JP2015113328A - Organic thin films, and photoelectric conversion element using these - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic film for a photoelectric conversion element with high optical density and heat resistance, and an imaging element using the same, particularly an organic film for a solid-state imaging element for a digital camera and a digital video camera.SOLUTION: The organic film contains a compound represented by the general formula (1). (Rto Rare each independently H, a halogen atom, a cyano group, an alkyl group, an alkoxy group, an aryl group or a heterocyclic group; X is O, or a nitrogen atom with a substituent R; and Ris an alkyl group, an aryl group or a heterocyclic group.)

Description

  The present invention relates to an organic thin film made of a photoelectric conversion material, and a photoelectric conversion element using these.

An organic thin film made of a photoelectric conversion material, that is, a photoelectric conversion film is widely used in, for example, an optical sensor, and is particularly preferably used as a solid-state image sensor (light-receiving element) of an image pickup apparatus (solid-state image pickup apparatus) such as a TV camera. Yes. As a material of a photoelectric conversion film used as a solid-state imaging element of an imaging device, an inorganic material film such as a Si film or an a-Se film is mainly used.

  Conventional photoelectric conversion films using these inorganic material films do not have a steep wavelength dependency with respect to the characteristics of the photoelectric conversion film, so that a color solid-state imaging device cannot be realized alone.

As a method for realizing a color solid-state image pickup device, a three-plate solid-state image pickup device in which incident light is separated into three primary colors of red, green, and blue, and three photoelectric conversion films are arranged after the prism, and an inorganic photoelectric sensor are used. A single-plate solid-state imaging device in which color separation color filters that transmit the three primary colors of blue, green, and red are regularly arranged on the light incident surface side of the conversion film has become mainstream.

However, the former three-plate solid-state image sensor cannot avoid the increase in size and mass due to the structure, and the latter single-plate solid-state image sensor color filter transmits only light of a limited wavelength. The light that does not pass through the color filter is not used and the light use efficiency is poor.

In order to reduce the size and weight of the imaging apparatus and improve the light utilization efficiency, it is not necessary to provide a spectroscopic prism, and a single-plate structure having a single light receiving element is desired. A single-plate photoelectric conversion element is an element that generates charge from a photoelectric conversion film in response to light incident from the transparent electrode side having a light transmitting property among a pair of electrodes, and reads the generated charge as a signal charge from the electrode. It is. As such a photoelectric conversion element, what was described in patent documents 1-6 as an example is known. In particular, as the material of the photoelectric conversion film, use of an organic material having advantages such as a variety of types and characteristics and a high degree of freedom in processing shape has been studied. The structure using the photoelectric converting layer which consists of organic semiconductors is described by patent documents 2-6. A photoelectric conversion film composed of an organic semiconductor has a large absorption coefficient and can be thinned. Therefore, high-definition imaging is possible, charge diffusion to adjacent pixels is small, optical color mixing and electric color mixing (crossing) A photoelectric conversion element capable of reducing (talk) can be realized. As the transparent electrode, a transparent conductive oxide produced on a glass substrate is generally used.
In particular, Patent Literature 4 describes an organic photoelectric conversion imaging device using a diketopyrrolopyrrole compound, and Patent Literature 5 describes an organic photoelectric conversion imaging device using a quinacridone compound.

  Considering application to a manufacturing process having a heating process such as laying of a protective film and soldering of an element and improvement in storage stability, a material for a photoelectric conversion element and a film including the material need to have high heat resistance. Patent Document 6 describes the result of a heat resistance test in which the produced solid-state imaging device is held at 200 ° C. for 30 minutes. In recent years, a lead-free solder having a melting point of 200 ° C. or higher at the time of wiring from the viewpoint of environmental consideration (For example, melting point 200 ° C. (Sn—Zn series), melting point 217 ° C. (Sn—Ag—Cu series), 227 ° C. (Sn—Cu series)) are often used. The heat resistance cannot be judged by the heat resistance test.

When an image sensor is composed of an organic thin film made of a photoelectric conversion material, it is possible to make the light-sensitive part thinner as the absorption coefficient of the thin film, that is, the absorbance per unit thickness, is larger. Can be obtained. However, in the above Patent Documents 2 to 5, there is no description relating to the absorbance of the thin film or a description suggesting it.

  Considering the storage stability of the element, it is desirable that not only the durability against heat but also the durability against moisture in the air (moisture heat resistance) and the durability against light (light resistance) are high. Furthermore, it is preferable that the ratio of the current amount taken out in the bright place to the current amount taken out from the device electrode in the dark place is high in photosensitivity. Further, it is more preferable that the current value that can be taken out in a dark place is small.

Japanese Patent Publication No. 1-334509 Patent No. 5225711 JP 2008-072090 A Patent No. 4945146 Patent No. 50222573 Japanese Patent No. 469951

  An object of the present invention is to provide an organic film, a photoelectric conversion element, and an imaging element (preferably a color image sensor) having high heat resistance and a thin film having a high extinction coefficient.

  As a result of intensive studies, the present inventors have found that an organic thin film containing a specific compound represented by the following general formula (1) solves the above-described problems, and thus the present invention. Was completed.

（式（１）中、Ｒ^１乃至Ｒ^８はそれぞれ独立に水素原子、ハロゲン原子、シアノ基、アルキル基、アルコキシ基、アリール基又は複素環基であり、Ｘは酸素原子又は置換基Ｒ^９を有する窒素原子であり、Ｒ^９はアルキル基、アリール基又は複素環基である。）、
（２）（１）に記載の有機膜を具備することを特徴とした光電変換素子、
（３）（２）に記載の光電変換素子を具備することを特徴とした固体撮像素子、
に関する。 That is, the present invention
(1) An organic film comprising a compound represented by the general formula (1)

(In formula (1), R ^{1 to} R ⁸ are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkoxy group, an aryl group or a heterocyclic group, and X represents an oxygen atom or a substituent R ⁹ . And R ⁹ is an alkyl group, an aryl group or a heterocyclic group).
(2) A photoelectric conversion element comprising the organic film according to (1),
(3) A solid-state imaging device comprising the photoelectric conversion device according to (2),
About.

