Patent Description:
In recent years, development of an element having a photoelectric conversion film (for example, an imaging element) has progressed.

Regarding a photoelectric conversion element using a photoelectric conversion film, for example, <CIT> discloses a photoelectric conversion element having a photoelectric conversion film containing a predetermined compound.

<CIT> discloses a merocyanine dye of formula (<NUM>)
<CHM>
wherein A<NUM> is a divalent atomic group, n is an integer of <NUM>-<NUM>, A<NUM> and A<NUM> each independently are an aromatic hydrocarbon ring or a heterocyclic ring having <NUM>-<NUM> carbon atoms, and R<NUM> and R<NUM> each independently Are H, C<NUM>-<NUM>-alkyl, C<NUM>-<NUM>-aryl, or a C<NUM>-<NUM>-heterocyclic group.

<CIT> relates methine dyes of a specified general Formula (I) or (II) and to polyester compositions having copolymerized therein or reacted therewith at least <NUM> wt. % of these colorants.

As one aspect of an imaging element, there is a laminated type imaging element in which a plurality of photoelectric conversion elements that receive different types of light are laminated. In a case where light is incident on the imaging element, a part of the incidence ray is absorbed by the photoelectric conversion elements arranged on the incident side, and the transmitted light is absorbed by the photoelectric conversion elements arranged further inside. In such an imaging element, since colors are easily separated, it is preferable that the absorption peak of each photoelectric conversion element has a narrow half-width.

The present inventors have examined the characteristics of the photoelectric conversion element specifically disclosed in Example section of <CIT>, and have found that the half-width of the absorption peak of the photoelectric conversion film in the photoelectric conversion element is wide, and further improvement is necessary.

Also, the photoelectric conversion element is required to have excellent photoelectric conversion efficiency.

In view of the circumstances, an object of the present invention is to provide a photoelectric conversion element including a photoelectric conversion film having a narrow half-width of absorption peak and an excellent photoelectric conversion efficiency.

Another object of the present invention is to provide an imaging element, an optical sensor, and a compound.

The inventors of the present invention have conducted extensive studies on the above-described problems. As a result, the inventors have found that it is possible to solve the above-described problems by applying the compound having a predetermined structure to the photoelectric conversion film, and have completed the present invention.

Thus, the present invention provides a compound of formula (2b-<NUM>) or (2b-<NUM>):
<CHM>
<CHM>
wherein.

Also, the invention provides a photoelectric conversion element which comprises (i) a conductive film, (ii) a photoelectric conversion film, and (iii) a transparent conductive film in this order; wherein the photoelectric conversion film contains a compound of formula (<NUM>) as defined above.

Yet further, the invention provides an imaging element and an optical sensor, each comprising the present photoelectric conversion element.

According to the present invention, it is possible to provide a photoelectric conversion element including a photoelectric conversion film having a narrow half-width of absorption peak and an excellent photoelectric conversion efficiency.

According to the present invention, it is possible to provide an imaging element, an optical sensor, and a compound.

Hereinafter, preferred embodiments of the present invention will be described. In the present specification, the following definitions apply.

A substituent for which whether it is substituted or unsubstituted is not specified may be further substituted with a substituent (for example, a substituent W described below) within the scope not impairing an intended effect. For example, the expression of "alkyl group" refers to an unsubstituted alkyl group or an alkyl group with which a substituent (for example, a substituent W described below) may be substituted.

Further, examples of the "substituent" include groups exemplified as the substituent W described later. The "substituent" is preferably alkyl, aryl or heteroaryl.

The "aromatic ring" means a ring exhibiting aromaticity. The "aromatic ring" may or may not have a substituent. The "aromatic ring" may be a "monocyclic aromatic ring" consisting of one ring exhibiting aromaticity, or a "polycyclic aromatic ring" in which two or more rings are condensed.

The "polycyclic aromatic ring" has two or more rings exhibiting aromaticity.

Examples of the aromatic ring may be either an aromatic hydrocarbon ring or an aromatic heterocyclic ring.

The substituents contained in the "aromatic ring (a monocyclic aromatic ring or a polycyclic aromatic ring)" may bond to each other to further form a ring.

Examples of the monocyclic aromatic ring include a monocyclic aromatic hydrocarbon ring such as a benzene ring, and a monocyclic aromatic heterocyclic ring such as a pyrrole ring, a furan ring, a thiophene ring, an imidazole ring, and an oxazole ring.

Examples of the polycyclic aromatic ring include a polycyclic aromatic hydrocarbon ring such as a naphthalene ring, an anthracene ring, a fluorene ring, and a phenanthrene ring, and polycyclic aromatic heterocyclic ring such as a quinoline ring and a benzothiophene ring.

The "non-aromatic ring" means a ring that does not exhibit aromaticity. The "non-aromatic ring" may or may not have a substituent. The "non-aromatic ring" may be a "monocyclic non-aromatic ring" consisting of one ring that does not exhibit aromaticity, or may be a "polycyclic non-aromatic ring" in which two or more rings that do not exhibit aromaticity are condensed and which does not exhibit aromaticity as a whole.

However, the substituents of the non-aromatic ring may bond to each other to form a ring, or the substituents of the non-aromatic ring may bond to each other to form an aromatic ring. Moreover, the non-aromatic ring may have an aromatic ring as a substituent (or a part thereof).

The "non-aromatic ring containing no aromatic structure" does not include an aromatic ring as a part of the non-aromatic ring. For example, in a non-aromatic ring containing no aromatic structure, the substituent (or part thereof) of the non-aromatic ring is not an aromatic ring, and a ring formed of the substituents of the non-aromatic ring bonding to each other is not an aromatic ring.

Examples of the non-aromatic ring include an aliphatic hydrocarbon ring (a cycloalkane ring and the like) and a cycloalkene ring.

In addition, the numerical range represented by "to" means a range including numerical values denoted before and after "to" as a lower limit value and an upper limit value.

A hydrogen atom may be a light hydrogen atom (an ordinary hydrogen atom) or a deuterium atom (a double hydrogen atom).

There is a feature of the present photoelectric conversion element that a bulky substituent is introduced into a compound of Formula (2b-<NUM>) or (2b-<NUM>) described below (hereinafter, also referred to as "specific compound") contained in the photoelectric conversion film. It is assumed that by introducing a bulky substituent in the specific compound, steric repulsion between specific compounds occurs to the extent that excellent photoelectric conversion efficiency is obtained, and by suppressing the association of specific compounds in the photoelectric conversion film, the half-width of the absorption peak of the photoelectric conversion film is narrowed, and excellent photoelectric conversion efficiency is obtained.

<FIG> shows a schematic cross-sectional view of one embodiment of a photoelectric conversion element of the present invention.

A photoelectric conversion element 10a shown in <FIG> has a configuration in which a conductive film (hereinafter, also referred to as a lower electrode) <NUM> functioning as the lower electrode, an electron blocking film 16A, a photoelectric conversion film <NUM> containing the specific compound described below, and a transparent conductive film (hereinafter, also referred to as an upper electrode) <NUM> functioning as the upper electrode are laminated in this order.

<FIG> shows a configuration example of another photoelectric conversion element. A photoelectric conversion element 10b shown in <FIG> has a configuration in which the electron blocking film 16A, the photoelectric conversion film <NUM>, a positive hole blocking film 16B, and the upper electrode <NUM> are laminated on the lower electrode <NUM> in this order. The lamination order of the electron blocking film 16A, the photoelectric conversion film <NUM>, and the positive hole blocking film 16B in <FIG> may be appropriately changed according to the application and the characteristics.

