printing method, an inkjet printing method or a dispenser printing method is preferable.

[0261] The coating solution for forming the hole transport layer by a coating method generally contains nanoparticles of metal oxide and a solvent. Examples and preferred examples of the nanoparticles of metal oxide that can be contained in the coating solution are the same as the examples and preferred examples of the nanoparticles of metal oxide that can be contained in the hole transport layer. Here, the solvent contains a dispersion medium.

[0262] Examples of the solvent that may be contained in the coating solution for forming the hole transport layer are the same as the examples explained above as the solvent that may be contained in the coating solution for forming the electron transport layer.

[0263] The coating liquid for forming the hole transport layer is generally a dispersion such as an emulsion or a suspension.

[0264] After the coating liquid is applied to the coating object to form a coating film, the solvent is usually removed from the coating film. Examples of the method for removing the solvent are the same as the examples of the method for removing the solvent described above in the step of forming the electron transport layer.

[0265] [Step (V)]

[0266] In this step, the second electrode is formed. The second electrode is usually formed on the hole transport layer.

[0267] The method for forming the second electrode is not particularly limited. For example, the second electrode can be formed by laminating the above-mentioned materials on a layer (eg, a hole transport layer) to form the second electrode by vacuum deposition, sputtering, ion plating, plating, coating, or the like.

[0268] In the method for manufacturing a light detection element, for example, the order of the above steps can be changed according to the embodiment of the light detection element to be manufactured. In addition, some of the above steps (such as the step of forming an electron transport layer) may not be included. In addition, in addition to the above steps, optional steps may also be included.

[0269] For example, the manufacturing method of the light detection element of other embodiments may include, in sequence: a process of preparing a supporting substrate provided with a second electrode; a process of forming a hole transport layer containing nanoparticles of metal oxide; a process of forming an active layer; a process of forming an electron transport layer; and a process of forming a first electrode.

[0270] [4. Application examples of light detection elements]

[0271] The light detection element according to the embodiment of the present invention described above can be suitably used in detection units included in various electronic devices such as workstations, personal computers, portable information terminals, entry and exit management systems, digital cameras, and medical equipment.

[0272] The light detection element of the present invention can be appropriately applied to image detection units (image sensors) for solid-state imaging devices such as X-ray imaging devices and CMOS image sensors, detection units for detecting specific local features of a biological body such as fingerprint detection units, face detection units, vein detection units and iris detection units, and detection units of optical biosensors such as pulse oximeters, etc., which are possessed by the electronic devices exemplified above.

[0273] [5. Fingerprint recognition device]

[0274] As described above, the light detection element of the present invention can be suitably used in a fingerprint detection unit provided in a fingerprint recognition device. Therefore, a fingerprint recognition device including the light detection element of the present invention can be provided.

[0275] Hereinafter, configuration examples of an image detection unit for a solid-state imaging device and a biometric authentication device (a fingerprint detection unit for a fingerprint recognition device) among detection units of a light detection element according to an embodiment of the present invention to which the present invention can be suitably applied will be described with reference to the drawings.

[0276] <Image Detection Unit>

[0277] Figure 2 It is a diagram schematically showing a configuration example of an image detection section for a solid-state imaging device.

[0278] The image detection unit 1 includes: a CMOS transistor substrate 20; an interlayer insulating film 30 arranged in a manner to cover the CMOS transistor substrate 20; a light detection element (photoelectric conversion element) 10 of an embodiment of the present invention arranged on the interlayer insulating film 30; an interlayer wiring portion 32 arranged in a manner to penetrate the interlayer insulating film 30 and electrically connect the CMOS transistor substrate 20 and the photoelectric conversion element (light detection element) 10; a sealing layer 40 arranged in a manner to cover the light detection element 10; and a color filter 50 arranged on the sealing layer.

[0279] The CMOS transistor substrate 20 has any suitable configuration known in the art in accordance with the design.

[0280] The CMOS transistor substrate 20 includes transistors, capacitors, and the like formed within the thickness of the substrate, and includes functional elements such as CMOS transistor circuits (MOS transistor circuits) for realizing various functions.

[0281] Examples of the functional element include a floating diffusion element, a reset transistor, an output transistor, and a selection transistor.

[0282] By using such functional elements, wirings, etc., a signal readout circuit and the like are manufactured on the CMOS transistor substrate 20 .

