JP2007059483A - Photoelectric conversion element, imaging device and method of applying electric field thereto - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric conversion element (preferably, color image sensor) which is high in photoelectric conversion efficiency and superior in color reproduction with the narrow half-value width of absorption. <P>SOLUTION: The photoelectric conversion element is comprised of a photoelectric conversion film containing an organic semiconductor compound with carrier mobility of 1×10<SP>-4</SP>cm<SP>2</SP>/V×s or higher, or preferably, an imaging device. The method is used to apply electric field to the photoelectric conversion element and to the imaging device. The element is provided to which the electric field is applied. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a photoelectric conversion element, an imaging element, a method for applying an electric field to the photoelectric conversion element and the imaging element, and the applied element.

  The photoelectric conversion film is widely used for, for example, an optical sensor, and is particularly preferably used as a solid-state imaging element (light-receiving element) of an imaging apparatus (solid-state imaging apparatus) such as a television camera. As a material of a photoelectric conversion film used as a solid-state imaging element of an imaging device, an inorganic material film such as a Si film or an a-Se film is mainly used.

  Conventional photoelectric conversion films using these inorganic material films do not have a steep wavelength dependence on the photoelectric conversion film characteristics. For this reason, an image pickup apparatus using a photoelectric conversion film 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 films 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. An image pickup device having a structure in which the structure is arranged is studied, and as a material of the photoelectric conversion film, there are various kinds 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 Unexamined Patent Application Publication No. 2003-158254 discloses a photoelectric conversion film with improved photosensitivity (sensitivity) and a light receiving element using the photoelectric conversion film. 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. The description in the paragraph also describes 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. Or there is no description of using as an n-type organic material.

Further, in order to realize a reduction in size and weight of the imaging apparatus, it is not necessary to provide a spectroscopic prism, and a low-resolution stacked photoelectric conversion film is disclosed in Japanese Patent Application Laid-Open No. 2003-234460 as having a single plate structure with a single light receiving element. It is described in the gazette. In this document, for example, a preferable stacked photoelectric conversion film absorbs light of a wavelength of any one of the three primary colors of light and a light of a wavelength of another color. It is described that a color image having high sensitivity and resolution can be obtained by laminating a photoelectric conversion film having a function of absorbing and a photoelectric conversion film 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 together with the red region are used as the photoelectric conversion film. 6 / Only the photoelectric conversion film having photosensitivity only in the substantially red region centering on 600 to 700 nm is described due to the filter function of the polysilane film.

Japanese Patent Laid-Open No. 2003-332551 describes a multilayer photoconductive film similar to that of Japanese Patent Laid-Open No. 2003-234460. However, the above Patent Documents 1 to 3 do not mention or suggest any use of the organic semiconductor compound having high carrier mobility of the present invention.
JP 2003-158254 A JP 2003-234460 A JP 2003-332551 A

  An object of the present invention is to provide a photoelectric conversion element (preferably an image pickup element, more preferably a color image sensor) that has high photoelectric conversion efficiency and has a narrow half-width of absorption and excellent color reproduction.