According to the present invention, an organic film for an organic photoconductive film, a photoelectric conversion element, particularly an imaging element (preferably a color image sensor) having high heat resistance and a high thin film absorption coefficient can be provided.

In the present invention, the compound represented by the above formula (1) is used. The organic film of the present invention containing the compound of formula (1) may be used as either an organic p-type semiconductor or an organic n-type semiconductor, but is preferably used as an organic n-type semiconductor.

Next, the compound represented by the general formula (1) of the present invention will be described in detail.

In the general formula (1), R ^{1 to} R ⁸ each independently represent a hydrogen atom or a substituent, and examples of the substituent include a halogen atom, a cyano group, an alkyl group, an alkoxy group, an aryl group, or a heterocyclic group. It is done. In the general formula (1), R ⁹ includes an alkyl group, an aryl group, or a heterocyclic group.
R ^{1 to} R ⁸ are preferably a hydrogen atom, a halogen atom or an aryl group, and more preferably a hydrogen atom or a halogen atom. R ^{1 to} R ⁸ may be the same or different, but R ¹ and R ⁵ , R ² and R ⁶ , R ³ and R ⁷ , and R ⁴ and R ⁸ are preferably the same. R ⁹ is preferably an aryl group or a heterocyclic group, and more preferably an aryl group.

In the present invention, when a specific moiety is referred to as a “group”, the moiety may be unsubstituted or substituted with one or more (up to the maximum possible) substituents. Means good. For example, “alkyl group” means a substituted or unsubstituted alkyl group. In addition, the substituent that can be used in the compound in the present invention may be any substituent.

Although the example of such a substituent is given to the following, there is no restriction | limiting in particular, It is not limited to these. For example, halogen atoms, alkyl groups (including cycloalkyl groups, bicycloalkyl groups, and tricycloalkyl groups), alkenyl groups (including cycloalkenyl groups and bicycloalkenyl groups), alkynyl groups, aryl groups, heterocyclic groups (heterocycles) Cyano group, hydroxyl group, nitro group, carboxyl group, alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkyl and arylsulfonylamino group, mercapto Group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, sulfo group, alkyl and arylsulfinyl group, alkyl and arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, carbamoyl group, Lumpur a heterocyclic azo group, an imido group, a phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, a phosphono group, a silyl group, a hydrazino group, a ureido group, boronic acid group (-B (OH) ₂ ), a phosphato group (—OPO (OH) ₂ ), a sulfato group (—OSO ₃ H), and other known substituents.