[0283] The interlayer insulating film 30 may be made of any suitable insulating material known in the art, such as silicon oxide, insulating resin, etc. The interlayer wiring portion 32 may be made of any suitable conductive material (wiring material) known in the art, such as copper, tungsten, etc. The interlayer wiring portion 32 may be, for example, an in-hole wiring formed simultaneously with the formation of the wiring layer, or may be an embedded plug formed separately from the wiring layer.

[0284] The sealing layer 40 may be formed of any suitable material known in the art as long as it can prevent or suppress the penetration of harmful substances such as oxygen and water that may deteriorate the function of the light detection element 10. The sealing layer 40 may also be formed of the sealing substrate 17 described above.

[0285] As the color filter 50, for example, a primary color filter made of any suitable material known in the art and corresponding to the design of the image detection unit 1 can be used. In addition, as the color filter 50, a complementary color filter that can be thinner than the primary color filter can also be used. As the complementary color filter, for example, a color filter composed of three colors (yellow, cyan, magenta), three colors (yellow, cyan, transparent), three colors (yellow, transparent, magenta) and a combination of three colors (transparent, cyan, magenta) can be used. They can adopt any suitable configuration corresponding to the design of the light detection element 10 and the CMOS transistor substrate 20 under the condition that color image data can be generated.

[0286] The light received by the photodetection element 10 via the color filter 50 is converted into an electrical signal according to the amount of received light by the photodetection element 10 and output to the outside of the photodetection element 10 via the electrode in the form of a received light signal, that is, an electrical signal corresponding to the object.

[0287] Next, the received light signal output from the light detection element 10 is input to the CMOS transistor substrate 20 via the interlayer wiring portion 32, is read out by a signal readout circuit manufactured on the CMOS transistor substrate 20, and is processed by any other suitable existing known functional portion not shown, thereby generating image information based on the photographed object.

[0288] <Fingerprint Detection Section>

[0289] Figure 3 FIG. 1 is a diagram schematically showing a configuration example of a fingerprint detection unit integrally configured with a display device.

[0290] The display device 2 of the portable information terminal includes a fingerprint detection unit 100 including the light detection element 10 according to the embodiment of the present invention as a main component, and a display panel unit 200 provided on the fingerprint detection unit 100 and displaying a predetermined image.

[0291] In this configuration example, the fingerprint detection unit 100 is provided in a region substantially coinciding with the display region 200 a of the display panel unit 200 . In other words, the display panel unit 200 is integrally stacked above the fingerprint detection unit 100 .

[0292] When fingerprint detection is performed only in a partial area of ​​the display area 200a, the fingerprint detection unit 100 may be provided only corresponding to the partial area. The fingerprint detection unit 100 may also adopt the configuration of the image detection unit described above.

[0293] The fingerprint detection unit 100 includes the light detection element 10 of the embodiment of the present invention as a functional unit that performs substantial functions. The fingerprint detection unit 100 may include any suitable existing known components such as a protection film (not shown), a support substrate, a sealing substrate, a sealing component, a barrier film, a bandpass filter, and an infrared cutoff film in a manner corresponding to a design that can obtain desired characteristics.

[0294] The light detection element 10 may be included in the display region 200 a in any manner. For example, two or more light detection elements 10 may be arranged in a matrix.

[0295] As described above, the light detection element 10 is provided on the support substrate 11 or the sealing substrate, and electrodes (anodes or cathodes) are provided on the support substrate 11 in a matrix form, for example.

[0296] The light received by the light detecting element 10 is converted into an electrical signal according to the amount of received light by the light detecting element 10 and output to the outside of the light detecting element 10 via the electrode in the form of a received light signal, that is, an electrical signal corresponding to the photographed fingerprint.

[0297] In this configuration example, the display panel unit 200 is configured as an organic electroluminescent display panel (organic EL display panel) including a touch sensor panel. Instead of the organic EL display panel, the display panel unit 200 may be configured as a display panel having any suitable existing known configuration, such as a liquid crystal display panel including a light source such as a backlight.

[0298] The display panel unit 200 is provided on the fingerprint detection unit 100 described above. The display panel unit 200 includes an organic electroluminescent element (organic EL element) 220 as a functional unit that performs substantial functions. The display panel unit 200 may further include any suitable existing known components such as a glass substrate (support substrate 210 or sealing substrate 240), a sealing component, a barrier film, a polarizing plate such as a circular polarizing plate, and a touch sensor panel 230 in a manner corresponding to the desired characteristics.

