JP2005340489A - Photoelectric conversion element, imaging device and photoelectric conversion method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric conversion element with high quantum efficiency using organic color elements. <P>SOLUTION: This photoelectric conversion element is provided with at least one type of semiconductor, at least one type of organic pigment having a pigment coloring group and at least one electrode, wherein the multi-layered pigment coloring group is sucked to the semiconductor surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photoelectric conversion element, an imaging element in which a plurality of photoelectric conversion elements are stacked, and a photoelectric conversion method applied to the photoelectric conversion element.

Patent Documents 1 to 3 describe a light receiving element using a semiconductor sensitized with a dye and a photosensor including the light receiving element. However, these documents do not describe semiconductor sensitization in which a dye is multilayer-adsorbed during dye sensitization. Patent Document 4 describes a semiconductor-sensitized photoelectric conversion element using a multilayer adsorbing dye, but the photoelectric conversion element of this document only discloses use in a photochemical cell that converts solar energy into electricity. . When used in a photochemical battery, the dye to be mixed is selected so as to make the wavelength range of photoelectric conversion as wide as possible. Therefore, sensitization of narrow sensitized wavelength regions such as the blue region, green region, and red region of the image sensor is not possible. Usually it is not in mind at all.
On the other hand, Patent Documents 5 to 8 describe the structure of an image sensor with high light utilization efficiency, but these documents do not describe any light receiving element sensitized with a multilayer adsorbent dye.

A photoelectric conversion element using an organic dye is excellent in spectral characteristics due to the degree of freedom in controlling the absorption wavelength of the organic dye, and can be used as a light receiving element of an image pickup element. However, the photoelectric conversion element has a lower quantum efficiency than a photoelectric conversion element using single crystal Si used in a conventional imaging element. For example, although a well-known titanium oxide / metal complex dye as a photoreceptor is a Gretzel solar cell, although it is a relatively high-efficiency device, it has disadvantages such as low efficiency compared to a single crystal Si solar cell (non-patent) Reference 1 and 2). Therefore, development of an improved technique has been desired for practical use of an image sensor using an organic dye.
JP 2002-176191 A JP 2002-299678 A JP 2002-310793 A JP-A-11-167937 JP 58-103165 A JP 58-103166 A JP 2003-234460 A Japanese Patent Laid-Open No. 2003-158254 R. Knadler et al; Solar energy materials and solar cells, vol.30, p277 (1993) H. Hagfeldt et al; Chem. Rev. vol95, p49 (1995)

  An object of the present invention is to provide a photoelectric conversion element having high quantum efficiency using an organic dye. It is another object of the present invention to provide an imaging device using such a highly efficient thin photoelectric conversion device. Furthermore, it is to provide a highly efficient photoelectric conversion method by applying a voltage to the photoelectric conversion element.

In the dye sensitization of semiconductors, it is a feature of the present invention that the dye chromophore is adsorbed in multiple layers for spectral sensitization. The above problems have been solved by the following means.
(1) A photoelectric conversion element having at least one semiconductor, at least one organic dye having a dye chromophore, and at least one electrode, wherein the dye chromophore is adsorbed in multiple layers on the semiconductor surface. A characteristic photoelectric conversion element.
(2) The photoelectric conversion element according to (1), further comprising a transparent conductive film in contact with the semiconductor.
(3) An imaging device having the photoelectric conversion device of (1) or (2).
(4) The imaging device according to (3), including at least two types of photoelectric conversion elements that absorb light of different wavelengths.
(5) The imaging device according to (3), wherein at least three types of photoelectric conversion elements that absorb blue, green, and red light are stacked.
(6) A photoelectric conversion method in which a positive voltage is applied to the semiconductor of the photoelectric conversion element according to (1) with respect to the one electrode.

  According to the present invention, by using a semiconductor that is spectrally sensitized by multilayer adsorption of a dye chromophore, a light absorption amount per unit surface area of the semiconductor is improved, and a photoelectric conversion element with high quantum efficiency is obtained. The thickness of the conversion element can be greatly reduced, and an excellent image sensor can be obtained.

  The photoelectric conversion element of the present invention comprises at least one electrode, at least one organic dye, and at least one semiconductor, and the organic dye is disposed in contact with the semiconductor. The present invention is characterized in that the chromophore of the dye is adsorbed on the semiconductor in a multilayer state of two or more layers. As a result, the amount of light absorption per unit surface area of the semiconductor can be improved, and the thickness of the photoelectric conversion element can be greatly reduced (for example, about one half of that during normal dye sensitization).