The present invention is solved by the following means.
(1) A photoelectric conversion element comprising a photoelectric conversion film comprising an organic semiconductor compound exhibiting a carrier mobility of 1 × 10 ⁻⁴ cm ² / V · s or higher.
(2) The photoelectric conversion element according to (1), wherein the organic semiconductor compound is an n-type organic semiconductor compound.
(3) The photoelectric conversion film includes a p-type semiconductor layer and an n-type semiconductor layer, and at least one of the p-type semiconductor layer and the n-type semiconductor layer is 1 × 10 ⁻⁴ cm ² / The photoelectric conversion element according to (1), comprising an organic semiconductor compound exhibiting carrier mobility of V · s or more.
(4) The photoelectric conversion film has a bulk heterojunction structure layer including the p-type semiconductor and the n-type semiconductor as an intermediate layer between the p-type semiconductor layer and the n-type semiconductor layer (3) The photoelectric conversion element as described.
(5) The photoelectric conversion film has a structure having two or more repeating structures of pn junction layers formed of the p-type semiconductor layer and the n-type semiconductor layer. Photoelectric conversion element.
(6) The photoelectric conversion element according to any one of (3) to (5), wherein both the p-type semiconductor and the n-type semiconductor are organic semiconductors.
(7) The photoelectric conversion element according to any one of (1) to (6), wherein the photoelectric conversion film has a thickness of 30 nm to 300 nm.
(8) The photoelectric conversion element according to any one of (1) to (7), wherein the p-type semiconductor or the n-type semiconductor on the incident light side is colorless.
(9) A photoelectric conversion element comprising the photoelectric conversion film according to any one of (1) to (8) between a pair of electrodes.
(10) A photoelectric conversion element in which two or more photoelectric conversion films are laminated, and at least one photoelectric conversion film is the photoelectric conversion film in the photoelectric conversion element according to any one of (1) to (9). The photoelectric conversion element characterized by the above-mentioned.
(11) The photoelectric conversion film according to (10), wherein three or more layers of the photoelectric conversion film are stacked, and the three layers are a blue photoelectric conversion film, a green photoelectric conversion film, and a red photoelectric conversion film. Conversion element.
(12) When the spectral absorption maximum values are λmax1, λmax2, and λmax3 in the order of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film described in (11), λmax1 is 400 nm or more and 500 nm or less, and λmax2 is (5) The photoelectric conversion element as described in (11), wherein λmax3 is in the range of not less than 600 nm and not more than 700 nm.
(13) When the spectral sensitivity maximum values are Smax1, Smax2, and Smax3 in the order of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film described in (11), Smax1 is 400 nm or more and 500 nm or less, and Smax2 is The photoelectric conversion element as described in (11), which is in a range of 500 nm to 600 nm and Smax3 is in a range of 600 nm to 700 nm.
(14) The interval between the shortest wavelength and the longest wavelength that indicates 50% of the spectral maximum absorption of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to (11) is 120 nm or less, respectively. The photoelectric conversion element as described in (11) characterized by these.
(15) The interval between the shortest wavelength and the longest wavelength that indicates 50% of the spectral maximum sensitivity of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to (11) is 120 nm or less, respectively. The photoelectric conversion element as described in (11) characterized by these.
(16) The interval between the shortest wavelength and the longest wavelength indicating 80% of the spectral maximum absorption of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to (11) is 20 nm or more and 100 nm or less, respectively. The photoelectric conversion element as described in (11), wherein
(17) The interval between the shortest wavelength and the longest wavelength, which indicates 80% of the spectral maximum sensitivity of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to (11), is 20 nm or more and 100 nm or less, respectively. The photoelectric conversion element as described in (11), wherein
(18) The interval between the shortest wavelength and the longest wavelength, which indicates 20% of the spectral maximum absorption of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to (11), is 180 nm or less, respectively. The photoelectric conversion element as described in (11) characterized by these.
(19) The interval between the shortest wavelength and the longest wavelength, which indicates 20% of the spectral maximum sensitivity of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to (11), is 180 nm or less, respectively. The photoelectric conversion element as described in (11) characterized by these.
(20) In the order of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to (11), the longest wavelengths indicating 50% of the spectral maximum absorption are 460 nm to 510 nm, 560 nm to 610 nm, and 640 nm, respectively. The photoelectric conversion element according to (11), which is from 730 nm to 730 nm.
(21) The longest wavelength showing 50% of the spectral maximum sensitivity in the order of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film described in (11) is 460 nm to 510 nm, 560 nm to 610 nm, and 640 nm, respectively. The photoelectric conversion element according to (11), which is from 730 nm to 730 nm.
(22) A photoelectric conversion element having at least two electromagnetic wave absorption / photoelectric conversion sites, wherein at least one of the sites comprises the photoelectric conversion film according to any one of (1) to (9) .
(23) The photoelectric conversion element according to (22), wherein at least two electromagnetic wave absorption / photoelectric conversion sites have a laminated structure of at least two layers.
(24) The photoelectric conversion element as set forth in (23), wherein the upper layer comprises a portion capable of absorbing green light and performing photoelectric conversion.
(25) A photoelectric conversion element having at least three electromagnetic wave absorption / photoelectric conversion sites, wherein at least one of the sites comprises the photoelectric conversion film according to any one of (1) to (9) .
(26) The photoelectric conversion element as described in (25), wherein the upper layer is composed of a portion capable of absorbing green light and performing photoelectric conversion.
(27) The photoelectric conversion element as described in (25) or (26), wherein at least two electromagnetic wave absorption / photoelectric conversion sites comprise an inorganic layer.
(28) The photoelectric conversion element according to (27), wherein at least two electromagnetic wave absorption / photoelectric conversion sites are formed in a silicon substrate.
(29) An imaging device comprising the photoelectric conversion device described in any one of (1) to (28).
(30) An electric field of 10 ⁻² V / cm or more and 1 × 10 ¹⁰ V / cm or less is applied to the photoelectric conversion device described in any one of (1) to (28) or the imaging device described in (29). how to.
(31) The photoelectric conversion element or imaging element applied according to (30).

The photoelectric conversion element of the present invention has a narrow half width of absorption and excellent color reproduction, and further has an effect of high photoelectric conversion efficiency and excellent durability. However, in 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.