[0299] In the configuration example described above, the organic EL element 220 is used as a light source for pixels in the display region 200 a and is also used as a light source for fingerprint imaging in the fingerprint detection unit 100 .

[0300] Here, the operation of the fingerprint detection unit 100 will be briefly described.

[0301] When performing fingerprint recognition, the fingerprint detection unit 100 detects the fingerprint using the light emitted from the organic EL element 220 of the display panel unit 200. Specifically, the light emitted from the organic EL element 220 is transmitted through the components existing between the organic EL element 220 and the light detection element 10 of the fingerprint detection unit 100, and is reflected by the skin (finger surface) of the fingertip of the finger placed in contact with the surface of the display panel unit 200 in the display area 200a. At least a portion of the light reflected by the finger surface is received by the light detection element 10 through the components existing therebetween, and is converted into an electrical signal corresponding to the amount of light received by the light detection element 10. Then, the converted electrical signal constitutes image information related to the fingerprint on the finger surface.

[0302] The portable information terminal including the display device 2 compares the obtained image information with fingerprint data for fingerprint recognition recorded in advance through any suitable procedure known in the art to perform fingerprint recognition.

[0303] Example

[0304] Hereinafter, examples will be described in order to explain the present invention in further detail. However, the present invention is not limited to the examples described below.

[0305] In this example and comparative example, the polymer compound represented by the formula P-1 described above was used as a p-type semiconductor material (electron donating compound), and C60 PCBM is used as an n-type semiconductor material (electron accepting compound). The polymer compound represented by Formula P-1 can be synthesized by referring to the method described in WO2013 / 051676, for example.

[0306] <Example 1> Production and Evaluation of Light Detection Element (Photoelectric Conversion Element)

[0307] (Manufacturing of light detection element (photoelectric conversion element))

[0308] (First Electrode Preparation Step)

[0309] A glass substrate on which an ITO thin film (cathode) as a first electrode was formed to a thickness of 150 nm by sputtering was prepared, and the surface of the glass substrate was subjected to ozone UV treatment.

[0310] (Step of Forming Electron Transport Layer)

[0311] Next, a coating solution prepared by diluting polyethyleneimine ethoxylate (PEIE) (manufactured by Aldrich, trade name polyethyleneimine, 80% ethoxylated solution, weight average molecular weight 110,000) with 2-methoxyethanol to 1 / 500 was applied by spin coating onto the ITO thin film of the glass ITO substrate subjected to ozone UV treatment.

[0312] The glass substrate coated with the coating liquid was heated at 120° C. for 10 minutes using a hot plate, thereby forming the electron transport layer 1 on the ITO thin film as the first electrode.

[0313] (Active Layer Formation Step)

[0314] Next, the polymer compound represented by formula P-1 and C 60 PCBM (manufactured by Frontier Carbon, trade name: E100) was mixed in a weight ratio of 1:2, added to a mixed solvent of o-xylene as the first solvent and acetophenone as the second solvent (o-xylene:acetophenone=95:5 (weight ratio)), and stirred at 80°C for 10 hours to prepare a coating liquid for forming an active layer.

[0315] The prepared coating liquid for forming an active layer was applied to the electron transport layer of the glass substrate by a doctor blade coating method to obtain a coating film. The obtained coating film was dried for 5 minutes using a hot plate heated to 100° C. to form an active layer. The thickness of the formed active layer was 600 nm.

[0316] The thickness of the active layer was measured using a stylus-type film thickness meter (“Surfcorder ET-200” manufactured by Kosaka Laboratory Co., Ltd.).

[0317] (Hole Transport Layer Formation Step)

[0318] Next, a nickel oxide (NiO) dispersion (manufactured by Avantama, trade name Avantama P21, average particle size: 7 nm) was applied to the active layer by spin coating to obtain a coating film. The obtained coating film was dried for 5 minutes using a hot plate heated to 70° C., thereby forming a hole transport layer 1. The thickness of the formed hole transport layer 1 was 30 nm.

[0319] (Second Electrode Formation Step)

[0320] Furthermore, a silver (Ag) layer as a second electrode (anode) was formed on the hole transport layer 1 to a thickness of about 80 nm using a vacuum deposition apparatus, thereby producing a light detection element (photoelectric conversion element).