The semiconductor applied to the present invention is a semiconductor according to a general semiconductor definition, and is usually a material having a conductivity in the range of 10 ³ to 10 ⁻¹⁰ S / cm at room temperature. In the present invention, the semiconductor is preferably a semiconductor that can inject electrons from the LUMO (excited molecular orbital) of the adsorbed dye. As a preferable semiconductor material, a compound semiconductor represented by metal chalcogenide or a compound having a perovskite structure can be used in addition to a single semiconductor such as silicon or germanium. Preferred metal chalcogenides are titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium or tantalum oxide, cadmium, zinc, lead, silver, antimony Bismuth sulfide, cadmium, lead selenide, cadmium telluride and the like. Examples of other compound semiconductors include phosphides such as zinc, gallium, indium, and cadmium, gallium arsenide, copper-indium selenide, copper-indium-sulfide, and the like. Examples of the compound having a perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate. Of course, it is not limited to these. Particularly preferable materials for the present invention include TiO ₂ , ZnO, SnO ₂ , ITO (indium-tin oxide), ATO (antimony-tin oxide), IZO (indium-zinc oxide), FTO (fluorine-added tin oxide). ), SrTiO ₃ , BaTiO ₂ , Ge, Si, III-V group elements or semiconductors thereof.

  In the present invention, the dye chromophore may exist as a partial structure of the dye compound, or the dye compound may be formed only from the dye chromophore. In the latter case, the dye chromophore represents a dye compound. A dye compound containing a dye chromophore can be used as a sensitizing dye.

The dye chromophore in the present invention will be described in the following chromophore [1].
Chromophore [1]
The chromophore mentioned here means an atomic group which mainly causes the absorption band of the molecule described in the physics and chemistry dictionary (5th edition, Iwanami Shoten, 1998), page 1052, for example, C = C Any atomic group is possible, such as an atomic group having an unsaturated bond such as N = N.
Specific examples of the dye chromophore include, for example, cyanine dyes, styryl dyes, hemicyanine dyes, merocyanine dyes (including zero methine merocyanine (simple merocyanine)), trinuclear merocyanine dyes, tetranuclear merocyanine dyes, rhodacyanine dyes, and complex cyanine dyes. , 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 compound, metallocene dye , Fluorenone dye, fulgide dye, perylene dye, phenazine dye, phenothiazine dye, quinone dye, indigo dye, diphenylmethane dye, polyene dye, Lysine dyes, acridinone dyes, diphenylamine dyes, quinacridone dyes, quinophthalone dyes, phenoxazine dyes, phthaloperylene dyes, porphyrin dyes, chlorophyll dyes, phthalocyanine dyes and metal complex dyes. Preferably, cyanine dye, styryl dye, hemicyanine dye, merocyanine dye, trinuclear merocyanine dye, tetranuclear merocyanine dye, rhodacyanine dye, complex cyanine dye, complex merocyanine dye, allopolar dye, oxonol dye, hemioxonol dye, squalium dye, Examples include methine dye chromophores such as croconium dyes and azamethine dyes. More preferred are cyanine dyes, merocyanine dyes, trinuclear merocyanine dyes, quadruple merocyanine dyes, rhodacyanine dyes, and oxonol dyes, more preferred are cyanine dyes, merocyanine dyes, rhodacyanine dyes, and oxonol dyes, and particularly preferred are cyanine dyes, Merocyanine dyes, most preferably cyanine dyes.
Details of these dyes are described in the following dye literature [2].

Dye literature [2]
“FM Hemer”, “Heterocyclic Compounds-Cyanine Dies and Related Compounds”, John Willy and h & h. Sons, Inc.-New York, London, 1964, by D.M. Sturmer, "Heterocyclic Compounds in Heterocyclic Compounds-Special Topics in Heterocyclics" chemistry ", Chapter 18, Section 14, 482-51. Page, John Wiley & Sons (John Wiley & Sons), Inc. - New York, London, published in 1977, "Rods Chemistry of Carbon Konpaunzu (Rodd's Chemistry of Carbon Compounds)" 2nd. Ed. vol. IV, part B, 1977, Chapter 15, pages 369 to 422, published by Elsevier Science Publishing Company, New York, and the like.
Further description is made from Research Disclosure (RD) 17643, pages 23 to 24, RD18716, page 648, right column to page 649, right column, RD308119, page 996, right column to page 998, right column, European Patent No. 0565096A1. Those described on page 65, lines 7 to 10 can be preferably used. Also, U.S. Pat. No. 5,747,236 (especially pages 30-39), U.S. Pat. No. 5,994,051 (especially pages 32-43), U.S. Pat. No. 5,340,694 (especially 21 to 58, provided that the number of n ₁₂ , n ₁₅ , n ₁₇ , n ₁₈ is not limited in the dyes shown in (XI), (XII), (XIII), and is an integer of 0 or more (preferably 4 or less), and a dye having a partial structure or structure shown in the general formula and specific examples can also be preferably used.