More specifically, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group [including a linear, branched, cyclic substituted or unsubstituted alkyl group. They are alkyl groups (preferably alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, t-butyl, n-octyl, eicosyl, 2-chloroethyl, 2-cyanoethyl, 2-ethylhexyl). A cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl, cyclopentyl, 4-n-dodecylcyclohexyl), a bicycloalkyl group (preferably having 5 to 30 carbon atoms). A substituted or unsubstituted bicycloalkyl group, that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms, for example, bicyclo [1,2,2] heptan-2-yl, bicyclo [2,2,2] octane-3-yl), a tricyclo structure with more ring structures Domo is intended to cover. An alkyl group (for example, an alkyl group of an alkylthio group) in the substituent described below represents an alkyl group having such a concept, but further includes an alkenyl group and an alkynyl group. ], An alkenyl group [including linear, branched and cyclic substituted or unsubstituted alkenyl groups. They are alkenyl groups (preferably substituted or unsubstituted alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, prenyl, geranyl, oleyl), cycloalkenyl groups (preferably substituted or substituted groups having 3 to 30 carbon atoms). An unsubstituted cycloalkenyl group, that is, a monovalent group obtained by removing one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms (for example, 2-cyclopenten-1-yl, 2-cyclohexen-1-yl), Bicycloalkenyl group (a substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom of a bicycloalkene having one double bond. For example, bicyclo [2,2,1] hept-2-en-1-yl, bicyclo 2,2,2] oct-2-en-4-yl). An alkynyl group (preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as ethynyl, propargyl, trimethylsilylethynyl group), an aryl group (preferably a substituted or unsubstituted aryl having 6 to 30 carbon atoms) Groups such as phenyl, biphenyl, p-tolyl, naphthyl, m-chlorophenyl, o-hexadecanoylaminophenyl), heterocyclic groups (preferably 5- or 6-membered substituted or unsubstituted, aromatic or non-aromatic A monovalent group obtained by removing one hydrogen atom from a heterocyclic compound, and more preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms, such as 2-furyl, 2- Thienyl, 2-pyrimidinyl, 2-benzothiazolyl, 1-methyl-2-pyridinio, 1-methyl-2-quinolini A cyano group, a hydroxyl group, a nitro group, a carboxyl group, an alkoxy group (preferably a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms such as methoxy, Ethoxy, isopropoxy, t-butoxy, n-octyloxy, 2-methoxyethoxy), aryloxy groups (preferably substituted or unsubstituted aryloxy groups having 6 to 30 carbon atoms, such as phenoxy, 2-methylphenoxy 4-t-butylphenoxy, 3-nitrophenoxy, 2-tetradecanoylaminophenoxy), a silyloxy group (preferably a silyloxy group having 3 to 20 carbon atoms such as trimethylsilyloxy, t-butyldimethylsilyloxy), Heterocyclic oxy group (preferably having 2 to 30 carbon atoms) Substituted or unsubstituted heterocyclic oxy group, 1-phenyltetrazole-5-oxy, 2-tetrahydropyranyloxy), acyloxy group (preferably formyloxy group, substituted or unsubstituted alkylcarbonyloxy having 2 to 30 carbon atoms) Groups, substituted or unsubstituted arylcarbonyloxy groups having 6 to 30 carbon atoms, such as formyloxy, acetyloxy, pivaloyloxy, stearoyloxy, benzoyloxy, p-methoxyphenylcarbonyloxy), carbamoyloxy groups (preferably carbon A substituted or unsubstituted carbamoyloxy group of 1 to 30, for example, N, N-dimethylcarbamoyloxy, N, N-diethylcarbamoyloxy, morpholinocarbonyloxy, N, N-di-n-octylaminocarbonyloxy Xy, Nn-octylcarbamoyloxy), alkyl and arylsulfonylamino groups (preferably substituted or unsubstituted alkylsulfonylamino having 1 to 30 carbon atoms, substituted or unsubstituted arylsulfonylamino having 6 to 30 carbon atoms, For example, methylsulfonylamino, butylsulfonylamino, phenylsulfonylamino, 2,3,5-trichlorophenylsulfonylamino, p-methylphenylsulfonylamino), mercapto group, alkylthio group (preferably having 1 to 30 carbon atoms or Unsubstituted alkylthio group such as methylthio, ethylthio, n-hexadecylthio), arylthio group (preferably substituted or unsubstituted arylthio having 6 to 30 carbon atoms such as phenylthio, p-chlorophenylthio, m Methoxyphenylthio), a heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms, such as 2-benzothiazolylthio, 1-phenyltetrazol-5-ylthio), sulfamoyl group ( Preferably a substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms, such as N-ethylsulfamoyl, N- (3-dodecyloxypropyl) sulfamoyl, N, N-dimethylsulfamoyl, N-acetylsulfa Moyl, N-benzoylsulfamoyl, N- (N′-phenylcarbamoyl) sulfamoyl), sulfo group, alkyl and arylsulfinyl group (preferably substituted or unsubstituted alkylsulfinyl group having 1 to 30 carbon atoms, 6 30 substituted or unsubstituted arylsulfinyl groups, eg , Methylsulfinyl, ethylsulfinyl, phenylsulfinyl, p-methylphenylsulfinyl), alkyl and arylsulfonyl groups (preferably substituted or unsubstituted alkylsulfonyl groups having 1 to 30 carbon atoms, substituted or unsubstituted groups having 6 to 30 carbon atoms) Arylsulfonyl group such as methylsulfonyl, ethylsulfonyl, phenylsulfonyl, p-methylphenylsulfonyl), acyl group (preferably formyl group, substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, 7 to 30 carbon atoms) A substituted or unsubstituted arylcarbonyl group, a heterocyclic carbonyl group bonded to a carbonyl group with a substituted or unsubstituted carbon atom having 4 to 30 carbon atoms, such as acetyl, pivaloyl, 2-chloroacetyl, stearoyl, benzo Yl, pn-octyloxyphenylcarbonyl, 2-pyridylcarbonyl, 2-furylcarbonyl), an aryloxycarbonyl group (preferably a substituted or unsubstituted aryloxycarbonyl group having 7 to 30 carbon atoms, such as phenoxycarbonyl , O-chlorophenoxycarbonyl, m-nitrophenoxycarbonyl, pt-butylphenoxycarbonyl), alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxycarbonyl group having 2 to 30 carbon atoms such as methoxycarbonyl, ethoxycarbonyl , T-butoxycarbonyl, n-octadecyloxycarbonyl), a carbamoyl group (preferably a substituted or unsubstituted carbamoyl having 1 to 30 carbon atoms such as carbamoyl, N-methylcarbamoyl, N N-dimethylcarbamoyl, N, N-di-n-octylcarbamoyl, N- (methylsulfonyl) carbamoyl), aryl and heterocyclic azo group (preferably a substituted or unsubstituted arylazo group having 6 to 30 carbon atoms, carbon number 3 to 30 substituted or unsubstituted heterocyclic azo groups such as phenylazo, p-chlorophenylazo, 5-ethylthio-1,3,4-thiadiazol-2-ylazo), imide groups (preferably N-succinimide, N-phthalimide), a phosphino group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, such as dimethylphosphino, diphenylphosphino, methylphenoxyphosphino), a phosphinyl group (preferably 2 carbon atoms). To 30 substituted or unsubstituted phosphinyl groups such as Phosphinyl, dioctyloxyphosphinyl, diethoxyphosphinyl), phosphinyloxy group (preferably a substituted or unsubstituted phosphinyloxy group having 2 to 30 carbon atoms, such as diphenoxyphosphinyloxy, Dioctyloxyphosphinyloxy), a phosphinylamino group (preferably a substituted or unsubstituted phosphinylamino group having 2 to 30 carbon atoms, such as dimethoxyphosphinylamino, dimethylaminophosphinylamino), Phosphor groups, silyl groups (preferably substituted or unsubstituted silyl groups having 3 to 30 carbon atoms, such as trimethylsilyl, t-butyldimethylsilyl, phenyldimethylsilyl), hydrazino groups (preferably substituted having 0 to 30 carbon atoms) Or an unsubstituted hydrazino group such as trimethyl Drazino), a ureido group (preferably a substituted or unsubstituted ureido group having 0 to 30 carbon atoms, such as N, N-dimethylureido), and the like.

In addition, two substituents can be combined to form a ring (aromatic or non-aromatic hydrocarbon ring or heterocyclic ring. These can be further combined to form a polycyclic condensed ring. For example, a benzene ring, Naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring, biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring , Indolizine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring, phenanthridine ring, acridine ring , Phenanthroline ring, thia Train ring, including chromene ring, xanthene ring, phenoxathiin ring, a phenothiazine ring and a phenazine ring.) Which was formed.

