JP2022181226A - Triscarbazolylphenyl derivative, organic thin film using the same, photoelectric conversion element using the same, and imaging element - Google Patents

Abstract

To provide an organic thin film for use in a photoelectric conversion element using a compound having a high glass transition temperature and excellent charge transport properties, and to provide various types of high-sensitivity imaging elements and optical sensors by reducing the dark current of the various types of high-sensitivity imaging elements to which the organic thin film is applied.SOLUTION: A compound is represented by the following general Formula (1). In Formula (1), Ar1, Ar2, and Ar3 represent substituted or unsubstituted aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, or substituted or unsubstituted fused polycyclic aromatic groups, wherein n represents an integer from 0 to 3.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a compound having a triscarbazolylphenyl derivative structure, an organic thin film for a photoelectric conversion device containing the compound, a photoelectric conversion device, and an imaging device including the photoelectric conversion device.

Photoelectric conversion devices are widely used, for example, in solar cells and optical sensors. Among them, image sensors, which are imaging devices, are beginning to be used not only for television cameras and smartphone cameras, but also for driving support systems. Applications and markets are expanding.

Until now, inorganic materials such as Si films and Se films have been used as materials for image sensors, and there are two main imaging methods: a three-plate type that uses a prism to separate colors, and a single-plate type that uses color filters. rice field. However, although the three-plate type has a high utilization rate of light, it is difficult to miniaturize because it uses a prism. , resolution, and light utilization rate were poor (Non-Patent Document 1).

On the other hand, organic matter absorbs light of specific wavelengths better than Si or Se films, so by combining materials that match each wavelength, light can be efficiently used for each of the three primary colors without using a prism. It is possible to construct an image sensor that can Therefore, light utilization efficiency is high, and it is possible to manufacture a small-sized imaging device. In addition, there is a possibility of adding value such as flexibility and large area by coating in the manufacturing process, which cannot be achieved with a Si film (Non-Patent Document 2).

A photoelectric conversion device using an organic substance is expected to be developed as a next-generation imaging device, and several reports have been made. For example, an example of using a quinacridone or quinazoline derivative in a photoelectric conversion device (Patent Document 1), an example of using a benzothienobenzothiophene derivative in a photoelectric conversion device (Patent Document 2), an example of using indolocarbazole in a photoelectric conversion device ( Patent Document 3) and the like. Organic imaging devices are being developed for the purpose of achieving high contrast and power saving, but compared to inorganic imaging devices, they tend to generate large dark currents. Therefore, it is necessary to reduce the dark current. In order to reduce the dark current, a method of inserting a hole blocking layer or an electron blocking layer between the photoelectric conversion portion and the electrode portion may be used (Patent Document 4).

Materials required for the blocking layer include physical properties such as thermal stability and mobility. In particular, for imaging devices, in order to improve storage stability and apply to manufacturing processes that involve heating processes such as the installation of color filters, the installation of protective films, and the soldering of elements, heat is required to be higher than that of organic EL and other organic electronic devices. Stability is required. Patent Document 4 reports that the use of an electron blocking material having a glass transition temperature of 140° C. or higher improves the thermal stability of the device.
In addition, responsiveness (the speed from when light enters the device to when it is actually detected) is also required for the image sensor. Therefore, the faster the transportation, the better.
Although there have been reports on blocking layers, there has been a need to further improve the properties.

Japanese Patent No. 4945146 JP 2018-170487 A JP 2018-085427 A JP 2011-187937 A JP 2018-85427 A

ITE Media Association Journal, 60, 3, 291 (2006) Adv. Mater. 28, 4766 (2016)

The present invention has been made in view of the above-mentioned current situation, and provides an organic thin film for use in a photoelectric conversion device by utilizing a compound having a high glass transition temperature and excellent charge transport properties. is applied to reduce the dark current of various photoelectric conversion elements, thereby providing various high-sensitivity imaging elements and photosensors.