  Furthermore, JP-A-10-239789, JP-A-11-133531, JP-A-2000-267216, JP-A-2000-275772, JP-A-2001-75222, JP-A-2001-75247, JP-A-2001-75221. JP-A-2001-75226, JP-A-2001-75223, JP-A-2001-255615, JP-A-2002-23294, JP-A-10-171058, JP-A-10-186559, JP-A-10-197980, JP-A-2000-81678, JP-A-2001-5132, JP-A-2001-166413, JP-A-2002-49113, JP-A-64-91134, JP-A-10-110107, JP-A-10-171058, JP-A-10-226758, JP-A-10-307358, JP-A-10 307359, JP-A-10-310715, JP-A-2000-231174, JP-A-2000-231172, JP-A-2000-231173, JP-A-2001-356442, European Patent Application Publication No. 0985965A, European Patent Application Publication No. 0985964A, European Patent Application Publication No. 0985966A, European Patent Application Publication No. 0985967A, European Patent Application Publication No. 1085372A, European Patent Application Publication No. 1085373A, European Patent Application Publication No. 1172688A, European Patent Application Publication No. 1199595A. , European Patent Application Publication No. 887700A1, Japanese Patent Application Laid-Open No. 10-239789, Japanese Patent Application Laid-Open No. 2001-75222, Japanese Patent Application Laid-Open No. 10-171058, and the partial structures or structures shown in the general formulas and specific examples Dyes with good It can be used well.

  Next, explanation will be given on multilayer adsorption in the present invention. In the present invention, multilayer adsorption means that more dye chromophores are adsorbed (stacked in another way) on the semiconductor surface.

  Specifically, for example, by using intermolecular force, the dye is adsorbed to the semiconductor surface more than the saturated coating amount, or a compound composed of a plurality of dye chromophores (so-called multichromophore dye compounds or linked dyes). ) (Preferably, a plurality of dye chromophores are not conjugated in the compound) is adsorbed on the semiconductor surface.

Specifically, the method described in the multilayer adsorption-related patent [3] shown below can be preferably used for the semiconductor of the present invention.
Patent for multilayer adsorption [3]
JP-A-10-239789, JP-A-11-133531, JP-A-2000-267216, JP-A-2000-275772, JP-A-2001-75222, JP-A-2001-75247, JP-A-2001-75221, JP 2001-75226, JP 2001-75223, JP 2001-255615, JP 2002-23294, JP 10-171058, JP 10-186559, JP 10-197980, JP JP 2000-81678, JP 2001-5132, JP 2001-166413, JP 2002-49113, JP 64-91134, JP 10-110107, JP 10-171058, JP 10-226758, JP-A-10-307358, JP-A-10-307 59, JP-A-10-310715, JP-A-2000-231174, JP-A-2000-231172, JP-A-2000-231173, JP-A-2001-356442, European Patent Application Publication No. 0985965A, European Patent Application Publication No. 0985964A, European Patent Application Publication No. 0985966A, European Patent Application Publication No. 0985967A, European Patent Application Publication No. 1085372A, European Patent Application Publication No. 1085373A, European Patent Application Publication No. 1172688A, European Patent Application Publication No. 1199595A. No., European Patent Application Publication No. 887700 A1.

  In the present invention, the fact that the dye chromophore is multilayer adsorbed on the semiconductor surface means a state in which more dye chromophore is adsorbed on the semiconductor surface, and among the dyes used, the area occupied by the dye on the semiconductor surface is the most. The saturated adsorption amount per unit surface area reached by a small dye is defined as a saturated coating amount, and the adsorption amount per unit area of the dye chromophore is larger than the saturated coating amount. Further, the number of adsorbing layers means the adsorbing amount of the dye chromophore per unit particle surface area based on the saturated coating amount of one layer. Here, in the case of a multichromophore dye compound, the area occupied by a dye having an individual dye chromophore in an unconnected state can be used as a reference. For example, there can be mentioned a dye having one dye chromophore in which the linking site is changed to an alkyl group.

Usually, the molecular occupation area of the dye used is approximately 80 ² , so that the approximate number of adsorbed layers can be estimated simply by setting the dye occupation area to 80 ² for all the dyes.

  Adsorption of the dye chromophore to the semiconductor surface is preferably 1.3 layers or more, more preferably 1.5 layers or more, and particularly preferably 1.7 layers or more. In addition, although there is no upper limit in particular, 10 layers or less are preferable, More preferably, it is 5 layers or less, Most preferably, it is 3 layers or less.

  In the present invention, in the case of a normal dye having one dye chromophore, the first layer dye is a dye adsorbed on the inside adjacent to the semiconductor surface, and the second and subsequent layers are the semiconductor surface. It is an outer dye that does not adsorb directly to the first dye and is adjacent to the first dye. In the case of a multichromophore dye compound, the first layer dye is the dye chromophore adsorbed on the inner side adjacent to the semiconductor surface, and the second and subsequent layer dyes are adjacent to the inner dye chromophore. It is the outer dye chromophore.

  In the present invention, the absorption maximum wavelength of the second and subsequent dyes is preferably the same or shorter than the absorption maximum wavelength of the first dye, and the distance between the two wavelengths is preferably from 0 nm to 50 nm, more preferably from 0 nm. 30 nm, particularly preferably 0 nm to 20 nm.