In the present invention, an organic semiconductor compound that exhibits a carrier mobility of 1 × 10 ⁻⁴ cm ² / V · s or higher at room temperature (25 ° C.) is used. The present inventors have found that in addition to the high photoelectric conversion efficiency of an image sensor using an organic semiconductor compound having the above characteristics, the half width of absorption is narrow and the color reproducibility is excellent, and the durability is also excellent. It was. Among these performances, it was an effect that the half-width of absorption was particularly narrow and excellent in color reproducibility, and also in durability, which was completely unpredictable. Since unnecessary light absorption that does not contribute to photoelectric conversion in a region near the wavelength has decreased, it is speculated that unintentional heat generation was hindered by the improvement in carrier mobility, but details are unknown.

The mobility of the organic semiconductor compound of the present invention is preferably 1 × 10 ⁻³ cm ² / V · s or more, more preferably 1 × 10 ⁻² cm ² / V · s or more, Particularly preferred is a case of 1 × 10 ⁻¹ cm ² / V · s or more, and most preferred is a case of 1 cm ² / V · s or more. There is no particular upper limit, but if the carrier mobility is too high, a very small amount of current flows even in the absence of light irradiation, which is not preferable, and an organic semiconductor compound having a carrier mobility of 10 cm ² / V · s or less is preferably used. Can do.

The imaging device of the present invention includes a p-type semiconductor layer and an n-type semiconductor layer, and at least one of the p-type semiconductor layer and the n-type semiconductor layer is 1 × 10 ⁻⁴ cm ² / V · s or more. The case where the organic semiconductor compound which shows a mobility is included is preferable. In particular, the case where a compound having a carrier mobility of 1 × 10 ⁻⁴ cm ² / V · s or more is used as the n-type organic semiconductor compound exhibits preferable performance. The carrier of the p-type organic semiconductor compound is a hole, and the carrier of the n-type organic semiconductor compound is an electron. Further, the carrier before charge separation is an exciton, and the present invention includes a case where the exciton has a high mobility.

Further, when the organic semiconductor compound of the present invention is evaluated as a field effect transistor, the on / off current ratio is preferably 1 × 10 ² or more, more preferably 1 × 10 ⁴ or more, and particularly preferably 1 × 10 6. This is the case of ⁶ or more. Although there is no upper limit in particular, a thing below 1x10 < ⁸ > can be used preferably.

  The carrier mobility (hole or electron) was evaluated using a time-of-flight (TOF) measurement or a field effect transistor element. For the evaluation of the on / off current ratio, a field effect transistor element was used. For these evaluations, see literature, Lowry et al. , Mechanism and Theory in Organic Chemistry, Harper & Row Publishers, 553 (1976), Garnier et al. , Synthetic Metals, 45, (1991) 163-171, and Dodabalapur et al. Science, 269, 1560 (1995) and the like.

The carrier mobility of an organic semiconductor compound is a characteristic determined by the chemical structure and molecular arrangement of the organic compound. When the organic compound has π electrons and the overlap between these π electrons is large, the carrier mobility becomes high.
In the present invention, an organic semiconductor compound having high carrier mobility by controlling the chemical structure and / or molecular arrangement is used. The method shown in [Orientation control of organic layer] described later can be preferably used. The compound having the carrier mobility of the present invention is present in, for example, diketopyrrolopyrrole dyes described later, and the carrier mobility can be measured by the above method.

[Organic layer]
The organic layer (organic film) in the present invention 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 ligands such as saziazole, 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 organic dye may be used for the organic layer, but it is preferable to use a p-type organic dye or an n-type organic dye. Any organic dye may be used, but preferably a cyanine dye, styryl dye, hemicyanine dye, merocyanine dye (including zero methine merocyanine (simple merocyanine)), trinuclear merocyanine dye, tetranuclear merocyanine dye, Rhodocyanine 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, triphenylmethane dye, azo dye, azomethine dye , Spiro compounds, metallocene dyes, fluorenone dyes, fulgide dyes, perylene dyes, phenazine dyes, phenothiazine dyes, quinone dyes, indigo dyes, diphenyl meta 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 dye, condensation Aromatic carbocyclic dyes (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), and dioxazine dyes.

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”, Springer-Verlag H. Examples include the ligands described in Yersin's 1987 issue, “Organometallic Chemistry-Fundamentals and Applications”, Akio Yamamoto's 1982 issue.
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.), aromatic heterocyclic oxy ligands (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms). , For example, pyridyloxy, pyrazyloxy, pyrimidyloxy, quinolyloxy, etc.), an alkylthio ligand (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, For example, methylthio, ethylthio, etc.), arylthio ligand (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, an aromatic heterocyclic oxy group, or a siloxy ligand, Preferably, a nitrogen-containing heterocyclic ligand, an aryloxy ligand, or a siloxy ligand is used.