Among the above substituents, those having a hydrogen atom may be removed and further substituted with the above groups. Examples of such substituents include halogen atoms, alkyl groups (including cycloalkyl groups, bicycloalkyl groups, and tricycloalkyl groups), alkenyl groups (including cycloalkenyl groups and bicycloalkenyl groups), and alkynyl groups described above. Groups, aryl groups, heterocyclic groups (which may be referred to as heterocyclic groups), cyano groups, hydroxyl groups, and nitro groups.

The organic film of the present invention will be described.

The organic film of the present invention is a film composed of a compound represented by the general formula (1), a film composed of a single compound represented by the general formula (1) (hereinafter referred to as a single film), and other substances. Both mixed films and laminated films are included.
In addition, for photoelectric conversion elements composed of organic photoelectric conversion materials, particularly solid-state imaging elements, organic p-type semiconductor materials, organic n-type semiconductor materials, electron transport materials, hole transport materials, electron blocking materials, hole blocking materials, crystals A plurality of materials are often used from the group consisting of an anti-oxidation material and an interlayer contact improving material, but the compound represented by the general formula (1) can be used as any of these, and an organic n-type semiconductor material It is preferable to be used as

In the case of a mixed film, it must contain at least one compound represented by the general formula (1), but there are no particular restrictions on the other substances used, and organic compounds are preferred. Specific examples include an electron transport material, a hole transport material, an electron blocking material, a hole blocking material, an anti-crystallization material, an electrode and an interlayer contact improving material, and more preferably an organic p-type compound having these functions. , An organic n-type compound.
The number of substance species added to the compound represented by the general formula (1) is not particularly limited, but is generally 1 to 5, preferably 1 to 4, more preferably 1 to 3, and still more preferably. 1-2 types.
The content of the compound represented by the general formula (1) in the mixed film and the substance used other than that can be appropriately set within a range of 100: 0 to 1:99 by mass ratio, and is preferably in a range. Is 100: 0 to 10:90, more preferably 100: 0 to 30:70, and still more preferably 100: 0 to 50:50. In addition, a concentration gradient can be set in any direction in the film.

In the case of a laminated film, it must contain at least one compound represented by the general formula (1), but there are no particular restrictions on the other materials used, and an organic compound is preferable. Specific examples include an electron transport material, a hole transport material, an electron blocking material, a hole blocking material, an anti-crystallization material, and an interlayer contact improving material, and more preferably an organic p-type compound, an organic material having these functions. It is an n-type compound.
The number of layers to be laminated is not particularly limited, but is generally 2 to 10 layers, preferably 2 to 7 layers, more preferably 2 to 5 layers, and further preferably 2 to 3 layers.
It is also possible to provide a layer composed of a mixed film in the laminated film. For example, a structure of “organic p-type compound layer / mixed layer of organic p-type compound and organic n-type compound / organic n-type compound layer” is used. Is mentioned. The “mixed layer of organic p-type compound and organic n-type compound” in this structure is also called a Berg heterojunction layer. The position of the mixed layer in the laminated film can be set at an arbitrary position from the uppermost layer to the lowermost layer.

In the above, when the organic film of the present invention is used as an organic n-type semiconductor, the organic p-type semiconductor is a donor organic semiconductor, which is typically represented by a hole transporting compound and has a property of easily donating electrons. Certain organic compounds can be used. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Therefore, any organic compound can be used as the donor organic compound as long as it is an electron-donating organic compound. For example, triarylamine compound, benzidine compound, pyrazoline compound, styrylamine compound, hydrazone compound, triphenylmethane compound, carbazole compound, polysilane compound, thiophene compound, phthalocyanine compound, cyanine compound, merocyanine compound, oxonol compound, polyamine compound, indole Compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), nitrogen-containing heterocyclic compounds The metal complex etc. which it has as can be used. Not limited to this, as described above, any organic compound having an ionization potential smaller than that of the organic compound used as the n-type (acceptor property) compound may be used as the donor organic semiconductor.

In the above, when the organic film of the present invention is used as an organic p-type semiconductor, the organic n-type semiconductor is an acceptor organic semiconductor, which is typically represented by an electron-transporting organic compound and has a property of easily accepting electrons. Certain organic compounds can be used. More specifically, the organic compound having the higher electron affinity when two organic compounds are used in contact with each other. Therefore, as the acceptor organic compound, any organic compound can be used as long as it is an electron-accepting organic compound. For example, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), 5- to 7-membered heterocyclic compounds containing nitrogen atoms, oxygen atoms, and sulfur atoms (E.g. pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazole, thiazole, oxazole, indazole, benzimidazole, benzotriazole, Benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, triazolopyrimidine, tetrazaindene, o Metal complexes having as ligands such as saziazole, imidazopyridine, pyralidine, pyrrolopyridine, thiadiazolopyridine, dibenzazepine, tribenzazepine), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, nitrogen-containing heterocyclic compounds Etc. Note that the present invention is not limited thereto, and as described above, any organic compound having an electron affinity higher than that of the organic compound used as the donor organic compound may be used as the acceptor organic semiconductor.