Therefore, the present inventors introduced three carbazolyl groups adjacent to the benzene ring as a measure to increase the glass transition temperature in order to achieve the above object, and by suppressing the rotation of the carbazolyl groups due to steric hindrance, the thin film We tried to improve the heat resistance. By incorporating the partial skeleton that raises the glass transition temperature and the arylamine used as the hole transport material into the same molecule and conducting intensive research, the compound represented by the following general formula (1) solved the above problem. The present inventors have found that it does, and have completed the present invention.

That is, the present invention relates to the following items.

1) A compound represented by the following general formula (1).

In formula (1), Ar ¹ , Ar ² and Ar ³ are substituted or unsubstituted aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, or substituted or unsubstituted condensed polycyclic aromatic represents a group.

2) The compound described in 1), represented by the following general formula (2).

In formula (2), Ar ¹ , Ar ² , Ar ³ and n are the same as defined in general formula (1).

3) The compound described in 1), which is represented by the following general formula (3).

In formula (3), Ar ¹ , Ar ² , Ar ³ and n are the same as defined in general formula (1).

4) An organic thin film for a photoelectric conversion device containing the compound according to any one of 1) to 3) above.

5) A photoelectric conversion device comprising the organic thin film for a photoelectric conversion device according to 4) above.

6) The photoelectric conversion device according to 5), wherein the organic thin film for photoelectric conversion devices is a blocking layer.

7) An imaging device comprising the photoelectric conversion device according to 5) or 6) above.

The organic thin film containing the compound represented by formula (1), (2) or (3) of the present invention can be applied to various photoelectric conversion elements. As a result, a photoelectric conversion element having good dark current characteristics can be provided, and an imaging element and an optical sensor using the photoelectric conversion element can be provided.

It is one structural example of the photoelectric conversion element of this invention.

TECHNICAL FIELD The present invention relates to an organic thin film containing a compound represented by general formula (1), (2) or (3) and an organic device using the organic thin film, particularly a photoelectric conversion element.

In formula (1), Ar ¹ , Ar ² and Ar ³ are substituted or unsubstituted aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, or substituted or unsubstituted condensed polycyclic aromatic represents the group,
Adjacent Ar ¹ , Ar ² and Ar ³ may be bonded to each other through a single bond, a substituted or unsubstituted methylene group, an oxygen atom or a sulfur atom to form a ring.

In formula (2), Ar ¹ , Ar ² and Ar ³ are the same as defined in general formula (1).

In formula (3), Ar ¹ , Ar ² and Ar ³ are the same as defined in general formula (1).

In Ar ¹ in the above general formulas (1) to (3), a “substituted or unsubstituted aromatic hydrocarbon group”, a “substituted or unsubstituted aromatic heterocyclic group”, or a “substituted or unsubstituted The "aromatic hydrocarbon group", "aromatic heterocyclic group" or "condensed polycyclic aromatic group" in the "condensed polycyclic aromatic group" is not particularly limited as long as it is a divalent group. group, biphenylylene group, terphenylylene group, naphthylene group, anthrylene group, thienylene group, furanylene group, fluorenylene group, spirofluorenylene group, phenanthrenylene group, pyridylene group, benzofuranylene group, benzothienylene group, dibenzofuranylene group, dibenzo thienylene group, triphenylenylene group, bithienylene group, indolylene group, carbazolylene group, carbolinylene group, benzimidazolylene group, quinolylene group, isoquinolylene group, pyrazolylene group, and the like. Furthermore, it can be selected from a C6-C30 bivalent aromatic ring and a C2-C30 bivalent heteroaromatic ring.

