JP2014197595A - Photoelectric conversion device, image pickup device, and optical sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion device superior in responsiveness and heat resistance.SOLUTION: A photoelectric conversion device comprises a conductive film, a photoelectric conversion film including a photoelectric conversion material, and a transparent conductive film which are stacked in this order. The photoelectric conversion material includes a compound expressed by the general formula (1).

Description

  The present invention relates to a photoelectric conversion element, an imaging element, and an optical sensor.

  A conventional optical sensor is an element in which a photodiode (PD) is formed in a semiconductor substrate such as silicon (Si). As a solid-state image sensor, signal charges generated in each PD are arranged in two dimensions. Are widely used.

In order to realize a color solid-state imaging device, a structure in which a color filter that transmits light of a specific wavelength is arranged on the light incident surface side of the flat solid-state imaging device is generally used. Color filters that transmit blue (B) light, green (G) light, and red (R) light are regularly arranged on each two-dimensionally arranged PD that is currently widely used in digital cameras and the like. Single-plate solid-state imaging devices are well known.
In this single-plate solid-state imaging device, the light that has not passed through the color filter is not used and the light use efficiency is poor. In recent years, as the number of pixels has increased, the pixel size has been reduced, and a decrease in aperture ratio and a decrease in light collection efficiency have become problems.

In order to solve these drawbacks, a structure is known in which a photoelectric conversion film made of amorphous silicon or a photoelectric conversion film is formed on a signal readout substrate.
There are some known examples of photoelectric conversion elements, imaging elements, and optical sensors using a photoelectric conversion film.
For example, Patent Document 1 discloses an imaging device using a photoelectric conversion film using a coumarin compound represented by the following formula.

JP 2006-100502 A

In recent years, along with demands for improving the performance of imaging devices, optical sensors, etc., improvements have also been required for various characteristics such as responsiveness and heat resistance required for photoelectric conversion films used for these. Note that excellent heat resistance means that the increase in dark current value after element heating is small.
When the present inventors made a photoelectric conversion film using the coumarin compound (53) disclosed in the Example column of Patent Document 1, the level required in recent years in terms of responsiveness and heat resistance. It was not reached, and it was found that further improvement was necessary.

An object of this invention is to provide the photoelectric conversion element which shows the outstanding responsiveness and heat resistance in view of the said situation.
Another object of the present invention is to provide an image sensor and a photosensor including a photoelectric conversion element.

As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by using a photoelectric conversion film containing a compound represented by the following general formula (1), and to complete the present invention. It came.
That is, the above problems can be solved by the following means.

(1) A photoelectric conversion element formed by laminating a conductive film, a photoelectric conversion film containing a photoelectric conversion material, and a transparent conductive film in this order,
The photoelectric conversion element in which a photoelectric conversion material contains the compound represented by General formula (1) mentioned later.
(2) The photoelectric conversion element according to (1), wherein A represents a group represented by General Formula (Z-1) described later, or * = C (CN) ₂ .
(3) The photoelectric conversion element according to (1) or (2), wherein any one of Ar ¹ and R ¹ and Ar ² and R ⁷ is bonded to each other to form a ring.
(4) The photoelectric conversion element according to any one of (1) to (3), wherein R ³ represents an aryl group or a heteroaryl group.
(5) The photoelectric conversion element according to any one of (1) to (4), wherein the photoelectric conversion film further contains an organic n-type compound.
(6) The photoelectric conversion element according to (5), wherein the organic n-type compound contains fullerene or a derivative thereof.
(7) a fullerene or its derivative, a fullerene C _60, a photoelectric conversion element according to (6).
(8) The volume ratio of the compound represented by the general formula (1) to be described later and fullerene or a derivative thereof (volume of the compound represented by the general formula (1) / volume of fullerene or a derivative thereof) is 10 to 50 volumes. % Of the photoelectric conversion element according to (6) or (7).
(9) The photoelectric conversion element according to any one of (1) to (8), wherein a charge blocking film is disposed between the conductive film and the transparent conductive film.
(10) An imaging device including the photoelectric conversion device according to any one of (1) to (9).
(11) An optical sensor including the photoelectric conversion element according to any one of (1) to (9).

ADVANTAGE OF THE INVENTION According to this invention, the photoelectric conversion element which shows the outstanding responsiveness and heat resistance can be provided.
Moreover, according to this invention, the image pick-up element and optical sensor containing a photoelectric conversion element can be provided.

FIG. 1A and FIG. 1B are schematic cross-sectional views each showing a configuration example of a photoelectric conversion element. It is a cross-sectional schematic diagram for 1 pixel of an image pick-up element.

Below, the suitable embodiment of the photoelectric conversion element of this invention is demonstrated.
First, the feature point compared with the prior art of this invention is explained in full detail.
As described above, in the present invention, it has been found that a desired effect can be obtained by using a photoelectric conversion film containing a compound having a predetermined structure.

Below, the suitable embodiment of the photoelectric conversion element of this invention is demonstrated with reference to drawings. In FIG. 1, the cross-sectional schematic diagram of one Embodiment of the photoelectric conversion element of this invention is shown.
A photoelectric conversion element 10a shown in FIG. 1A includes a conductive film (hereinafter also referred to as a lower electrode) 11 that functions as a lower electrode, an electron blocking film 16A formed on the lower electrode 11, and an electron blocking film 16A. The photoelectric conversion film 12 formed above and a transparent conductive film (hereinafter also referred to as an upper electrode) 15 functioning as an upper electrode are stacked in this order.
FIG. 1B shows a configuration example of another photoelectric conversion element. The photoelectric conversion element 10b shown in FIG. 1B has a configuration in which an electron blocking film 16A, a photoelectric conversion film 12, a hole blocking film 16B, and an upper electrode 15 are laminated on the lower electrode 11 in this order. Have. Note that the stacking order of the electron blocking film 16A, the photoelectric conversion film 12, and the hole blocking film 16B in FIGS. 1A and 1B may be reversed depending on the application and characteristics. For example, the positions of the electron blocking film 16A and the photoelectric conversion film 12 may be reversed.

In the configuration of the photoelectric conversion element 10 a (10 b), it is preferable that light is incident on the photoelectric conversion film 12 through the transparent conductive film 15.
Moreover, when using the photoelectric conversion element 10a (10b), an electric field can be applied. In this case, it is preferable that the conductive film 11 and the transparent conductive film 15 form a pair of electrodes, and an electric field of 1 × 10 ⁻⁵ to 1 × 10 ⁷ V / cm is applied between the pair of electrodes. From the viewpoint of performance and power consumption, an electric field of 1 × 10 ⁻⁴ to 1 × 10 ⁶ V / cm is preferable, and an electric field of 1 × 10 ^{−3 to} 5 × 10 ⁵ V / cm is particularly preferable.
In addition, about the voltage application method, in FIG. 1 (a) and (b), it is preferable to apply so that the electron blocking film | membrane 16A side may become a cathode and the photoelectric converting film 12 side may become an anode. When the photoelectric conversion element 10a (10b) is used as an optical sensor, or when it is incorporated into an image sensor, voltage can be applied by the same method.