Especially as an organic pigment | dye used for this invention, a quinacridone pigment | dye and a diketopyrrolopyrrole pigment | dye can be used preferably.
In particular, a quinacridone dye (preferably a quinacridone derivative represented by the general formula (I) described in Japanese Patent Application No. 2005-65395) is a p-type diketopyrrolopyrrole dye (preferably a general formula described in Japanese Patent Application No. 2005-162613 ( It is preferable to use the compound represented by I) as the n-type.

  The film formed by the 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.

  The compounding ratio of the p-type organic semiconductor and the n-type organic semiconductor in the intermediate layer (bulk heterojunction structure layer) of the photoelectric conversion film is within a range of 0.1: 99.9 to 99.9 to 0.1 by mass ratio. It can be set appropriately.

[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). I found it 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 is 2 or more (preferably 2 to 8). ) Represents an integer, and 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.

(Organic layer orientation control)
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, Preferably it is 5000 kJ / mol or less, More preferably, it is 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 in which the orientation of both the heterojunction plane and the π-electron plane of the organic compound is controlled, it is particularly possible to improve the photoelectric conversion efficiency, and particularly preferably used when a bulk heterostructure is taken. Can do.

(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.

[Molecular weight of organic dyes]
The organic dye used in the present invention may have any molecular weight, but is preferably 250 or more and 1200 or less, more preferably 280 or more and 1000 or less, and particularly preferably 280 or more and 500 or less. When the molecular weight of the organic dye compound of the present invention is within these ranges, in addition to the advantage that the photoelectric conversion film can be easily formed by vacuum vapor deposition, the photoelectric conversion efficiency of the obtained photoelectric conversion film is high and excellent. Furthermore, the variation in the light absorptance between the pixels of the image sensor and the photoelectric conversion efficiency is reduced.

[Providing hydrophobicity]
The hydrophilicity / hydrophobicity of the organic dye used in the present invention may be any, but preferably ClogP is preferably 2 or more and 10 or less, more preferably 3 or more and 8 or less, and particularly preferably 4 or more and 6 or less. When the hydrophilicity / hydrophobicity of the organic dye compound of the present invention is in these ranges, in addition to the advantage that the photoelectric conversion film can be easily formed by vacuum deposition or the like, the resulting photoelectric conversion film has high photoelectric conversion efficiency and is excellent. Furthermore, the variation in the light absorption rate between the pixels of the image sensor and the photoelectric conversion efficiency is reduced. Moreover, when the hydrophilicity / hydrophobicity of the organic dye compound of the present invention is within these ranges, durability of the resulting film, particularly durability under high humidity conditions is improved.

ClogP is used as a measure of the hydrophilicity / hydrophobicity of a compound. Usually, hydrophilicity / hydrophobicity can be determined by the octanol / water partition coefficient (logP) of a compound. Specifically, it can be obtained by actual measurement by the flask-shaking method described in the following document (1).
Reference (1): Structure-activity relationship social gathering (representative) Ikuo Fujita, edited by Chemistry Special Issue 122 “Structure-activity relationship of drugs-Guidelines for drug design and mechanism of action research”, Nanedo, 1979, Chapter 2 Pages 43-203. In particular, Flask Shaking is described on pages 86-89.

Since the measurement may be difficult when logP is 3 or more, a model for calculating logP can be used in the present invention. In the present invention, logP (hereinafter referred to as ClogP) based on this calculated value is used. Can be defined using.
For the purpose of the present invention, the logP calculation value is calculated using Hansch-Leo CLOGP program (Daylight Chemical Information Systems, USA) (version is algorithm = 4.01, fragment database = 17 (* 3)). If this software is not available, Applicants will provide their ClogP values for all specific compounds.
If multiple tautomers can be taken in the organic dye compound of the present invention, ClogP can be calculated for each of these isomers, and if at least one of these values is within a certain range, Compounds are within the preferred scope of the present invention. Further, when there is no molecular fragment in the database of the above program, ClogP can be obtained by supplementing the data by actual measurement of the hydrophilicity / hydrophobicity. The organic dye compound of the present invention calculates ClogP based on the state at pH = 7.

