JP2005303266A - Imaging element, method of applying electric field thereto and electric field-applied element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging element including a photoelectric conversion film having a high efficiency. <P>SOLUTION: The imaging element includes, between a pair of electrodes, a photoelectric conversion film (a photosensitive layer) having a bulk hetero-junction structure layer as an intermediate layer, or a photoelectric conversion film having a structure comprising two or more repeated structures of pn junction layers respectively formed of p-type and n-type semiconductor layers. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging device, an electric field application method thereof, and an applied device.

  The photoelectric conversion element is widely used for, 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 television camera. As a material of a photoelectric conversion element used as a solid-state imaging element of an imaging apparatus, an inorganic material film such as a Si film or an a-Se film is mainly used.

  Conventional photoelectric conversion elements using films of these inorganic materials do not have a steep wavelength dependence on the photoconductive characteristics. For this reason, an image pickup apparatus using photoelectric conversion elements has a three-plate structure including a prism that separates incident light into three primary colors of red, green, and blue, and three photoelectric conversion elements that are arranged at the subsequent stage of the prism. Things have become mainstream.

  However, this three-plate type imaging device cannot avoid an increase in size and mass due to its structure.

  In order to reduce the size and weight of the imaging apparatus, it is not necessary to provide a spectral prism, and a single-plate structure with a single light-receiving element is desired. For example, red, green, and blue filters are used for the single-plate light-receiving element. As a material of the photoelectric conversion element, there are various types and characteristics, and it is also considered to use an organic material having advantages such as a large degree of freedom of processing shape, Japanese Patent Application Laid-Open No. 2003-158254 discloses a photoelectric conversion element having improved photosensitivity (sensitivity) and a light receiving element using the photoelectric conversion element. In this document, an organic material is used as the p-type semiconductor and the n-type semiconductor. However, in the example of the publication, polymethylphenylsilane (PMPS) is used as the p-type organic material, and 8-hydroxyquinoline is used as the n-type organic material. Only an example in which 5.0 parts by mass of coumarin 6 as an organic dye is added to 100 parts by mass of the above PMPS using an aluminum complex (Alq3) is described. In the description of the term, it is only described that the organic dye is preferably used in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the p-type or n-type organic material constituting the photoelectric conversion film. There is no description of a photoelectric conversion element having a pn junction, and the same publication discloses a pn junction repetitive structure formed by stacking a p-type organic material layer and an n-type organic material layer. Although the photoelectric conversion device using a structure referred to as a "tandem structure") has been described, no description of the embodiment level, there is no description of inserting a conductive material layer between the repetitive structure.

Further, in order to realize a reduction in size and weight of the imaging device, it is not necessary to provide a spectroscopic prism, and a low-resolution stacked photoelectric conversion element is disclosed in Japanese Patent Application Laid-Open No. 2003-234460. It is described in the gazette. In this document, for example, a preferable stacked photoelectric conversion element absorbs light of a wavelength of any one of the three primary colors of light and a light of a wavelength of one other color. It is described that a high-sensitivity and high-resolution color image can be obtained by stacking a photoelectric conversion element having a function of absorbing and a photoelectric conversion element having a function of absorbing the remaining light of one color. .
However, in the example of the publication, a coumarin 6 / polysilane film having photosensitivity in the entire blue region of 500 nm or less and a ZnPc / Alq3 film having an absorption region in the blue region as well as the red region are used as photoelectric conversion elements. 6 / Only a photoelectric conversion element having photosensitivity only in the entire substantially red region centered at 600 to 700 nm is described due to the filter function of the polysilane film.

  In the above element, there is no specific description about the green region, there is no description about a photoelectric conversion element having a bulk heterojunction structure, and there is no description about the organic tandem structure.

  Japanese Patent Application Laid-Open No. 2003-332551 describes a stacked photoelectric conversion element similar to that of the above-mentioned Japanese Patent Application Laid-Open No. 2003-234460, but there is no description about a photoelectric conversion element having a bulk heterojunction structure, and tandem The structure is not described in the same publication.

On the other hand, Non-Patent Document 1 (M. Hiramoto, H. Fujiwara, M. Yokoyama, J. Appl. Phys., 72, 3781) describes a photoelectric conversion element having a bulk heterojunction structure layer as an intermediate layer between pn junction layers. (1992)), and perylene-based pigments and phthalocyanine-based pigments are described as organic semiconductors. However, this photoelectric conversion element is only described for application of solar cells, and is not described for an imaging element.
Regarding the organic tandem structure, Non-Patent Document 2 (M. Hiramoto, M. Suezaki, M. Yokoyama, Chem. Lett., 327 (1990)) and Non-Patent Document 3 (A. Yakimov, SRForrest, Appl. Phys. Lett., 80, 1667 (2002)), but these are intended for use of energy such as solar cells, and are not described for use in an image sensor. Furthermore, there is no description such as applying an electric field between the electrodes.
JP 2003-158254 A JP 2003-234460 A JP 2003-332551 A Masahiro Hiromoto, Hiroshi Fujisawa, M. Hiramoto, H. Fujiwara, and M. Yokoyama, J. Appl. Phys. 1992, 72, 3781 M. Hiramoto, M. Suezaki, M. Yokoyama, Chem. Letters 1990, 327-330. A. Yakimov, SRForrest, Applied Physics Letters, 2002, 80, 1667-1669

  An object of the present invention is to provide a photoelectric conversion element with high efficiency, and to provide an image pickup element (preferably a color image sensor) with good color separation.

The present invention is solved by the following means.
(1) It has a p-type semiconductor layer and an n-type semiconductor layer between a pair of electrodes, and at least one of the p-type semiconductor and the n-type semiconductor is an organic semiconductor, and between these semiconductor layers And a photoelectric conversion film (photosensitive layer) having a bulk heterojunction structure layer including the p-type semiconductor and the n-type semiconductor as an intermediate layer.
(2) The imaging device according to (1), wherein both the p-type semiconductor and the n-type semiconductor are organic semiconductors.
(3) The imaging device according to (2), wherein at least one of the p-type organic semiconductor and the n-type organic semiconductor is an organic dye.
(4) A photoelectric conversion film (photosensitive layer) having a structure having two or more repeating structures of pn junction layers formed of a p-type semiconductor layer and an n-type semiconductor layer between a pair of electrodes. An image sensor characterized by the above.
(5) The imaging device according to (4), wherein the number of repeating structures of the pn junction layer is 2 or more and 10 or less.
(6) The imaging device according to (4) or (5), wherein a thin layer of a conductive material is inserted between the repeating structures.
(7) The imaging device according to (6), wherein the conductive material is silver or gold.
(8) The imaging device according to any one of (4) to (7), wherein the p-type semiconductor and / or the n-type semiconductor is an organic compound.
(9) The imaging device according to (8), wherein the organic compound is an organic dye.
(10) The image sensor according to (3) or (9), wherein the organic dye is a merocyanine dye.
(11) The imaging element according to (3), (9), or (10), wherein the layer having the organic dye has a thickness of 30 nm to 300 nm.
(12) An imaging device, wherein two or more photoelectric conversion films (photosensitive layers) according to any one of (1) to (11) are laminated.
(13) The imaging device according to (12), wherein the two or more layers are three layers of a blue photoelectric conversion film, a green photoelectric conversion film, and a red photoelectric conversion film.
(14) An organic dye is added to a p-type organic semiconductor or an n-type organic semiconductor, and the p-type organic semiconductor or the n-type organic semiconductor on the incident light side is colorless (1) to ( 13) The imaging device according to any one of
(15) The interval between the shortest wavelength and the longest wavelength, each indicating 50% of the maximum value Amax of the spectral absorption rate of the photoelectric conversion film and the maximum value Smax of the spectral sensitivity, is 100 nm or less ( The imaging device according to any one of 1) to (14).
(16) The interval between the shortest wavelength and the longest wavelength that indicates 80% of the maximum value Amax of the spectral absorption rate and the maximum value Smax of the spectral sensitivity of the photoelectric conversion film is 20 nm or more and 80 nm or less. The imaging device according to any one of (1) to (15).
(17) The interval between the shortest wavelength and the longest wavelength indicating 20% of the maximum value Amax of the spectral absorption rate of the photoelectric conversion film and the maximum value Smax of the spectral sensitivity is 150 nm or less (1) ) To (16).
(18) The longest wavelength showing a spectral absorption rate of 50% of the maximum value Amax of the spectral absorption rate of the photoelectric conversion film and the maximum value Smax of the spectral sensitivity is 460 nm to 510 nm, 560 nm to 610 nm, or 640 nm or more. The imaging device according to any one of (1) to (17), wherein the imaging device is 730 nm or less.
(19) When the maximum value of the spectral sensitivity of the photoelectric conversion film is S1max, S1max is in the range of not less than 400 nm and not more than 500 nm, or not less than 500 nm and not more than 600 nm, or not less than 600 nm and not more than 700 nm (1) -(18) The image pick-up element in any one.
(20) When the maximum value of the spectral absorptance of the photoelectric conversion film is A1max, A1max is in the range of 400 nm to 500 nm, 500 nm to 600 nm, or 600 nm to 700 nm (1) ) To (19).
(21) A method of applying an electric field of 10 V / m or more and 1 × 10 ¹² V / m or less to the imaging device according to any one of (1) to (20), and the applied device.
(22) An element having at least two electromagnetic wave absorption / photoelectric conversion sites, wherein at least one of the sites is composed of the imaging device according to any one of (1) to (20).
(23) The device according to (22), wherein at least two electromagnetic wave absorption / photoelectric conversion sites have a laminated structure of at least two layers.
(24) The device according to (23), wherein the upper layer comprises a portion capable of absorbing green light and performing photoelectric conversion.
(25) It has at least three electromagnetic wave absorption / photoelectric conversion sites, and at least one of them comprises the imaging device according to any one of (1) to (20). (24) The element according to any one of
(26) The element according to (25), wherein the upper layer is composed of a portion capable of absorbing green light and performing photoelectric conversion.
(27) The element according to (25) or (26), wherein at least two electromagnetic wave absorption / photoelectric conversion sites comprise an inorganic layer.
(28) The element according to (25) or (26), wherein at least two electromagnetic wave absorption / photoelectric conversion sites are formed in a silicon substrate.
(29) A method of applying an electric field of 1 V / m or more and 1 × 10 ¹² V / m or less to the imaging device according to any one of (1) to (20) according to any one of (22) to (28) , And applied elements.