In the photoelectric conversion element 10a (or 10b), it is preferable that light is incident on the photoelectric conversion film <NUM> through the upper electrode <NUM>.

In a case where the photoelectric conversion element 10a (or 10b) is used, the voltage can be applied. In this case, it is preferable that the lower electrode <NUM> and the upper electrode <NUM> form a pair of electrodes and the voltage of <NUM> × <NUM>-<NUM> to <NUM> × <NUM><NUM> V/cm is applied thereto. From the viewpoint of performance and power consumption, the voltage to be applied is more preferably <NUM> × <NUM>-<NUM> to <NUM> × <NUM><NUM> V/cm, and still more preferably <NUM> × <NUM>-<NUM> to <NUM> × <NUM><NUM> V/cm.

The voltage application method is preferable that the voltage is applied such that the electron blocking film 16A side is a cathode and the photoelectric conversion film <NUM> side is an anode, in <FIG>. In a case where the photoelectric conversion element 10a (or 10b) is used as an optical sensor, or also in a case where the photoelectric conversion element 10a (or 10b) is incorporated in an imaging element, the voltage can be applied by the same method.

As described in detail below, the photoelectric conversion element 10a (or 10b) can be suitably applied to applications of the imaging element.

Hereinafter, the form of each layer constituting the photoelectric conversion element according to the embodiment of the present invention will be described in detail.

The photoelectric conversion film is a film containing a specific compound as a photoelectric conversion material. By using the compound, a photoelectric conversion element including a photoelectric conversion film having a narrow half-width of absorption peak and an excellent photoelectric conversion efficiency can be obtained.

Hereinafter, the specific compound will be described in detail.

Formulae (2b-<NUM>) and (2b-<NUM>) (<NUM>) include all geometric isomers that can be distinguished based on the C=C double bond constituted by a carbon atom to which R<NUM> (or R<NUM>) bonds and a carbon atom adjacent thereto. That is, both the cis isomer and the trans isomer which are distinguished based on the C=C double bond are included.

The present compound is a compound of Formula (2b-<NUM>) or (2b-<NUM>):
<CHM>
<CHM>.

R<NUM> and R<NUM> each independently represent a substituent. The substituents represented by R<NUM> and R<NUM> are preferably alkyl (preferably having <NUM>-<NUM> carbon atoms), or aryl. The aryl group is an aryl group which may have a substituent.

The carbon atoms of the aryl group are not particularly limited, but is preferably <NUM>-<NUM>, more preferably <NUM>-<NUM>, and still more preferably <NUM>. The aryl group may have a monocyclic structure or a condensed ring structure (a fused ring structure) in which two or more rings are condensed.

As the aryl group, for example, phenyl, naphthyl, anthryl or fluorenyl is preferable.

Examples of the substituent that the aryl group may have include the substituent W described below, and examples thereof include alkyl and halogen, and alkyl is preferable.

The aryl group may have a plurality of types of substituents.

In a case where the aryl group has a substituent, the number of substituents that the aryl group has is not particularly limited, but is preferably <NUM>-<NUM>, and more preferably <NUM>-<NUM>.

The aryl group is preferably an aryl group which may be substituted with a substituent other than halogen.

The total number of carbon atoms contained in R<NUM> and R<NUM> is not particularly limited, is often <NUM> or more, and <NUM> or more is preferable from the viewpoint of obtaining a superior effect of the present invention. The total number of carbon atoms is not particularly limited, but is preferably <NUM> or less.

R<NUM> and R<NUM> may bond to each other to form a ring. More specifically, R<NUM> and R<NUM> may each independently bond to each other via a single bond or a linking group to form a ring. Examples of the type of ring formed include an aromatic ring (an aromatic hydrocarbon ring or an aromatic heterocyclic ring) and a non-aromatic ring.

R<NUM> and R<NUM> each independently are H or a substituent. The substituents represented by R<NUM> and R<NUM> are preferably alkyl (preferably having <NUM>-<NUM> carbon atoms), or aryl. The definition of the aryl group is the same as the definition of the aryl group described for R<NUM> and R<NUM>.

Among these, from the viewpoint of obtaining a superior effect of the present invention, R<NUM> and R<NUM> are preferably H.

Rg<NUM> to Rg<NUM> each independently are H or a substituent.

Rg<NUM> to Rg<NUM> may bond to each other to form a ring. For example, Rg<NUM> and Rg<NUM>, Rg<NUM> and Rg<NUM>, and Rg<NUM> and Rg<NUM> may respectively independently bond to each other to form a ring through a single bond or a linking group.

Examples of the type of ring formed include an aromatic ring (an aromatic hydrocarbon ring or an aromatic heterocyclic ring) and a non-aromatic ring.

R<NUM>-R<NUM> each independently are H or a substituent. The substituents represented by R<NUM> and R<NUM> are preferably alkyl (preferably having <NUM>-<NUM> carbon atoms), or aryl. The definition of the aryl group is the same as the definition of the aryl group described for R<NUM> and R<NUM>.

R<NUM>-R<NUM> may bond to each other to form a non-aromatic ring containing no aromatic ring structure, or a fluorene ring. For example, R<NUM> and R<NUM>, R<NUM> and R<NUM>, R<NUM> and R<NUM>, R<NUM> and R<NUM>, and R<NUM> and R<NUM> may respectively independently bond to each other to form a non-aromatic ring containing no aromatic ring structure through a single bond or a linking group, or a fluorene ring.

R<NUM>-R<NUM> each independently are H or a substituent. The substituents represented by R<NUM>-R<NUM> are preferably alkyl (preferably having <NUM>-<NUM> carbon atoms), or aryl. The definition of the aryl group is the same as the definition of the aryl group described for R<NUM> and R<NUM>.

R<NUM>-R<NUM> may bond to each other to form a non-aromatic ring containing no aromatic ring structure, or a fluorene ring. For example, R<NUM> and R<NUM>, R<NUM> and R<NUM>, R<NUM> and R<NUM>, R<NUM> and R<NUM>, R<NUM> and R<NUM>, R<NUM> and R<NUM>, and R<NUM> and R<NUM> may respectively independently bond to each other to form a non-aromatic ring containing no aromatic ring structure through a single bond or a linking group, or a fluorene ring. In addition, R<NUM> and R<NUM> may bond to each other to form a fluorene ring. In this case, a <NUM>,<NUM>'-spirobi[<NUM>-fluorene] ring may be formed with the carbon atom to which R<NUM> and R<NUM> directly bond to each other as a spiro atom.

Rc3 is a group of Formula (4A) or a polycyclic aromatic ring which may have a substituent, and is preferably a group of Formula (5A) or (5B), or a naphthyl group which may have a substituent:
<CHM>.

In Formula (4A), T<NUM>-T<NUM> each independently are CRe12 or a nitrogen atom. Re12 is H or a substituent (C<NUM>-<NUM>-alkyl or halogen. Rf2 is alkyl (preferably having <NUM>-<NUM> carbon atoms), cyano, aryl which may have a substituent, or heteroaryl which may have a substituent.

The definitions of the aryl group and the heteroaryl group are as follows.

The aryl group is preferably aryl which may be substituted with a substituent other than halogen.

The carbon atoms of the heteroaryl group (a monovalent aromatic heterocyclic group) are not particularly limited, but is preferably <NUM>-<NUM>, and more preferably <NUM>-<NUM>.