〔potential〕
The potential of the organic dye used in the present invention may be any, but the oxidation potential is preferably 0.3 V to 1.8 V (vs SCE), more preferably 0.5 V to 1.5 V, particularly Preferably they are 0.8V or more and 1.3V or less. The reduction potential is preferably −2 V or more and −0.5 V or less (vs SCE), more preferably −1.6 V or more and −0.8 V or less, and particularly preferably −1.4 V or more and −1 V or less.
When the potential of the organic dye compound of the present invention is within these ranges, the durability of the photoelectric conversion film is improved in addition to the advantage that the photoelectric conversion efficiency of the obtained photoelectric conversion film is increased.

  Various methods can be used to measure the reduction potential and the oxidation potential. Preferably, the reduction potential and the oxidation potential are measured by phase discrimination type second harmonic AC polarography, and an accurate value can be obtained. The method of measuring the potential by the above-described phase discrimination type second harmonic alternating current polarography is described in Journal of Imaging Science, Volume 30, Page 27 (1986). Yes.

〔fluorescence〕
The organic dye used in the present invention may have any fluorescence quantum yield and fluorescence lifetime, but the fluorescence quantum yield is preferably 0.1 or more and 1 or less, more preferably 0.5 or more and 1 or less. Preferably it is 0.8 or more and 1 or less. The fluorescence lifetime is preferably 10 ps or more, more preferably 40 ps or more, and particularly preferably 160 ps or more. There is no particular upper limit, but it is preferably 1 ms or less.
When the fluorescence quantum yield and the fluorescence lifetime of the organic dye compound of the present invention are within these ranges, in addition to the advantage that the photoelectric conversion efficiency of the obtained photoelectric conversion film is increased, the durability of the photoelectric conversion film is improved.

  The fluorescence quantum yield can be measured by the method described in JP-A-63-138341. The method is described below. The fluorescence quantum yield in the dye film can be measured by basically the same method as in the case of the luminescence quantum yield of the solution. Usually, standard samples having known absolute quantum yields (for example, rhodamine B, quinine sulfate, 9 10-diphenylanthracene) and the like, and can be obtained through relative measurement comparing the incident light intensity and the light emission intensity of the sample under a fixed optical arrangement. Regarding this relative measurement method, for example, C.I. A. Parker and W.W. T. T. et al. Rees, Analyst, 1960, 85, 587. The fluorescence quantum yield in the present invention may be a value in a solution state or a film state, but is preferably a value in a film state.

  The fluorescence lifetime of the organic dye compound of the present invention can be measured by the method of Tadaaki Tani, Takeshi Suzuki, Klaus Chemnitz, Keitaro Yoshihara, The Journal of Physical Chemistry, 1992, Vol. 96, 78.

[Absorption wavelength regulation]
We have further found that the organic dye compounds of the present invention have a preferred spectral absorption wavelength and spectral sensitivity range.
In the present invention, a BGR photoelectric conversion film with good color reproduction, that is, a photoelectric conversion element (preferably an image pickup element) in which three layers of a blue photoelectric conversion film, a green photoelectric conversion film, and a red photoelectric conversion film are stacked can be preferably used. . Each photoelectric conversion film preferably has the following spectral absorption and / or spectral sensitivity characteristics.
When the spectral absorption maximum values are λmax1, λmax2, and λmax3 in the order of BGR, and the spectral sensitivity maximum values are Smax1, Smax2, and Smax3 in the order of BGR, λmax1 and Smax1 are preferably 400 nm or more and 500 nm or less, more preferably 420 nm or more. It is a case where it exists in the range of 430 nm or more and 470 nm or less especially preferably. λmax2 and Smax2 are preferably 500 nm to 600 nm, more preferably 520 nm to 580 nm, and particularly preferably 530 nm to 570 nm. λmax3 and Smax3 are preferably 600 nm to 700 nm, more preferably 620 nm to 680 nm, and particularly preferably 630 nm to 670 nm.

In addition, when the photoelectric conversion film of the present invention has a laminated structure of three or more layers, the shortest wavelength and the longest wavelength that each show 50% of the spectral maximum absorption of λmax1, λmax2, λmax3 and the spectral maximum sensitivity of Smax1, Smax2, Smax3. The wavelength interval is preferably 120 nm or less, more preferably 100 nm or less, particularly preferably 80 nm or less, and most preferably 70 nm or less.
In addition, the interval between the shortest wavelength and the longest wavelength that shows 80% of the spectral maximum absorption of λmax1, λmax2, and λmax3 and the spectral maximum sensitivity of Smax1, Smax2, and Smax3 is preferably 20 nm or more, preferably 100 nm or less, and more preferably Is 80 nm or less, particularly preferably 50 nm or less.
Further, the interval between the shortest wavelength and the longest wavelength, which shows 20% of the spectral maximum absorption of λmax1, λmax2, λmax3 and the spectral maximum sensitivity of Smax1, Smax2, Smax3, is preferably 180 nm or less, more preferably 150 nm or less, and particularly preferably Is 120 nm or less, most preferably 100 nm or less.
Further, on the long wave side of λmax1, λmax2, λmax3 and Smax1, Smax2, Smax3, the longest wavelength that shows the spectral maximum absorption of λmax1, λmax2, λmax3 and the spectral absorption of 50% of the spectral maximum of Smax1, Smax2, Smax3 is λmax1 and Smax1 are preferably 460 to 510 nm, λmax2 and Smax2 are preferably 560 to 610 nm, and λmax3 and Smax3 are preferably 640 to 730 nm.
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.