  In the present invention, any reduction potential and oxidation potential may be used for the first-layer dye and the second-layer and subsequent dyes. However, the reduction potential of the first-layer dye is 0.2 V from the value of the reduction potential of the second-layer and subsequent dyes. Is more preferable than the value obtained by subtracting 0.1 V, more preferably noble value than the value obtained by subtracting 0.1 V, and particularly preferably, the reduction potential of the first layer dye is lower than the reduction potential of the dyes in the second and subsequent layers. Is also noble.

  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.

Moreover, it is preferable that the pigment | dye after the 2nd layer is luminescent. As the kind of the luminescent dye, those having a skeleton structure of a dye used for a dye laser are preferable. These include, for example, Maeda Mitsuo, Laser Research, Vol. 8, 694, 803, 958 (1980) and Vol. 9, 85 (1981), and F. Sehaefer, “Dye Lasers”, Springer. (1973).
The light emission yield of the dye only in the second layer dye part is preferably 0.05 or more, more preferably 0.1 or more, still more preferably 0.2 or more, and particularly preferably 0.5. That's it.

In the case where energy transfer from the second and subsequent dyes to the first dye occurs by the non-equilibrium excitation energy transfer mechanism, it is preferable that the excitation life of only the second dye part is long. In this case, the light emission yield of the second layer dye portion may be high or low. The fluorescence lifetime of only the second-layer dye portion is preferably 10 ps or more, more preferably 40 ps or more, and further preferably 160 ps or more. Although there is no upper limit in particular in the fluorescence lifetime of the pigment | dye after the 2nd layer, Preferably it is 1 ms or less.
It is preferable that the overlap between the light emission of the second and subsequent dyes and the absorption of the first dye is large. When the emission spectrum of the second and subsequent dyes is l (ν) and the absorption spectrum of the first layer dye is a (ν), the product l (ν) · a (ν) is preferably 0.001 or more. Yes, more preferably 0.01 or more, still more preferably 0.1 or more, particularly preferably 0.5 or more. Here, ν is a wave number (cm ⁻¹ ), and each spectrum is normalized to a spectral area of 1.

The energy transfer efficiency of the excitation energy of the second and subsequent dyes to the first dye is preferably 10% or more, more preferably 30%, particularly preferably 60% or more, and most preferably 90% or more. Here, the excitation energy of the dyes in the second and subsequent layers refers to the energy of the dye in the excited state generated by absorbing the light energy from the dyes in the second and subsequent layers. When the excitation energy of a molecule moves to another molecule, it is considered that the excitation energy moves via an excited electron transfer mechanism, a Forster model energy transfer mechanism (Forster Model), a Dexter energy transfer mechanism (Dextor Model), etc. Therefore, even in the multilayer adsorption system of this research, it is preferable that the conditions for causing efficient excitation energy transfer considered from these mechanisms are satisfied. Furthermore, it is particularly preferable to satisfy the conditions for causing the Forster-type energy transfer mechanism. In order to increase the Forster-type energy transfer efficiency, it is also effective to reduce the refractive index in the vicinity of the semiconductor surface.
The efficiency of energy transfer from the second and subsequent layer dyes to the first layer dye can be determined by analyzing the fluorescence decay rate of the second layer dye and analyzing the dynamics of the photoexcited state such as the rise rate of the fluorescence of the first layer dye.
In addition, the efficiency of energy transfer from the second and subsequent layer dyes to the first layer dye can also be obtained as the spectral sensitization efficiency at the second layer and subsequent dye excitation / the spectral sensitization efficiency at the first layer dye excitation. .

  In the present invention, the dye adsorbed in the first layer preferably forms a J aggregate. The dyes in the second and subsequent layers may adsorb with monomers or form short wavelength associations such as H-aggregates, but particularly preferably form J-aggregates and adsorb. J-aggregates have a high extinction coefficient and are preferable in terms of sharp absorption, so they are very useful for spectral sensitization in ordinary single-layer adsorption, but the dyes in the second and subsequent layers also have the above-mentioned spectral characteristics. Highly preferred. In addition, since the fluorescence yield is high and the Stokes shift is small, it is also preferable to transmit the light energy absorbed by the second and subsequent dyes to the first dye having a light absorption wavelength close by Förster energy transfer.

The interval between the shortest wavelength and the longest wavelength, each showing 50% of the maximum value Amax of the spectral absorption rate due to the sensitizing dye adsorbed on the semiconductor and the maximum value Smax of the spectral sensitivity, is preferably 120 nm or less. The thickness is preferably 100 nm or less, particularly preferably 80 nm or less, and most preferably 60 nm or less.
Further, the interval between the shortest wavelength and the longest wavelength showing 80% of Amax and Smax is preferably 20 nm or more, preferably 100 nm or less, more preferably 80 nm or less, and particularly preferably 50 nm or less.
The interval between the shortest wavelength and the longest wavelength that represents 20% of Amax and Smax is preferably 180 nm or less, more preferably 150 nm or less, particularly preferably 120 nm or less, and most preferably 100 nm or less.
The longest wavelength exhibiting a spectral absorption of 50% of Amax or Smax is preferably 460 nm to 510 nm, or 560 nm to 610 nm, or 640 nm to 730 nm.