The heteroaryl group includes a hetero atom in addition to C and H. Examples of the hetero atom include S, O, N, Se, Te, P, Si and B, and S, O or N is preferable.

The number of hetero atoms of the heteroaryl group is not particularly limited, but is preferably <NUM>-<NUM>, more preferably <NUM>-<NUM>, and still more preferably <NUM>-<NUM>.

The number of ring members of the heteroaryl group is not particularly limited, but is preferably <NUM>-<NUM>, more preferably <NUM>-<NUM>, and still more preferably <NUM>-<NUM>. The heteroaryl group may have a monocyclic structure or a condensed ring structure in which two or more rings are condensed. In a case of the condensed ring structure, an aromatic hydrocarbon ring having no hetero atom (for example, a benzene ring) may be included.

Examples of the heteroaryl group include furyl, pyridyl, quinolyl, isoquinolyl, acridinyl, phenanthridinyl, pteridinyl, pyrazinyl, quinoxalinyl, pyrimidinyl, quinazolyl, pyridazinyl, cinnolinyl, phthalazinyl, triazinyl, oxazolyl, benzoxazolyl, thiazolyl, benzothiazolyl, imidazolyl, benzimidazolyl, pyrazolyl, indazolyl, isoxazolyl, benzisoxazolyl, isothiazolyl, benzisothiazolyl, oxadiazolyl, thiadiazolyl, triazolyl, tetrazolyl, benzofuryl, thienyl, benzothienyl, dibenzofuryl, dibenzothienyl, pyrrolyl, indolyl, imidazopyridinyl, and carbazolyl.

Among these, furyl, thienyl, pyridyl, quinolyl, isoquinolyl or carbazolyl is preferable.

Examples of the substituent that the heteroaryl group may have include the same substituent that the aryl group may have.

In a case where the heteroaryl group has a substituent, the number of substituents that the heteroaryl group has is not particularly limited, but is preferably <NUM>-<NUM>, and more preferably <NUM>-<NUM>.

In a case where a plurality of Re12s are present in Formula (4A), Re12s may be the same as or different from each other, and Re12s may bond to each other to form a non-aromatic ring containing no aromatic ring structure.

In Formula (5A), Re1-Re4 each independently are H or a substituent (C<NUM>-<NUM>-alkyl or halogen). Re1-Re4 may bond to each other to form a non-aromatic ring containing no aromatic ring structure. Rf1 is alkyl (preferably having <NUM>-<NUM> carbon atoms).

In Formula (5B), Re5-Re11, and Re13-Re14 each independently are H or a substituent (C<NUM>-<NUM>-alkyl). Re5-Re11 and Re13-Re14 may bond to each other to form a ring.

Among these, one or both of Re13-Re14 preferably represent a substituent (C<NUM>-<NUM>-alkyl).

In formula (2b-<NUM>) the total number of carbon atoms contained in Res, R<NUM>, R<NUM>, and R<NUM> to R<NUM> is <NUM> or more. That is, the total number of carbon atoms contained in Rc<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, and the carbon atoms contained in R<NUM> is <NUM> or more.

Among these, the total number of carbon atoms is preferably <NUM> or more, more preferably <NUM> or more, from the viewpoint of obtaining a superior effect of the present invention. The total number of carbon atoms is not particularly limited, but is preferably <NUM> or less.

In formula (2b-<NUM>) the total number of carbon atoms contained in Rc<NUM>, R<NUM>, R<NUM>, and R<NUM> to R<NUM> is <NUM> or more. That is, the total number of carbon atoms contained in Rc<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, the carbon atoms contained in R<NUM>, and the carbon atoms contained in R<NUM> is <NUM> or more.

Further, in Formula (2b-<NUM>), the total number of carbon atoms contained in R<NUM> and R<NUM> is <NUM> or more. That is, the total number of carbon atoms contained in R<NUM> and the number of carbon atoms contained in R<NUM> is <NUM> or more.

However, the compounds of the Formulae (2b-<NUM>) and (2b-<NUM>) have none of a carboxy group, a salt of a carboxy group, a phosphoric acid group, a salt of a phosphoric acid group, a sulfonic acid group, or a salt of a sulfonic acid group.

The substituent W in the present specification will be described below.

Examples of the substituent W include halogen (such as F, Cl, Br and I), alkyl (including cycloalkyl, bicycloalkyl and tricycloalkyl), alkenyl (including cycloalkenyl and bicycloalkenyl), alkynyl, aryl, heteroaryl (may be referred to as a heterocyclic group), cyano, hydroxy, nitro, alkoxy, aryloxy, silyloxy, heterocyclic oxy, acyloxy, carbamoyloxy, alkoxycarbonyloxy, aryloxycarbonyloxy, amino (including anilino), ammonium, acylamino, aminocarbonylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfamoylamino, alkyl- or arylsulfonylamino, mercapto, alkylthio, arylthio, heterocyclic thio, sulfamoyl, alkyl- or arylsulfinyl, alkyl- or arylsulfonyl, acyl, aryloxycarbonyl, alkoxycarbonyl, carbamoyl, aryl- or heterocyclic azo, imide, phosphino, phosphinyl, phosphinyloxy, phosphinylamino, phosphono, silyl, hydrazino, ureido, and a boronic acid (-B(OH)<NUM>).

Also, the substituent W may be further substituted with the substituent W. For example, an alkyl group may be substituted with a halogen atom.

The specific compounds are exemplified below, but the specific compounds according to the embodiment of the present invention are not limited thereto. <CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

The specific compound is particularly useful as a material of the photoelectric conversion film used for the imaging element, the optical sensor, or a photoelectric cell. In addition, the specific compound usually functions as the p-type organic semiconductor in the photoelectric conversion film in many cases. The specific compound can also be used as a coloring material, a liquid crystal material, an organic semiconductor material, a charge transport material, a pharmaceutical material, and a fluorescent diagnostic material.

The specific compound is preferably a compound in which an ionization potential in a single film is -<NUM> to -<NUM> eV from the viewpoints of stability in a case of using the compound as the p-type organic semiconductor and matching of energy levels between the compound and the n-type organic semiconductor.

The maximum absorption wavelength of the specific compound is not particularly limited, but is preferably in the range of <NUM> to < <NUM>, more preferably in the range of <NUM> to < <NUM>, and still more preferably in the range of <NUM> to < <NUM> from the point that the photoelectric conversion film in the present photoelectric conversion element is suitably used as an organic photoelectric conversion film that receives (absorbs) green light and performs photoelectrically conversion.

The maximum absorption wavelength is a value obtained by adjusting the absorption spectrum of the specific compound to a concentration at which the light absorbance becomes <NUM>-<NUM>, and measuring the solution in a solution state (solvent: chloroform).

The maximum absorption wavelength of the photoelectric conversion film is not particularly limited, but is preferably in the range of <NUM> to < <NUM>, more preferably in the range of <NUM> to < <NUM>, and still more preferably in the range of <NUM> to < <NUM> from the point that the photoelectric conversion film in the present photoelectric conversion element is suitably used as an organic photoelectric conversion film that receives (absorbs) green light and performs photoelectrically conversion.

It is preferable that the photoelectric conversion film contains the n-type organic semiconductor as a component other than the specific compound.

The n-type organic semiconductor is an acceptor-property organic semiconductor material (a compound), and refers to an organic compound having a property of easily accepting an electron. More specifically, the n-type organic semiconductor refers to an organic compound having a large electron affinity of two organic compounds used in contact with each other. Therefore, any organic compound having an electron accepting property can be used as the acceptor type organic semiconductor.