[Organic dye layer thickness regulation]
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, the thickness of the organic dye layer is preferably as large as possible in terms of light absorption, but considering the ratio contributing to charge separation, the film thickness of the organic dye layer in the present invention is preferably 30 nm to 300 nm, more preferably 50 nm. The thickness is from 250 nm to 250 nm, particularly preferably from 60 nm to 200 nm, and most preferably from 80 nm to 130 nm.

[Voltage application]
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. Preferably electric field to be applied to the photoelectric conversion film includes at ^10- 2 V / cm or more, more preferably 10V / cm or more, more preferably 1 × ¹⁰ 3 V / cm or more, particularly preferably 1 × ¹⁰ 4 V / cm As described above, it is most preferably 1 × 10 ⁵ V / cm or more. There is no particular upper limit, but if an electric field is applied too much, an electric current flows even in a dark place, which is not preferable. Therefore, it is preferably 1 × 10 ¹⁰ V / cm or less, more preferably 1 × 10 ⁷ V / cm or less.

[General requirements]
In the present invention, it is preferable to use a structure in which at least two photoelectric conversion films are laminated, 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.

[Bulk heterojunction structure]
In the present invention, a p-type semiconductor layer and an n-type semiconductor layer are provided between a pair of electrodes, and at least one of the p-type semiconductor and the n-type semiconductor is an organic semiconductor, and these semiconductor layers It is preferable to contain a photoelectric conversion film (photosensitive layer) having a bulk heterojunction structure layer containing the p-type semiconductor and the n-type semiconductor as an intermediate layer. In such a case, in the photoelectric conversion film, by incorporating a bulk heterojunction structure in the organic layer, the disadvantage that the carrier diffusion length of the organic layer is short can be compensated, and the photoelectric conversion efficiency can be improved.
The bulk heterojunction structure is described in detail in Japanese Patent Application No. 2004-080639.

[Tandem structure]
In the present invention, a photoelectric conversion film (photosensitive layer) having 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 ) Is preferable. Further, a thin layer of a conductive material may be inserted between the repetitive structures. Silver or gold is preferable as the conductive material, and silver is most preferable. The number of repeating structures (tandem structures) of the pn junction layer may be any number, but is preferably 2 or more and 100 or less, more preferably 2 or more and 50 or less, and particularly preferably 5 in order to increase the photoelectric conversion efficiency. It is 40 or less and most preferably 10 or more and 30 or less.
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.
The tandem structure is described in detail in Japanese Patent Application No. 2004-079930.

[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 this embodiment. 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 portion of the MOS transistor, and charges are stored in the charge storage portion. 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.
A photoelectric conversion element (preferably an image pickup element) of the present invention comprises an electromagnetic wave absorption / photoelectric conversion part and a charge accumulation / transfer / readout part of a charge 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 is composed of 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 a case where at least two electromagnetic wave absorption / photoelectric conversion sites are included, and at least one of these sites is the photoelectric conversion element (preferably an image sensor) 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 photoelectric conversion element (preferably an image sensor) 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 (indium zinc oxide) are preferable in terms of productivity, high conductivity, transparency, and the like. Although the film thickness can be appropriately selected depending on the material, it is usually preferably in the range of 10 nm to 1 μm, more preferably 30 nm to 500 nm, and still more preferably 50 nm to 300 nm.

Various methods are used for 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, And so on. Also, supervised by Yutaka Sawada “New Development of Transparent Conductive Film” (published by CMC, 1999), supervised by Yutaka Sawada “New Development of Transparent Conductive Film II” (published by CMC, 2002), “Transparency by Japan Society for the Promotion of Science” Those described in detail in “Technology of Conductive Film” (Ohm Co., 1999) may be used.
Particularly preferred as the material 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, In _x Ga ₁ - a composition of 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 efficiency 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 preferred 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 parts, it is necessary to install each contact part between the charge transfer / readout part. 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 operation of arrangement (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 to 10 microns, but 3 to 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 (preferably imaging 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 layers 11 and 12 are provided with plugs for sending the signal charges 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 total thickness of the organic layer composed of 7, 8, 9, 10 is preferably 0.5 μm or less, more preferably 0.4 μm or less, and particularly preferably 0.3 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 a resist pattern, 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 with reference to FIG. 2 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.