Below, the aspect of each layer (The photoelectric conversion film 12, the electron blocking film | membrane 16A, the lower electrode 11, the upper electrode 15, the hole blocking film | membrane 16B etc.) which comprises the photoelectric conversion element 10a (10b) is explained in full detail.
First, the photoelectric conversion film 12 will be described in detail.

[Photoelectric conversion film]
The photoelectric conversion film 12 is a film containing a compound represented by the following general formula (1) as a photoelectric conversion material. By using this compound, a photoelectric conversion element exhibiting excellent photoelectric conversion efficiency, responsiveness and heat resistance can be obtained.
First, the compound represented by the general formula (1) used in the photoelectric conversion film 12 will be described in detail.

In general formula (1), R < ¹ > -R < ⁷ > represents a hydrogen atom or a substituent each independently. Substituent W mentioned later is mentioned as a substituent, but it has the aryl group which may have a substituent, or a substituent in the point that the characteristic (responsiveness or heat resistance) of a photoelectric conversion element is more excellent. The heteroaryl group which may be sufficient is mentioned preferably.
Among these, R ³ is an aryl group which may have a substituent or a heteroaryl group which may have a substituent in that the characteristics (responsiveness or heat resistance) of the photoelectric conversion element are more excellent. It is preferable. The definitions of the aryl group and heteroaryl group will be described in detail later. Moreover, it is preferable that R < ¹ > -R < ² >, R < ⁴ > -R < ⁷ > is a hydrogen atom at the point which the characteristic (responsiveness or heat resistance) of a photoelectric conversion element is more excellent.

Ar ¹ and Ar ² each independently represents an aryl group or a heteroaryl group.
Although carbon number in an aryl group is not specifically limited, 6-30 are preferable and 6-18 are more preferable at the point which the characteristic (responsiveness or heat resistance) of a photoelectric conversion element is more excellent. The aryl group may be a monocyclic structure or a condensed ring structure in which two or more rings are condensed, and may have a substituent W described later.
Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a pyrenyl group, a phenanthrenyl group, a methylphenyl group, a dimethylphenyl group, a biphenyl group, and a fluorenyl group. A phenyl group, a naphthyl group, or an anthryl group is exemplified. Preferably, a phenyl group or a naphthyl group is more preferable.

The number of carbon atoms in the heteroaryl group (monovalent aromatic heterocyclic group) is not particularly limited, but is preferably 3 to 30, more preferably 3 to 18 in terms of more excellent characteristics (responsiveness or heat resistance) of the photoelectric conversion element. Is more preferable. The heteroaryl group may have a substituent W described later.
The heteroaryl group includes a heteroatom other than a carbon atom and a hydrogen atom. Examples of the heteroatom include a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a phosphorus atom, a silicon atom, or a boron atom. And a nitrogen atom, a sulfur atom, or an oxygen atom is preferable. The number of heteroatoms contained in the heteroaryl group is not particularly limited, and is usually about 1 to 10, preferably 1 to 4, more preferably 1 to 3, and further preferably 1 to 2.
The number of members of the heteroaryl group is not particularly limited, but is preferably a 3- to 8-membered ring, more preferably a 5- to 7-membered ring, and particularly preferably a 5- to 6-membered ring.
Examples of heteroaryl groups include pyridyl, quinolyl, isoquinolyl, acridinyl, phenanthridinyl, pteridinyl, pyrazinyl, quinoxalinyl, pyrimidinyl, quinazolyl, pyridazinyl, cinnolinyl, phthalazinyl, Triazinyl group, oxazolyl group, benzoxazolyl group, thiazolyl group, benzothiazolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, indazolyl group, isoxazolyl group, benzisoxazolyl group, isothiazolyl group, benzoisothiazolyl group, oxadiazolyl Group, thiadiazolyl group, triazolyl group, tetrazolyl group, furyl group, benzofuryl group, thienyl group, benzothienyl group, dibenzofuryl group, dibenzothienyl group, pyrrolyl group, indoline Group, imidazopyridinyl group, and carbazolyl group.

Ar ¹ and Ar ² , Ar ¹ and R ¹ , or Ar ² and R ⁷ may be bonded to each other to form a ring. In particular, Ar ¹ and R ¹ , and Ar ² and R ⁷ are bonded to each other to form a ring from the viewpoint of more excellent characteristics (responsiveness or heat resistance) of the photoelectric conversion element. Is preferred.
At the time of bonding, Ar ¹ and Ar ² , Ar ¹ and R ¹ , Ar ² and R ⁷ are bonded to each other directly or via a linking group to form a ring.
The structure of the linking group is not particularly limited. For example, an oxygen atom, a sulfur atom, an alkylene group, a silylene group, an alkenylene group, a cycloalkylene group, a cycloalkenylene group, an arylene group, a divalent heterocyclic group, an imino group, Or the group which combined these is mentioned, These may have a substituent further. An alkylene group, an oxygen atom, an imino group, an arylene group and the like are preferable.

  X represents an oxygen atom or a sulfur atom. Especially, an oxygen atom is preferable at the point which the characteristic (responsiveness or heat resistance) of a photoelectric conversion element is more excellent.

A represents an oxygen atom, a sulfur atom, N—R ^N , or CR ^C1 R ^C2 . Among these, CR ^C1 R ^C2 is preferable in that the characteristics (responsiveness or heat resistance) of the photoelectric conversion element are more excellent. R ^C1 and R ^C2 may be bonded to each other to form a ring.
R ^N , R ^C1 and R ^C2 each independently represent a substituent. Although there are substituents W, which will be described later as the substituent, in that the characteristics of the photoelectric conversion element (responsive or heat resistance) is more excellent, R ^N represents a cyano group, an alkyl group or an aryl group, preferably, R ^C1 and R ^C2 is preferably each independently a cyano group, an alkyl group, an aryl group, an acyl group, or an alkoxycarbonyl group.

Among these, as a preferred embodiment of A, a group represented by the general formula (Z1) or * = C (CN) ₂ is preferable in that the characteristics (responsiveness or heat resistance) of the photoelectric conversion element are more excellent. Can be mentioned. * Indicates a binding position.

In the general formula (Z1), Z is a ring which contains at least two carbon atoms and may have a substituent, and is a 5-membered ring, a 6-membered ring, or a 5-membered ring and a 6-membered ring. A condensed ring containing at least one of them is represented. As a condensed ring containing at least one of a 5-membered ring, a 6-membered ring, and a 5-membered ring and a 6-membered ring, those usually used as an acidic nucleus in a merocyanine dye are preferable, and specific examples thereof include the following: Is mentioned.
Note that * represents a binding position.