Further, when the maximum value of the spectral absorptance due to the dye chromophore of the first layer on the semiconductor surface is A1max and the maximum value of the spectral absorptance due to the dye chromophore after the second layer is A2max, A1max and A2max are 400 to 500 nm. Or in the range of 500 to 600 nm, or 600 to 700 nm, or 700 to 1000 nm.
Furthermore, when the maximum value of spectral sensitivity due to the dye chromophore of the first layer on the semiconductor surface is S1max, and the maximum value of spectral sensitivity due to the dye chromophore after the second layer is S2max, S1max and S2max are 400 to 500 nm, or It is preferable to be in the range of 500 to 600 nm, or 600 to 700 nm, or 700 to 1000 nm.

In the multilayer adsorption of the dye of the present invention, the case where the dyes are “bonded to each other by an attractive force other than a covalent bond” will be described.
Any attractive force other than a covalent bond may be used. For example, van der Waals force (more precisely, an orientation force acting between a permanent dipole and a permanent dipole, a permanent dipole-induced dipole) It can be expressed in terms of induced force acting between the children, dispersion force acting between the temporary dipole-induced dipole), charge transfer force (CT), Coulomb force (electrostatic force), hydrophobic bond force, hydrogen bond force, distribution For example, cohesive strength. 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.

  Being bonded to each other means that the dye chromophore is bound by these attractive forces. In other words, the attractive energy (ie, adsorption energy (ΔG)) is preferably 15 kJ / mol or more, more preferably 20 kJ / mol or more, and particularly preferably 40 kJ / mol or more. Although there is no upper limit in particular, it is preferably 5000 kJ / mol or less, more preferably 1000 kJ / mol or less.

  Specifically, for example, a dye having an aromatic group described in JP-A-10-239789, or a method in which a cationic dye having an aromatic group and an anion dye are used in combination, described in JP-A-10-171058. A method using a dye having a polyvalent charge, a method using a dye having a hydrophobic group described in JP-A-10-186559, and a coordination bond group described in JP-A-10-197980 A method using a dye, a method using a dye having a trinuclear basic nucleus described in JP-A No. 2001-5132, and a method using a dye having a specific hydrophilicity / hydrophobicity described in JP-A No. 2001-13614 , A method using a specific intramolecular basic dye described in JP-A No. 2001-75220, a specific method other than cyanine described in JP-A No. 2001-75221 A method using an element, a method using a dye having an acid-dissociable group having a specific pKa described in JP-A-2001-152038, JP-A-2001-166413, JP-A-2001-323180, JP-A-2001-337409 Described in JP-A No. 2001-264913, a method using a dye having a specific hydrogen bond group described in No. 1, a method using a dye having a specific fluorescence quantum yield described in JP-A No. 2001-209143, and JP-A No. 2001-264913 A method using a specific decoloring dye, a method using a dye contained in a gel matrix described in JP-A No. 2001-343720, a specific infrared described in JP-A No. 2002-23294 A method using a dye, a method using a dye having a specific potential described in JP-A-2002-99053, EP 0985 The methods using the specific cationic dyes described in US Pat. Nos. 964, 0985965, 0985966, 0985967, 1085372, 1085373, 1172688, and 1199595 are preferably used.

In the multilayer adsorption of the dye of the present invention, a compound comprising a plurality of dye chromophores can also be used. The multichromophore dye compound is a dye compound containing a plurality of dye chromophores.
In the compound, a plurality of dye chromophores can be linked by a covalent bond or a coordinate bond, but preferably it is a covalent bond. (Note that the coordination bond can also be regarded as one coordination bond force of intermolecular forces.) In the compound, a covalent bond or a coordinate bond is formed on the surface of the semiconductor even if it is formed in advance. The dye may be formed in the process of multilayer adsorption. As for the latter method, for example, the method described in JP-A No. 2000-81678 can be used. Preferably, the bond is formed in advance.

  In the multichromophore dye compound, the number of dye chromophores may be any number as long as it is at least two, preferably 2-7, more preferably 2-5, particularly preferably 2 and 3, most preferably Two. The plurality of dye chromophores may be the same or different. Any dye chromophore may be used, but the dye chromophore described in the above-mentioned chromophore [1] is preferable, and the same are preferable.