The organic film of the present invention is formed by a dry film forming method or a wet film forming method. Specific examples of the dry film forming method include a vacuum vapor deposition method, a sputtering method, an ion plating method, a physical vapor deposition method such as an MBE method, or a CVD method such as plasma polymerization. As the wet film forming method, a casting method, a spin coating method, a dipping method, an LB method, or the like is used.
In the case where a polymer compound is used as at least one of the p-type semiconductor compound or the n-type semiconductor compound, it is preferable to form the film by a wet film formation method that is easy to create. When a dry film formation method such as vapor deposition is used, it is difficult to use a polymer because it may be decomposed, and an oligomer thereof can be preferably used instead.
On the other hand, in the present invention, when a low molecule is used, a dry film forming method is preferably used, and a vacuum deposition method is particularly preferably used. The basic parameters of the vacuum deposition method are the method of heating the compound such as resistance heating deposition and electron beam heating deposition, the shape of the deposition source such as the crucible and the boat, the degree of vacuum, the substrate temperature and the deposition rate. -. In order to make uniform deposition possible, it is preferable to perform deposition by rotating the substrate. It is preferable that all steps during the vapor deposition are performed in a vacuum, and basically the compound is not directly in contact with oxygen and moisture in the outside air. The above-described conditions for vacuum deposition need to be strictly controlled because they affect the crystallinity, amorphousness, density, density, etc. of the organic film. It is preferable to use PI or PID control of the deposition rate using a film thickness monitor such as a quartz crystal resonator or an interferometer. When two or more kinds of compounds are vapor-deposited simultaneously, a co-evaporation method, a flash vapor deposition method, or the like can be preferably used.

The degree of vacuum during vacuum deposition is preferably high, and vacuum deposition is performed at 10 ⁻¹ Pa or less, preferably 10 ⁻³ Pa or less, particularly preferably 10 ⁻⁴ Pa or less.
Although the substrate temperature can be appropriately selected depending on the material, it is generally −50 ° C. to 200 ° C., preferably 0 ° C. to 150 ° C., more preferably 0 ° C. to 100 ° C.
The deposition rate can be appropriately selected depending on the material, but is generally 0.1 to 10 to 10 seconds / second, preferably 0.5 to 50 to / second, and more preferably 1 to 50 to / second.
When the organic film of the present invention is used as a color image sensor (image sensor), the light absorption rate of each organic dye layer of the B, G, and R layers is preferably 50% or more, more preferably 70% or more, and particularly preferably. 90% (absorbance = 1) or more, most preferably 99% or more is preferred in order to improve the photoelectric conversion efficiency and to improve color separation without passing excessive light through the lower layer. Therefore, from the viewpoint of light absorption, the larger the film thickness of the organic film used for the photoelectric conversion element and the solid-state imaging element, the better. On the other hand, as the photoelectric conversion film is thinner, photoelectric conversion is possible in the vicinity of the focal point of the light collected by the lens, so that a clearer image can be obtained. Therefore, from the viewpoint of image clarity, it is preferable that the photoelectric conversion film, particularly the organic film used for it, is as small as possible. In order to achieve this balance, the thickness of the organic film in the present invention is preferably 10 nm to 1000 nm, more preferably 10 nm to 300 nm, still more preferably 20 nm to 250 nm, and particularly preferably 60 nm to 200 nm.

  In the case where the organic films have the same thickness, higher absorbance is preferable from the viewpoint of the above-described light absorption and from the viewpoint of image sharpness. Specifically, the absorbance at the maximum absorption wavelength of the organic film formed with a thickness of 50 nm is preferably 0.4 or more, and more preferably 0.6 or more.

The heat resistance stability of the organic film is preferably such that the appearance and spectral waveform do not change even when the organic film or the substrate on which the organic film is formed is heated at 200 ° C. for 30 minutes, and even when heated at 230 ° C. for 30 minutes. It is more preferable that the appearance and the spectral waveform are not changed, and it is further preferable that the appearance and the spectral waveform are not changed even when heated at 250 ° C. for 30 minutes.

It is preferable that the organic film or the substrate on which the organic film is formed has no change in appearance and spectral waveform even if the organic film or the substrate on which the organic film is formed is left at a temperature of 85 ° C. and a humidity of 85%.

The light stability of the organic film is preferably such that the appearance and spectral waveform do not change even when the organic film or the substrate on which the organic film is formed is exposed for a long time.

The organic film may be in any of an amorphous state, a liquid crystal state, and a crystalline state, but the crystalline state is preferable in consideration of the heat resistance stability of the organic film.

The photoelectric conversion element in this invention is demonstrated.

  The photoelectric conversion element of the present invention has a structure in which the organic film of the present invention is sandwiched between a pair of an anode and a cathode, and at least one of the electrodes is a transparent electrode.

Specific examples of transparent electrodes include conductive metal oxides such as tin oxide, zinc oxide, indium oxide and indium tin oxide (ITO), or metals such as gold, silver, chromium and nickel, and these metals and conductive metals. Preferred examples include mixtures or laminates with oxides, inorganic conductive materials such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene, and polypyrrole, silicon compounds, and laminates of these with ITO. Is a conductive metal oxide, and in particular, ITO and IZO (indium zinc oxide) are preferable in terms of productivity, high conductivity, transparency, and the like. Although the film thickness can be appropriately selected depending on the material, it is usually preferably in the range of 10 nm to 1 μm, more preferably 30 nm to 500 nm, and still more preferably 50 nm to 300 nm.

Various methods are used for the production of the transparent electrode depending on the material. For example, in the case of ITO, an electron beam method, a sputtering method, a resistance heating vapor deposition method, a chemical reaction method (such as a sol-gel method), and a dispersion of indium tin oxide are applied. A film is formed by such a method. In the case of ITO, UV-ozone treatment, plasma treatment, etc. can be performed.
In the present invention, it is preferable to produce the transparent electrode film free of plasma. By creating a transparent electrode film free of plasma, the influence of plasma on the substrate and the organic film can be reduced, and the photoelectric conversion characteristics can be improved. Here, plasma free means that no plasma is generated during the formation of the transparent electrode film, or the distance from the plasma generation source to the substrate is 2 cm or more, preferably 10 cm or more, more preferably 20 cm or more. It means a state in which the plasma that reaches is reduced.