The photoelectric conversion element of the present invention has an effect that the photoelectric conversion efficiency is high and the sensitivity is high. However, the two-layer stacked and BGR three-layer stacked solid-state imaging element has the following characteristics.
Due to the laminated structure, there is no moiré, no optical low-pass filter is required, so the resolution is high and there is no color blur. Further, signal processing is simple and no pseudo signal is generated. Furthermore, in the case of CMOS, pixel mixing is easy and partial reading is easy.
Since the aperture ratio is 100% and no microlens is required, there is no limitation on the exit pupil distance with respect to the imaging lens, and there is no shading. Therefore, it is suitable for a lens interchangeable camera, and in this case, the lens can be thinned.
Since there is no microlens, it is possible to seal the glass by filling the adhesive, reducing the package thickness, increasing the yield, and reducing the cost.
Because of the use of organic dyes, high sensitivity is obtained, no IR filter is required, and flare is reduced.

[Bulk heterostructure]
One preferred embodiment of the present invention includes a p-type semiconductor layer and an n-type semiconductor layer between a pair of electrodes, and at least one of the p-type semiconductor and the n-type semiconductor is an organic semiconductor, and The solid-state imaging device includes a photoelectric conversion film (photosensitive layer) having a bulk heterojunction structure layer including the p-type semiconductor and the n-type semiconductor as an intermediate layer between the semiconductor layers. The present invention may be any photoelectric conversion film including a bulk heterojunction structure.
The present invention includes at least one organic photoelectric conversion film having a bulk heterojunction structure, an organic imaging element having at least two layers of photoelectric conversion films, and an organic photoelectric conversion element having a bulk heterojunction structure An organic imaging device used by applying a voltage to is more preferable.
In the photoelectric conversion film, the organic layer contains a bulk heterojunction structure to compensate for the short carrier diffusion length of the organic layer and to improve the photoelectric conversion efficiency.

  The present invention provides an organic imaging device including at least one organic photoelectric conversion film having a bulk heterojunction structure, at least two photoelectric conversion films stacked, and a photoelectric conversion film having a bulk heterojunction structure. An organic imaging device that is used by applying a voltage is preferable.

[Tandem structure]
Another preferred embodiment of the present invention has a structure having two or more repeating structures (tandem structures) of a pn junction layer formed of a p-type semiconductor layer and an n-type semiconductor layer between a pair of electrodes. An imaging device characterized by containing a photoelectric conversion film (photosensitive layer), and preferably a thin layer of a conductive material is inserted between the repetitive structures. The number of repeating structures (tandem structures) of the pn junction layer may be any number, but is preferably 2 or more and 10 or less, more preferably 2 or more and 5 or less, and particularly preferably 2 in order to increase the photoelectric conversion efficiency. Or 3, most preferably 3. Silver or gold is preferable as the conductive material, and silver is most preferable.

In the present invention, a structure (bulk heterojunction structure) layer in which a p-type organic semiconductor and an n-type organic semiconductor are mixed and dispersed may be provided between the p-type organic semiconductor layer and the n-type organic semiconductor layer.
In the present invention, an imaging device including at least one of these photoelectric conversion films having a tandem structure, at least two such photoelectric conversion films, preferably three layers or four layers, more preferably three layers stacked, and such photoelectric conversion films. An image sensor in which a voltage is applied to the conversion film is preferable.
In the present invention, the semiconductor having a tandem structure may be an inorganic material, but is preferably an organic semiconductor, and more preferably an organic dye.

[Organic layer]
In the present invention, the organic layer will be described. The electromagnetic wave absorption / photoelectric conversion site comprising the organic layer of the present invention comprises an organic layer sandwiched between a pair of electrodes. The organic layer is formed by stacking or mixing parts that absorb electromagnetic waves, photoelectric conversion parts, electron transport parts, hole transport parts, electron blocking parts, hole blocking parts, crystallization prevention parts, electrodes and interlayer contact improvement parts, etc. The
The organic layer preferably contains an organic p-type compound or an organic n-type compound.
The organic layer preferably contains an organic p-type semiconductor (compound) and an organic n-type semiconductor (compound), and any of these may be used. Further, it may or may not have absorption in the visible and infrared regions, but it is preferable to use at least one compound (organic dye) having absorption in the visible region. Further, a colorless p-type compound and an n-type compound may be used, and an organic dye may be added thereto.
In the case of a three-layer structure of p-type layer / bulk heterojunction layer / n-type layer, the p-type or n-type semiconductor (compound) on the incident light side is preferably colorless.

  The organic p-type semiconductor (compound) is a donor-type organic semiconductor (compound), which is mainly represented by a hole-transporting organic compound and refers to an organic compound having a property of easily donating electrons. 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 compounds, benzidine compounds, pyrazoline compounds, styrylamine compounds, hydrazone compounds, triphenylmethane compounds, carbazole compounds, polysilane compounds, thiophene compounds, phthalocyanine compounds, cyanine compounds, merocyanine compounds, oxonol compounds, polyamine compounds, indoles 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.

  Organic n-type semiconductors (compounds) are acceptor organic semiconductors (compounds), which are mainly represented by electron-transporting organic compounds and refer to organic compounds that easily accept electrons. 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 sadiazole, imidazopyridine, pyralidine, pyrrolopyridine, thiadiazolopyridine, dibenzazepine, tribenzazepine), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, and 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.

Any p-type organic dye or n-type organic dye may be used, but preferably a cyanine dye, styryl dye, hemicyanine dye, merocyanine dye (including zero methine merocyanine (simple merocyanine)), three nucleus Merocyanine dye, tetranuclear merocyanine dye, rhodacyanine dye, complex cyanine dye, complex merocyanine dye, allopolar dye, oxonol dye, hemioxonol dye, squalium dye, croconium dye, azamethine dye, coumarin dye, arylidene dye, anthraquinone dye, triphenyl Methane dye, azo dye, azomethine dye, spiro compound, metallocene dye, fluorenone dye, fulgide dye, perylene dye, phenazine dye, phenothiazine dye, quinone dye, indigo Dye, diphenylmethane dye, polyene dye, acridine dye, acridinone dye, diphenylamine dye, quinacridone dye, quinophthalone dye, phenoxazine dye, phthaloperylene dye, diketopyrrolopyrrole dye, dioxane dye, porphyrin dye, chlorophyll dye, phthalocyanine dye, metal complex And dyes and condensed aromatic carbocyclic dyes (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives).
The film formed by the p-type organic dye and the n-type organic dye may be in an amorphous state, a liquid crystal state, or a crystalline state. When used in a crystalline state, it is preferable to use a pigment.

  Next, the metal complex compound will be described. The metal complex compound is a metal complex having a ligand having at least one nitrogen atom or oxygen atom or sulfur atom coordinated to the metal, and the metal ion in the metal complex is not particularly limited, but preferably beryllium ion, magnesium Ion, aluminum ion, gallium ion, zinc ion, indium ion, or tin ion, more preferably beryllium ion, aluminum ion, gallium ion, or zinc ion, and still more preferably aluminum ion or zinc ion. There are various known ligands contained in the metal complex. For example, “Photochemistry and Photophysics of Coordination Compounds” published by Springer-Verlag H. Yersin in 1987, “Organometallic Chemistry— Examples of the ligands described in “Basics and Applications—” published by Akio Yamamoto, 1982, etc.