(A) 1,3-dicarbonyl nucleus: For example, 1,3-indandione nucleus, 1,3-cyclohexanedione, 5,5-dimethyl-1,3-cyclohexanedione, 1,3-dioxane-4,6 -Dione etc.
(B) pyrazolinone nucleus: for example, 1-phenyl-2-pyrazolin-5-one, 3-methyl-1-phenyl-2-pyrazolin-5-one, 1- (2-benzothiazolyl) -3-methyl-2- Pyrazolin-5-one and the like.
(C) Isoxazolinone nucleus: For example, 3-phenyl-2-isoxazolin-5-one, 3-methyl-2-isoxazolin-5-one and the like.
(D) Oxindole nucleus: For example, 1-alkyl-2,3-dihydro-2-oxindole and the like.
(E) 2,4,6-trioxohexahydropyrimidine nucleus: for example, barbituric acid or 2-thiobarbituric acid and its derivatives. Examples of the derivatives include 1-alkyl compounds such as 1-methyl and 1-ethyl, 1,3-dialkyl compounds such as 1,3-dimethyl, 1,3-diethyl and 1,3-dibutyl, 1,3-diaryls such as diphenyl, 1,3-di (p-chlorophenyl), 1,3-di (p-ethoxycarbonylphenyl), 1-alkyl-1-aryls such as 1-ethyl-3-phenyl And 1,3-diheteroaryls such as 1,3-di (2-pyridyl) and the like.
(F) 2-thio-2,4-thiazolidinedione nucleus: for example, rhodanine and derivatives thereof. Examples of the derivatives include 3-alkylrhodanine such as 3-methylrhodanine, 3-ethylrhodanine and 3-allylrhodanine, 3-arylrhodanine such as 3-phenylrhodanine, and 3- (2-pyridyl). And 3-heteroaryl rhodanine such as rhodanine.

(G) 2-thio-2,4-oxazolidinedione (2-thio-2,4- (3H, 5H) -oxazoledione nucleus: for example, 3-ethyl-2-thio-2,4-oxazolidinedione and the like.
(H) Tianaphthenone nucleus: For example, 3 (2H) -thianaphthenone-1,1-dioxide and the like.
(I) 2-thio-2,5-thiazolidinedione nucleus: For example, 3-ethyl-2-thio-2,5-thiazolidinedione and the like.
(J) 2,4-thiazolidinedione nucleus: For example, 2,4-thiazolidinedione, 3-ethyl-2,4-thiazolidinedione, 3-phenyl-2,4-thiazolidinedione and the like.
(K) Thiazolin-4-one nucleus: For example, 4-thiazolinone, 2-ethyl-4-thiazolinone and the like.
(L) 2,4-imidazolidinedione (hydantoin) nucleus: for example, 2,4-imidazolidinedione, 3-ethyl-2,4-imidazolidinedione, etc.
(M) 2-thio-2,4-imidazolidinedione (2-thiohydantoin) nucleus: for example, 2-thio-2,4-imidazolidinedione, 3-ethyl-2-thio-2,4-imidazolidine Zeon etc.
(N) Imidazolin-5-one nucleus: For example, 2-propylmercapto-2-imidazolin-5-one and the like.
(O) 3,5-pyrazolidinedione nucleus: for example, 1,2-diphenyl-3,5-pyrazolidinedione, 1,2-dimethyl-3,5-pyrazolidinedione and the like.
(P) Benzothiophene-3 (2H) -one nucleus: for example, benzothiophene-3 (2H) -one, oxobenzothiophene-3 (2H) -one, dioxobenzothiophene-3 (2H) -one and the like.
(Q) Indanone nucleus: For example, 1-indanone, 3-phenyl-1-indanone, 3-methyl-1-indanone, 3,3-diphenyl-1-indanone, 3,3-dimethyl-1-indanone and the like.
(R) Benzofuran-3- (2H) -one nucleus: for example, benzofuran-3- (2H) -one and the like.
(S) 2,2-dihydrophenalene-1,3-dione nucleus and the like.
These may further have a substituent, and another ring may be condensed.

The ring represented by Z ₁ is preferably a 1,3-dicarbonyl nucleus, a 2,4,6-trioxohexahydropyrimidine nucleus, a thianaphthenone nucleus, a benzothiophene-3 (2H) -one nucleus, a benzofuran-3- (2H) -one nucleus, indanone nucleus, 2,2-dihydrophenalene-1,3-dione nucleus, more preferably 1,3-dicarbonyl nucleus, 2,4,6-trioxotohexahydropyrimidine nucleus (Benzothiophene-3 (2H) -one nucleus, benzofuran-3- (2H) -one nucleus, indanone nucleus, 2,2-dihydrophenalene-1,3-dione nucleus, more preferably 1,3- A dicarbonyl nucleus, a benzofuran-3- (2H) -one nucleus, an indanone nucleus, and a 2,2-dihydrophenalene-1,3-dione nucleus.

  In addition, when Z has a substituent, the substituent W mentioned later is mentioned as the substituent.

  The ring represented by Z is preferably represented by the following general formula (Z2) in that the characteristics (responsiveness or heat resistance) of the photoelectric conversion element are more excellent.

Z ¹ is a ring containing at least 3 carbon atoms and represents a 5-membered ring, a 6-membered ring, or a condensed ring containing at least one of a 5-membered ring and a 6-membered ring. * Represents a binding position.

Z ¹ can be selected from the ring formed by Z, and is preferably a 1,3-dicarbonyl nucleus, particularly preferably a 1,3-indandione nucleus and derivatives thereof.

In the case where the ring represented by Z ¹ is a 1,3-indandione nucleus, the group represented by the following general formula (Z3) or the following general formula is preferred in that the characteristics (responsiveness or heat resistance) of the photoelectric conversion element are more excellent. The case where it is group represented by a formula (Z4) is preferable. * Represents a binding position. In addition, the group represented by general formula (Z4) is preferable at the point which the characteristic (responsiveness or heat resistance) of a photoelectric conversion element is more excellent.

In the group represented by the general formula (Z3), R ^{11 to} R ¹⁴ each independently represents a hydrogen atom or a substituent. As the substituent, for example, those mentioned below as the substituent W can be applied, and preferably an alkyl group, an aryl group, a chlorine atom, or a fluorine atom. Two adjacent R ^{11 to} R ¹⁴ may be bonded to each other to form a ring. In the case of forming a ring, it is preferable that R ¹² and R ¹³ are bonded to form a ring (for example, a benzene ring, a pyridine ring, a pyrazine ring).

In the group represented by the general formula (Z4), R ^{21 to} R ²⁶ each independently represents a hydrogen atom or a substituent. As the substituent, for example, those mentioned below as the substituent W can be applied, and preferably an alkyl group, an aryl group, a chlorine atom, or a fluorine atom.