A " ^substituted or unsubstituted aromatic hydrocarbon group", a "substituted or unsubstituted aromatic heterocyclic group", ^or a "substituted or unsubstituted The "aromatic hydrocarbon group", "aromatic heterocyclic group" or "condensed polycyclic aromatic group" in "unsubstituted condensed polycyclic aromatic group" is not particularly limited, but for example, phenyl group, biphenylyl group , terphenylyl group, naphthyl group, anthracenyl group, thienyl group, furyl group, fluorenyl group, spirofluorenyl group, phenanthrenyl group, pyridyl group, benzofuranyl group, benzothienyl group, dibenzofuranyl group, dibenzothienyl group, triphenylenyl group, Bitienyl group, indolyl group, carbazolyl group, carbolinyl group, benzimidazolyl group, quinolyl group, isoquinolyl group, pyrazolyl group and the like can be mentioned. Furthermore, it can be selected from aromatic rings having 6 to 30 carbon atoms and heteroaromatic rings having 2 to 30 carbon atoms.

"Substituted or unsubstituted aromatic hydrocarbon group", "substituted or unsubstituted aromatic heterocyclic group", or "substituted or unsubstituted condensed polycyclic aromatic group" in general formulas (1) to (3) above Substituents in "group group" are not particularly limited, but for example, specifically, deuterium atom, cyano group, nitro group; fluorine atom, chlorine atom, bromine atom, halogen atom such as iodine atom; trimethylsilyl group, triphenyl a silyl group such as a silyl group; a linear or branched alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group and a propyl group; a carbon atom number of 1 such as a methyloxy group, an ethyloxy group and a propyloxy group to 6 linear or branched alkyloxy groups; alkenyl groups such as a vinyl group and an allyl group; aryloxy groups such as a phenyloxy group and a tolyloxy group; arylalkyloxy groups such as a benzyloxy group and a phenethyloxy group; Aromatic hydrocarbons such as phenyl group, biphenylyl group, terphenylyl group, naphthyl group, anthracenyl group, phenanthrenyl group, fluorenyl group, spirobifluorenyl group, indenyl group, pyrenyl group, perylenyl group, fluoranthenyl group and triphenylenyl group group or condensed polycyclic aromatic group; pyridyl group, thienyl group, furyl group, pyrrolyl group, quinolyl group, isoquinolyl group, benzofuranyl group, benzothienyl group, indolyl group, carbazolyl group, benzoxazolyl group, benzothiazolyl group, quinoxalinyl aromatic heterocyclic groups such as groups, benzimidazolyl groups, pyrazolyl groups, dibenzofuranyl groups, dibenzothienyl groups, carbolinyl groups.

Specific examples of preferred compounds among the compounds represented by formulas (1) to (2) are shown below, but the present invention is not limited to these compounds.

The compounds described above can be synthesized by a general nucleophilic substitution reaction, Suzuki-Miyaura coupling, or the like.

The compounds represented by general formulas (1) to (3) can be purified by column chromatography, adsorption purification using silica gel, activated carbon, activated clay, or the like, recrystallization using a solvent, crystallization, or the like. . Identification of compounds can be performed by NMR analysis. As physical property values, it is preferable to measure the glass transition temperature (Tg) and the work function. The glass transition temperature (Tg) is an index of the stability of the thin film state, and the HOMO level is an index of the hole transportability.

The glass transition temperature (Tg) can be determined using a powder with a high-sensitivity differential scanning calorimeter (DSC3100SA, manufactured by Bruker AXS).

The HOMO level can be obtained by forming a thin film of 100 nm on an ITO substrate and using an ionization potential measurement device (PYS-202, manufactured by Sumitomo Heavy Industries, Ltd.).

The compounds represented by formulas (1) to (3) can be used to form organic thin films by known methods such as vapor deposition, spin coating and inkjet. In addition, the compounds represented by the general formulas (1) to (3) may be used alone to form a film, but they can also be mixed to form a film. Furthermore, it can be mixed with other compounds to form a film as long as the effect of the present invention is not impaired.

Organic thin films containing compounds represented by formulas (1) to (3) are suitable for use in photoelectric conversion devices, particularly imaging devices. The structure of the photoelectric conversion element, for example, has a first electrode (anode), an electron blocking layer, a photoelectric conversion layer, and a second electrode (cathode) in that order, and the electron blocking layer is represented by general formulas (1) to (3). and a structure that is an organic thin film containing a compound of. Additional layers can be added to such a multi-layer structure, for example, the structure can have a first electrode, an electron blocking layer, a photoelectric conversion layer, a hole blocking layer, and a second electrode in that order. Moreover, it can also be used for a photoelectric conversion layer.