  The ligand is preferably a nitrogen-containing heterocyclic ligand (preferably having 1 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 3 to 15 carbon atoms, and a monodentate ligand. Or a bidentate or higher ligand, preferably a bidentate ligand such as a pyridine ligand, a bipyridyl ligand, a quinolinol ligand, a hydroxyphenylazole ligand (hydroxyphenyl) Benzimidazole, hydroxyphenylbenzoxazole ligand, hydroxyphenylimidazole ligand)), alkoxy ligand (preferably 1-30 carbon atoms, more preferably 1-20 carbon atoms, particularly preferably carbon 1-10, for example, methoxy, ethoxy, butoxy, 2-ethylhexyloxy, etc.), aryloxy ligands Preferably it has 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 1-naphthyloxy, 2-naphthyloxy, 2,4,6-trimethylphenyl Oxy, 4-biphenyloxy, etc.), heteroaryloxy ligands (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as pyridyl. Oxy, pyrazyloxy, pyrimidyloxy, quinolyloxy, etc.), alkylthio ligands (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, Ethylthio, etc.), arylthio ligands (preferably having 6 to 30 carbon atoms, more preferred) Has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, etc.), a heterocyclic substituted thio ligand (preferably 1 to 30 carbon atoms, more preferably 1 to carbon atoms). 20, particularly preferably 1 to 12 carbon atoms, such as pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio and the like, or siloxy ligand (preferably Has 1 to 30 carbon atoms, more preferably 3 to 25 carbon atoms, particularly preferably 6 to 20 carbon atoms, and examples thereof include a triphenylsiloxy group, a triethoxysiloxy group, and a triisopropylsiloxy group. More preferably a nitrogen-containing heterocyclic ligand, an aryloxy ligand, a heteroaryloxy group, or a siloxy ligand, Preferably, a nitrogen-containing heterocyclic ligand, an aryloxy ligand, or a siloxy ligand is used.

  Cyanine dye, styryl dye, hemicyanine dye, merocyanine dye, trinuclear merocyanine dye, tetranuclear merocyanine dye having a high degree of freedom in adjusting the absorption wavelength for use as a color imaging device, which is one of the objects of the present invention A methine dye such as rhodacyanine dye, complex cyanine dye, complex merocyanine dye, allopolar dye, oxonol dye, hemioxonol dye, squalium dye, croconium dye or azamethine dye can be preferably used. More preferred are merocyanine dyes, trinuclear merocyanine dyes, and tetranuclear merocyanine dyes, and more preferred are merocyanine dyes.

Details of these methine dyes are described in the following dye literature.
[Dye literature]
FMHarmer, Heterocyclic Compounds-Cyanine Dyes and Related Compounds, John Wiley & Sons -New York, London, 1964, DMSturmer, "Heterocyclic Compounds-Special topics in cyclic chemistry", Chapter 18. 14: 482-515, John Wiley & Sons-New York, London, 1977, "Rodd's Chemistry of Carbon Compounds" 2nd.Ed.vol.IV, part B, 1977, Chapter 15, 369 from 422 pp., Elsevier Science Public Company, Inc. (Elsevier Science Publishing Company Inc.) published by, New York, and so on.

Further description is made from Research Disclosure (RD) 17643, pages 23 to 24, RD18716, page 648, right column to page 649, right column, RD308119, page 996, right column to page 998, right column, European Patent No. 0565096A1. Those described on page 65, lines 7 to 10 can be preferably used. Also, U.S. Pat. No. 5,747,236 (especially pages 30-39), U.S. Pat. No. 5,994,051 (especially pages 32-43), U.S. Pat. No. 5,340,694 (especially 21-58, provided that the number of n ₁₂ , n ₁₅ , n ₁₇ , n ₁₈ is not limited in the dyes shown in (XI), (XII), (XIII), and is an integer of 0 or more (preferably 4 or less), and a dye having a partial structure or structure shown in the general formula and specific examples can also be preferably used.
The blending ratio of the p-type organic semiconductor and the n-type organic semiconductor in the intermediate layer of the photoelectric conversion film can be appropriately set within a range of 0.1: 99.9 to 99.9 to 0.1 by mass ratio. .

[Electron transporting materials]
In the photoelectric conversion film of the present invention, the organic material (n-type compound) having an electron transporting property preferably has an ionization potential larger than 6.0 eV, and may be represented by the following general formula (X). preferable.

Formula (X) L- (A) m
(In the formula, A represents a heterocyclic group in which two or more aromatic heterocycles are condensed, and the heterocyclic group represented by A may be the same or different. M represents an integer of 2 or more. L Represents a linking group.)
Details and preferred ranges of these organic materials having electron transport properties are described in detail in Japanese Patent Application No. 2004-082002.
When these electron transporting organic materials are used, the photoelectric conversion efficiency of the obtained photoelectric conversion film is remarkably increased.

In the present invention, the orientation control described below can be applied.
In the present invention, the orientation of the organic compound is preferably ordered as compared to a random state. If it is not random, the degree of order may be low or high, but high order is preferable.

In a photoelectric conversion film having a p-type semiconductor layer, an n-type semiconductor layer (preferably a mixed / dispersed (bulk heterojunction structure) layer) between a pair of electrodes, at least one of the p-type semiconductor and the n-type semiconductor In the case of a photoelectric conversion film characterized in that it includes an organic compound whose orientation is controlled in the direction, more preferably in the case where an organic compound whose orientation is controlled is included in both the p-type semiconductor and the n-type semiconductor. It is.
As the organic compound used in the organic layer of the photoelectric conversion element, one having π-conjugated electrons is preferably used, but the π-electron plane is not perpendicular to the substrate (electrode substrate) but oriented at an angle close to parallel. The better it is. The angle with respect to the substrate is preferably 0 ° or more and 80 ° or less, more preferably 0 ° or more and 60 ° or less, further preferably 0 ° or more and 40 ° or less, and further preferably 0 ° or more and 20 ° or less. Particularly preferably, it is 0 ° or more and 10 ° or less, and most preferably 0 ° (that is, parallel to the substrate).

As described above, the organic compound layer whose orientation is controlled may be partially included in the entire organic layer. Preferably, the proportion of the portion where the orientation is controlled with respect to the entire organic layer is 10% or more, more preferably 30% or more, more preferably 50% or more, further preferably 70% or more, and particularly preferably 90%. Above, most preferably 100%. Such a state compensates for the shortcoming of the short carrier diffusion length of the organic layer by controlling the orientation of the organic compound in the organic layer in the photoelectric conversion film, and improves the photoelectric conversion efficiency.
The orientation of the organic compound can be controlled by selecting the substrate and adjusting the deposition conditions. For example, the method of giving anisotropy to the organic compound which gives a rubbing process to the substrate surface and grows on it etc. is mentioned. However, the structure depending on the substrate crystal is observed only at a thickness of at most a dozen layers, and when the film thickness is increased, a bulk crystal structure is taken. In the photoelectric conversion element of the present invention, in order to increase the light absorption rate, the film thickness is preferably 100 nm or more (100 layers or more as molecules). In such a case, the interaction between organic compounds in addition to the substrate is used. Therefore, it is necessary to control the orientation.

Any interaction force between organic compounds may be used. For example, as an intermolecular force, van der Waals force (more specifically, an orientation force acting between a permanent dipole and a permanent dipole) It can be expressed in terms of induced force acting between permanent dipole and induced dipole, and dispersion force acting between temporary dipole and induced dipole.), Charge transfer force (CT), Coulomb force (electrostatic force), hydrophobic bond Force, hydrogen bond strength, coordination bond strength and the like. Only one of these binding forces can be used, or a plurality of arbitrary binding forces can be used in combination.
Preferred are van der Waals force, charge transfer force, coulomb force, hydrophobic bond force and hydrogen bond force, more preferred are van der Waals force, coulomb force and hydrogen bond force, and particularly preferred is fan. -Del Waals force and Coulomb force, most preferably van der Waals force.

  As one of the interactions between the organic compounds in the present invention, it is possible to use a covalent bond or a coordinate bond, and it is preferably a case where they are linked by a covalent bond ( It can also be regarded as a single coordination bond of intermolecular forces). In these cases, the covalent bond or the coordinate bond may be formed in advance or may be formed in the process of forming the organic layer.

Of the above intermolecular forces and covalent bonds, the intermolecular force is preferably used to control the orientation of the organic compound.
The attractive energy of these intermolecular forces is preferably 15 kJ / mol or more, more preferably 20 kJ / mol or more, and particularly preferably 40 kJ / mol or more. Although there is no upper limit in particular, it is preferably 5000 kJ / mol or less, more preferably 1000 kJ / mol or less.

  It is also possible to use a method in which dielectric anisotropy or polarization is imparted to an organic compound, and an electric field is applied during growth to align molecules.

  In the case where the orientation of the organic compound is controlled, it is more preferable that the heterojunction plane (for example, the pn junction plane) is not parallel to the substrate. In this case, it is preferable that the heterojunction plane is oriented not at an angle close to the substrate (electrode substrate) but at an angle close to the vertical. The angle with respect to the substrate is preferably 10 ° or more and 90 ° or less, more preferably 30 ° or more and 90 ° or less, further preferably 50 ° or more and 90 ° or less, and further preferably 70 ° or more and 90 ° or less. Particularly preferably, it is 80 ° or more and 90 ° or less, and most preferably 90 ° (that is, perpendicular to the substrate).