  The cleaned ITO substrate was put into a vapor deposition apparatus, and the following (S-1) was vapor-deposited by 25 nm. On top of that, a compound (S-3) satisfying the conditions of the present invention was deposited to a thickness of 25 nm to prepare an organic pn stacked photoelectric conversion layer. Next, a patterned mask (a mask with a light receiving area of 2 mm × 2 mm) is placed on the organic thin film, 100 nm of aluminum is deposited in a deposition apparatus, a desiccant is subsequently added, the element is sealed, and a photoelectric conversion element ( Element No. 101) was produced. A comparative photoelectric conversion element (element No. 102) in which the compound (S-3) satisfying the conditions of the present invention was replaced with (S-2) was produced.

Next, each element was evaluated as follows.
Element No. For 101, the case where the ITO side was minus and the aluminum electrode side was plus and a bias of 5 V was applied and the case where no bias was applied were evaluated. Element No. For 102, the case where no bias was applied was evaluated.
The wavelength dependence of the external quantum yield was evaluated using an Optel solar cell evaluation apparatus. Simulation was performed using the obtained photoelectric conversion spectrum to evaluate the spectral characteristics when the element for G was used, and the level of color reproducibility (spectral characteristics) was represented by ○ and ×. These results are shown in Table 1.
In this example, the element No. 101 is a comparative element No. 101. On the other hand, when there was no bias, the external quantum yield was high. In addition, element No. 101 showed a higher external quantum yield with bias compared to no bias. Furthermore, element No. 101 is a comparative element No. 101. Compared to 102, the spectral characteristics in the green region were excellent.
The carrier mobility of (S-2) was 1 × 10 ⁻⁵ cm ² / v · s, and the carrier mobility of (S-3) was 1 × 10 ⁻³ cm ² / v · s.

  The cleaned ITO substrate is put into a vapor deposition apparatus, the compound (S-3) satisfying the conditions of the present invention is deposited by 40 nm, the following (S-4) is vapor deposited by 40 nm, and an organic pn stacked photoelectric conversion layer is formed. Created. Next, a patterned mask (a mask with a light receiving area of 2 mm × 2 mm) is placed on the organic thin film, 100 nm of aluminum is deposited in a deposition apparatus, a desiccant is subsequently added, the element is sealed, and a photoelectric conversion element ( Element No. 103) was produced.

Next, each element was evaluated as follows.
This element was evaluated when a bias of 5 V was applied with the ITO side being positive and the aluminum electrode side being negative.
The wavelength dependence of the external quantum yield was evaluated using an Optel solar cell evaluation apparatus. A simulation was performed using the obtained photoelectric conversion spectrum to evaluate the spectral characteristics when the element for G was used, and the level of color reproducibility (spectral characteristics) was evaluated. .

By using the element of the present invention of Example 1 or 2 for the G film shown in FIG. 1, a color imaging element exhibiting excellent color separation can be produced.
When the photoelectric conversion site that absorbs the G light of Example 1 or 2 is used for the portions 8 and 9 of the photoelectric conversion site in FIG. 2, a color imaging device that exhibits excellent color separation can be manufactured.

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 of the preferable photoelectric conversion element by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antireflection film 2 Infrared cut dielectric multilayer film 3, 4, 5 Protective film 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 Base 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 layers 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 150 Semiconductor Substrate

Claims (30)