[0321] (Sealing process)

[0322] Next, a UV curable sealant is applied to the glass substrate around the manufactured light detection element (photoelectric conversion element), and after bonding the glass substrate as a sealing substrate, UV light is irradiated to seal the light detection element. The plane shape of the obtained light detection element when observed from the thickness direction is a square of 2 mm × 2 mm.

[0323] (Evaluation of Characteristics of Photodetection Element)

[0324] The characteristics of the manufactured light detection element were evaluated. The applied voltage was set to -10 V, and the dark current under the applied voltage was measured using a semiconductor parameter analyzer (Agilent Technology B1500A, manufactured by Agilent Technologies, Inc.). Table 1 shows the results of the dark current measurement.

[0325] <Examples 2 to 4, Comparative Examples 1 and 2>

[0326] A photodetection element was produced in the same manner as in Example 1 except that the following items were changed, and the dark current was measured.

[0327] In the step of forming the active layer, the coating speed and the gap between the blade of the blade coater and the coating surface are adjusted so that the film thickness of the active layer is 100 nm (Comparative Example 1), 300 nm (Comparative Example 2), 750 nm (Example 2), 1400 nm (Example 3), or 2000 nm (Example 4)

[0328] The results are shown in Table 1.

[0329] <Examples 5 to 7, Comparative Examples 3 and 4>

[0330] A photodetection element was produced in the same manner as in Example 1 except that the following items were changed, and the dark current was measured.

[0331] In the process of forming the active layer, the coating speed and the gap between the blade of the blade coater and the coating surface are adjusted so that the thickness of the active layer is 100 nm (Comparative Example 3), 300 nm (Comparative Example 4), 600 nm (Example 5), 750 nm (Example 6) or 1000 nm (Example 7).

[0332] In the hole transport layer forming step, a tungsten oxide (WO 3 ) dispersion (Avantama P10, trade name, average particle size: 10 to 20 nm) was used instead of the nickel oxide dispersion to form a hole transport layer 2 having a thickness of 30 nm.

[0333] The results are shown in Table 1.

[0334] <Examples 8 to 9, Comparative Examples 5 and 6>

[0335] A photodetection element was produced in the same manner as in Example 1 except that the following items were changed, and the dark current was measured.

[0336] In the process of forming the active layer, the coating speed and the gap between the blade of the blade coater and the coating surface are adjusted so that the thickness of the active layer is 100 nm (Comparative Example 5), 300 nm (Comparative Example 6), 600 nm (Example 8) or 1000 nm (Example 9).

[0337] In the hole transport layer formation step, a molybdenum oxide (MoO 3 ) dispersion (manufactured by Avantama, trade name MoO 3 ethanol solution, average particle size: about 10 nm) was used instead of the nickel oxide dispersion to form a hole transport layer 3 having a thickness of 30 nm.

[0338] The results are shown in Table 1.

[0339] <Comparative Examples 7 to 10>

[0340] A photodetection element was produced in the same manner as in Example 1 except that the following items were changed, and the dark current was measured.

[0341] In the process of forming the active layer, the coating speed and the gap between the blade of the blade coater and the coating surface are adjusted so that the thickness of the active layer is 100 nm (Comparative Example 7), 600 nm (Comparative Example 8), 750 nm (Comparative Example 9) or 1000 nm (Comparative Example 10).

[0342] In the hole transport layer forming step, an ink containing a polythiophene derivative (manufactured by Aldrich, trade name: Plexcore OC AQ1100) was used instead of the nickel oxide dispersion liquid to form a hole transport layer 4 having a thickness of 30 nm.

[0343] The results are shown in Table 1.

[0344] <Comparative Examples 11 to 14>

[0345] A photodetection element was produced in the same manner as in Example 1 except that the following items were changed, and the dark current was measured.

[0346] In the process of forming the active layer, the coating speed and the gap between the blade of the blade coater and the coating surface are adjusted so that the thickness of the active layer is 300 nm (Comparative Example 11), 600 nm (Comparative Example 12), 750 nm (Comparative Example 13) or 1000 nm (Comparative Example 14).

[0347] In the hole transport layer forming step, PEDOT:PSS (manufactured by Heraeus, trade name HTL-Solar) was used instead of the nickel oxide dispersion to form a hole transport layer 5 having a thickness of 30 nm.