The organic compound layer whose heterojunction surface is controlled as described above may be partially included in the entire organic layer. Preferably, the proportion of the portion where the orientation is controlled with respect to the entire organic layer is 10% or more, more preferably 30% or more, more preferably 50% or more, further preferably 70% or more, and particularly preferably 90%. Above, most preferably 100%. In such a case, the area of the heterojunction surface in the organic layer increases, the amount of carriers of electrons, holes, electron-hole pairs, etc. generated at the interface increases, and the photoelectric conversion efficiency can be improved.
As examples of specific drawings of the photoelectric conversion film having the heterojunction layer (surface), those described in FIGS. 1 to 8 of JP-A-2003-298152 can be applied.
In the above-described photoelectric conversion film (photoelectric conversion film) in which the orientation of both the heterojunction plane and the π-electron plane of the organic compound is controlled, the photoelectric conversion efficiency can be particularly improved, and a bulk heterostructure is particularly preferable. It can be preferably used in some cases.

(Formation method of organic layer)
The layer containing these organic compounds is formed by a dry film formation method or a wet film formation 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 of using a polymer compound 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 forming 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 vacuum deposition method is basically based on the method of heating compounds such as resistance heating deposition method and electron beam heating deposition method, shape of deposition source such as crucible and boat, degree of vacuum, deposition temperature, base temperature, deposition rate, etc. It is a parameter. In order to make uniform deposition possible, it is preferable to perform deposition by rotating the substrate. The degree of vacuum is preferably higher, and vacuum deposition is performed at 10 ⁻⁴ Torr or less, preferably 10 ⁻⁶ Torr or less, particularly preferably 10 ⁻⁸ Torr or less. 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.

[About BGR spectroscopy]
In one embodiment of the present invention, a BGR photoelectric conversion film having good color reproduction, that is, a photoelectric conversion film in which three layers of a blue photoelectric conversion film (layer), a green photoelectric conversion film (layer), and a red photoelectric conversion film (layer) are stacked. Is preferable.
Furthermore, we have found that each photoelectric conversion film (layer) is preferable when it is in the following spectral absorption wavelength and / or spectral sensitivity range.
The interval between the shortest wavelength and the longest wavelength, each showing 50% of the maximum value Amax of the spectral absorption rate and the maximum value Smax of the spectral sensitivity of the photoelectric conversion film having a laminated structure, is preferably 120 nm or less, and more preferably It is 100 nm or less, particularly preferably 80 nm or less, and most preferably 70 nm or less.
Further, the interval between the shortest wavelength and the longest wavelength showing 80% of Amax and Smax is preferably 20 nm or more, preferably 100 nm or less, more preferably 80 nm or less, and particularly preferably 50 nm or less.
The interval between the shortest wavelength and the longest wavelength that represents 20% of Amax and Smax is preferably 180 nm or less, more preferably 150 nm or less, particularly preferably 120 nm or less, and most preferably 100 nm or less.
The longest wavelength exhibiting a spectral absorption rate of 50% of Amax or Smax is preferably 460 nm to 510 nm for the blue photoelectric conversion film, 560 nm to 610 nm for the green photoelectric conversion film, or 640 nm to 730 nm for the red photoelectric conversion film. is there.

Further, when the maximum value of the spectral absorptance of the photoelectric conversion element having a laminated structure is A1max, A1max is 400 nm to 500 nm, more preferably 420 nm to 480 nm, and particularly preferably 430 nm to 470 nm in the case of a blue photoelectric conversion film. Or in the range of 500 nm to 600 nm for the green photoelectric conversion film, more preferably in the range of 520 nm to 580 nm, particularly preferably in the range of 530 nm to 570 nm, or 600 nm or more for the red photoelectric conversion film. 700 nm or less, more preferably 620 nm or more and 680 nm or less, particularly preferably 630 nm or more and 670 nm or less.
Furthermore, when the maximum value of the spectral sensitivity of the photoelectric conversion film having a laminated structure is S1max, S1max is 400 nm to 500 nm, more preferably 420 nm to 480 nm, and particularly preferably 430 nm to 470 nm in the blue photoelectric conversion film. Or in the range of 500 nm to 600 nm, more preferably in the range of 520 nm to 580 nm, particularly preferably in the range of 530 nm to 570 nm, or 600 nm to 700 nm in the case of the red photoelectric conversion film. Hereinafter, it is more preferably 620 nm or more and 680 nm or less, particularly preferably 630 nm or more and 670 nm or less.
When the spectral absorption wavelength and spectral sensitivity range of the compound of the present invention are within these ranges, the color reproducibility of the color image obtained by the imaging device can be improved.

[Thickness regulation of organic dye layer]
When the photoelectric conversion film of the present invention is used as a color image sensor (image sensor), the light absorption rate of each of the organic dye layers of the B, G, and R layers is preferably 50% or more, more preferably 70% or more, and particularly preferably. Is preferably 90% (absorbance = 1) or more, most preferably 99% or more in order to improve the photoelectric conversion efficiency and to improve color separation without passing excess light through the lower layer. Therefore, in terms of light absorption, the larger the thickness of the organic dye layer, the better. However, considering the ratio contributing to charge separation, the thickness of the organic dye layer in the present invention is preferably 30 nm or more and 300 nm or less, more preferably It is 50 nm or more and 250 nm or less, particularly preferably 60 nm or more and 200 nm or less, and most preferably 80 nm or more and 130 nm or less.

[Apply voltage]
When a voltage is applied to the photoelectric conversion film of the present invention, it is preferable in terms of improving the photoelectric conversion efficiency. The applied voltage may be any voltage, but the required voltage varies depending on the film thickness of the photoelectric conversion film. That is, the photoelectric conversion efficiency improves as the electric field applied to the photoelectric conversion film increases, but the applied electric field increases as the film thickness of the photoelectric conversion film decreases even at the same applied voltage. Therefore, when the photoelectric conversion film is thin, the applied voltage may be relatively small. The electric field applied to the photoelectric conversion film is preferably 10 V / m or more, more preferably 1 × 10 ³ V / m or more, more preferably 1 × 10 ⁵ V / m or more, and particularly preferably 1 × 10 ⁶ V / m. m or more, most preferably 1 × 10 ⁷ V / m or more. There is no particular upper limit, but if an electric field is applied too much, an electric current flows unfavorably in a dark place, so 1 × 10 ¹² V / m or less is preferable, and 1 × 10 ⁹ V / m or less is more preferable.

[General requirements]
In the present invention, it is preferable to use a configuration in which at least two or more photoelectric conversion elements are stacked, more preferably three or four layers, and particularly preferably three layers.
In the present invention, these photoelectric conversion elements can be preferably used as an image sensor, particularly preferably as a solid-state image sensor.
Moreover, in this invention, the case where a voltage is applied to these photoelectric conversion films, photoelectric conversion elements, and image sensors is preferable.
The photoelectric conversion element in the present invention is preferably a case where a p-type semiconductor layer and an n-type semiconductor layer have a photoelectric conversion film having a stacked structure between a pair of electrodes. Preferably, at least one of the p-type and n-type semiconductors contains an organic compound, and more preferably, both the p-type and n-type semiconductors contain an organic compound.

[Laminated structure]
As one preferable aspect of the present invention, when no voltage is applied to the photoelectric conversion film, it is preferable that at least two photoelectric conversion films are laminated. There are no particular limitations on the multilayer imaging device, and any of those used in this field can be applied, but a BGR three-layer stacked structure is preferable, and a preferred example of the BGR stacked structure is shown in FIG.
Next, the solid-state imaging device according to the present invention has, for example, a photoelectric conversion film as shown in FIG. In the solid-state imaging device as shown in FIG. 1, a stacked photoelectric conversion film is provided on the scanning circuit unit. The scanning circuit unit can appropriately adopt a configuration in which a MOS transistor is formed on a semiconductor substrate for each pixel unit, or a configuration having a CCD as an image sensor.
For example, in the case of a solid-state imaging device using a MOS transistor, charges are generated in the photoelectric conversion film by incident light transmitted through the electrodes, and the charges are generated by an electric field generated between the electrodes by applying a voltage to the electrodes. It travels to the electrode through the photoelectric conversion film, and further moves to the charge storage part of the MOS transistor, and charges are stored in the charge storage part. The charge accumulated in the charge accumulation unit moves to the charge readout unit by switching of the MOS transistor, and is further output as an electric signal. Thereby, a full-color image signal is input to the solid-state imaging device including the signal processing unit.
As these laminated image pickup devices, solid color image pickup devices represented by FIG. 2 of JP-A-58-103165, FIG. 2 of JP-A-58-103166, and the like can also be applied.

  The method described in JP-A-2002-83946 (see FIGS. 7 to 23 and paragraph numbers 0026 to 0038 of the same publication) can be applied to the manufacturing process of the above-described multilayer image sensor, preferably a three-layer image sensor.

(Photoelectric conversion element)
The photoelectric conversion element of the preferable aspect of this invention is demonstrated below.
The photoelectric conversion element of the present invention comprises an electromagnetic wave absorption / photoelectric conversion site and a charge accumulation / transfer / readout site for charges generated by photoelectric conversion.
In the present invention, the electromagnetic wave absorption / photoelectric conversion site has a laminated structure of at least two layers capable of absorbing and photoelectrically converting at least blue light, green light, and red light. The blue light absorbing layer (B) can absorb light of at least 400 nm or more and 500 nm or less, and preferably the peak wavelength absorptance in the wavelength region is 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.
In the present invention, the charge accumulation / transfer / readout part is provided under the electromagnetic wave absorption / photoelectric conversion part. It is preferable that the electromagnetic wave absorption / photoelectric conversion site in the lower layer also serves as a charge storage / transfer / readout site.