<Photoelectric conversion layer>
The photoelectric conversion layer may be an organic material, an inorganic material, or a quantum dot, as long as it can generate signal charges according to the amount of light received. When the photoelectric conversion layer is made of an organic material, the organic semiconductor film may be a single layer or a plurality of layers. and n-type organic semiconductor mixed films (bulk heterostructures) are used. In the case of a plurality of layers, it is a structure in which two or more of a p-type organic semiconductor film, an n-type organic semiconductor film, or a p-type organic semiconductor and n-type organic semiconductor mixed film are laminated, and a buffer is provided between the layers. It is also possible to insert layers.

The p-type semiconductor used in the photoelectric conversion layer is a donor organic semiconductor, and is mainly represented by a hole-transporting organic compound, and is a compound that easily donates electrons.
Examples of p-type semiconductors include, but are not limited to, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, pentacene derivatives, quinacridone derivatives, chrysene derivatives, fluoranthene derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, Metal Complexes with Heterocyclic Compounds as Ligand, Benzothiophene Derivatives, Dinaphthothienothiophene Derivatives, Dianthracenothienothiophene Derivatives, Benzobisbenzothiophene Derivatives, Thienobisbenzothiophene, Dibenzothienobisbenzothiophene Derivatives, Dithienobenzone Dithiophene derivatives, dibenzothienodithiophene derivatives, benzodithiophene derivatives, naphthodithiophene derivatives, anthracenodithiophene derivatives, tetracenodithiophene derivatives, pentacenodithiophene derivatives, acene-based materials and triarylamines compounds, amine derivatives such as carbazole compounds, and indenocarbazole derivatives.

The n-type organic semiconductor used in the photoelectric conversion layer is an acceptor organic semiconductor, which is mainly represented by an electron-transporting organic compound, and refers to an organic compound that easily accepts electrons. More specifically, it refers to the organic compound with the higher electron affinity when two organic compounds are brought into contact with each other. Therefore, any organic compound can be used as the acceptor organic compound as long as it is an electron-accepting organic compound. For example, condensed aromatic carbocyclic compounds (naphthalene, anthracene, fullerene, phenanthrene, tetracene, pyrene, perylene, fluoranthene, or derivatives thereof), 5- to 7-membered heterocyclic compounds containing nitrogen, oxygen and sulfur atoms (e.g. pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazole, thiazole, oxazole, indazole, benzimidazole, benzotriazole, benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, triazolopyrimidine, tetrazaindene, oxadiazole, imidazopyridine, pyraridine, pyrrolopyridine, thiadiazolopyridine, dibenzazepine, tribenzazepine, etc.), polyarylene compounds , fluorene compounds, cyclopentadiene compounds, silyl compounds, and metal complexes having nitrogen-containing heterocyclic compounds as ligands. In addition, as described above, any organic compound having a higher electron affinity than the organic compound used as the donor organic compound may be used as the acceptor organic semiconductor.

The thickness of the photoelectric conversion layer is preferably 100-1000 nm, more preferably 100-500 nm.

<Conductive thin film>
The conductive thin films are anode and cathode electrodes, which are made of a conductive material. It may be a transparent conductive thin film. The anode and cathode are not particularly limited as long as they are conductive materials generally used as electrodes, and examples thereof include metals, metal oxides, metal nitrides, metal borides, organic conductive compounds, and mixtures thereof. Specific examples include conductive metal oxides such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), indium tungsten oxide (IWO), molybdenum oxide (MoO), and titanium oxide. , metal nitrides such as titanium oxynitride (TiNxOx) and titanium nitride (TiN), gold (Au), platinum (Pt), silver (Ag), chromium (Cr), nickel (Ni), aluminum (Al), etc. Examples include metals, mixtures or laminates of these metals and conductive metal oxides, organic conductive compounds such as polyaniline, polythiophene and polypyrrole, and laminates of these with ITO.