A photoelectric conversion element comprising a photoelectric conversion film comprising an organic semiconductor compound exhibiting a carrier mobility of 1 × 10 ⁻⁴ cm ² / V · s or higher.   The photoelectric conversion element according to claim 1, wherein the organic semiconductor compound is an n-type organic semiconductor compound. The 1 × 10 ⁻⁴ cm ² / V · s according to claim 1, wherein the photoelectric conversion film includes a p-type semiconductor layer and an n-type semiconductor layer, and at least one of the p-type semiconductor layer and the n-type semiconductor layer. The photoelectric conversion element according to claim 1, comprising an organic semiconductor compound exhibiting the above carrier mobility.   The photoelectric conversion film according to claim 3, wherein the photoelectric conversion film has a bulk heterojunction structure layer including the p-type semiconductor and the n-type semiconductor as an intermediate layer between the p-type semiconductor layer and the n-type semiconductor layer. Conversion element.   The photoelectric conversion element according to claim 3, wherein the photoelectric conversion film has a structure having two or more repeating structures of pn junction layers formed of the p-type semiconductor layer and the n-type semiconductor layer. .   6. The photoelectric conversion element according to claim 3, wherein both the p-type semiconductor and the n-type semiconductor are organic semiconductors.   The photoelectric conversion element according to claim 1, wherein the photoelectric conversion film has a thickness of 30 nm to 300 nm.   The photoelectric conversion element according to claim 1, wherein the p-type semiconductor or the n-type semiconductor on the incident light side is colorless.   A photoelectric conversion element comprising the photoelectric conversion film according to claim 1 between a pair of electrodes.   A photoelectric conversion element in which two or more photoelectric conversion films are stacked, wherein at least one photoelectric conversion film is the photoelectric conversion film according to any one of claims 1 to 9.   The photoelectric conversion element according to claim 10, wherein three or more layers of the photoelectric conversion film are stacked, and the three layers are a blue photoelectric conversion film, a green photoelectric conversion film, and a red photoelectric conversion film.   When the spectral absorption maximum values are λmax1, λmax2, and λmax3 in the order of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to claim 11, λmax1 is 400 nm to 500 nm and λmax2 is 500 nm to 600 nm. The photoelectric conversion element according to claim 11, wherein λmax3 is in the range of 600 nm to 700 nm.   When the spectral sensitivity maximum values are Smax1, Smax2, and Smax3 in the order of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to claim 11, Smax1 is 400 nm to 500 nm and Smax2 is 500 nm to 600 nm. The photoelectric conversion element according to claim 11, wherein Smax3 is in the range of 600 nm to 700 nm.   The distance between the shortest wavelength and the longest wavelength, which indicates 50% of the spectral maximum absorption of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to claim 11, is 120 nm or less, respectively. The photoelectric conversion element according to claim 11.   The distance between the shortest wavelength and the longest wavelength, which indicates 50% of the spectral maximum sensitivity of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to claim 11, is 120 nm or less, respectively. The photoelectric conversion element according to claim 11.   The distance between the shortest wavelength and the longest wavelength, which represents 80% of the spectral maximum absorption of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to claim 11, is 20 nm or more and 100 nm or less, respectively. The photoelectric conversion element according to claim 11.   The distance between the shortest wavelength and the longest wavelength, which indicates 80% of the spectral maximum sensitivity of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to claim 11, is 20 nm or more and 100 nm or less, respectively. The photoelectric conversion element according to claim 11.   The distance between the shortest wavelength and the longest wavelength, which represents 20% of the spectral maximum absorption of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to claim 11, is 180 nm or less, respectively. The photoelectric conversion element according to claim 11.   The distance between the shortest wavelength and the longest wavelength, which indicates 20% of the spectral maximum sensitivity of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to claim 11, is 180 nm or less, respectively. The photoelectric conversion element according to claim 11.   The longest wavelengths showing 50% of the spectral maximum absorption in the order of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to claim 11 are 460 nm to 510 nm, 560 nm to 610 nm, and 640 nm to 730 nm, respectively. The photoelectric conversion element according to claim 11, wherein the photoelectric conversion element is provided.   The longest wavelengths showing 50% of the spectral maximum sensitivity in the order of the blue photoelectric conversion film, the green photoelectric conversion film, and the red photoelectric conversion film according to claim 11 are 460 nm to 510 nm, 560 nm to 610 nm, and 640 nm to 730 nm, respectively. The photoelectric conversion element according to claim 11, wherein the photoelectric conversion element is provided.   A photoelectric conversion element comprising at least two electromagnetic wave absorption / photoelectric conversion sites, at least one of which comprises the photoelectric conversion film according to claim 1.   The photoelectric conversion element 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 photoelectric conversion element according to claim 23, wherein the upper layer comprises a portion capable of absorbing green light and performing photoelectric conversion.   A photoelectric conversion element comprising at least three electromagnetic wave absorption / photoelectric conversion sites, at least one of which comprises the photoelectric conversion film according to claim 1.   26. The photoelectric conversion element according to claim 25, wherein the upper layer comprises a portion capable of absorbing green light and performing photoelectric conversion.   27. The photoelectric conversion element according to claim 25 or 26, wherein at least two electromagnetic wave absorption / photoelectric conversion sites comprise an inorganic layer.   28. The photoelectric conversion element according to claim 27, wherein at least two electromagnetic wave absorption / photoelectric conversion sites are formed in a silicon substrate. An image pickup device comprising the photoelectric conversion device according to claim 1. A method for applying an electric field of 10 ⁻² V / cm or more and 1 × 10 ¹⁰ V / cm or less to the photoelectric conversion device according to claim 1 or the imaging device according to claim 29.

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