  In the present invention, the electromagnetic wave absorption / photoelectric conversion site comprises an organic layer, an inorganic layer, or a mixture of an organic layer and an inorganic layer. The organic layer may form a B / G / R layer, or the inorganic layer may form a B / G / R layer. A mixture of an organic layer and an inorganic layer is preferred. In this case, basically, when the organic layer is one layer, the inorganic layer is one or two layers, and when the organic layer is two layers, the inorganic layer is one layer. When the organic layer and the inorganic layer are one layer, the inorganic layer forms electromagnetic wave absorption / photoelectric conversion sites of two or more colors on the same plane. Preferably, the upper layer is an organic layer and is a G layer, and the lower layer is an inorganic layer and is an order of B layer and R layer from the top. In some cases, it is possible to provide a fourth layer or more as a new layer or in the same plane. In the case where the organic layer forms a B / G / R layer, a charge accumulation / transfer / readout portion is provided thereunder. When an inorganic layer is used as the electromagnetic wave absorption / photoelectric conversion site, this inorganic layer also serves as a charge accumulation / transfer / readout site.

In the present invention, one particularly preferable aspect among the elements described above is as follows.
This is the case of having at least two electromagnetic wave absorption / photoelectric conversion sites, and at least one of these sites is the element (imaging device) of the present invention.
Furthermore, it is preferable that the element has a laminated structure in which at least two electromagnetic wave absorption / photoelectric conversion sites have at least two layers. Furthermore, it is preferable that the upper layer is an element composed of a part capable of absorbing green light and performing photoelectric conversion.
Particularly preferably, there are at least three electromagnetic wave absorption / photoelectric conversion sites, 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, at least two of the three electromagnetic wave absorption / photoelectric conversion sites are inorganic layers (preferably formed in a silicon substrate).

(electrode)
The electromagnetic wave absorption / photoelectric conversion site made of the organic layer of the present invention is sandwiched between a pair of electrodes, each of which forms a pixel electrode and a counter electrode. The lower layer is preferably a pixel electrode.
The counter electrode is preferably a material that can take out holes from the hole transport photoelectric conversion film or the hole transport layer, and can use a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof. . The pixel electrode preferably takes out electrons from the electron-transporting photoelectric conversion layer or the electron-transporting layer. Adhesion with adjacent layers such as the electron-transporting photoelectric conversion layer and the electron-transporting layer, electron affinity, ionization potential, stability, etc. Selected in consideration of Specific examples of these 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 metal 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, etc. In particular, ITO and IZO are preferable from the viewpoints 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 manufacturing the pixel electrode and the counter electrode depending on the material. For example, in the case of ITO, electron beam method, sputtering method, resistance heating vapor deposition method, chemical reaction method (sol-gel method, etc.), dispersion of indium tin oxide A film is formed by a method such as application of an object. 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 from plasma, the influence of plasma on the substrate 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 electrode of the organic electromagnetic wave absorption / photoelectric conversion site of the present invention will be described in more detail. The photoelectric conversion film of the organic layer is sandwiched between the pixel electrode film and the counter electrode film, and can include an interelectrode material or the like. The pixel electrode film is an electrode film formed above the substrate on which the charge accumulation / transfer / read-out site is formed, and is usually divided for each pixel. This is to obtain an image by reading out the signal charges converted by the photoelectric conversion film on a charge storage / transfer / signal readout circuit substrate for each pixel.
The counter electrode film has a function of discharging a signal charge having a polarity opposite to that of the signal charge by sandwiching the photoelectric conversion film together with the pixel electrode film. Since the discharge of the signal charge does not need to be divided between the pixels, the counter electrode film can be commonly used between the pixels. Therefore, it may be called a common electrode film (common electrode film).

The photoelectric conversion film is located between the pixel electrode film and the counter electrode film. The photoelectric conversion function functions by the photoelectric conversion film, the pixel electrode film, and the counter electrode film.
As a configuration example of the photoelectric conversion film lamination, first, in the case where there is one organic layer laminated on the substrate, the pixel electrode film (basically a transparent electrode film), the photoelectric conversion film, the counter electrode film (transparent electrode film) from the substrate ) In order, but is not limited thereto.
Further, when there are two organic layers stacked on the substrate, for example, from the substrate to the pixel electrode film (basically a transparent electrode film), a photoelectric conversion film, a counter electrode film (transparent electrode film), an interlayer insulating film, a pixel electrode A configuration in which a film (basically a transparent electrode film), a photoelectric conversion film, and a counter electrode film (transparent electrode film) are stacked in order.

  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, Etc. 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), “Transparent 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 preferred range of the surface resistance of the transparent electrode film varies depending on whether it is a pixel electrode or a counter electrode, and whether the charge storage / transfer / read-out site is a CCD structure or a CMOS structure. When it is used for the counter electrode and the charge storage / transfer / readout part has a CMOS structure, it is preferably 10000Ω / □ or less, more preferably 1000Ω / □ or less. When it is used for the counter electrode and the charge storage / transfer / readout part has a CCD structure, it is preferably 1000Ω / □ or less, more preferably 100Ω / □ or less. When used for a pixel electrode, it is preferably 1000000 Ω / □ or less, more preferably 100000 Ω / □ or less.

  The conditions at the time of forming the transparent electrode film will be 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.

(Inorganic layer)
The inorganic layer as the electromagnetic wave absorption / photoelectric conversion site will be described. In this case, light passing through the upper organic layer is photoelectrically converted by the inorganic layer. As the inorganic layer, a pn junction or a pin junction of a compound semiconductor such as crystalline silicon, amorphous silicon, or GaAs is generally used. The method disclosed in US Pat. No. 5,965,875 can be adopted as the laminated structure. In other words, a stacked light receiving portion is formed using the wavelength dependence of the absorption coefficient of silicon, and color separation is performed in the depth direction. In this case, since color separation is performed based on the light penetration depth of silicon, the spectral range detected by each stacked light receiving unit is broad. However, color separation is remarkably improved by using the above-described organic layer as an upper layer, that is, by detecting light transmitted through the organic layer in the depth direction of silicon. In particular, when the G layer is disposed in the organic layer, the light transmitted through the organic layer becomes B light and R light, so that the separation of light in the depth direction in silicon becomes only BR light, and color separation is improved. Even when the organic layer is a B layer or an R layer, color separation is remarkably improved by appropriately selecting the electromagnetic wave absorption / photoelectric conversion site of silicon in the depth direction. When the organic layer has two layers, the function as an electromagnetic wave absorption / photoelectric conversion site in silicon may be basically one color, and preferable color separation can be achieved.

The inorganic layer is preferably formed by stacking a plurality of photodiodes for each pixel in the depth direction in the semiconductor substrate, and a color signal corresponding to a signal charge generated in each photodiode by light absorbed by the plurality of photodiodes. It is a structure that reads out to the outside. Preferably, the plurality of photodiodes include a first photodiode provided at a depth that absorbs B light and at least one of a second photodiode provided at a depth that absorbs R light, It is preferable to include a color signal readout circuit that reads out a color signal corresponding to the signal charge generated in each of the plurality of photodiodes. With this configuration, color separation can be performed without using a color filter. In some cases, light of a negative sensitivity component can also be detected, so that color imaging with good color reproducibility is possible. In the present invention, the junction portion of the first photodiode is formed to a depth of about 0.2 μm from the surface of the semiconductor substrate, and the junction portion of the second photodiode is the surface of the semiconductor substrate. To a depth of about 2 μm.
The inorganic layer will be described in more detail. As a preferable configuration of the inorganic layer, a photoconductive type, a pn junction type, a Schottky junction type, a PIN junction type, an MSM (metal-semiconductor-metal) type light receiving element or a phototransistor type light receiving element can be given. In the present invention, a plurality of first conductivity type regions and second conductivity type regions opposite to the first conductivity type are alternately stacked in a single semiconductor substrate, and the first conductivity type is stacked. It is preferable to use a light receiving element in which each joint surface of the region of the mold and the second conductivity type is formed to a depth suitable for mainly photoelectrically converting light in a plurality of different wavelength bands. As the single semiconductor substrate, single crystal silicon is preferable, and color separation can be performed using absorption wavelength characteristics depending on the depth direction of the silicon substrate.

As the inorganic semiconductor, an InGaN-based, InAlN-based, InAlP-based, or InGaAlP-based inorganic semiconductor can also be used. The InGaN-based inorganic semiconductor is adjusted so as to have a maximum absorption value in a blue wavelength range by appropriately changing the In-containing composition. That is, the composition is In _x Ga _1-x N (0 <X <1). Such a compound semiconductor is manufactured using a metal organic chemical vapor deposition method (MOCVD method). A nitride semiconductor InAlN system using Al, which is the same group 13 raw material as Ga, can also be used as a short wavelength light receiving section in the same manner as the InGaN system. InAlP or InGaAlP lattice-matched to the GaAs substrate can also be used.
The inorganic semiconductor may have a buried structure. The embedded structure means a structure in which both ends of the short wavelength light receiving part are covered with a semiconductor different from the short wavelength light receiving part. The semiconductor covering both ends is preferably a semiconductor having a band gap wavelength shorter than or equivalent to the band gap wavelength of the short wavelength light receiving part.
The organic layer and the inorganic layer may be combined in any form. In addition, it is preferable to provide an insulating layer between the organic layer and the inorganic layer in order to electrically insulate.