Examples of the n-type organic semiconductor include fullerenes selected from the group consisting of a fullerene and derivatives thereof, fused aromatic carbocyclic compounds (for example, a naphthalene derivative, an anthracene derivative, a phenanthrene derivative, a tetracene derivative, a pyrene derivative, a perylene derivative, and a fluoranthene derivative); a heterocyclic compound having a <NUM>- to <NUM>-membered ring having at least one of a nitrogen atom, an oxygen atom, and a sulfur atom (for example, pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazole, and thiazole); polyarylene compounds; fluorene compounds; cyclopentadiene compounds; silyl compounds; <NUM>,<NUM>,<NUM>,<NUM>-naphthalenetetracarboxylic acid anhydride; <NUM>,<NUM>,<NUM>,<NUM>-naphthalenetetracarboxylic acid anhydride imide derivative, oxadiazole derivative ; anthraquinodimethane derivatives; diphenylquinone derivatives; bathocuproine, bathophenanthroline, and derivatives thereof; triazole compounds; a distyrylarylene derivative; a metal complex having a nitrogen-containing heterocyclic compound as a ligand; a silole compound; and compounds disclosed in paragraphs [<NUM>]-[<NUM>] of J-A-P2006-<NUM>.

Among these, it is preferable that examples of the n-type organic semiconductor (compound) include fullerenes selected from the group consisting of a fullerene and derivatives thereof.

Examples of fullerene include fullerene C60, fullerene C70, fullerene C76, fullerene C78, fullerene C80, fullerene C82, fullerene C84, fullerene C90, fullerene C96, fullerene C240, fullerene C540, and mixed fullerene.

Examples of fullerene derivatives include compounds in which a substituent is added to the above fullerenes. As the substituent, alkyl, aryl, or a heterocyclic group is preferable. As the fullerene derivative, the compounds described in <CIT> are preferable.

An organic dye may be used as the n-type organic semiconductor. Examples of the organic dye include a cyanine dye, a styryl dye, a hemicyanine dye, a merocyanine dye (including zeromethine merocyanine (simple merocyanine)), a rhodacyanine dye, an allopolar dye, an oxonol dye, a hemioxonol dye, a squarylium dye, a croconium dye, an azamethine dye, a coumarin dye, an arylidene dye, an anthraquinone dye, a triphenylmethane dye, an azo dye, an azomethine dye, a metallocene dye, a fluorenone dye, a flugide dye, a perylene dye, a phenazine dye, a phenothiazine dye, a quinone dye, a diphenylmethane dye, a polyene dye, an acridine dye, an acridinone dye, a diphenylamine dye, a quinophthalone dye, a phenoxazine dye, a phthaloperylene dye, a dioxane dye, a porphyrin dye, a chlorophyll dye, a phthalocyanine dye, a subphthalocyanine dye, and a metal complex dye.

The molecular weight of the n-type organic semiconductor is preferably <NUM>-<NUM>, and more preferably <NUM>-<NUM>.

From the point that the photoelectric conversion film in the photoelectric conversion element according to the embodiment of the present invention is suitably used as an organic photoelectric conversion film that receives (absorbs) green light and performs photoelectrically conversion, it is preferable that the n-type organic semiconductor is colorless or has an absorption maximum wavelength and/or an absorption waveform close to that of the specific compound, and as the specific value, the absorption maximum wavelength of the n-type organic semiconductor is preferably <NUM> or less or in the range of <NUM>-<NUM>.

It is preferable that the photoelectric conversion film has a bulk hetero structure formed in a state in which the specific compound and the n-type organic semiconductor are mixed. The bulk hetero structure refers to a layer in which the specific compound and the n-type organic semiconductor are mixed and dispersed in the photoelectric conversion film. The photoelectric conversion film having the bulk hetero structure can be formed by either a wet method or a dry method. The bulk hetero structure is described in detail in, for example, paragraphs [<NUM>]-[<NUM>] of <CIT>.

From the viewpoint of responsiveness of the photoelectric conversion element, the content of the specific compound to the total content of the specific compound and the n-type organic semiconductor (= film thickness in terms of single layer of specific compound/(film thickness in terms of single layer of specific compound + film thickness in terms of single layer of n-type organic semiconductor) × <NUM>) is preferably <NUM>-<NUM> volume%, and more preferably <NUM>-<NUM> volume%.

Also, in a case where the photoelectric conversion film contains a p-type organic semiconductor described below, the content of the specific (= film thickness in terms of single layer of specific compound/(film thickness in terms of single layer of specific compound + film thickness in terms of single layer of n-type organic semiconductor + film thickness in terms of single layer of p-type organic semiconductor) × <NUM>) is preferably <NUM>-<NUM> volume%, and more preferably <NUM>-<NUM> volume%.

It is preferable that the photoelectric conversion film is substantially formed of the specific compound and the n-type organic semiconductor. The term "substantially" means that the total content of the specific compound and the n-type organic semiconductor to the total mass of the photoelectric conversion film is <NUM> mass% or more.

The n-type organic semiconductor contained in the photoelectric conversion film may be used alone or in combination of two or more.

In addition to the specific compound and the n-type organic semiconductor, the photoelectric conversion film may further contain the p-type organic semiconductor. Examples of the p-type organic semiconductor include the compounds shown below.

The p-type organic semiconductor here means a p-type organic semiconductor which is a compound different from the specific compound. In a case where the photoelectric conversion film contains the p-type organic semiconductor, the p-type organic semiconductor may be used alone or in combination of two or more.

The p-type organic semiconductor is a donor organic semiconductor material (a compound), and refers to an organic compound having a property of easily donating an electron. More specifically, the p-type organic semiconductor means an organic compound having a smaller ionization potential in a case where two organic compounds are used in contact with each other.

Examples of p-type organic semiconductors include triarylamine compounds (for example, N, N'-bis (<NUM>-methylphenyl)-(<NUM>,<NUM>'-biphenyl)-<NUM>,<NUM>'-diamine (TPD), <NUM>,<NUM>'-bis [N-(naphthyl)-N-Phenyl-amino] biphenyl (α-NPD), the compounds disclosed in paragraphs [<NUM>]-[<NUM>] of <CIT>, the compounds disclosed in paragraphs [<NUM>]-[<NUM>] of <CIT>, the compounds disclosed in paragraphs [<NUM>]-[<NUM>] of <CIT>, the compounds disclosed in paragraphs [<NUM>]-[<NUM>] of <CIT>, and the compounds disclosed in paragraphs [<NUM>]-[<NUM>] of <CIT>, pyrazoline compounds, styrylamine compounds, hydrazone compounds, polysilane compounds, thiophene compounds (for example, a thienothiophene derivative, a dibenzothiophene derivative, a benzodithiophene derivative, a dithienothiophene derivative, a [<NUM>] benzothieno [<NUM>,<NUM>-b] thiophene (BTBT) derivative, a thieno [<NUM>,<NUM>-f: <NUM>,<NUM>-f] bis [<NUM>] benzothiophene (TBBT) derivative, the compounds disclosed in paragraphs [<NUM>]-[<NUM>] of <CIT>, the compounds disclosed in paragraphs [<NUM>]-[<NUM>] of <CIT>, the compounds disclosed in paragraphs [<NUM>]-[<NUM>], and [<NUM>]-[<NUM>] of <CIT>, the compounds disclosed in paragraphs [<NUM>]-[<NUM>] of <CIT>, a cyanine compound, an oxonol compound, a polyamine compound, an indole compound, a pyrrole compound, a pyrazole compound, a polyarylene compound, a fused aromatic carbocyclic compound (for example, a naphthalene derivative, an anthracene derivative, a phenanthrene derivative, a tetracene derivative, a pentacene derivative, a pyrene derivative, a perylene derivative, and a fluoranthene derivative), a porphyrin compound, a phthalocyanine compound, a triazole compound, an oxadiazole compound, an imidazole compound, a polyarylalkane compound, a pyrazolone compound, an amino-substituted chalcone compound, an oxazole compound, a fluorenone compound, a silazane compound, and a metal complex having nitrogen-containing heterocyclic compounds as ligands.