It describes about the substituent W in this specification.
Examples of the substituent W include a halogen atom, an alkyl group (including a cycloalkyl group, a bicycloalkyl group, and a tricycloalkyl group), an alkenyl group (including a cycloalkenyl group and a bicycloalkenyl group), an alkynyl group, an aryl group, and a heterocyclic ring. Group (may be referred to as a heterocyclic group), cyano group, hydroxy group, nitro group, carboxy group, alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group , Aryloxycarbonyloxy group, amino group (including anilino group), ammonio group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkyl or arylsulfonylamino Group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, sulfo group, alkyl or arylsulfinyl group, alkyl or arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, carbamoyl group, aryl Alternatively, a heterocyclic azo group, imide group, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, phosphono group, silyl group, hydrazino group, ureido group, boronic acid group (-B (OH) ₂ ) , Phosphato groups (—OPO (OH) ₂ ), sulfato groups (—OSO ₃ H), and other known substituents.
The details of the substituent W are described in paragraph [0023] of JP-A-2007-234651.

  Below, the compound represented by General formula (1) is illustrated.

The compound represented by the general formula (1) preferably has an absorption maximum at 400 nm or more and less than 720 nm in the ultraviolet-visible absorption spectrum. The peak wavelength (absorption maximum wavelength) of the absorption spectrum is more preferably 450 nm or more and 700 nm or less, more preferably 480 nm or more and 700 nm or less, and more preferably 510 nm or more and 680 nm or less from the viewpoint of broadly absorbing light in the visible region. Particularly preferred.
The absorption maximum wavelength of the compound can be measured by using a chloroform solution of the compound with UV-2550 manufactured by Shimadzu Corporation. The concentration of the chloroform solution is preferably 5 × 10 ⁻⁵ to 1 × 10 ⁻⁷ mol / l, more preferably 3 × 10 ⁻⁵ to 2 × 10 ⁻⁶ mol / l, and 2 × 10 ^{−5 to} 5 × 10 ^{−. 6} mol / l is particularly preferred.

The compound represented by the general formula (1) has an absorption maximum at 400 nm or more and less than 720 nm in the ultraviolet-visible absorption spectrum, and the molar extinction coefficient at the absorption maximum wavelength is 10,000 mol ⁻¹ · l · cm ⁻¹ or more. Is preferred. In order to reduce the film thickness of the photoelectric conversion film and obtain an element having high charge collection efficiency, high-speed response, and high sensitivity characteristics, a material having a large molar extinction coefficient is preferable. More preferably 30000mol ^-1 · l · cm ^-1 or more as a molar extinction coefficient of the compound represented by the general formula (1), more preferably 50000mol ^-1 · l · cm ^-1 or more. The molar extinction coefficient of the compound represented by the general formula (1) is measured with a chloroform solution.

  The larger the difference between the melting point and the deposition temperature (melting point-deposition temperature), the more the compound represented by the general formula (1) is more easily decomposed during deposition, and the higher the temperature, the greater the deposition rate. Further, the difference between the melting point and the deposition temperature (melting point−deposition temperature) is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, still more preferably 60 ° C. or higher, and particularly preferably 80 ° C. or higher.

  300-1500 are preferable, as for the molecular weight of the compound represented by General formula (1), 500-1000 are more preferable, and 500-900 are especially preferable. When the molecular weight of the compound is 1500 or less, the deposition temperature does not increase and the compound is hardly decomposed. If the molecular weight of the compound is 300 or more, the glass transition point of the deposited film is not lowered, and the heat resistance of the device is hardly lowered.

  The glass transition point (Tg) of the compound represented by the general formula (1) is preferably 95 ° C or higher, more preferably 110 ° C or higher, further preferably 135 ° C or higher, particularly preferably 150 ° C or higher, and 160 ° C or higher. Most preferred. A high glass transition point is preferable because the heat resistance of the device is improved.

  The compound represented by the general formula (1) is particularly useful as a material for a photoelectric conversion film used for an image sensor, a photosensor, or a photovoltaic cell. In general, the compound represented by the general formula (1) functions as an organic p-type compound in the photoelectric conversion film. As other applications, it can also be used as a coloring material, a liquid crystal material, an organic semiconductor material, an organic EL material, a charge transport material, a pharmaceutical material, a fluorescent diagnostic material, and the like.

(Other materials)
The photoelectric conversion film may further contain a photoelectric conversion material of an organic p-type compound or an organic n-type compound.
The organic p-type semiconductor (compound) is a donor-type organic semiconductor (compound), which is mainly represented by a hole-transporting organic compound and refers to an organic compound having a property of easily donating electrons. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Therefore, any organic compound can be used as the donor organic compound as long as it is an electron-donating organic compound. For example, a triarylamine compound, a benzidine compound, a pyrazoline compound, a styrylamine compound, a hydrazone compound, a triphenylmethane compound, a carbazole compound, or the like can be used.

  An organic n-type semiconductor (compound) is an acceptor organic semiconductor, and is mainly represented by an electron-transporting organic compound and means an organic compound having a property of easily accepting electrons. More specifically, the organic compound having the higher electron affinity when two organic compounds are used in contact with each other. Therefore, any organic compound may be used as the acceptor organic semiconductor as long as it is an organic compound having an electron accepting property. Preferably, fullerene or a fullerene derivative, a condensed aromatic carbocyclic compound (naphthalene derivative, anthracene derivative, phenanthrene derivative, tetracene derivative, pyrene derivative, perylene derivative, fluoranthene derivative), nitrogen atom, oxygen atom, sulfur atom 5 7-membered heterocyclic compounds (eg, pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazole, thiazole, oxazole, indazole , Benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, tria Ropyrimidine, tetrazaindene, oxadiazole, imidazopyridine, pyralidine, pyrrolopyridine, thiadiazolopyridine, dibenzoazepine, tribenzazepine, etc.), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, nitrogen-containing heterocycles Examples thereof include metal complexes having a compound as a ligand.

The organic n-type compound is preferably fullerene or a fullerene derivative. The fullerene, fullerene C _60, fullerene C _70, fullerene C _76, fullerene C _78, fullerene C _80, fullerene C _82, fullerene C _84, fullerene C _90, fullerene C _96, fullerene C _240, fullerene C _540, mixed Fullerene is represented, and the fullerene derivative represents a compound having a substituent added thereto. As the substituent, an alkyl group, an aryl group, or a heterocyclic group is preferable. As a fullerene derivative, the compound as described in Unexamined-Japanese-Patent No. 2007-123707 is preferable.
Of these, fullerene C ₆₀ is most preferable.

  The photoelectric conversion film preferably has a bulk heterostructure formed by mixing the compound represented by the above general formula (1) and fullerene or a fullerene derivative. A bulk heterostructure is a layer in which a p-type organic semiconductor (compound represented by the general formula (1)) and an n-type organic semiconductor are mixed and dispersed in a photoelectric conversion film, and can be formed by either a wet method or a dry method. However, it is preferable to use a co-evaporation method. By including the heterojunction structure, it is possible to make up for the disadvantage that the carrier diffusion length of the photoelectric conversion film is short, and to improve the photoelectric conversion efficiency of the photoelectric conversion film. The bulk heterojunction structure is described in detail in JP-A-2005-303266, [0013] to [0014].