Examples of an apparatus that does not generate plasma during the formation of the transparent electrode film include an electron beam vapor deposition apparatus (EB vapor deposition apparatus) and a pulse laser vapor deposition apparatus. Regarding EB deposition equipment or pulse laser deposition equipment, “Surveillance of Transparent Conductive Films” supervised by Yutaka Sawada (published by CMC, 1999), “New Development of Transparent Conductive Films II” supervised by Yutaka Sawada (published by CMC, 2002) ), "Transparent conductive film technology" by the Japan Society for the Promotion of Science (Ohm Co., 1999), and the references attached thereto, etc. can be used. Hereinafter, a method of forming a transparent electrode film using an EB vapor deposition apparatus is referred to as an EB vapor deposition method, and a method of forming a transparent electrode film using a pulse laser vapor deposition apparatus is referred to as a pulse laser vapor deposition method.
For an apparatus that can realize a state in which the distance from the plasma generation source to the substrate is 2 cm or more and the arrival of plasma to the substrate is reduced (hereinafter referred to as a plasma-free film forming apparatus), for example, an opposed target sputtering Equipment, arc plasma deposition, etc. are considered, and these are supervised by Yutaka Sawada "New development of transparent conductive film" (published by CMC, 1999), and supervised by Yutaka Sawada "New development of transparent conductive film II" (published by CMC) 2002), “Transparent conductive film technology” (Ohm Co., 1999) by the Japan Society for the Promotion of Science, and references and the like attached thereto can be used.

The photoelectric conversion film is located between the anode and the cathode. A photoelectric conversion function functions by this photoelectric conversion film, an anode, and a cathode.
As a configuration example of the photoelectric conversion film stacking, there is a configuration in which an anode (transparent electrode film), a photoelectric conversion film, and a cathode are sequentially stacked from the substrate in the case where there is one organic layer stacked on the substrate. It is not limited to.
Furthermore, when there are two organic layers stacked on the substrate, for example, the anode (transparent electrode film), the photoelectric conversion film, the cathode, the interlayer insulating film, the anode (transparent electrode film), the photoelectric conversion film, and the cathode are sequentially arranged from the substrate. A stacked configuration is exemplified.

The material of the transparent electrode film constituting the photoelectric conversion site of the present invention is preferably one that can be formed by a plasma-free film forming apparatus, an EB vapor deposition apparatus, and a pulse laser vapor deposition apparatus. For example, a metal, an alloy, a metal oxide, a metal nitride, a metal boride, an organic conductive compound, a mixture thereof, and the like are preferable. Specific examples include tin oxide, zinc oxide, indium oxide, and indium zinc oxide. (IZO), indium tin oxide (ITO), conductive metal oxides such as indium tungsten oxide (IWO), metal nitrides such as titanium nitride, metals such as gold, platinum, silver, chromium, nickel, aluminum, and these A mixture or laminate of a metal and a conductive metal oxide, an inorganic conductive material such as copper iodide or copper sulfide, an organic conductive material such as polyaniline, polythiophene or polypyrrole, a laminate of these and ITO, And so on. Also, supervised by Yutaka Sawada “New Development of Transparent Conductive Film” (published by CMC, 1999), supervised by Yutaka Sawada “New Development of Transparent Conductive Film II” (published by CMC, 2002), “Transparency by Japan Society for the Promotion of Science” Those described in detail in “Technology of Conductive Film” (Ohm Co., 1999) may be used.
Particularly preferable materials for the transparent electrode film are ITO, IZO, SnO ₂ , ATO (antimony-doped tin oxide), ZnO, AZO (Al-doped zinc oxide), GZO (gallium-doped zinc oxide), TiO ₂ , FTO (fluorine). Doped tin oxide).
The light transmittance of the transparent electrode film is preferably 60% or more, more preferably 80% or more, more preferably, in the photoelectric conversion light absorption peak wavelength of the photoelectric conversion film included in the photoelectric conversion element including the transparent electrode film. It is 90% or more, more preferably 95% or more. The surface resistance of the transparent electrode film is preferably low, more specifically 10,000Ω / □ or less, more preferably 1000Ω / □ or less, and most preferably 100Ω / □ or less.
The conditions at the time of forming the transparent electrode film are mentioned. The substrate temperature at the time of forming the transparent electrode film is preferably 500 ° C. or lower, more preferably 300 ° C. or lower, further preferably 200 ° C. or lower, and further preferably 150 ° C. or lower. Further, a gas may be introduced during the formation of the transparent electrode film, and basically the gas species is not limited, but Ar, He, oxygen, nitrogen and the like can be used. Further, a mixed gas of these gases may be used. In particular, in the case of an oxide material, oxygen defects are often introduced, so that oxygen is preferably used.

The solid-state image sensor in the present invention will be described.

The solid-state imaging device of the present invention comprises an organic film portion for performing photoelectric conversion and a charge accumulation / transfer / readout portion for charges generated by photoelectric conversion.
In the present invention, the organic film portion that performs photoelectric conversion has at least one layered structure that can absorb and photoelectrically convert at least blue light, green light, and red light. The blue light absorbing layer (B) can absorb light having a wavelength of 400 nm or more and 500 nm or less, and preferably has an absorptance of a peak wavelength in the wavelength region of 50% or more. The green light absorbing layer (G) can absorb light of at least 500 nm to 600 nm, and preferably the peak wavelength absorptance in the wavelength region is 50% or more. The red light absorbing layer (R) can absorb light of at least 600 nm or more and 700 nm or less, and preferably has an absorptance of a peak wavelength in the wavelength region of 50% or more. The order of these layers may be any order, and in the case of a three-layer stacked structure, the order of BGR, BRG, GBR, GRB, RBG, and RGB is possible from the upper layer (light incident side). Preferably, the uppermost layer is G. In the case of a two-layer structure, when the upper layer is the R layer, the lower layer is the same BG layer, when the upper layer is the B layer, the lower layer is the same planar GR layer, and when the upper layer is the G layer, the lower layer is the same A BR layer is formed in a planar shape. Preferably, the upper layer is a G layer and the lower layer is a BR layer on the same plane. Thus, when two light absorption layers are provided on the same plane of the lower layer, it is preferable to provide, for example, a mosaic layer on the upper layer or a filter layer capable of color separation between the upper layer and the lower layer. In some cases, it is possible to provide a fourth layer or more as a new layer or in the same plane. Further, by providing a BG layer or a GR layer on top of a known CCD or CMOS made of a silicon material having sensitivity in the entire visible range of 400 nm to 700 nm, the known CCD or CMOS made of a silicon material is converted into an R layer or a B layer. It can also be used as