Examples of the p-type organic semiconductor include compounds having an ionization potential smaller than that of the n-type organic semiconductor, and in a case where this condition is satisfied, the organic dyes exemplified as the n-type organic semiconductor can be used.

The compounds that can be used as the p-type semiconductor compound are exemplified below. <CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

The photoelectric conversion film containing the specific compound is a non-luminescent film, and has a feature different from an organic light emitting diode (OLED). The non-luminescent film means a film having a luminescence quantum efficiency of ≤ <NUM>%, and the luminescence quantum efficiency is preferably ≤ <NUM>%, and more preferably ≤ <NUM>%.

The photoelectric conversion film can be formed mostly by a dry film formation method. Examples of the dry film formation method include a physical vapor deposition method such as a vapor deposition method (in particular, a vacuum evaporation method), a sputtering method, an ion plating method, and molecular beam epitaxy (MBE), and chemical vapor deposition (CVD) such as plasma polymerization. Among these, the vacuum evaporation method is preferable. In a case where the photoelectric conversion film is formed by the vacuum evaporation method, producing conditions such as a degree of vacuum and a vapor deposition temperature can be set according to the normal method.

The thickness of the photoelectric conversion film is preferably <NUM>-<NUM>, more preferably <NUM>-<NUM>, still more preferably <NUM>-<NUM>, and particularly preferably <NUM>-<NUM>.

The electrode (the upper electrode (the transparent conductive film) <NUM> and the lower electrode (the conductive film) <NUM>) is formed of a conductive material. Examples of the conductive material include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof.

Since light is incident through the upper electrode <NUM>, the upper electrode <NUM> is preferably transparent to light to be detected. Examples of the material forming the upper electrode <NUM> include conductive metal oxides such as tin oxide (ATO, FTO) doped with antimony, fluorine, or the like, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); metal thin films such as gold, silver, chromium, and nickel; mixtures or laminates of these metals and the conductive metal oxides; and organic conductive materials such as polyaniline, polythiophene, and polypyrrole. Among these, conductive metal oxides are preferable from the viewpoints of high conductivity, transparency, and the like.

In general, in a case where the conductive film is made to be thinner than a certain range, a resistance value is rapidly increased. However, in the solid-state imaging element into which the photoelectric conversion element according to the present embodiment is incorporated, the sheet resistance is preferably <NUM>-<NUM>Ω/□, and the degree of freedom of the range of the film thickness that can be thinned is large. In addition, as the thickness of the upper electrode (the transparent conductive film) <NUM> is thinner, the amount of light that the upper electrode absorbs becomes smaller, and the light transmittance usually increases. The increase in the light transmittance causes an increase in light absorbance in the photoelectric conversion film and an increase in the photoelectric conversion ability, which is preferable. Considering the suppression of leakage current, an increase in the resistance value of the thin film, and an increase in transmittance accompanied by the thinning, the film thickness of the upper electrode <NUM> is preferably <NUM>-<NUM>, and more preferably <NUM>-<NUM>.

There is a case where the lower electrode <NUM> has transparency or an opposite case where the lower electrode does not have transparency and reflects light, depending on the application. Examples of a material constituting the lower electrode <NUM> include conductive metal oxides such as tin oxide (ATO, FTO) doped with antimony, fluorine, or the like, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); metals such as gold, silver, chromium, nickel, titanium, tungsten, and aluminum, conductive compounds (for example, titanium nitride (TiN)) such as oxides or nitrides of these metals; mixtures or laminates of these metals and conductive metal oxides; and organic conductive materials such as polyaniline, polythiophene, and polypyrrole.

The method of forming electrodes is not particularly limited, and can be appropriately selected in accordance with the electrode material. Specific examples thereof include a wet method such as a printing method and a coating method; a physical method such as a vacuum evaporation method, a sputtering method, and an ion plating method; and a chemical method such as a CVD method and a plasma CVD method.

In a case where the material of the electrode is ITO, examples thereof include an electron beam method, a sputtering method, a resistance thermal vapor deposition method, a chemical reaction method (such as a sol-gel method), and a coating method with a dispersion of indium tin oxide.

It is also preferable that the photoelectric conversion element according to the embodiment of the present invention has one or more interlayers between the conductive film and the transparent conductive film, in addition to the photoelectric conversion film. Example of the interlayer includes the charge blocking film. In the case where the photoelectric conversion element has this film, the characteristics (such as photoelectric conversion efficiency and responsiveness) of the photoelectric conversion element to be obtained become superior. Examples of the charge blocking film include the electron blocking film and the positive hole blocking film. Hereinafter, the films will be described in detail.

The electron blocking film is a donor organic semiconductor material (a compound), and the p-type organic semiconductor described above can be used.

A polymer material can also be used as the electron blocking film.

Specific examples of a polymer material include a polymer such as phenylenevinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, and a derivative thereof.

The electron blocking film may be configured by a plurality of films.

The electron blocking film may be formed of an inorganic material. In general, an inorganic material has a dielectric constant larger than that of an organic material. Therefore, in a case where the inorganic material is used in the electron blocking film, a large voltage is applied to the photoelectric conversion film. Therefore, the photoelectric conversion efficiency increases. Examples of the inorganic material that can be used in the electron blocking film include calcium oxide, chromium oxide, copper chromium oxide, manganese oxide, cobalt oxide, nickel oxide, copper oxide, copper gallium oxide, copper strontium oxide, niobium oxide, molybdenum oxide, copper indium oxide, silver indium oxide, and iridium oxide.

A positive hole blocking film is an acceptor-property organic semiconductor material (a compound), and the n-type organic semiconductor described above can be used.

The method of producing the charge blocking film is not particularly limited, but a dry film formation method and a wet film formation method are exemplified. Examples of the dry film formation method include a vapor deposition method and a sputtering method. The vapor deposition method may be any of physical vapor deposition (PVD) method and chemical vapor deposition (CVD) method, and physical vapor deposition method such as vacuum evaporation method is preferable. Examples of the wet film formation method include an inkjet method, a spray method, a nozzle printing method, a spin coating method, a dip coating method, a casting method, a die coating method, a roll coating method, a bar coating method, and a gravure coating method, and an inkjet method is preferable from the viewpoint of high precision patterning.

Each thickness of the charge blocking films (the electron blocking film and the positive hole blocking film) is preferably <NUM>-<NUM>, more preferably <NUM>-<NUM>, and still more preferably <NUM>-<NUM>.

The photoelectric conversion element may further include a substrate. The type of substrate to be used is not particularly limited, but a semiconductor substrate, a glass substrate, and a plastic substrate are exemplified.

The position of the substrate is not particularly limited, but in general, the conductive film, the photoelectric conversion film, and the transparent conductive film are laminated on the substrate in this order.

