Dye material for photoelectric conversion element, photoelectric conversion element using same, and image sensor using same

Abstract

Provided are: a dye material for a photoelectric conversion element for imaging, the dye material realizing higher sensitivity and higher resolution; a photoelectric conversion element that is for imaging and that uses the dye material; and an image sensor that uses a stack of the photoelectric conversion elements.　Specifically, the present invention provides: a dye material for a photoelectric conversion element for imaging that is characterized by satisfying all of the below conditions 1 to 3; a photoelectric conversion element for imaging, which uses the dye material; and an image sensor in which the photoelectric conversion elements for imaging are stacked. 1. The molar extinction coefficient at the maximum absorption wavelength of the peak positioned on the longest wavelength side of the absorption spectrum is 104 Lmol-1 cm-1 or more. 2. The half-value width of the peak positioned on the longest wavelength side of the absorption spectrum is 50 nm or less. 3. ΔEst is 0.50 eV or less.

Description

Dye material for photoelectric conversion element, photoelectric conversion element using the same, and image sensor using the same

[0001] The present invention relates to a dye material for a photoelectric conversion element, a photoelectric conversion element using the same, and an image sensor using the same, and particularly to a dye material for a photoelectric conversion element that is useful for an imaging device.

[0002] In recent years, the development of organic electronics devices using thin films formed from organic semiconductors has progressed. Examples include electroluminescent elements, solar cells, transistor elements, and photoelectric conversion elements. In particular, the development of organic electroluminescent elements, which are electroluminescent elements made of organic materials, has progressed the most. As their application to smartphones, TVs, and the like progresses, development aimed at further increasing their functionality is also ongoing.

[0003] Among these, photoelectric conversion elements for imaging have been developed and put into practical use using P-N junctions of inorganic semiconductors such as silicon, and studies are being conducted to improve the functionality of digital cameras and smartphone cameras, as well as for applications such as surveillance cameras and automotive sensors. However, challenges to meeting these various applications include increasing sensitivity and miniaturizing pixels (increasing resolution). Photoelectric conversion elements using inorganic semiconductors typically employ a method in which color filters corresponding to the three primary colors of light, RGB, are placed on the light-receiving section of the photoelectric conversion element to obtain color images. This method involves placing RGB color filters on a flat surface, which poses problems in terms of the efficiency of incident light utilization and resolution (Non-Patent Documents 1 and 2).

[0004] As one solution to these problems with photoelectric conversion elements for imaging, development is underway of photoelectric conversion elements that use organic semiconductors instead of inorganic semiconductors (Non-Patent Documents 1 and 2). This takes advantage of the property of organic semiconductors, which allows them to selectively absorb only light in a specific wavelength range with high sensitivity, and it has been proposed to solve the problem of high sensitivity and high resolution by stacking photoelectric conversion elements made of organic semiconductors corresponding to the three primary colors of light. In addition, a device has been proposed in which a photoelectric conversion element made of an organic semiconductor and a photoelectric conversion element made of an inorganic semiconductor are stacked (Non-Patent Document 3).

[0005] Here, the organic semiconductor photoelectric conversion element is an element configured by having a photoelectric conversion layer made of a thin film of an organic semiconductor between two electrodes, with a hole-blocking layer and / or an electron-blocking layer disposed between the photoelectric conversion layer and the two electrodes as needed. The photoelectric conversion layer is configured with an organic dye material and, as needed, a hole-transporting material and / or an electron-transporting material. In a photoelectric conversion element for imaging, excitons are generated in the photoelectric conversion layer when the organic dye material absorbs light of a desired wavelength, and then holes and electrons are generated by charge separation of the excitons. The holes and electrons then migrate to the respective electrodes, converting light into an electrical signal. The organic dye material contained in the photoelectric conversion layer is involved in processes such as (i) absorbing light of the desired wavelength, (ii) charge separation from the excitons, (iii) transferring the charge-separated holes to the hole-transporting material, and (iv) transferring the charge-separated electrons to the electron-transporting material. In other words, the organic dye material used to realize a photoelectric conversion element for imaging with high resolution and high sensitivity using an organic semiconductor is required to be able to selectively absorb only light in a desired wavelength range (narrow band) with high sensitivity in order to distinguish the color of the light source, and to have properties that facilitate charge separation from excitons and promote the transfer of charge-separated holes and electrons in order to increase the photoelectric conversion efficiency.