The solid-state imaging device of the present invention using the compound represented by the general formula (1) can be used in any wavelength region, but is preferably used in the visible region and more preferably in the green region.

In the present invention, one particularly preferable aspect among the elements described above has at least one organic film part that performs photoelectric conversion, and at least one of these parts is the element (imaging element) of the present invention. Is the case.
Furthermore, it is preferable that at least two electromagnetic wave absorption / photoelectric conversion sites are provided, and at least one of these sites is the element (imaging device) of the present invention. Furthermore, it is preferable that the upper layer is an element composed of a part capable of absorbing green light and performing photoelectric conversion.
Further, it is particularly preferable that at least three portions of the organic film that perform photoelectric conversion are provided, and at least one of these portions is the element (imaging device) of the present invention.
Furthermore, it is preferable that the upper layer is an element composed of a part capable of absorbing green light and performing photoelectric conversion.

The organic film in the solid-state imaging device is preferably separated by an insulating layer. The insulating layer can be formed using a transparent insulating material such as glass, polyethylene, polyethylene terephthalate, polyethersulfone, and polypropylene. Silicon nitride, silicon oxide and the like are also preferably used. Silicon nitride formed by plasma CVD is preferably used in the present invention because it has high density and good transparency.
A protective layer or a sealing layer can be provided for the purpose of preventing contact with oxygen or moisture.
Examples of protective layers include diamond thin films, inorganic material films such as metal oxides and metal nitrides, polymer films such as fluororesins, polyparaxylene, polyethylene, silicon resins, and polystyrene resins, and photocurable resins. Can be mentioned. Further, the element portion can be covered with glass, gas-impermeable plastic, metal, etc., and the element itself can be packaged with an appropriate sealing resin. In this case, a substance having high water absorption can be present in the packaging.
Furthermore, since the light collection efficiency can be improved by forming the microlens array on the light receiving element, such an embodiment is also preferable.

The larger the pixel size in the solid-state imaging device, the larger the amount of light received by one pixel, and the imaging with reduced noise becomes possible, which is preferable from the viewpoint of image clarity. On the other hand, a high number of pixels is necessary to perform high-resolution imaging, and the pixel size is small in order to realize this within the determined final device chip size. In order to balance this, the pixel size in the solid-state imaging device of the organic film in the present invention is preferably 0.01 μm or more and 100 μm or less, more preferably 0.1 μm or more and 80 μm or less, and further preferably 0.5 μm or more and 50 μm or less. .

In the solid-state imaging device, the thinner the photoelectric conversion film, the more photoelectric conversion can be performed in the vicinity of the focal point of the light collected by the lens, so that a clearer image can be obtained. Therefore, the thickness of the photoelectric conversion film is preferably as thin as possible in the solid-state imaging device, and the specific thickness depends on the aperture value of the lens and the diameter of the Airy disk allowed for the device, but is generally particularly preferably 1000 μm or less, more preferably 700 μm or less. More preferably, it is 500 μm or less. In the case of a solid-state imaging device formed by stacking photoelectric conversion films, the distance from the uppermost surface of the uppermost photoelectric conversion film to the lowermost surface of the lowermost photoelectric conversion film is preferably the above thickness.

The final device chip size can be selected from brownie size, 135 size, APS size, 1 / 1.8 inch, and even smaller sizes. The pixel size of the laminated photoelectric conversion element of the present invention is represented by a circle-equivalent diameter corresponding to the maximum area of the organic film portion that performs a plurality of photoelectric conversions.
The photoelectric conversion element of the present invention can be used for a digital still camera. It is also preferable to use it for a TV camera. Other applications include digital video cameras, surveillance cameras for the following applications (office buildings, parking lots, financial institutions and unmanned contractors, shopping centers, convenience stores, outlet malls, department stores, pachinko halls, karaoke boxes, game centers, Hospital), various other sensors (TV door phone, personal authentication sensor, factory automation sensor, home robot, industrial robot, piping inspection system), medical sensor (endoscope, fundus camera), video conference system, It can be used for applications such as videophones, mobile phones with cameras, safe driving systems for vehicles (back guide monitors, collision prediction, lane keeping systems), and video game sensors.