  In the photoelectric conversion film, the volume ratio between the compound represented by the general formula (1) and fullerene or a derivative thereof is not particularly limited, and is generally in that the characteristics (responsiveness or heat resistance) of the photoelectric conversion element are more excellent. The volume ratio of the compound represented by formula (1) to fullerene or a derivative thereof (volume of compound represented by general formula (1) / volume of fullerene or derivative thereof) is preferably 3 to 75% by volume. 10 to 50% by volume is more preferable.

  The photoelectric conversion film (in which an organic n-type compound may be mixed) containing the compound represented by the general formula (1) of the present invention is a non-light-emitting film, and an organic electroluminescent element (OLED) and Have different characteristics. The non-light-emitting film is a film having an emission quantum efficiency of 1% or less, more preferably 0.5% or less, and still more preferably 0.1% or less.

(Film formation method)
The photoelectric conversion film 12 can be formed by a dry film formation method or a wet film formation method. Specific examples of the dry film forming method include a physical vapor deposition method such as a vacuum deposition method, a sputtering method, an ion plating method, and an MBE method, or a CVD method such as plasma polymerization. As the wet film forming method, a casting method, a spin coating method, a dipping method, an LB method, or the like is used. A dry film forming method is preferable, and a vacuum evaporation method is more preferable. When forming a film by a vacuum evaporation method, manufacturing conditions such as the degree of vacuum and the evaporation temperature can be set according to a conventional method.

  The thickness of the photoelectric conversion film 12 is preferably 10 nm to 1000 nm, more preferably 50 nm to 800 nm, and particularly preferably 100 nm to 500 nm. By setting it to 10 nm or more, a suitable dark current suppressing effect is obtained, and by setting it to 1000 nm or less, suitable photoelectric conversion efficiency is obtained.

[electrode]
The electrodes (upper electrode (transparent conductive film) 15 and lower electrode (conductive film) 11) are made of a conductive material. As the conductive material, a metal, an alloy, a metal oxide, an electrically conductive compound, or a mixture thereof can be used.
Since light is incident from the upper electrode 15, the upper electrode 15 needs to be sufficiently transparent to the light to be detected. Specifically, conductive metal oxides such as tin oxide (ATO, FTO) doped with antimony or fluorine, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), Metal thin films such as gold, silver, chromium, nickel, etc., and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, organics such as polyaniline, polythiophene, and polypyrrole Examples thereof include conductive materials and laminates of these with ITO. Among these, a transparent conductive metal oxide is preferable from the viewpoint of high conductivity and transparency.

  Usually, when the conductive film is made thinner than a certain range, a rapid increase in resistance value is caused. However, in the solid-state imaging device incorporating the photoelectric conversion element according to the present embodiment, the sheet resistance is preferably 100 to 10,000 Ω / □. Well, there is a large degree of freedom in the range of film thickness that can be made thin. Further, as the thickness of the upper electrode (transparent conductive film) 15 decreases, the amount of light absorbed decreases, and the light transmittance generally increases. An increase in light transmittance is very preferable because it increases the light absorption in the photoelectric conversion film 12 and increases the photoelectric conversion ability. Considering the suppression of leakage current, the increase in the resistance value of the thin film, and the increase in transmittance due to the thinning, the thickness of the upper electrode 15 is preferably 5 to 100 nm, more preferably 5 to 20 nm. It is desirable.

  Depending on the application, the lower electrode 11 may have transparency, or conversely, may use a material that does not have transparency and reflects light. Specifically, conductive metal oxides such as tin oxide (ATO, FTO) doped with antimony or fluorine, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), Metals such as gold, silver, chromium, nickel, titanium, tungsten, and aluminum, and conductive compounds such as oxides and nitrides of these metals (for example, titanium nitride (TiN)), and these metals and conductivity Examples include mixtures or laminates with metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene, and polypyrrole, and laminates of these with ITO or titanium nitride. .

The method for forming the electrode is not particularly limited, and can be appropriately selected depending on the electrode material. Specifically, it can be formed by a wet method such as a printing method or a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as CVD or plasma CVD method.
When the material of the electrode is ITO, it can be formed by a method such as an electron beam method, a sputtering method, a resistance heating vapor deposition method, a chemical reaction method (such as a sol-gel method), or a dispersion of indium tin oxide. Furthermore, UV-ozone treatment, plasma treatment, or the like can be performed on a film formed using ITO. When the electrode material is TiN, various methods including a reactive sputtering method can be used, and further UV-ozone treatment, plasma treatment, and the like can be performed.

[Charge blocking film: electron blocking film, hole blocking film]
The photoelectric conversion element of the present invention may have a charge blocking film. By having this film, the characteristics (photoelectric conversion efficiency, responsiveness, etc.) of the obtained photoelectric conversion element are more excellent. Examples of the charge blocking film include an electron blocking film and a hole blocking film. Below, each film | membrane is explained in full detail.

(Electronic blocking film)
An electron donating organic material can be used for the electron blocking film. Specifically, for low molecular weight materials, N, N′-bis (3-methylphenyl)-(1,1′-biphenyl) -4,4′-diamine (TPD) or 4,4′-bis [N Aromatic diamine compounds such as-(naphthyl) -N-phenyl-amino] biphenyl (α-NPD), oxazole, oxadiazole, triazole, imidazole, imidazolone, stilbene derivative, pyrazoline derivative, tetrahydroimidazole, polyarylalkane, butadiene 4,4 ′, 4 ″ tris (N- (3-methylphenyl) N-phenylamino) triphenylamine (m-MTDATA), porphyrin, tetraphenylporphyrin copper, phthalocyanine, copper phthalocyanine, titanium phthalocyanine oxide, etc. Compounds, triazole derivatives, oxazizazole derivatives, Midazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, silazane derivatives, etc. can be used. As the molecular material, polymers such as phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, diacetylene, and derivatives thereof can be used. Any compound having transportability can be used, and specifically, compounds described in [0083] to [0089] of JP-A-2008-72090 are preferred.

The electron blocking film may be composed of a plurality of films.
An inorganic material can also be used as the electron blocking film. In general, since an inorganic material has a dielectric constant larger than that of an organic material, a large voltage is applied to the photoelectric conversion film when used as an electron blocking film, and the photoelectric conversion efficiency can be increased. Materials that can be used as electron blocking films include calcium oxide, chromium oxide, chromium copper oxide, manganese oxide, cobalt oxide, nickel oxide, copper oxide, gallium copper oxide, strontium copper oxide, niobium oxide, molybdenum oxide, indium copper oxide, and oxide. Examples include indium silver and iridium oxide. In the case where the electron blocking film is a single layer, the layer can be a layer made of an inorganic material, or in the case of a plurality of layers, one or more layers can be a layer made of an inorganic material. .