  The junction is preferably npn or pnpn from the light incident side. In particular, by providing a p layer on the surface and increasing the surface potential, holes generated in the vicinity of the surface and dark current can be trapped and dark current can be reduced. preferable.

In such a photodiode, an n-type layer, a p-type layer, an n-type layer, and a p-type layer that are sequentially diffused from the surface of the p-type silicon substrate are formed deeply in this order, so that the pn junction diode has a silicon depth. Four layers of pnpn are formed in the direction. The light incident on the diode from the surface side penetrates deeper as the wavelength is longer, and the incident wavelength and attenuation coefficient show values specific to silicon, so that the depth of the pn junction surface covers each wavelength band of visible light. design. Similarly, an n-type layer, a p-type layer, and an n-type layer are formed in this order to obtain a npn three-layer junction diode. Here, an optical signal is taken out from the n-type layer, and the p-type layer is connected to the ground.
Further, when an extraction electrode is provided in each region and a predetermined reset potential is applied, each region is depleted, and the capacitance of each junction becomes an extremely small value. Thereby, the capacity | capacitance produced in a joint surface can be made very small.

(Auxiliary layer)
In the present invention, an ultraviolet absorption layer and / or an infrared absorption layer are preferably provided on the uppermost layer of the electromagnetic wave absorption / photoelectric conversion site. The ultraviolet absorbing layer can absorb or reflect at least light of 400 nm or less, and preferably has an absorptance of 50% or more in a wavelength region of 400 nm or less. The infrared absorbing layer can absorb or reflect light of at least 700 nm or more, and preferably has an absorptance of 50% or more in a wavelength region of 700 nm or more.

These ultraviolet absorbing layer and infrared absorbing layer can be formed by a conventionally known method. For example, a method of forming a colored layer by providing a mordanting layer made of a hydrophilic polymer material such as gelatin, casein, mulled or polyvinyl alcohol on a substrate and adding or dyeing a dye having a desired absorption wavelength to the mordanting layer. Are known. Furthermore, a method using a colored resin in which a certain kind of coloring material is dispersed in a transparent resin is known. For example, JP-A-58-46325, JP-A-60-78401, JP-A-60-184202, JP-A-60-184203, JP-A-60-184204, JP-A-60-184204 As shown in Japanese Patent Application Laid-Open No. 60-184205 and the like, a colored resin film obtained by mixing a colorant with a polyamino resin can be used. A colorant using a polyimide resin having photosensitivity is also possible.
Dispersing a coloring material in an aromatic polyamide resin having a photosensitivity group described in JP-B-7-113685 in the molecule and capable of obtaining a cured film at 200 ° C. or lower, JP-B-7-69486 It is also possible to use dispersed colored resins with the stated content.

In the present invention, a dielectric multilayer film is preferably used. The dielectric multilayer film is preferably used because the wavelength dependency of light transmission is sharp.
Each electromagnetic wave absorption / photoelectric conversion site 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 rate can be improved by forming the microlens array on the light receiving element, such an embodiment is also preferable.

(Charge accumulation / transfer / readout part)
Regarding the charge transfer / readout part, reference can be made to JP-A-58-103166, JP-A-58-103165, JP-A-2003-332551 and the like. A configuration in which a MOS transistor is formed in each pixel unit on a semiconductor substrate or a configuration having a CCD as an element can be appropriately employed. For example, in the case of a photoelectric conversion element using a MOS transistor, charges are generated in the photoconductive film by incident light transmitted through the electrodes, and the charges are generated by an electric field generated between the electrodes by applying a voltage to the electrodes. It travels to the electrode through the photoconductive film, and further moves to the charge storage part of the MOS transistor, and charges are stored in the charge storage part. The charge accumulated in the charge accumulation unit moves to the charge readout unit by switching of the MOS transistor, and is further output as an electric signal. Thereby, a full-color image signal is input to the solid-state imaging device including the signal processing unit.
It is possible to inject a certain amount of bias charge into the storage diode (refresh mode) and store the constant charge (photoelectric conversion mode), and then read out the signal charge. The light receiving element itself can be used as a storage diode, or a storage diode can be additionally provided.

The signal readout will be described in more detail. An ordinary color readout circuit can be used for signal readout. The signal charge or signal current optically / electrically converted by the light receiving unit is stored in the light receiving unit itself or an attached capacitor. The stored charge is read out together with the selection of the pixel position by a technique of a MOS type image pickup device (so-called CMOS sensor) using an XY address method. In addition, as an address selection method, there is a method in which each pixel is sequentially selected by a multiplexer switch and a digital shift register and read as a signal voltage (or charge) to a common output line. An image sensor for XY address operation that is two-dimensionally arrayed is known as a CMOS sensor. This is because a switch connected to a pixel connected to the intersection of XY is connected to a vertical shift register, and when a switch is turned on by a voltage from the vertical scanning shift register, it is read from a pixel placed in the same row. The signal is read out to the output line in the column direction. This signal is sequentially read from the output through a switch driven by a horizontal scanning shift register.
For reading out the output signal, a floating diffusion detector or a floating gate detector can be used. Further, the S / N can be improved by providing a signal amplification circuit in the pixel portion or a correlated double sampling technique.

For signal processing, gamma correction by an ADC circuit, digitization by an AD converter, luminance signal processing, and color signal signal processing can be performed. Examples of the color signal processing include white balance processing, color separation processing, and color matrix processing. When used for NTSC signals, RGB signals can be converted to YIQ signals.
The charge transfer / readout site needs to have a charge mobility of 100 cm ² / volt · sec or more, and this mobility is selected from a group IV, III-V, or II-VI group semiconductor. Can be obtained. Of these, silicon semiconductors (also referred to as Si semiconductors) are preferable because miniaturization technology is advanced and the cost is low. Many methods of charge transfer and charge reading have been proposed, but any method may be used. A particularly preferable method is a CMOS type or CCD type device.
Furthermore, in the case of the present invention, the CMOS type is often preferable in terms of high-speed readout, pixel addition, partial readout, power consumption, and the like.

(Connection)
A plurality of contact parts for connecting the electromagnetic wave absorption / photoelectric conversion part and the charge transfer / reading part may be connected by any metal, but preferably selected from copper, aluminum, silver, gold, chromium, and tungsten. In particular, copper is preferred. In accordance with a plurality of electromagnetic wave absorption / photoelectric conversion sites, it is necessary to install each contact site between the charge transfer / readout site. When a laminated structure of a plurality of photosensitive units of blue, green, and red light is adopted, between the blue light extraction electrode and the charge transfer / readout portion, between the green light extraction electrode and the charge transfer / readout portion, and the red light extraction electrode; It is necessary to connect between the charge transfer / readout portions.

(process)
The laminated photoelectric conversion device of the present invention can be manufactured according to a so-called microfabrication process used for manufacturing a known integrated circuit or the like. Basically, this method uses pattern exposure by active light or electron beam (mercury i, g emission line, excimer laser, X-ray, electron beam), pattern formation by development and / or burning, element formation material By repeated operations of placement (coating, vapor deposition, sputtering, CV, etc.) and removal of non-patterned material (heat treatment, dissolution treatment, etc.).

(Use)
The chip size of the device can be selected from brownie size, 135 size, APS size, 1 / 1.8 inch, and even smaller size. 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 a plurality of electromagnetic wave absorption / photoelectric conversion sites. Any pixel size may be used, but a pixel size of 2 to 20 microns is preferable. More preferably, it is 2-10 microns, but 3-8 microns is particularly preferable.
When the pixel size exceeds 20 microns, the resolving power decreases, and even if the pixel size is smaller than 2 microns, the resolving power decreases due to radio wave interference between the sizes.

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 photoelectric conversion element 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 meet a variety of 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 can be obtained by referring to the description in Chapter 2 of the TV Information Technology Society, Television Camera Design Technology (August 20, 1999, Corona, ISBN 4-339-00714-5). Fig. 2.1 The television camera can be manufactured by replacing the part of the color separation optical system and the imaging device in the basic configuration with the photoelectric conversion element of the present invention.
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.