  Examples of the multichromophore dye compound include a multichromophore dye linked by a methine chain described in JP-A-9-265144 and an oxonol dye described in JP-A-10-226758. Multichromophore dyes, specific multichromophore dyes having a benzimidazole nucleus described in JP-A-10-110107, JP-A-10-307358, JP-A-10-307359, and JP-A-10-310715, 9-265143, JP-A Nos. 2000-231172, 2000-231173, 2002-55406, 2002-82403, 2002-82404, and 2002-82405 Multi-chromophore dyes, and emulsions containing reactive group dyes described in JP-A-2000-81678 The produced multichromophore dye, the specific multichromophore dye having a specific benzoxazole nucleus described in JP-A No. 2000-231174, the specific characteristic or dissociation group described in JP-A No. 2001-31115 A multi-chromophore dye having a specific property described in JP-A No. 2001-356442, a multi-chromophore dye having a specific merocyanine described in JP-A No. 2002-90927, Examples thereof include multichromophore dyes having specific dissociation groups described in 2002-90928 and 2002-90929.

In addition, specifically, the dye described in the above-mentioned multilayer adsorption-related patent [3] can be used as the other dye constituting the multilayer adsorption.
Specific examples are shown below, but are not limited thereto.

  The dyes of the present invention are described by FM Harmer, “Heterocyclic Compounds-Cyanine Dyes and Related Compounds”, John Willy and Sons. (JohnWiley & Sons)-New York, London, 1964, DMSturmer, "Heterocyclic Compounds-Special topics in cyclic" chemistry) ", Chapter 18, Section 14, 482-515, John Wiley & Sons, Inc.-New York, London, 1977," Rods Chemistry of Carbon Compounds. " (Rodd's Chemistry of Carbon Compounds) ”2nd.Ed.vol.IV, partB, 1 77 published, Chapter 15, # 369 from 422 pages, can be synthesized by the processes described Elsevier Science Public Company Inc. (Elsevier Science Publishing Company Inc.) published by New York, and the like.

  In order to adsorb the dye to the semiconductor, a method of immersing the semiconductor in the dye solution, a method of applying the dye solution to the semiconductor, or a method of depositing the dye on the semiconductor can be used. When different dye compounds are adsorbed in multiple layers, the dye can be adsorbed in multiple layers by repeating this.

Next, a preferable configuration of the photoelectric conversion element of the present invention will be described. For example, as shown in FIG. 1, a semiconductor, an organic dye, an interelectrode material, and at least one electrode are arranged from below. Further, it is preferable that a positive bias can be applied to the semiconductor as indicated by a DC power supply symbol in FIG. It is also very desirable to place another electrode in contact with the semiconductor under the semiconductor as shown in FIG. This is because the characteristics of the semiconductor into which electrons and the like are injected from the organic dye and the electrode characteristics can be separated. In addition, it is often desirable for the semiconductor to have a larger surface area because a large amount of organic dye can be arranged, and it is preferable that the surface area be increased. For example, it is also preferable to create a porous porous film by sintering particles, and the surface area may be increased by a process such as making holes in the thin film.
The electrode may be any conductive material, but is preferably a transparent transparent conductive film. It is also very preferable that the semiconductor is a transparent conductive film, and the semiconductor in that case also has a function as an electrode.

  As the transparent conductive film, any known one may be used. For example, a metal (thin film), an alloy (thin film), a metal oxide, an organic conductive compound, a mixture thereof, and the like are preferably exemplified. Specific examples include conductive metal oxides such as tin oxide, zinc oxide, indium oxide, IZO (indium zinc oxide), ITO (indium tin oxide), metals such as gold, platinum, silver, chromium, nickel, and the like. A mixture or laminate of a metal and a conductive metal oxide, an inorganic conductive material such as copper iodide or copper sulfide, an organic conductive material such as polyaniline, polythiophene or polypyrrole, a laminate of these and ITO, Etc. Also described in detail by Yutaka Sawada, "New development of transparent conductive film" (published by CMC, 1999), Japan Society for the Promotion of Science "Transparent conductive film technology" (Ohm, 1999), etc. May be used.

  In the present invention, any electrode may be used as the other electrode brought into contact with the semiconductor, but the transparent conductive film is preferable. Of course, any other metal, oxide, or semiconductor may be used. For example, Li, Na, Mg, K, Ca, Rb, Sr, Cs, Ba, Fr, Ra, Sc, Ti, Y, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, Sb, Bi, Se, Te, Po, Br, I, At, B, C, N, F, O, S, N Any combination is acceptable.

  The interelectrode material may be a dielectric, a conductor, an inorganic semiconductor, an organic semiconductor, an electrolyte, or the like, but a molten salt electrolyte or a solid electrolyte is preferable among the organic semiconductor and the electrolyte. For example, in the case of an organic semiconductor, there are a hole transport material and an electron transport material. As the hole transport material, poly-N-vinylcarbazole derivative, polyphenylene vinylene derivative, polyphenylene, polythiophene, polymethylphenylsilane, polyaniline, triazole derivative Oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, carbazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbenes Derivatives, porphyrin derivatives (phthalocyanine, etc.), aromatic tertiary amine compounds and styrylamine compounds, butadiene compounds, benzidine derivatives Polystyrene derivatives, triphenylmethane derivatives, tetraphenyl benzene derivatives, starburst polyamine derivative or the like can be used. Electron transport (organic) materials include oxadiazole derivatives, triazole derivatives, triazine derivatives, nitro-substituted fluorenone derivatives, thiopyrandioxide derivatives, diphenylquinone derivatives, perylene tetracarboxyl derivatives, anthraquinodimethane derivatives, fluoreni. Examples thereof include redenemethane derivatives, anthrone derivatives, perinone derivatives, oxine derivatives, quinoline complex derivatives, and the like.