The photoelectric conversion element may further include a sealing layer. The performance of the photoelectric conversion material may deteriorate noticeably due to the presence of deterioration factors such as water molecules. The deterioration can be prevented by sealing and coating the entirety of the photoelectric conversion film with the sealing layer such as diamond-like carbon (DLC) or ceramics such as metal oxide, or metal nitride, and metal nitride oxide which are dense and into which water molecules do not permeate.

The material of the sealing layer may be selected and the sealing layer may be produced according to the description in paragraphs [<NUM>]-[<NUM>] of <CIT>.

An example of the application of the photoelectric conversion element includes an imaging element. The imaging element is an element that converts optical information of an image into an electric signal, and usually, a plurality of photoelectric conversion elements are arranged in a matrix on the same plane, and an optical signal is converted into the electric signal in each photoelectric conversion element (pixels) to sequentially output the electric signal to the outside of the imaging element for each pixel. Therefore, each pixel is formed of one or more photoelectric conversion elements and one or more transistors.

<FIG> is a schematic cross-sectional view showing a schematic configuration of an imaging element for describing an embodiment of the present invention. This imaging element is mounted on an imaging element such as a digital camera and a digital video camera, an electronic endoscope, and imaging modules such as a cellular phone.

An imaging element 20a shown in <FIG> includes a photoelectric conversion element 10a according to the embodiment of the present invention, a blue photoelectric conversion element <NUM>, and a red photoelectric conversion element <NUM>, which are laminated along the light incident direction. As described above, the photoelectric conversion element 10a can mainly function as a green photoelectric conversion element capable of receiving green light.

The imaging element 20a is a so-called laminated type color separation imaging element. The photoelectric conversion element 10a, the blue photoelectric conversion element <NUM>, and the red photoelectric conversion element <NUM> have different wavelength spectra to be detected. That is, the blue photoelectric conversion element <NUM> and the red photoelectric conversion element <NUM> correspond to photoelectric conversion elements that receive (absorb) light having a wavelength different from a wavelength of the light received by the photoelectric conversion element 10a. The photoelectric conversion element 10a can mainly receive green light, the blue photoelectric conversion element <NUM> can mainly receive blue light, and the red photoelectric conversion element can mainly receive red light.

Green light means light in the wavelength range of <NUM>-<NUM>, blue light means light in the wavelength range of <NUM>-<NUM>, and red light means light in the wavelength range of <NUM>-<NUM>.

In a case where light is incident on the imaging element 20a in the direction of the arrow, first, green light is mainly absorbed by the photoelectric conversion element 10a, but blue light and red light are transmitted through the photoelectric conversion element 10a. In a case where the light transmitted through the photoelectric conversion element 10a travels to the blue photoelectric conversion element <NUM>, the blue light is mainly absorbed, but the red light is transmitted through the blue photoelectric conversion element <NUM>. Then, light transmitted through the blue photoelectric conversion element <NUM> is absorbed by the red photoelectric conversion element <NUM>. As described above, in the imaging element 20a, which is a laminated type color separation imaging element, one pixel can be configured with three light receiving sections of green, blue, and red, and a large area of the light receiving section can be taken.

In particular, the photoelectric conversion element 10a according to the embodiment of the present invention has a narrow absorption peak half-width, and thus absorptions of blue light and red light do not occur, and it is difficult to affect the detectability of the blue photoelectric conversion element <NUM> and the red photoelectric conversion element <NUM>.

The configurations of the blue photoelectric conversion element <NUM> and the red photoelectric conversion element <NUM> are not particularly limited.

For example, the photoelectric conversion element having a configuration in which colors are separated by using silicon using a difference in light absorption length may be used. As a more specific example, both the blue photoelectric conversion element <NUM> and the red photoelectric conversion element <NUM> may be made of silicon. In this case, as for the light including the blue light, the green light, and the red light that has entered the imaging element 20a in the direction of the arrow, the photoelectric conversion element 10a mainly receives the green light having the center wavelength, and the remaining blue light and red light are easily separated. Blue light and red light have different light absorption lengths for silicon (wavelength dependence of absorption coefficient for silicon), blue light is easily absorbed near the surface of silicon, and red light can penetrate deeper into the silicon. Based on such a difference in light absorption length, blue light is mainly received by the blue photoelectric conversion element <NUM> existing in a shallower position, and red light is mainly received by the red photoelectric conversion element <NUM> existing in a deeper position.

Further, the blue photoelectric conversion element <NUM> and the red photoelectric conversion element <NUM> may be the photoelectric conversion element (the blue photoelectric conversion element <NUM> or the red photoelectric conversion element <NUM>) having a configuration including a conductive film, an organic photoelectric conversion film having an absorption maximum for blue light or red light, and the transparent conductive film in this order.

In <FIG>, the photoelectric conversion element according to the embodiment of the present invention, the blue photoelectric conversion element, and the red photoelectric conversion element are arranged in this order from the light incident side, but the arrangement is not limited to the aspect, and may be another aspect. For example, the blue photoelectric conversion element, the photoelectric conversion element according to the embodiment of the present invention, and the red photoelectric conversion element may be arranged in this order from the light incident side.

As described above, the configuration in which the photoelectric conversion elements of the three primary colors of blue, green, and red are laminated as the imaging element is described, but the configuration may be two layers (two colors) or four layers (four colors) or more.

For example, the photoelectric conversion element 10a according to the embodiment of the present invention may be arranged on the arrayed blue photoelectric conversion element <NUM> and red photoelectric conversion element <NUM>. As needed, a color filter that absorbs light of a predetermined wavelength may be arranged on the light incident side.

The form of the imaging element is not limited to the forms shown in <FIG> and may be other forms.

For example, the photoelectric conversion element according to the embodiment of the present invention, the blue photoelectric conversion element, and the red photoelectric conversion element may be arranged in the same plane position.

Alternatively, the photoelectric conversion element may be used in a single layer. For example, blue, red, and green color filters may be arranged on the photoelectric conversion element 10a according to the embodiment of the present invention.

Examples of another application of the photoelectric conversion element include the photoelectric cell and the optical sensor, but the photoelectric conversion element according to the embodiment of the present invention is preferably used as the optical sensor. The photoelectric conversion element may be used alone as the optical sensor. Alternately, the photoelectric conversion element may be used as a line sensor in which the photoelectric conversion elements are linearly arranged or as a two-dimensional sensor in which the photoelectric conversion elements are arranged on a plane.

Hereinafter, the present invention will be described in more detail with reference to examples. The materials, usage amounts, proportion, processing contents, and processing procedures shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the following examples.

A compound (D-<NUM>) was synthesized according to the following scheme.

<NUM>,<NUM>-Difluoroaniline (<NUM>, <NUM> mmol), <NUM>-bromonaphthalene (<NUM>, <NUM> mmol), palladium (II) acetate (<NUM>, <NUM> mmol), <NUM>-dicyclohexylphosphino-<NUM>', <NUM>'-Dimethoxybiphenyl (S-Phos) (<NUM>, <NUM> mmol), cesium carbonate (<NUM>, <NUM> mmol), and toluene (<NUM>) were placed in a three-necked flask of <NUM>, and degassing and nitrogen gas replacement were performed. The solution in the flask was heated to <NUM> under a nitrogen atmosphere and stirred for <NUM> hours. Then, after cooling the solution to room temperature, the solution was added to water. The obtained organic layer was extracted with ethyl acetate, the obtained extract was washed with brine, and the washed extract was concentrated under reduced pressure. The concentrated residue was purified by silica gel column chromatography (toluene: hexane = <NUM>: <NUM>) to obtain a compound <NUM> (<NUM>, <NUM> mmol, yield <NUM>%) as a pale yellow solid.