(Hole blocking film)
An electron-accepting organic material can be used for the hole blocking film.
Examples of electron accepting materials include 1,3-bis (4-tert-butylphenyl-1,3,4-oxadiazolyl) phenylene (OXD-7) and other oxadiazole derivatives, anthraquinodimethane derivatives, and diphenylquinone derivatives. , Bathocuproine, bathophenanthroline, and derivatives thereof, triazole compounds, aluminum (III) tris (8-hydroxyquinolinate), aluminum (III) bis (2-methyl-8-quinolinato) 4-phenylphenolate, etc. Complexes, distyrylarylene derivatives, silole compounds, and the like can be used. Moreover, even if it is not an electron-accepting organic material, it can be used if it is a material which has sufficient electron transport property. A porphyrin compound, a styryl compound such as DCM (4-dicyanomethylene-2-methyl-6- (4- (dimethylaminostyryl))-4H pyran), or a 4H pyran compound can be used. Specifically, compounds described in JP-A-2008-72090, [0073] to [0078] are preferable.

  The method for producing the charge blocking film is not particularly limited, and can be formed by a dry film forming method or a wet film forming method. As a dry film forming method, a vapor deposition method, a sputtering method, or the like can be used. The vapor deposition may be either physical vapor deposition (PVD) or chemical vapor deposition (CVD), but physical vapor deposition such as vacuum vapor deposition is preferred. As the wet film forming method, 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, a gravure coating method, etc. can be used. From the viewpoint of high-precision patterning, the inkjet method is preferable.

  The thickness of the charge blocking film (electron blocking film and hole blocking film) is preferably 5 to 200 nm, more preferably 10 to 100 nm, and particularly preferably 20 to 80 nm. This is because if the thickness is too thin, the dark current suppressing effect is lowered, and if it is too thick, the response speed is lowered.

[substrate]
The photoelectric conversion element may further include a substrate. The type of the substrate used is not particularly limited, and a semiconductor substrate, a glass substrate, or a plastic substrate can be used.
The position of the substrate is not particularly limited, but usually a conductive film, a photoelectric conversion film, and a transparent conductive film are laminated on the substrate in this order.
[Sealing layer]
The photoelectric conversion element may further include a sealing layer. The performance of photoelectric conversion materials may deteriorate significantly due to the presence of degradation factors such as water molecules. Ceramics such as dense metal oxides, metal nitrides, and metal nitride oxides that do not penetrate water molecules and diamond-like materials Covering and sealing the entire photoelectric conversion film with a sealing layer such as carbon (DLC) can prevent the deterioration.
In addition, as a sealing layer, you may select and manufacture a material according to description of Paragraph [0210]-[0215] of Unexamined-Japanese-Patent No. 2011-082508.

[Optical sensor]
Examples of the use of the photoelectric conversion element include a photovoltaic cell and an optical sensor, but the photoelectric conversion element of the present invention is preferably used as an optical sensor. As an optical sensor, the photoelectric conversion element used alone may be used, or a line sensor in which the photoelectric conversion elements are linearly arranged or a two-dimensional sensor arranged on a plane is preferable. The photoelectric conversion element of the present invention converts optical image information into an electrical signal using an optical system and a drive unit like a scanner in a line sensor, and optically converts optical image information like an imaging module in a two-dimensional sensor. The system functions as an image sensor by forming an image on a sensor and converting it into an electrical signal.
Since the photovoltaic cell is a power generation device, the efficiency of converting light energy into electrical energy is an important performance, but dark current, which is a current in a dark place, is not a functional problem. Further, a subsequent heating step such as installation of a color filter is not necessary. Since it is important to convert light and dark signals into electrical signals with high accuracy, the efficiency of converting light intensity into current is also important for optical sensors. Low dark current is required. In addition, resistance to subsequent processes is also important.

[Image sensor]
Next, a configuration example of an image sensor including the photoelectric conversion element 10a will be described.
In the configuration examples described below, members having the same configuration / action as those already described are denoted by the same or corresponding reference numerals in the drawings, and the description is simplified or omitted.
An image sensor is an element that converts optical information of an image into an electric signal. A plurality of photoelectric conversion elements are arranged on a matrix in the same plane, and an optical signal is converted into an electric signal in each photoelectric conversion element (pixel). That can be output to the outside of the imaging device for each pixel sequentially. Therefore, one pixel is composed of one photoelectric conversion element and one or more transistors.
FIG. 2 is a schematic cross-sectional view showing a schematic configuration of an image sensor for explaining an embodiment of the present invention. This imaging device is used by being mounted on an imaging device such as a digital camera or a digital video camera, an imaging module such as an electronic endoscope or a mobile phone, or the like.
This imaging element has a plurality of photoelectric conversion elements having the configuration shown in FIG. 1 and a circuit board on which a readout circuit for reading a signal corresponding to the charge generated in the photoelectric conversion film of each photoelectric conversion element is formed. A plurality of photoelectric conversion elements are arranged one-dimensionally or two-dimensionally on the same surface above the circuit board.

  2 includes a substrate 101, an insulating layer 102, a connection electrode 103, a pixel electrode (lower electrode) 104, a connection portion 105, a connection portion 106, a photoelectric conversion film 107, and a counter electrode. (Upper electrode) 108, buffer layer 109, sealing layer 110, color filter (CF) 111, partition 112, light shielding layer 113, protective layer 114, counter electrode voltage supply 115, and readout circuit 116.

  The pixel electrode 104 has the same function as the electrode 11 of the photoelectric conversion element 10a illustrated in FIG. The counter electrode 108 has the same function as the electrode 15 of the photoelectric conversion element 10a shown in FIG. The photoelectric conversion film 107 has the same configuration as the layer provided between the electrode 11 and the electrode 15 of the photoelectric conversion element 10a illustrated in FIG.

  The substrate 101 is a glass substrate or a semiconductor substrate such as Si. An insulating layer 102 is formed on the substrate 101. A plurality of pixel electrodes 104 and a plurality of connection electrodes 103 are formed on the surface of the insulating layer 102.

  The photoelectric conversion film 107 is a layer common to all the photoelectric conversion elements provided on the plurality of pixel electrodes 104 so as to cover them.

  The counter electrode 108 is one electrode provided on the photoelectric conversion film 107 and common to all the photoelectric conversion elements. The counter electrode 108 is formed up to the connection electrode 103 disposed outside the photoelectric conversion film 107, and is electrically connected to the connection electrode 103.

  The connection part 106 is embedded in the insulating layer 102 and is a plug or the like for electrically connecting the connection electrode 103 and the counter electrode voltage supply part 115. The counter electrode voltage supply unit 115 is formed on the substrate 101 and applies a predetermined voltage to the counter electrode 108 via the connection unit 106 and the connection electrode 103. When the voltage to be applied to the counter electrode 108 is higher than the power supply voltage of the image sensor, the power supply voltage is boosted by a booster circuit such as a charge pump to supply the predetermined voltage.