<Hole blocking layer>
A hole-blocking layer may be inserted between the second electrode (cathode) and the photoelectric conversion layer, but the material used for this layer preferably has a deeper work function than the material used for the electron-blocking layer. For example, organic molecules and organometallic complexes containing nitrogen-containing heterocycles such as pyridine, quinoline, acridine, indole, imidazole benzimidazole, and phenanthroline, and materials with low absorption in the visible light region are preferred. Further, when forming a thin film having a thickness of about 5 nm to 20 nm, fullerene having absorption in the visible light region and derivatives thereof can be used.

<Image sensor>
The imaging element is configured by including the photoelectric conversion element.

Hereinafter, the embodiments of the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.

Examples of synthesis routes are shown below, but are not particularly limited.

<Synthesis of 3,4,5-tri-(carbazol-9-yl)-nitrobenzene>
15.60 g of carbazole, 60% sodium hydride (dispersed in liquid paraffin), and 300 mL of dimethylformamide were placed in a nitrogen gas-aerated reactor and heated to 30°C. 5.01 g of 3,4,5-trifluoronitrobenzene diluted with 20 mL of dimethylformamide was added thereto, and the mixture was heated to 55° C. and stirred for 3 hours.
After allowing to cool, 320 mL of water was added to the reaction solution, and the precipitated solid was collected by filtration. 200 mL of methanol was added to the resulting orange powder, and the mixture was stirred under reflux. After standing to cool, the solid was collected by filtration. This solid was dissolved in 220 mL of 1,2-dichlorobenzene by heating, allowed to cool, and 220 mL of methanol was added. The precipitated solid was collected by filtration to obtain 11.6 g of orange powder (yield 66%).

The structure was identified by analyzing the resulting orange powder with ¹ H NMR.

¹ H NMR (CDCl ₃ ) detected the following 26 hydrogen signals. δ (ppm) = 8.80 (2H), 7.79 (4H), 7.37 (2H), 7.17 (4H), 7.09 (4H), 7.03 (4H), 6.87 (2H), 6.80 (2H), 6.64 (2H).

<Synthesis of 3,4,5-tri-(carbazol-9-yl)-aniline>
12.7 g of 3,4,5-tri-(carbazol-9-yl)-nitrobenzene, 5.80 g of iron powder, 2.5 mL of concentrated hydrochloric acid, and 240 mL of tetrahydrofuran were placed in a reaction vessel ventilated with nitrogen gas and stirred under reflux. did. 50 mL of tetrahydrofuran, 5.0 mL of concentrated hydrochloric acid, and 1.15 mL of iron powder were added on the way, and the reaction was allowed to proceed for a total of 15 hours.
After allowing to cool, 100 mL of an aqueous sodium hydrogencarbonate solution was added to the reaction solution, and the precipitated solid was removed by filtration. After tetrahydrofuran was roughly distilled off from the filtrate, 300 mL of toluene was added to separate the layers. Sodium sulfate and 10 g of silica were added to the obtained organic phase and stirred. Filtration was performed, the resulting solution was concentrated, and hexane was added. By filtering the deposited solid, 10.7 g of a yellow-orange white powder was obtained (88% yield).

The structure was identified by analyzing the obtained yellow-orange white powder by ¹ H NMR.

¹ H NMR (CDCl ₃ ) detected the following 28 hydrogen signals. δ (ppm) = 7.75 (4H), 7.34 (2H), 7.26 (4H), 7.16 (2H), 7.04-7.00 (8H), 6.95 (2H) , 6.72 (2H), 6.64 (2H), 4.13 (2H).

<Synthesis of 3,4,5-tri-(carbazol-9-yl)-bromobenzene>
In Example 1, 3,4,5-trifluorobromobenzene was used in place of 3,4,5-trifluoronitrobenzene, and dimethylsulfoxide was used in place of dimethylformamide. .7 g (82% yield) was obtained.