A compound <NUM> (<NUM>, <NUM> mmol) was added to a mixed solvent of tetrahydrofuran (<NUM>) and acetic acid (<NUM>), and the obtained solution was added with an aqueous sodium nitrite solution (<NUM>, <NUM> mmol) dropwise at room temperature and reacted for <NUM> minutes. The obtained solution was extracted with toluene (<NUM>), the obtained extract was washed with water (<NUM>), and the aqueous layer was removed. Water (<NUM>) and ethanol (<NUM>) were added to the obtained organic layer containing a compound <NUM>, and the obtained solution was cooled to <NUM> in an ice bath to add zinc powder (<NUM>, <NUM>. <NUM> mmol). After acetic acid (<NUM>) was added dropwise to the obtained solution so as not to exceed <NUM>, the obtained solution was reacted at room temperature for <NUM> hours. The insoluble matter was filtered from the solution, the filtrate was collected, brine (<NUM>) was added to the filtrate to wash the organic layer, and the collected organic layer was concentrated under reduced pressure to about <NUM>. MTBE (<NUM>) and <NUM>% hydrochloric acid (<NUM>, <NUM> mmol) were added to the concentrated solution, and the mixture was stirred. The precipitated powder in the solution was filtered to collect the solid, and the collected solid was washed with MTBE and isopropanol and then dried by heating to obtain a compound <NUM> (<NUM>, <NUM> mmol, yield <NUM>%).

A compound <NUM> (<NUM>, <NUM> mmol), cyclohexyl methyl ketone (<NUM>, <NUM> mmol), and <NUM>% hexafluorophosphoric acid (<NUM>) were added to ethanol (<NUM>) and the obtained solution was heated and refluxed for <NUM> hours under a nitrogen atmosphere. The obtained solution was cooled to room temperature, <NUM> aqueous sodium hydroxide solution (<NUM>) was added to the solution for neutralization, the organic layer was extracted with MTBE, and the obtained extract was washed with brine, and the washed extract was concentrated under reduced pressure to about <NUM>.

MTBE (<NUM>) and <NUM>% hexafluorophosphoric acid (<NUM>, <NUM> mmol) were added to the concentrated solution, and the mixture was stirred. The salt of a compound <NUM> precipitated in the solution was collected by filtration, and the collected solid was washed with MTBE. The salt of the obtained compound <NUM> was added to dichloromethane (<NUM>), and a <NUM> aqueous sodium hydroxide solution (<NUM>) was added dropwise to the solution to neutralize and dissolve in dichloromethane. Dichloromethane was concentrated under reduced pressure to obtain the compound <NUM> (<NUM>, <NUM> mmol, yield <NUM>%).

Under a nitrogen atmosphere, (chloromethylene) dimethyliminium (<NUM>, <NUM> mmol) was added to dichloromethane (<NUM>), and cooled to <NUM> in an ice bath. A dichloromethane solution (<NUM>) of the compound <NUM> (<NUM>, <NUM> mmol) was added dropwise to the obtained solution, and the mixture was reacted at room temperature for <NUM> hours. A <NUM> aqueous sodium hydroxide solution (<NUM>) was added dropwise to the obtained solution to cause hydrolysis. The obtained organic layer was extracted with dichloromethane, the obtained extract was washed with brine, and the washed extract was concentrated under reduced pressure. The concentrated residue was purified by silica gel column chromatography (chloroform: ethyl acetate = <NUM>: <NUM>) to obtain a compound <NUM> (<NUM>, <NUM> mmol, yield <NUM>%) as a pale yellow solid.

A compound <NUM> (<NUM>, <NUM> mmol) and Ac3 (<NUM>, <NUM> mmol) were added to acetic anhydride (<NUM>), and the obtained solution was reacted at <NUM> for <NUM> hours under a nitrogen atmosphere. After the obtained solution was cooled to room temperature and the solvent was removed by concentration under reduced pressure, the obtained crude product was purified by silica gel column chromatography (chloroform: ethyl acetate = <NUM>: <NUM>), and the obtained compound was recrystallized from a chloroform-acetonitrile mixed solvent and washed with acetonitrile to obtain a compound (D-<NUM>) (<NUM>, <NUM> mmol, yield <NUM>%).

The obtained compound (D-<NUM>) was identified by NMR and MS.

A compound <NUM> (<NUM>, <NUM> mmol), <NUM>-methyl-<NUM>-butanone (<NUM>, <NUM> mmol), and <NUM>% hexafluorophosphoric acid (<NUM>) were added to ethanol (<NUM>) and the obtained solution was heated and refluxed for <NUM> hours under a nitrogen atmosphere. The obtained solution was cooled to room temperature, <NUM> aqueous sodium hydroxide solution (<NUM>) was added to the solution for neutralization, the organic layer was extracted with MTBE, and the obtained extract was washed with brine, and the washed extract was concentrated under reduced pressure. MTBE (<NUM>) and <NUM>% hexafluorophosphoric acid (<NUM>, <NUM> mmol) were added to the concentrated solution, and the mixture was stirred. The salt of a compound <NUM> precipitated in the solution was collected by filtration, and the collected solid was washed with MTBE. The salt of the obtained compound <NUM> was added to dichloromethane (<NUM>), and a <NUM> aqueous sodium hydroxide solution (<NUM>) was added dropwise to neutralize and dissolve in dichloromethane. The obtained dichloromethane was concentrated under reduced pressure to obtain the compound <NUM> (<NUM>, <NUM> mmol, yield <NUM>%).

Under a nitrogen atmosphere, (chloromethylene) dimethyliminium (<NUM>, <NUM> mmol) was added to dichloromethane (<NUM>), and the obtained solution was cooled to <NUM> in an ice bath. A dichloromethane solution (<NUM>) of the compound <NUM> (<NUM>, <NUM> mmol) was added dropwise to the solution, and the mixture was reacted at room temperature for <NUM> hours. A <NUM> aqueous sodium hydroxide solution (<NUM>) was added dropwise to the obtained solution to cause hydrolysis. The organic layer was extracted with dichloromethane, the obtained extract was washed with brine, and the washed extract was concentrated under reduced pressure. The concentrated residue was purified by silica gel column chromatography (chloroform: ethyl acetate = <NUM>: <NUM>) to obtain a compound <NUM> (<NUM>, <NUM> mmol, yield <NUM>%) as a pale yellow solid.

A compound (D-<NUM>) was synthesized according to the following scheme in the same manner as the compound (D-<NUM>).

A compound (D-<NUM>) was synthesized according to the following scheme with reference to the synthesis of the compound (D-<NUM>). <CHM>
MS(ESI+)m/z: <NUM> ([M + H]+).

A compound (D-<NUM>) was synthesized according to the following scheme in the same manner as the synthesis of the compound (D-<NUM>).

A compound (D-<NUM>) was synthesized according to the following scheme with reference to the synthesis of the compounds (D-<NUM>) and (D-<NUM>).

Compounds (D-<NUM>), (D-<NUM>) to (D-<NUM>), (D30) and (D-<NUM>) were synthesized according to the following scheme with reference to the synthesis of the compounds (D-<NUM>) to (D-<NUM>).