(Preferred photoelectric conversion element of the present invention)
A preferred photoelectric conversion element of the present invention will be described with reference to FIG. Reference numeral 13 denotes a silicon single crystal substrate, which serves as an electromagnetic wave absorption / photoelectric conversion site for B light and R light and a charge accumulation / transfer / readout site for charges generated by photoelectric conversion. Usually, a p-type silicon substrate is used. Reference numerals 21, 22, and 23 denote an n layer, a p layer, and an n layer provided in the silicon substrate, respectively. The n layer 21 is an R light signal charge accumulating unit for accumulating the R light signal charge photoelectrically converted by the pn junction. The accumulated charges are connected to 27 signal readout pads through 19 transistors through 19 transistors. The n layer 23 is a B light signal charge accumulating unit for accumulating B light signal charges photoelectrically converted by a pn junction. The accumulated electric charge is connected to 27 signal readout pads through 19 metal wires through transistors similar to 26. Here, the p layer, the n layer, the transistor, the metal wiring, and the like are schematically shown. However, as described in detail in the previous discussion, an optimal structure is appropriately selected. Since B light and R light are separated according to the depth of the silicon substrate, selection of the depth from the silicon substrate such as a pn junction and the doping concentration is important. Reference numeral 12 denotes a layer containing metal wiring, which is mainly composed of silicon oxide, silicon nitride, or the like. The thickness of the layer 12 is preferably as small as possible, and is 5 μm or less, preferably 3 μm or less, more preferably 2 μm or less. Similarly, 11 is a layer mainly composed of silicon oxide, silicon nitride or the like. The 1112 layer is provided with a plug for sending the signal light of G light to the silicon substrate. The plug is connected by 16 pads between the 11 and 12 layers. The plug is preferably made mainly of tungsten. A pad mainly composed of aluminum is preferably used. It is preferable that a barrier layer is provided including the metal wiring described above. The signal charges of G light transmitted through the 15 plugs are accumulated in the n layer indicated by 25 in the silicon substrate. The n layer shown in 25 is separated by the p layer shown in 24. The accumulated electric charge is connected to 27 signal readout pads through 19 metal wires through transistors similar to 26. Since photoelectric conversion by the pn junctions 24 and 25 causes noise, the light shielding film shown in 17 is provided in 11 layers. As the light shielding film, a film mainly composed of tungsten, aluminum or the like is usually used. The thickness of the layer 12 is preferably as small as possible, and is 3 μm or less, preferably 2 μm or less, more preferably 1 μm or less. 27 signal readout pads are preferably provided for each of the B, G, and R signals. The above process can be prepared by a conventionally known process, a so-called CMOS process.

The electromagnetic wave absorption / photoelectric conversion site of G light is indicated by 6, 7, 8, 9, 10, and 14. Reference numerals 6 and 14 denote transparent electrodes, which correspond to a counter electrode and a pixel electrode, respectively. Although the pixel electrode 14 is a transparent electrode, a part such as aluminum or molybdenum is often required for the connection portion in order to improve electrical connection with the 15 plugs. A bias is applied between these transparent electrodes through wiring from 18 connection electrodes and 20 counter electrode pads. A structure in which electrons can be stored in 25 by applying a positive bias to the pixel electrode 14 with respect to the transparent counter electrode 6 is preferable. In this case, 7 is an electron blocking layer, 8 is a p layer, 9 is an n layer, and 10 is a hole blocking layer, showing a typical organic layer structure. The thickness of the organic layer composed of 7, 8, 9, 10 is preferably 0.5 μm or less, more preferably 0.3 μm or less, and particularly preferably 0.2 μm or less. The thicknesses of the transparent counter electrode 6 and the transparent pixel electrode 14 are particularly preferably 0.2 μm or less. Reference numerals 3, 4, and 5 are protective films mainly composed of silicon nitride or the like. These protective films facilitate the manufacturing process of the layer including the organic layer. In particular, these layers can reduce damage to the organic layer at the time of forming a resist pattern at the time of forming connection electrodes such as 18 and etching. Further, in order to avoid the formation of resist patterns, etching, etc., it is possible to manufacture with a mask. The thicknesses of the protective films 3, 4, and 5 are preferably 0.5 μm or less as long as the above-described conditions are satisfied.
3 is a protective film of 18 connection electrodes. Reference numeral 2 denotes an infrared cut dielectric multilayer film. Reference numeral 1 denotes an antireflection film. The total thickness of the layers 1, 2, and 3 is preferably 1 μm or less.
The photoelectric conversion element described in FIG. 1 has a configuration in which the G pixel is 4 pixels and the B pixel and the R pixel are 1 pixel. The G pixel may be configured with one B pixel and the R pixel for one pixel, or the G pixel may be configured with one pixel for the B pixel and the R pixel for three pixels. In addition, the B pixel and the R pixel may be configured as one pixel with respect to the G pixel as two pixels. Furthermore, arbitrary combinations may be used. Although the above shows the preferable aspect of this invention, it is not limited to this.

[Example]
Examples and embodiment examples of the present invention will be described below, but the present invention is not limited thereto.

A 10 nm-thick layer of copper phthalocyanine (compound 1) is formed on the indium tin oxide (ITO) thin film using a vacuum deposition method, and then (compound 1) and perylene-3,4,9, 10-Tetracarboxyl-bis-benzimidazole (compound 2) is co-evaporated at a ratio of 1: 1 to form an 80 nm-thick layer having these bulk heterojunction structures. 2) A layer having a thickness of 10 nm is formed. Furthermore, a semi-transparent aluminum electrode having a film thickness of 40 nm can be formed to obtain the photoconductive film A.
In the photoconductive film A, the film thickness of the compound 1 was changed to 50 nm, the film thickness of the compound 2 was changed to 10 nm, and the layer having the bulk heterojunction structure was removed, and the same as the photoconductive film A was used. Photoconductive film B is used as a comparison. In addition, the image pick-up element which divided these photoconductive films A and B into a pixel is set as image pick-up element A and B, respectively.
The optical response current of the image sensor A is twice that of the image sensor B. Furthermore, by applying a forward voltage of 5v between the electrodes (a positive voltage is applied to the aluminum electrode) (that is, an electric field of 5 × 10 ⁷ V / m), the photoresponsive current of the image sensor A does not apply a voltage. Compared to the case, the photoresponse current of the comparative image pickup element B is only twice that in the case where no voltage is applied.
The same result can be obtained even if the stacking order of (Compound 1) and (Compound 2) is reversed. In this case, the polarity of voltage application is reversed. Similar results can be obtained by using a translucent gold electrode having a thickness of 20 nm instead of the aluminum electrode.
As described above, an image sensor having a bulk heterojunction structure has a higher photoresponse current and a higher sensitivity as an image sensor compared to an image sensor not having these structures, and is remarkable when a voltage is applied. High sensitivity.

The same element as in Example 1 shows excellent performance as compared to 1, except that the compound used in the imaging element described in Example 1 was changed as follows.
(Compound 1) was converted to 1,3-diethyl-5-[(3-ethyl-2 (3H) -5,6-dimethylbenzoxazolylidene) ethylden] ethylidene] -2,4,6 (1H, 3H, 5H ) -Pyrimidinetrione (dimethine merocyanine: Compound 3) (Compound 2) was changed to 1,3-diethyl-5-[(3-ethyl-2 (3H) -5-nitrobenzoxazolylidene) ethylden] ethylidene] Changed to -2,4,6 (1H, 3H, 5H) -pyrimidinetrione (dimethine merocyanine: compound 4)

The same elements as in Example 2 show superior performance as compared with Example 2 except that the compounds used in the image sensor described in Example 2 were changed as follows.
(Compound 3) is changed to tetramethine merocyanine (compound 5) with two methine chains of (compound 3) (compound 5) Tetramethine merocyanine with two methine chains of (compound 4) to four Change to (Compound 6)

The same elements as in Example 2 show superior performance as compared with Example 2 except that the compounds used in the image sensor described in Example 2 were changed as follows.
(Compound 3) was changed to zero methine merocyanine (Compound 7) from which the methine chain of (Compound 3) was removed (Compound 4) was changed to zero methine merocyanine (Compound 8) from which the methine chain of (Compound 4) was removed

  In the imaging device shown in FIG. 1 in which the imaging device of Example 4 is a B layer, the imaging device of Example 2 is a G layer, the imaging device of Example 3 is an R layer, and the three layers are stacked, each layer is compared. On the other hand, it exhibits an excellent photoresponse current, has high sensitivity, and is excellent as a color imaging device.

  A conceptual diagram of the present invention is shown in FIG.

  The photoelectric conversion element of Non-Patent Document 1, which is a conventional technique, is suitable only for the purpose of energy utilization, and Patent Documents 1 to 3 are imaging elements including a bulk heterojunction structure. Different.

A 33 nm thick layer of copper phthalocyanine (compound 1) is formed on an indium tin oxide (ITO) thin film by vacuum deposition, and then perylene-3,4,9,10-tetracarboxyl- A 33 nm thick layer of bis-benzimidazole (compound 2) is formed, and then a 0.5 nm thick layer of silver clusters is formed. Similarly, (compound 9) 33 nm / (compound 10) 33 nm / silver Clusters 0.5 nm / (compound 1) 33 nm / (compound 2) 33 nm are sequentially formed. Furthermore, a photoconductive film A can be obtained by forming a translucent aluminum electrode having a thickness of 40 nm. A photoconductive film B having a 50 nm-thick (compound 9) layer and a 50 nm-thick (compound 10) layer is used for comparison. In addition, the image pick-up element which divided these photoconductive films A and B into a pixel is set as image pick-up element A and B, respectively.
The optical response current of the image sensor A is 1.3 times that of the image sensor B. Furthermore, by applying a forward voltage of 5v between the electrodes (a positive voltage is applied to the aluminum electrode) (that is, an electric field of 5 × 10 ⁷ V / m), the photoresponsive current of the image sensor A does not apply a voltage. In contrast to the case of 2.2 times, the photoresponse current of the comparative image sensor B is only twice that of the case where no voltage is applied.