  The readout circuit 116 is provided on the substrate 101 corresponding to each of the plurality of pixel electrodes 104, and reads out a signal corresponding to the charge collected by the corresponding pixel electrode 104. The readout circuit 116 is configured by, for example, a CCD, a CMOS circuit, a TFT circuit, or the like, and is shielded by a light shielding layer (not shown) disposed in the insulating layer 102. The readout circuit 116 is electrically connected to the corresponding pixel electrode 104 via the connection unit 105.

  The buffer layer 109 is formed on the counter electrode 108 so as to cover the counter electrode 108. The sealing layer 110 is formed on the buffer layer 109 so as to cover the buffer layer 109. The color filter 111 is formed at a position facing each pixel electrode 104 on the sealing layer 110. The partition wall 112 is provided between the color filters 111 and is for improving the light transmission efficiency of the color filter 111.

  The light shielding layer 113 is formed in a region other than the region where the color filter 111 and the partition 112 are provided on the sealing layer 110, and prevents light from entering the photoelectric conversion film 107 formed outside the effective pixel region. The protective layer 114 is formed on the color filter 111, the partition 112, and the light shielding layer 113, and protects the entire image sensor 100.

  In the imaging device 100 configured as described above, when light is incident, the light is incident on the photoelectric conversion film 107, and charges are generated here. Holes in the generated charges are collected by the pixel electrode 104, and a voltage signal corresponding to the amount is output to the outside of the image sensor 100 by the readout circuit 116.

The manufacturing method of the image sensor 100 is as follows.
On the circuit board on which the common electrode voltage supply unit 115 and the readout circuit 116 are formed, the connection units 105 and 106, the plurality of connection electrodes 103, the plurality of pixel electrodes 104, and the insulating layer 102 are formed. The plurality of pixel electrodes 104 are arranged on the surface of the insulating layer 102 in a square lattice pattern, for example.

  Next, the photoelectric conversion film 107 is formed on the plurality of pixel electrodes 104 by, for example, a vacuum heating deposition method. Next, the counter electrode 108 is formed on the photoelectric conversion film 107 under vacuum by, for example, sputtering. Next, the buffer layer 109 and the sealing layer 110 are sequentially formed on the counter electrode 108 by, for example, a vacuum heating deposition method. Next, after forming the color filter 111, the partition 112, and the light shielding layer 113, the protective layer 114 is formed, and the imaging element 100 is completed.

  Even in the method of manufacturing the image sensor 100, a plurality of processes can be performed even when a step of placing the image sensor 100 being manufactured under non-vacuum is added between the process of forming the photoelectric conversion film 107 and the process of forming the sealing layer 110. The performance deterioration of the photoelectric conversion element can be prevented. By adding this step, it is possible to suppress the manufacturing cost while preventing the performance degradation of the image sensor 100.

  Examples are shown below, but the present invention is not limited thereto.

  The compounds 1 to 14 and the compounds R-1 to R-3 used in the examples and comparative examples are collectively shown below.

<Example A: non-bulk hetero type>
A photoelectric conversion element having the configuration shown in FIG. Here, the photoelectric conversion element includes the lower electrode 11, the electron blocking film 16 </ b> A, the photoelectric conversion film 12, and the upper electrode 15.
Specifically, an amorphous ITO film is formed on a glass substrate by sputtering to form the lower electrode 11 (thickness: 30 nm), and the following compound (EB-1) is vacuum heated on the lower electrode 11. An electron blocking film 16A (thickness: 100 nm) was formed by vapor deposition. Further, with the substrate temperature controlled at 25 ° C., the compound (compounds 1 to 14) is formed on the electron blocking film 16A by vacuum heating vapor deposition so as to have a layer conversion of 200 nm, and the photoelectric conversion film 12 is formed. Formed. Further, an amorphous ITO film was formed on the photoelectric conversion film 12 by sputtering to form an upper electrode 15 (transparent conductive film) (thickness: 10 nm). An SiO film was formed as a sealing layer on the upper electrode 15 by heating vapor deposition, and then an aluminum oxide (Al ₂ O ₃ ) layer was formed thereon by ALCVD to produce a photoelectric conversion element.

(Evaluation of response speed (98% signal rise time))
Relative response speed when applied to the obtained photoelectric conversion element with an electric field of 2 × 10 ⁵ V / cm (measured rise time from 0 to 98% signal intensity, relative value with Example 1-1 as 10) And listed in the “response speed (relative value)” column of Table 1. Light was incident from the upper electrode (transparent conductive film) side when measuring the photoelectric conversion performance of each element. Shows how to find the relative value.
(Value of each example and comparative example)
= 10 × [Rise Time from 0 to 98% Signal Strength in Example (or Comparative Example) X] / [Rise Time from 0 to 98% Signal Strength in Example 1-1]
In practice, it is preferably within 15 and more preferably within 5.

(Element heat resistance)
Each element obtained was subjected to thermal annealing by holding it on a hot plate at 110 ° C. for 35 minutes in a nitrogen atmosphere. After returning to room temperature, the dark current was measured and the rate of increase in dark current from before the annealing [{ (A dark current value after annealing−dark current value before annealing) / dark current value before annealing} × 100 (%)] is less than 5%, “A”, 5% or more and less than 40% In Table 1, “B” was used, and “C” was 40% or more. In practice, it must be A or B.

As shown in Table 1 above, it was confirmed that the photoelectric conversion element of the present invention exhibits excellent responsiveness and heat resistance.
For example, as can be seen from the comparison of Examples 1-1, 1-3, 1-5 and 1-8, when A is CR ^C1 R ^C2 (in particular, a group represented by the general formula (Z1), or C (CN) ₂ ) was confirmed to be more responsive.
As can be seen from the comparison between Example 1-13 and other examples, it was confirmed that the responsiveness was more excellent in the case where X was an oxygen atom and Ar ¹ and Ar ² were aryl groups.
As can be seen from the comparison between Example 1-7 and Example 1-14, when any one of Ar ¹ and R ¹ and Ar ² and R ⁷ is bonded to each other to form a ring, the responsiveness and heat resistance It was confirmed that the property is superior.
As shown in Example 7, A is a group represented by the general formula (Z1) (particularly, a group represented by the general formula (Z4)), Ar ¹ and R ¹ , and Ar ² and R ^When any one of ⁷ was bonded to each other to form a ring, it was confirmed that the responsiveness and heat resistance were more excellent.

On the other hand, when the compound R-1 used in the Example column of Patent Document 1 or the compound R-3 was used, the responsiveness and heat resistance were inferior.
In addition, when the known compound R-2 (disclosed in Japanese Patent Application Laid-Open No. 2004-14137) was used, no film could be formed.

(Production of image sensor)
An image sensor similar to that shown in FIG. 2 was produced. That is, after depositing amorphous TiN 30 nm on the CMOS substrate by sputtering, patterning is performed by photolithography so that one pixel exists on each photodiode (PD) on the CMOS substrate to form the lower electrode. After film formation of the electron blocking material, it was produced in the same manner as in Examples 1-1 to 1-14 and Comparative Examples 1-1 to 1-3. The evaluation was performed in the same manner, and the same results as in Table 1 were obtained. It was found that the imaging element is suitable for manufacturing and exhibits excellent performance.