<FIG> show <NUM>H NMR spectra (<NUM>, DMSO) of the compounds (D-<NUM>) and (D-<NUM>)-(D-<NUM>), respectively.

Comparative compounds (R-<NUM>), (R-<NUM>), (R-<NUM>), and (R-<NUM>) are disclosed in <CIT>, and a comparative compound (R-<NUM>) is disclosed in <NPL> and a comparative compound (R-<NUM>) were synthesized with reference to <CIT>. <CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

The photoelectric conversion element of the form of <FIG> was produced using the obtained compound. Here, the photoelectric conversion element includes a lower electrode <NUM>, an electron blocking film 16A, a photoelectric conversion film <NUM>, and an upper electrode <NUM>.

Specifically, an amorphous ITO was formed into a film on the glass substrate by the sputtering method to form the lower electrode <NUM> (a thickness: <NUM>). Furthermore, the compound (EB-<NUM>) was formed into a film on the lower electrode <NUM> by the vacuum thermal vapor deposition method to form the electron blocking film 16A (a thickness: <NUM>).

Furthermore, the compound (D-<NUM>) and the fullerene (C<NUM>) were subjected to co-vapor deposition by the vacuum evaporation method so as to be respectively <NUM> in terms of single layer on the electron blocking film 16A to form a film in a state where the temperature of the substrate was controlled to <NUM>, and the photoelectric conversion film <NUM> having the bulk hetero structure of <NUM> was formed.

Furthermore, amorphous ITO was formed into a film on the photoelectric conversion film <NUM> by a sputtering method to form the upper electrode <NUM> (the transparent conductive film) (the thickness: <NUM>). After the SiO film was formed as the sealing layer on the upper electrode <NUM> by a vacuum evaporation method, an aluminum oxide (Al<NUM>O<NUM>) layer was formed thereon by an atomic layer chemical vapor deposition (ALCVD) method to produce a photoelectric conversion element.

Similarly, the photoelectric conversion elements were produced using the compounds (D-<NUM>) to (D-<NUM>) and comparative compounds (R-<NUM>) to (R-<NUM>). However, the comparative compound (R-<NUM>) was thermally decomposed during vapor deposition and a photoelectric conversion element could not be produced.

A voltage was applied to each of the photoelectric conversion elements manufactured in Examples and Comparative Examples so that the electric field strength was <NUM> × <NUM><NUM> V/cm.

Then, light was irradiated from the upper electrode (the transparent conductive film) side to measure the external quantum efficiency at <NUM>. The external quantum efficiency was measured using a constant energy quantum efficiency measuring device (manufactured by Optel). The irradiation light amount was <NUM>µW/cm<NUM>. Further, in order to remove the influence of the reflected light on the surface of the photoelectric conversion element, the measured value of the external quantum efficiency at <NUM> was divided by the light absorption rate at <NUM> to obtain the external quantum efficiency.

The photoelectric conversion efficiency of each photoelectric conversion element with respect to the photoelectric conversion element formed by using the compound (D-<NUM>) was evaluated as a relative value.

The relative value of the photoelectric conversion efficiency with respect to the photoelectric conversion element formed by using the compound (D-<NUM>) was assumed as "AA" in a case of ≥ <NUM>, "A" in a case of <NUM> to < <NUM>, "B" in a case of <NUM> to < <NUM>, "C" in a case of <NUM> to < <NUM>, and "D" in a case of < <NUM>. Table <NUM> shows the results.

Practically, "AA", "A" or "B" is preferable, and "AA" or "A" is more preferable.

The compound (D-<NUM>) and the fullerene (C<NUM>) were subjected to co-vapor deposition by the vacuum thermal vapor deposition method so as to be respectively <NUM> in terms of single layer to form a film in a state where the temperature of the glass substrate was controlled to <NUM>, and the photoelectric conversion film having the bulk hetero structure of <NUM> was formed.

The maximum absorption wavelength and absorption half-width of the photoelectric conversion film were measured using a spectrophotometer U3310 manufactured by Hitachi High-Tech Co. The absorption half-width represents the difference between the two wavelengths at which the light absorbance at the maximum absorption wavelength was <NUM> times that of the maximum absorption wavelength (the point at which the light absorbance at <NUM> times the maximum absorption is at the maximum absorption wavelength was observed at two points on the long wavelength side and the short wavelength side).

The maximum absorption wavelength was evaluated according to the following criteria. The results are summarized in Table <NUM>.

The absorption half-width was evaluated according to the following criteria. The results are summarized in Table <NUM>.

Practically, the absorption half-width is preferably "AA", "A" or "B", and more preferably "AA" or "A".

The compound (D-<NUM>) was changed to the compounds (D-<NUM>) to (D-<NUM>) and the comparative compounds (R-<NUM>) to (R-<NUM>), and the same evaluations as above were carried out.

The "Formula " column indicates which compound of the examples falls under (2b-<NUM>) or (2b-<NUM>).

As shown in Table <NUM>, in the photoelectric conversion element according to the embodiment of the present invention, the half-width of the absorption peak of the photoelectric conversion film was narrow.

It was confirmed that the performance of the photoelectric conversion element according to the embodiment of the present invention is "A" or higher in all evaluation items of <NUM>-<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>-<NUM>, <NUM> and <NUM> (are)).

In a case where in the specific compound of Formula (2b-<NUM>) or (2b-<NUM>), Res is a group of Formula (5Aor (5B), or a naphthyl group which may have a substituent, it was confirmed that the performance of the photoelectric conversion element according to the embodiment of the present invention is particularly better (results of Examples <NUM>-<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>-<NUM> and <NUM> (all evaluation items are "A" or higher and "AA" evaluation item is present)).

The same imaging element as shown in <FIG> was produced using the compounds (D-<NUM>) to (D-<NUM>).

The photoelectric conversion element functioning as a green photoelectric conversion element was produced by the method described above.

The blue photoelectric conversion element and the red photoelectric conversion element were produced with reference to the description of <CIT>.

Claim 1:
A compound of formula (2b-<NUM>) or (2b-<NUM>):
<CHM>
<CHM>
wherein
Rc<NUM> is an optionally substituted polycyclic aromatic ring, or a group of formula (4A):
<CHM>
wherein
T<NUM>-T<NUM> each independently are N or CRe12 wherein Re12 each independently is H or a substituent, and if a plurality of Re12s are present they may bond to each other to form a non-aromatic ring containing no aromatic ring structure, and
Rf2 is alkyl, cyano, optionally substituted aryl, or optionally substituted heteroaryl;
R<NUM>, R<NUM> each independently are a substituent, and R<NUM> and R<NUM> may bond to each other to form a ring,
R<NUM>, R<NUM> each independently are H or a substituent,
R<NUM>-R<NUM> each independently are H or a substituent, and R<NUM>-R<NUM> and R<NUM>-R<NUM> may bond to each other to form a non-aromatic ring containing no aromatic ring structure or a fluorene ring,
Rg<NUM>-Rg<NUM> each independently are H or a substituent, and Rg<NUM>-Rg<NUM> may bond to each other to form a ring,
in formula (2b-<NUM>) the total number of carbon atoms contained in Res, R<NUM>, R<NUM>, and R<NUM>-R<NUM> is >_ <NUM>, and
in formula (2b-<NUM>) the total number of carbon atoms contained in R<NUM> and R<NUM> is ≥ <NUM>, and the total number of carbon atoms contained in Rc<NUM>, R<NUM>, R<NUM>, and R<NUM>-R<NUM> is ≥ <NUM>.