  The molten salt electrolyte is a salt that is liquid at room temperature or has a low melting point. For example, International Publication (WO) 95/18456, JP-A-8-259543 and Electrochemistry, Vol. 65, 11 No., page 923 (1997) and the like, and known electrolytes such as pyridinium salts, imidazolium salts, and triazolium salts. A molten salt that becomes liquid at 100 ° C. or lower, particularly near room temperature, is preferred.

  Examples of the molten salt that can be preferably used include those represented by the general formulas (Y-a), (Y-b), and (Y-c) described in JP-A-2002-299678 and exemplified compounds thereof.

The molten salt electrolyte is preferably in a molten state at room temperature, and preferably does not use a solvent. Although the solvent described later may be added, the content of the molten salt is preferably 50% by mass or more, and particularly preferably 90% by mass or more with respect to the entire electrolyte composition.
In addition, the gel electrolyte can be prepared by adding polymer, oil gelling agent, polymerization containing polyfunctional monomers, polymer cross-linking reaction, etc. It can also be used after being solidified. When gelation is performed by adding a polymer, compounds described in “Polymer Electrolyte Reviews-1 and 2” (JRMacCallum and CA Vincent, ELSEVIER APPLIED SCIENCE) can be used. Can be preferably used. In the case of gelation by adding an oil gelling agent, J. Chem Soc. Japan, Ind. Chem. Sec., 46, 779 (1943), J. Am. Chem. Soc., 111, 5542 (1989) , J. Chem. Soc., Chem. Commun., 1993, 390, Angew. Chem. Int. Ed. Engl., 35, 1949 (1996), Chem. Lett., 1996, p. 885, J. Although compounds described in Chm. Soc., Chem. Commun., 1997, page 545 can be used, preferred compounds are compounds having an amide structure in the molecular structure. An example of gelling the electrolytic solution is described in JP-A No. 11-185863, and an example of gelling the molten salt electrolyte is described in JP-A No. 2000-58140, which can also be applied to the present invention.

When the electrolyte is gelled by a polymer crosslinking reaction, it is desirable to use a polymer containing a crosslinkable reactive group and a crosslinking agent in combination. In this case, preferred crosslinkable reactive groups are amino groups and nitrogen-containing heterocycles (for example, pyridine ring, imidazole ring, thiazole ring, oxazole ring, triazole ring, morpholine ring, piperidine ring, piperazine ring, etc.) Preferred cross-linking agents are bifunctional or higher reagents capable of electrophilic reaction with a nitrogen atom (for example, alkyl halide, halogenated aralkyl, sulfonate ester, acid anhydride, acid chloride, isocyanate, α, β-unsaturated). A sulfonyl group, an α, β-unsaturated carbonyl group, an α, β-unsaturated nitrile group, etc.), and the crosslinking techniques described in JP-A Nos. 2000-17076 and 2000-86724 can also be applied.
Next, as the polymer compound, the polymer compound itself dissolves the electrolyte salt and exhibits ionic conductivity, or the polymer compound itself dissolves the electrolyte salt even if it cannot dissolve the electrolyte salt. A solvent that can exhibit high ionic conductivity can be used using a solvent that can be used.

  Examples of the former polymer compound include, for example, polyethylene glycol, polyacrylic acid, polymethacrylic acid, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyphosphazene, polysilane, etc. in the main chain, and their copolymers. And a polymer compound having a polyoxyethylene structure in the side chain can be used. Even if it is a high molecular compound which can melt | dissolve these electrolyte salts, the solvent which can melt | dissolve the above-mentioned electrolyte salt can be used together.

  On the other hand, as the latter polymer compound, for example, polyvinyl chloride, polyacrylonitrile, polyethylene, polypropylene, polyester, polyacrylate, or a copolymer thereof can be used. Note that the above-described polymer compound may have a crosslinked structure.

The image sensor of the present invention will be described below.
In the present invention, the image sensor has at least one photoelectric conversion element on a substrate. In the present invention, the meaning of applying a positive bias to at least one electrode in a semiconductor is, for example, applying a voltage higher than 0 to the semiconductor if the one electrode is ground. If one electrode has a negative potential, a higher potential is applied to the semiconductor. The bias application in the present invention effectively prevents the electrons of the photoexcited dye injected into the semiconductor from recombining with the dye holes.