Especially, the solid-state image sensor characterized by using the organic film of this invention is suitable also for a television camera use. This is because a television camera can be reduced in size and weight because no color separation optical system is required. Further, since it has high sensitivity and high resolution, it is particularly preferable for a television camera for high-definition broadcasting. In this case, the high-definition broadcast television camera includes a digital high-definition broadcast camera.
Furthermore, the photoelectric conversion element of the present invention is preferable in that an optical low-pass filter can be omitted, and higher sensitivity and higher resolution can be expected.
Furthermore, in the photoelectric conversion element of the present invention, it is possible to reduce the thickness and eliminate the need for a color separation optical system, so that "an environment with different brightness such as daytime and nighttime" For shooting scenes that require different sensitivities, such as `` subjects that are moving and subjects that are moving, '' and other shooting scenes that require different spectral sensitivity and color reproducibility, replace the photoelectric conversion element of the present invention and shoot. A single camera can respond to various shooting needs, and it is not necessary to carry multiple cameras at the same time, reducing the burden on the photographer. As the photoelectric conversion element to be exchanged, an exchange photoelectric conversion element can be prepared for infrared light photography, black-and-white photography, and dynamic range change in addition to the above.
The TV camera of the present invention is a television camera design technology (August 20, 1999, issued by Corona, ISBN), edited by the Institute of Image Information and Television Engineers.
4-339-00714-5) With reference to the description in Chapter 2, for example, the part of the color separation optical system and the imaging device in the basic configuration of the TV camera in FIG. 2.1 is replaced with the photoelectric conversion element of the present invention. Can be produced.
The above-described stacked light receiving elements can be used not only as an image pickup element by arranging them but also as a light sensor such as a biosensor or a chemical sensor or a color light receiving element as a single unit.

Examples and embodiment examples of the present invention will be described below, but the present invention is not limited thereto. The formulas (A), (B), (C) and (D) used in the following examples are generally readily available, and the formulas (A), (C) and (D) are Tokyo Chemical Industry products. And formula (B) is an Aldrich product.

Example 1
The washed quartz substrate was placed in a vapor deposition apparatus, and an organic film was obtained by vapor-depositing a compound represented by the following formula (A) by 50 nm. The heating method in that case is resistance heating, a boat charged with a compound represented by the following formula (A) is manufactured by Niraco (model number SS-1), and the degree of vacuum during vapor deposition is 1.0 × 10 ⁻³ Pa to 1.0 × 10 ⁻⁴ Pa, the substrate temperature was room temperature, and the deposition rate was 0.1 nm / second.

使用する化合物を式（Ａ）で表される化合物から、下記の式（Ｂ）で表される化合物に変更する以外は実施例１と同様にして、有機膜を得た。

An organic film was obtained in the same manner as in Example 1 except that the compound used was changed from the compound represented by the formula (A) to the compound represented by the following formula (B).

Comparative Example 1
An organic film was obtained in the same manner as in Example 1 except that the compound used was changed from the compound represented by the formula (A) to the compound represented by the following formula (C).

Example 2
An organic film was obtained in the same manner as in Example 1 except that the compound used was changed from the compound represented by the formula (A) to the compound represented by the following formula (D).

About Spectroscopic Measurement The obtained organic film was measured using a spectrophotometer (manufactured by Shimadzu Corporation, UV-visible spectrophotometer UV-3150), and the absorbance of the optical filter was measured in the range of 200 to 800 nm at a sampling pitch of 1 nm.
In Examples 1 and 2 and Comparative Examples 1 and 2, the thickness of the organic film is unified, so that an organic film having a larger absorbance at the maximum absorption wavelength can be used to design and manufacture an imaging device with a thinner photosensitive portion. Since a clearer image can be obtained, it can be said that the organic film is more excellent for an image sensor.

From the results shown in Table 1, Examples 1 and 2 showed higher absorbance at the same film thickness than Comparative Examples 1 and 2. From the above, in the present invention, the imaging device provided with the organic film containing the compounds represented by the formulas (A) and (B) showed a result that the film thickness can be further reduced.

About heat resistance comparison Subsequently, the obtained organic film was placed on a hot plate (model number HI-400, manufactured by Seiei Inai Co., Ltd., model number HI-400) set at 250 ° C., and a heat resistance test was performed. The result after progress for minutes was evaluated by ○ and ×. ○ When there is no visual change before and after the test and there is no change in the spectral waveform, ○ When there is a visual change before and after the test, such as white turbidity changes, or when a change in the spectral waveform such as an increase in baseline is observed Is x.

From the results shown in Table 2, compared to Comparative Examples 1 and 2, Example 1 had the least change in both visual and spectral waveforms after the heat test, and the results showed high heat resistance. From the above, in the present invention, the imaging device provided with the organic film containing the compound represented by the formula (A) showed the result that the process heat resistance was higher.

Moisture and heat resistance comparison Subsequently, the obtained organic film was installed in a moisture and heat tester (model number H110K-30D5, manufactured by Hoshiwa Riko Co., Ltd.) set at a temperature of 85 ° C. and a humidity of 85%, and a moisture and heat resistance test was performed. The result after the 73-hour progress was evaluated by (circle) and x. ○ When there is no visual change before and after the test and there is no change in the spectral waveform, ○ When there is a visual change before and after the test, such as white turbidity changes, or when a change in the spectral waveform such as an increase in baseline is observed Is x.

From the results shown in Table 3, compared to Comparative Examples 1 and 2, Example 1 was higher in moisture and heat resistance after the moisture and heat resistance test. From the above, in the present invention, the image sensor provided with the organic film containing the compound represented by the formula (A) showed the result that the heat and humidity resistance is high.

  From the results of the comparison of spectral intensity, heat resistance, and heat and humidity resistance, the organic film of the present invention showed the results of having excellent spectral intensity and heat / humidity and heat resistance for solid-state imaging device production.

The organic film of the present invention and the solid-state image sensor obtained thereby have a small change in spectral waveform even when a thermal load is applied, and the heat resistance is high. In addition, since the optical density is high, the solid-state image sensor for various uses, particularly color It is very useful as an image sensor.

Claims (3)

An organic film comprising a compound represented by the general formula (1)

(In formula (1), R ^{1 to} R ⁸ are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkoxy group, an aryl group or a heterocyclic group, and X represents an oxygen atom or a substituent R ⁹ . And R ⁹ is an alkyl group, an aryl group, or a heterocyclic group. A photoelectric conversion element comprising the organic film according to claim 1. A solid-state imaging device comprising the photoelectric conversion device according to claim 2.