The same result can be obtained even if the stacking order of (Compound 1) and (Compound 2) is reversed. In this case, the polarity of voltage application is reversed. Similar results can be obtained by using a translucent gold electrode having a thickness of 20 nm instead of the aluminum electrode.
As described above, an image sensor having a pn structure repetitive structure has a higher photoresponse current and a higher sensitivity as an image sensor compared to an image sensor not having these structures, and is remarkable when a voltage is applied. High sensitivity.

The same element as in Example 1 shows excellent performance as compared to 1, except that the compound used in the imaging element described in Example 6 was changed as follows.
(Compound 1) was converted to 1,3-diethyl-5-[(3-ethyl-2 (3H) -5,6-dimethylbenzoxazolylidene) ethylden] ethylidene] -2,4,6 (1H, 3H, 5H ) -Pyrimidinetrione (dimethine merocyanine: Compound 11) (Compound 2) was changed to 1,3-diethyl-5-[(3-ethyl-2 (3H) -5-nitrobenzoxazolylidene) ethylden] ethylidene] Changed to -2,4,6 (1H, 3H, 5H) -pyrimidinetrione (dimethine merocyanine: Compound 12)

The same element as in Example 2 shows excellent performance as compared with 2, except that the compound used in the imaging element described in Example 2 was changed as follows.
(Compound 11) is changed to tetramethine merocyanine (compound 13) in which two methine chains of (compound 11) are four (compound 12) tetramethine merocyanine in which two methine chains of (compound 12) are four Change to (Compound 14)

The same element as in Example 2 shows excellent performance as compared with 2, except that the compound used in the imaging element described in Example 2 was changed as follows.
(Compound 11) changed to zero methine merocyanine (Compound 15) from which the methine chain of (Compound 11) was removed (Compound 12) changed to Zero methine merocyanine (Compound 16) from which the methine chain of (Compound 12) was removed

  In the imaging device shown in FIG. 1 in which the imaging device of Example 9 is a B layer, the imaging device of Example 7 is a G layer, the imaging device of Example 8 is an R layer, and three layers are stacked, each layer is compared for comparison. It exhibits excellent photoresponse current and high sensitivity, and is excellent as a color imaging device.

A schematic cross-sectional view of a preferred embodiment of the present invention is shown in FIG. The element shown in FIG. 3 is a tandem type having two or more layers, and has a structure in which a silver cluster film is inserted.
Non-Patent Documents 2 and 3 which are prior arts are intended to use energy for a photoelectric conversion film, and are different from an image pickup device capable of applying a voltage and having a tandem structure according to the present invention.

  When the photoelectric conversion part that absorbs the G light of Example 2 or Example 7 is used for the parts 8 and 9 of the photoelectric conversion part in FIG. 4, it shows an excellent photoresponse current for comparison and high sensitivity. In addition, it exhibits excellent color separation as a color imaging device.

It is a cross-sectional schematic diagram for 1 pixel of the photoelectric conversion film laminated | stacked image pick-up element of BGR 3 layer lamination by this invention. It is a cross-sectional schematic diagram which shows the photoelectric converting film which has the bulk heterojunction structure by this invention. It is a cross-sectional schematic diagram which shows the photoelectric converting film with a tandem structure by this invention. Photoelectric conversion element according to a preferred embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antireflection film 2 Infrared cut dielectric multilayer film 3, 4 Protective film 5 Counter electrode 6 Transparent counter electrode 7 Electron blocking layer 8 P layer 9 N layer 10 Hole blocking layer 11, 12 Layer including metal wiring 13 Silicon single Crystal substrate 14 Transparent pixel electrode 15 Plug 16 Pad 17 Light shielding film 18 Connection electrode 19 Metal wiring 20 Counter electrode pad 21 n layer 22 p layer 23 n layer 24 p layer 25 n layer 26 Transistor 27 Signal readout pad 101 P well layer 102, 104, 106 High-concentration impurity regions 103, 105, 107 MOS circuit 108 Gate insulating film 109, 110 Insulating film 111, 114, 116, 119, 121, 124, transparent electrode film 112, 117, 122, electrode 113, 118, 123 Photoelectric conversion film 110, 115, 120, 125 Transparent insulating film 126 Light shielding film 15 A semiconductor substrate

Claims (29)

  Between the pair of electrodes, a p-type semiconductor layer and an n-type semiconductor layer are provided, at least one of the p-type semiconductor and the n-type semiconductor is an organic semiconductor, and the semiconductor layer includes An imaging device comprising a photoelectric conversion film (photosensitive layer) having a bulk heterojunction structure layer including a p-type semiconductor and an n-type semiconductor as an intermediate layer.   2. The imaging device according to claim 1, wherein both the p-type semiconductor and the n-type semiconductor are organic semiconductors.   The imaging device according to claim 2, wherein at least one of the p-type organic semiconductor and the n-type organic semiconductor is an organic dye.   A photoelectric conversion film (photosensitive layer) having a structure in which the number of repeating structures of a pn junction layer formed of a p-type semiconductor layer and an n-type semiconductor layer is two or more is included between a pair of electrodes. An image sensor.   The imaging device according to claim 4, wherein the number of repeating structures of the pn junction layer is 2 or more and 10 or less.   The imaging device according to claim 4, wherein a thin layer of a conductive material is inserted between the repetitive structures.   The imaging device according to claim 6, wherein the conductive material is silver or gold.   The image pickup device according to claim 4, wherein the p-type semiconductor and / or the n-type semiconductor is an organic compound.   The image pickup device according to claim 8, wherein the organic compound is an organic dye.   The image pickup device according to claim 3 or 9, wherein the organic dye is a merocyanine dye.   11. The imaging device according to claim 3, wherein the layer having the organic dye has a thickness of 30 nm to 300 nm.   An image pickup device, wherein two or more photoelectric conversion films (photosensitive layers) according to claim 1 are laminated.   The imaging device according to claim 12, wherein the two or more layers are three layers of a blue photoelectric conversion film, a green photoelectric conversion film, and a red photoelectric conversion film.   The organic dye is added to the p-type organic semiconductor or the n-type organic semiconductor, and the p-type organic semiconductor or the n-type organic semiconductor on the incident light side is colorless. The imaging device described in 1.   The interval between the shortest wavelength and the longest wavelength, each of which indicates 50% of the maximum value Amax of the spectral absorption rate of the photoelectric conversion film and the maximum value Smax of the spectral sensitivity, is 100 nm or less. The imaging device according to any one of 14.   The interval between the shortest wavelength and the longest wavelength that shows 80% of the maximum value Amax of the spectral absorption rate and the maximum value Smax of spectral sensitivity of the photoelectric conversion film is 20 nm or more and 80 nm or less. Item 16. The imaging device according to any one of Items 1 to 15.   The interval between the shortest wavelength and the longest wavelength, which indicates 20% of the maximum value Amax of spectral absorption rate and the maximum value Smax of spectral sensitivity of the photoelectric conversion film, is 150 nm or less. The imaging device according to any one of the above.   The longest wavelength exhibiting a spectral absorption rate of 50% of the maximum value Amax of the spectral absorption rate of the photoelectric conversion film and the maximum value Smax of the spectral sensitivity is 460 nm to 510 nm, 560 nm to 610 nm, or 640 nm to 730 nm. The image pickup device according to claim 1, wherein the image pickup device is provided.   The S1max is in the range of 400 nm to 500 nm, or 500 nm to 600 nm, or 600 nm to 700 nm, where S1max is the maximum spectral sensitivity of the photoelectric conversion film. An imaging device according to claim 1.   21. A1max is in the range of 400 nm to 500 nm, or 500 nm to 600 nm, or 600 nm to 700 nm, where A1max is the maximum value of the spectral absorptance of the photoelectric conversion film. The imaging device according to any one of the above. 21. A method of applying an electric field of 10 V / m or more and 1 × 10 ¹² V / m or less to the imaging device according to claim 1 and an applied device.   21. An element comprising at least two electromagnetic wave absorption / photoelectric conversion parts, and at least one of these parts comprising the imaging device according to any one of claims 1 to 20.   23. The device according to claim 22, wherein at least two electromagnetic wave absorption / photoelectric conversion sites have a laminated structure of at least two layers.   24. The device according to claim 23, wherein the upper layer comprises a portion capable of absorbing green light and performing photoelectric conversion.   25. It has at least three electromagnetic wave absorption / photoelectric conversion parts, and at least one of these parts consists of the imaging device according to any one of claims 1 to 20. The described element.   26. The device according to claim 25, wherein the upper layer comprises a portion capable of absorbing green light and performing photoelectric conversion.   27. The device according to claim 25 or 26, wherein at least two electromagnetic wave absorption / photoelectric conversion sites comprise an inorganic layer.   27. The element according to claim 25 or 26, wherein at least two electromagnetic wave absorption / photoelectric conversion sites are formed in a silicon substrate. A method for applying an electric field of 10 V / m or more and 1 × 10 ¹² V / m or less to the imaging device according to any one of claims 22 to 28, and an applied device.