The structure was identified by analyzing the resulting white powder with ¹ H NMR.

¹ H NMR (CDCl ₃ ) detected the following 26 hydrogen signals. δ (ppm) = 8.08 (2H), 7.76 (4H), 7.36 (2H), 7.20 (4H), 7.06-7.02 (8H), 6.90 (2H) , 6.76 (2H), 6.64 (2H).

<Synthesis of Compound 1>
4.50 g of 3,4,5-tri-(carbazol-9-yl)-aniline, 3.93 g of 4-bromobiphenyl, 54.9 mg of palladium acetate, tri-t-butylphosphine (50 wt% toluene solution) were placed in a reaction vessel. 202 mg of sodium-t-butoxide, 1.84 g of sodium-t-butoxide, and 135 mL of toluene were charged, degassed under reduced pressure, and then stirred under heating and reflux for 2 hours. 72.5 mg of tris(dibenzodylideneacetone)dipalladium and 171 mg of tri-t-butylphosphine (50 wt % toluene solution) were added thereto, and the reaction was further performed for 6 hours.
After allowing to cool to room temperature, filtration and inorganic matter were removed. 7 g of silica and 7 g of activated clay were added to the resulting solution and stirred at 80°C. Inorganic matter was removed by filtration, the obtained solution was concentrated, 50 mL of methanol was added to the obtained crude, and the precipitated solid was collected by filtration.
By repeating crystallization using toluene/methanol/acetone for the resulting brownish white powder, 5.64 g of almost white powder was obtained (yield: 82%).

The structure of the obtained nearly white powder was identified using NMR.

The following 44 hydrogen signals were detected by ¹ H NMR (CDCl ₃ ), indicating compound 1. δ (ppm) = ppm) = 7.71 (4H), 7.64-7.51 (14H), 7.44 (4H), 7.35 (4H), 7.23 (4H), 7.04 -6.94 (10H), 6.74 (2H), 6.65 (2H).

<Synthesis of compound 2>
In Example 4, 4-(naphthalen-2-yl)-bromobenzene was used in place of 4-bromobiphenyl, and the reaction was carried out under the same conditions to obtain 3.8 g of white powder (yield 57%). .

The structure of the resulting white powder was identified using NMR.

The following 48 hydrogen signals were detected by ¹ H NMR (CDCl ₃ ), indicating compound 2. δ (ppm) = ppm) = 8.02 (2H), 7.92-7.85 (6H), 7.76 (4H), 7.73-7.71 (6H), 7.64 (2H) , 7.58 (4H), 7.52-7.46 (4H), 7.36 (2H), 7.24 (4H), 7.03-6.98 (10H), 6.74 (2H) , 6.66 (2H).

<Synthesis of compound 3>
4.00 g of 3,4,5-tri-(carbazol-9-yl)-bromobenzene, bis(biphenyl-4-yl)-[4-(4,4,5,5-tetramethyl-[ 1,3,2]dioxaboran-2-yl)phenyl]amine 3.53 g, tetrakistriphenylphosphine palladium (0) 147.2 mg, potassium carbonate 1.28 g, toluene 89 mL, ethanol 22 mL, and water 9 mL were charged under reduced pressure. After degassing, the mixture was heated and stirred under reflux for 2 hours.
After allowing to cool to room temperature, the liquid was separated and the organic phase was washed with 50 mL of water. Magnesium sulfate, 9 g of silica, and 9 g of activated clay were added to the obtained organic phase, and the mixture was stirred at 80° C., after which inorganic substances were removed by filtration. After concentration, 150 mL of toluene and 90 mL of tetrahydrofuran were added to the resulting solid and stirred. The precipitated solid was collected by filtration. After dissolving the obtained solid in 250 mL of tetrahydrofuran with heating, 100 mL of toluene was added thereto. After 250 mL of the solvent was distilled off using Dean Stark, the residue was allowed to cool to room temperature and the precipitated solid was collected to obtain 2.72 g of pale yellowish white powder (yield: 46%).