<Example B>
A photoelectric conversion element having the configuration shown in FIG. Here, the photoelectric conversion element includes the lower electrode 11, the electron blocking film 16 </ b> A, the photoelectric conversion film 12, and the upper electrode 15.
Specifically, an amorphous ITO film is formed on a glass substrate by sputtering to form the lower electrode 11 (thickness: 30 nm), and the following compound (EB-2) is vacuum-heated on the lower electrode 11. An electron blocking film 16A (thickness: 100 nm) was formed by vapor deposition. Further, in a state where the temperature of the substrate is controlled at 25 ° C., the above compounds (compounds 1, 5, 7, 12, R-1, R-3) and fullerene (C ₆₀ ) are volumetrically formed on the electron blocking film 16A. The photoelectric conversion film 12 was formed by co-evaporation by vacuum heating deposition so that the ratio shown in Table 2 was achieved. Further, an amorphous ITO film was formed on the photoelectric conversion film 12 by sputtering to form an upper electrode 15 (transparent conductive film) (thickness: 10 nm). An SiO film was formed as a sealing layer on the upper electrode 15 by heating vapor deposition, and then an aluminum oxide (Al ₂ O ₃ ) layer was formed thereon by ALCVD to produce a photoelectric conversion element.

(Evaluation of response speed (98% signal rise time))
Relative response speed when applied to the obtained photoelectric conversion element with an electric field of 2 × 10 ⁵ V / cm (measured rise time from 0 to 98% signal intensity, relative value with Example 2-1 = 10) And listed in the “response speed (relative value)” column of Table 2. In the measurement of the photoelectric conversion performance of each element, light was incident from the upper electrode (transparent conductive film) side. Shows how to find the relative value.
(Value of each example and comparative example)
= 10 × [Rise Time from 0 to 98% Signal Strength in Example (or Comparative Example) X] / [Rise Time from 0 to 98% Signal Strength in Example 2-1]
In practical terms, it is preferably within 100, more preferably within 50, and particularly preferably within 10.

(Element heat resistance)
Each element obtained was thermally annealed by holding it on a hot plate at 150 ° C. for 20 minutes under a nitrogen atmosphere, and after returning to room temperature, the dark current was measured and the rate of increase in dark current from before the annealing [{ (A dark current value after annealing−dark current value before annealing) / dark current value before annealing} × 100 (%)] was less than 5%, “A”, 5% or more and less than 10% The thing which was 10% or more as "B" was described in the "heat resistance" column of Table 1 as "C". In practice, it must be A or B.

As shown in Table 2 above, it was confirmed that the photoelectric conversion element of the present invention exhibits excellent responsiveness and heat resistance.
In particular, as can be seen from the comparison of Examples 2-4 to 2-8, the volume ratio of the compound represented by the general formula (1) to the fullerene or a derivative thereof (of the compound represented by the general formula (1)). When the volume / volume of fullerene or a derivative thereof is 10 to 50% by volume, it was confirmed that the responsiveness and heat resistance were superior.
On the other hand, as shown in Comparative Example 2-1 and Comparative Example 2-2, when the compound shown in Patent Document 1 was used, it was confirmed that the response and heat resistance were poor.

(Production of image sensor)
An image sensor similar to that shown in FIG. 2 was produced. That is, after depositing amorphous TiN 30 nm on the CMOS substrate by sputtering, patterning is performed by photolithography so that one pixel exists on each photodiode (PD) on the CMOS substrate to form the lower electrode. After the film formation of the electron blocking material, it was produced in the same manner as in Examples 2-1 to 2-8 and Comparative Examples 2-1 to 2-2. The evaluation was performed in the same manner, and the same results as in Table 1 were obtained. It was found that the imaging element is suitable for manufacturing and exhibits excellent performance.

10a, 10b Photoelectric conversion element 11 Lower electrode (conductive film)
12 Photoelectric conversion film 15 Upper electrode (transparent conductive film)
16A Electron blocking film 16B Hole blocking film 100 Image sensor 101 Substrate 102 Insulating layer 103 Connection electrode 104 Pixel electrode (lower electrode)
105 connecting portion 106 connecting portion 107 photoelectric conversion film 108 counter electrode (upper electrode)
109 Buffer layer 110 Sealing layer 111 Color filter (CF)
112 partition wall 113 light shielding layer 114 protective layer 115 counter electrode voltage supply unit 116 readout circuit

Claims (11)

A photoelectric conversion element formed by laminating a conductive film, a photoelectric conversion film containing a photoelectric conversion material, and a transparent conductive film in this order,
The photoelectric conversion element in which the said photoelectric conversion material contains the compound represented by General formula (1).

(In the general formula (1), R ^{1 to} R ⁷ each independently represents a hydrogen atom or a substituent. Ar ¹ and Ar ² each independently represent an aryl group or a heteroaryl group. Represents an oxygen atom or a sulfur atom, Ar ¹ and Ar ² , Ar ¹ and R ¹ , or Ar ² and R ⁷ may be bonded to each other to form a ring, where A is an oxygen atom, sulfur Represents an atom, N—R ^N , or CR ^C1 R ^C2 , R ^N , R ^C1 and R ^C2 each independently represents a substituent, and R ^C1 and R ^C2 may be bonded to each other to form a ring; Good.) The photoelectric conversion element of Claim 1 in which A represents group represented by general formula (Z-1) or * = C (CN) ₂ .

(In General Formula (Z1), Z is a ring which contains at least two carbon atoms and may have a substituent, and is a 5-membered ring, a 6-membered ring, or a 5-membered ring and a 6-membered ring. (It represents a condensed ring containing at least one of them, and * indicates a bonding position.) The photoelectric conversion element according to claim 1, wherein any one of Ar ¹ and R ¹ and Ar ² and R ⁷ is bonded to each other to form a ring. The photoelectric conversion element according to claim 1, wherein R ³ represents an aryl group or a heteroaryl group.   The photoelectric conversion element according to claim 1, wherein the photoelectric conversion film further contains an organic n-type compound.   The photoelectric conversion element according to claim 5, wherein the organic n-type compound contains fullerene or a derivative thereof. The photoelectric conversion element according to claim 6, wherein the fullerene or a derivative thereof is fullerene C ₆₀ .   The volume ratio of the compound represented by the general formula (1) and the fullerene or a derivative thereof (the volume of the compound represented by the general formula (1) / the volume of the fullerene or a derivative thereof) is 10 to 50% by volume. The photoelectric conversion element according to claim 6, wherein   The photoelectric conversion element according to claim 1, wherein a charge blocking film is disposed between the conductive film and the transparent conductive film.   The image pick-up element containing the photoelectric conversion element of any one of Claims 1-9.   The optical sensor containing the photoelectric conversion element of any one of Claims 1-9.