In the present invention, it is preferable that at least two photoelectric conversion elements are laminated, and more preferably, three or more layers. This is because the light utilization efficiency can be increased by doing so. In addition, if at least three photoelectric conversion elements are a blue photoelectric conversion site, a green photoelectric conversion site, and a red photoelectric conversion site, one pixel can function as a full-color imaging device, which is very preferable. For this purpose, it is possible to select a dye having spectral characteristics suitable for each color, and it is preferable to have the spectral absorption characteristics described above. Of course, the photoelectric conversion element of the present invention and a conventional element (photoelectric conversion films described in JP-A-58-103165 and JP-A-2003-234460) can be used in combination.
The substrate used in the present invention is most preferably a Si substrate such as a Si wafer on which a charge transfer device is mounted, a Si wafer on which a CMOS image sensor driving circuit is mounted, and any other substrate such as a semiconductor substrate, a glass substrate, or a plastic substrate is used. May be. FIG. 3 is a schematic cross-sectional view of one pixel of an image sensor having a BGR stacked configuration. In FIG. 3, a B film, a G film, and an R film contain a semiconductor and a dye adsorbed in multiple layers thereon, and together with the upper and lower electrodes, form the photoelectric conversion element of the present invention. Other than this, one or two layers of B, G, and R are semiconductor films that are adsorbed in a multilayer and other layers are semiconductor layers that absorb in the visible region, or the order of B, G, and R is The present invention can also be applied to changed configurations (for example, G / B / R order, R / G / B order, etc.).

[Example]
Further, the present invention will be described with reference to examples, but the present invention is of course not limited to these examples.

In the light receiving element P-110 of Example 1 of JP-A-2002-176191, after the sensitizing dye DR-1 is adsorbed, the sensitizing dyes (S-1) and (S-2) of the present invention are further added. A light receiving element X-1 is formed in the same manner as the light receiving element P-110 except that the surface of the TiO ₂ fine particles is adsorbed in an amount of 1: 1 so as to cover the monomolecular layer. Further, after the sensitizing dye DR-1 is adsorbed in the same manner, the surface of the TiO ₂ fine particles on the surface of the TiO ₂ fine particles in the ratio of 1: 3 is added to the sensitizing dyes (S-3) and (S-4) of the present invention. The light receiving element X-2 is formed in the same manner as the light receiving element P-110 except that the amount covered with the is covered. The photoresponse currents of X-1 and X-2 are improved about twice that of P-110 by the adsorption of about 2 molecular layers on the surface of the TiO ₂ fine particle surface to contribute to photoelectric conversion.
Further, similar light receiving elements P-110A, X-1A, and X-2A were prepared except that the electrolyte of the light receiving element was changed to E-302 in Example 3 of JP-A-2002-176191. These light receiving elements exhibit a stationary photoresponse current, and the response currents of X-1A and X-2A are improved to about twice that of P-110A.

In the BGR light receiving part of the image sensor of Example 2 of JP-A No. 2002-176191, as in Example 1, the BGR dye layer on the surface of the TiO ₂ fine particles is adsorbed by about two molecular layers, so that the photoresponse current is increased. Doubled.
In addition, after adsorbing the sensitizing dye DB-1 in the light receiving element P-108 of Example 1 of JP-A-2002-176191 as the B light receiving portion, the sensitizing dye (S-5) of the present invention is further added. And (S-6) in the ratio of 1: 3 was adsorbed in the same amount as that of the light receiving element P-108 except that the surface of the TiO ₂ fine particles was adsorbed by an amount covering the monomolecular layer.
After the sensitizing dye DG-1 is adsorbed in the light receiving element P-109 of Example 1 of JP-A No. 2002-176191 as the G light receiving portion, the sensitizing dye (S-7) of the present invention is A light receiving element was prepared in the same manner as the light receiving element P-109, except that S-8) was adsorbed at a ratio of 1: 3 by an amount covering the surface of the TiO ₂ fine particles with a monomolecular layer.

It is a figure which shows the one aspect | mode of the structure of the photoelectric conversion element of this invention. It is a figure which shows the one aspect | mode of the structure which added the 2nd electrode of the photoelectric conversion element of this invention. It is a cross-sectional schematic diagram for 1 pixel of the image pick-up element of the BGR laminated structure of this invention.

Claims (6)

  A photoelectric conversion element having at least one semiconductor, at least one organic dye having a dye chromophore, and at least one electrode, wherein the dye chromophore is adsorbed in multiple layers on the semiconductor surface Photoelectric conversion element.   Furthermore, the photoelectric conversion element of Claim 1 which has a transparent conductive film which touches a semiconductor.   An imaging device comprising the photoelectric conversion device according to claim 1.   The imaging device according to claim 3, comprising at least two types of photoelectric conversion elements that absorb light of different wavelengths.   The imaging device according to claim 3, wherein at least three types of photoelectric conversion elements that absorb blue, green, and red light are stacked.   The photoelectric conversion method which applies a positive voltage with respect to said one electrode to the semiconductor of the photoelectric conversion element of Claim 1.

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