[0348] The results are shown in Table 1.

[0349] <Comparative Examples 15 to 17>

[0350] A photodetection element was produced in the same manner as in Example 1 except that the following items were changed, and the dark current was measured.

[0351] The thickness of the active layer was set to 600 nm (Comparative Example 15), 750 nm (Comparative Example 16), or 1000 nm (Comparative Example 17).

[0352] In the hole transport layer forming step, PEDOT:PSS (manufactured by Heraeus, trade name FHC Solar) was used instead of the nickel oxide dispersion to form a hole transport layer 6 having a thickness of 30 nm.

[0353] The results are shown in Table 1.

[0354] <Comparative Examples 18 to 21>

[0355] A photodetection element was produced in the same manner as in Example 1 except that the following items were changed, and the dark current was measured.

[0356] In the step of forming the active layer, the coating speed and the gap between the blade of the blade coater and the coating surface are adjusted so that the thickness of the active layer is 100 nm (Comparative Example 18), 300 nm (Comparative Example 19), 600 nm (Comparative Example 20), or 1000 nm (Comparative Example 21).

[0357] In the step of forming the hole transport layer, molybdenum oxide was vacuum-deposited on the active layer to a thickness of 30 nm to form the hole transport layer 7 .

[0358] The results are shown in Table 1.

[0359] <Comparative Examples 22 to 26>

[0360] A photodetection element was produced in the same manner as in Example 1 except that the following items were changed, and the dark current was measured.

[0361] The thickness of the active layer was set to 100 nm (Comparative Example 22), 300 nm (Comparative Example 23), 600 nm (Comparative Example 24), 750 nm (Comparative Example 25), or 1000 nm (Comparative Example 26).

[0362] The first electrode is formed on the active layer without performing the step of forming the hole transport layer.

[0363] The results are shown in Table 1.

[0364] In the table below, "dark current" refers to the dark current (A / cm 2 ).

[0365] [Table 1]

[0366] Table 1

[0367]

[0368] According to the above results, it can be seen that compared with the light detection elements of comparison examples 1 or 2 in which the thickness of the active layer is less than 600nm, the light detection elements of comparison examples 7 to 21 that do not contain metal oxide nanoparticles, and the light detection elements of comparison examples 22 to 26 that do not contain a hole transport layer, the light detection elements of embodiments 1 to 9 in which the hole transport layer contains metal oxide nanoparticles and the thickness of the active layer is greater than 600nm significantly reduce the dark current.

[0369] Explanation of symbols

[0370] 1 Image detection unit

[0371] 2 Display device

[0372] 10 Light detection element

[0373] 11. 210 Support base plate

[0374] 12. 1st electrode (cathode)

[0375] 13 Electron transport layer

[0376] 14 Active layer

[0377] 15. Hole transport layer

[0378] 16. Second electrode (anode)

[0379] 17 Sealing base plate

[0380] 20 CMOS transistor substrate

[0381] 30 interlayer insulation film

[0382] 32 Interlayer wiring section

[0383] 40 Sealing layer

[0384] 50 Color Filters

[0385] 100 Fingerprint detection unit

[0386] 200 Display panel unit

[0387] 200a Display area

[0388] 220 Organic EL elements

[0389] 230 Touch sensor panel

[0390] 240 sealed substrate

Claims

1. A light detection element, comprising: a first electrode and a second electrode; an active layer disposed between the first electrode and the second electrode; and a hole transport layer disposed between the second electrode and the active layer, The active layer comprises an organic compound, and the thickness of the active layer is greater than 600 nm. The hole transport layer comprises nanoparticles of metal oxide, The average particle size of the metal oxide nanoparticles is 5 nm or more and 30 nm or less.

2. The light detecting element according to claim 1, wherein The metal oxide includes one or more atoms selected from the group consisting of molybdenum atoms, tungsten atoms, and nickel atoms.

3. The light detecting element according to claim 2, wherein: The metal oxide is one or more selected from the group consisting of molybdenum oxide, tungsten oxide, and nickel oxide.

4. The light detection element according to any one of claims 1 to 3, wherein The active layer contains a conjugated polymer compound.

5. The light detection element according to any one of claims 1 to 3, wherein The active layer includes a fullerene derivative. 6 . A fingerprint recognition device comprising the light detection element according to claim 1 .

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