The structure of the resulting pale yellow powder was identified using NMR.

The following 48 hydrogen signals were detected by ¹ H NMR (CDCl ₃ ), indicating compound 3. δ (ppm) = ppm) = 8.14 (2H), 7.80 (4H), 7.65 (2H), 7.59 (4H), 7.54 (4H), 7.43 (4H), 7.37 (2H), 7.34-7.23 (12H), 7.08-6.97 (10H), 6.76 (2H), 6.66 (2H).

<Synthesis of Compound 16>
In Example 6, 9- Using phenyl-3(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)carbazole, the reaction was carried out under the same conditions to obtain 3.5 g of white powder (yield 62%). ).

The structure of the resulting white powder was identified using NMR.

The following 38 hydrogen signals were detected by ¹ H-NMR (CDCl ₃ ), indicating compound 16. δ (ppm) = 8.52 (1H), 8.30 (2H), 8.17 (1H), 7.82-7.78 (5H), 7.67-7.57 (4H), 7. 54-7.23 (11H), 7.08-7.01 (10H), 6.77 (2H), 6.68 (2H).

The glass transition temperature of the compound of the present invention of Example 1 was measured with a high-sensitivity differential scanning calorimeter (DSC3100SA, manufactured by Bruker AXS).

Table 1 shows that the compounds of Examples have a high glass transition temperature of 150° C. or higher, indicating that the thin film state is stable.

<Measurement of HOMO level>
Using the compound of Example 1 and the comparative compound EBL-1 (see Patent Document 5), a deposited film with a thickness of 100 nm was prepared on an ITO substrate, and an ionization potential measuring device (Sumitomo Heavy Industries, Ltd. , PYS-202) are summarized in Table 2.

From Table 2, it can be seen that the compounds of the examples have the same energy level as the comparative compound EBL-1, which shows the effect as an electron blocking layer, and the HOMO level, and have an appropriate HOMO level as an electron blocking layer. know that you have.

The bright current and dark current of the photoelectric conversion element can be evaluated with the element having the configuration as shown in FIG. Specifically, it can be produced by vapor-depositing an electron blocking layer 3, a photoelectric conversion layer 4, and a metal cathode 5 in this order on a glass substrate 1 on which an ITO electrode has been previously formed as a transparent anode 2. can be used to evaluate the bright current and dark current of a photoelectric conversion element.

From the above results, the photoelectric conversion element using the organic thin film containing the photoelectric conversion material represented by the general formulas (1) to (3) of the present invention has the HOMO level required for the electron blocking layer of the organic photoelectric conversion element. , high heat resistance, and sufficiently high mobility, it is possible to fabricate an element with a low dark current value.

According to the present invention, an organic thin film having high heat resistance and good charge mobility can be applied to various photoelectric conversion devices. Sensors can be provided.

1. glass substrate2. transparent anode3. electron blocking layer4. Photoelectric conversion layer 5 . cathode

Claims (7)

A compound represented by the following general formula (1).

(In formula (1),
Ar ¹ , Ar ² and Ar ³ represent a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted condensed polycyclic aromatic group;
n represents an integer of 0 to 3; ) 2. The compound according to claim 1, represented by the following general formula (2).

(In formula (2), Ar ¹ , Ar ² , Ar ³ and n are the same as defined in general formula (1).) The compound according to claim 1, represented by the following general formula (3).

(In formula (3), Ar ¹ , Ar ² , Ar ³ and n are the same as defined in general formula (1).) An organic thin film for a photoelectric conversion device, containing the compound according to any one of claims 1 to 3. A photoelectric conversion device comprising the organic thin film for a photoelectric conversion device according to claim 4 . 6. The photoelectric conversion device according to claim 5, wherein the organic thin film for photoelectric conversion device is a blocking layer. An imaging device comprising the photoelectric conversion device according to claim 5 .

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