[0006] On the other hand, photoelectric conversion materials used in organic thin-film solar cells and dye-sensitized solar cells, which do not need to distinguish the color of the light source, must absorb light over a wide wavelength range to increase energy conversion efficiency. Therefore, the required properties are different from those of organic dye materials used in photoelectric conversion elements for imaging, which are required to selectively absorb only light in a specific wavelength range (narrow band) with high sensitivity.

[0007] Furthermore, fluorescent and phosphorescent materials used in organic EL devices must emit energy as light when excitons relax and return to the ground state. Therefore, a low level of charge separation is a requirement for a good luminescent material, as it can increase luminescence quantum efficiency. Therefore, the required properties differ from those of organic dye materials used in imaging photoelectric conversion devices, which are required to absorb light and rapidly induce charge separation to increase photoelectric conversion efficiency. The ease of charge separation from excitons is related to the overlap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of a molecule, which is proportional to the energy difference (ΔEst) between the lowest excited singlet state (S1) and the lowest excited triplet state (T1) of the molecule. Therefore, calculating the value of ΔEst allows for a precise expression of the ease of charge separation in a molecule. A large ΔEst value indicates that charge separation is unlikely to occur, while a small value indicates that charge separation is likely to occur. Therefore, if we substitute ΔEst for charge separation in the above description, then photoelectric conversion elements for imaging require organic dye materials with a small ΔEst, while organic EL elements require light-emitting materials with a large ΔEst. Organic EL elements sometimes use thermally activated delayed fluorescence (TADF) light-emitting materials that efficiently emit light by converting T1 to S1. For these light-emitting materials, it can be beneficial to increase the efficiency of TADF by reducing the energy difference (ΔEst) between T1 and S1. However, the ease of charge separation required for organic dye materials in photoelectric conversion elements for imaging is not directly required for light-emitting materials in organic EL elements, and the technical backgrounds are completely different.

[0008] As organic dye materials for conventional photoelectric conversion elements for imaging, compounds containing acene rings, such as subphthalocyanine (Patent Documents 1 and 2) and perylene (Patent Document 3), have been proposed to promote the transfer of holes and electrons by strengthening the π-stacking interaction with hole-transporting materials and electron-transporting materials. Specifically, Patent Documents 1 and 2 propose elements using subphthalocyanine chloride derivatives as dye materials in the photoelectric conversion layer. Patent Document 3 also proposes elements using perylene derivatives as dye materials in the photoelectric conversion layer. However, these compounds have the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) distribution in the electron orbitals related to the bonds in the benzene ring, which creates multiple vibrational levels in the ground state due to bond stretching motion (molecular vibration), resulting in a broadband absorption spectrum. Furthermore, since the HOMO-LUMO of an acene ring is highly distributed in the same orbital (the HOMO-LUMO overlap is large, i.e., ΔEST is large), the average distance between the hole and electron in the exciton state is short and the Coulomb interaction is large, making it difficult for charge separation to occur.

[0009] Patent Documents 4, 5, and 6 propose using a polycyclic fused ring compound containing a boron atom as a light-emitting material for an organic EL device. However, since the properties required for the light-emitting material of an organic EL device and the dye material of a photoelectric conversion device for imaging differ as described above, it remains unclear until experimental confirmation whether a compound useful as a light-emitting material for an organic EL device can be directly applied as an organic dye material to obtain a photoelectric conversion device for imaging that exhibits useful device properties.

[0010] The color resolution of organic dye materials in conventional photoelectric conversion elements for imaging is limited to distinguishing red, green, and blue, and the color reproducibility of image sensors is based on the three primary colors. This is because the absorption spectrum of typical dye materials, such as those shown in Patent Document 7, has a half-width of 50 nm or more, making it impossible to respond to finer changes in the wavelength of light. In order to improve the color reproducibility of image sensors, it is desirable to develop materials with high color resolution, i.e., organic dye materials with a narrow half-width of the absorption spectrum.

[0011] Japanese Patent Application Laid-Open No. 2018-85427, WO2016 / 194717, WO2020 / 196029, WO2015 / 102118, WO2021 / 200252, WO2022 / 45272, JPWO2016 / 129298

[0012] NHK Research Institute R&D No. 132, pp. 4-11 (2012.3) NHK Research Institute R&D No. 174, pp. 4-17 (2019.3) 2019 IEEE International Electron Devices Meeting (IEDM), pp. 16.6.1-16.6.4 (2019)

[0013] The dye material for a photoelectric conversion element for imaging of the present invention has a molar absorption coefficient of 10 at the maximum absorption wavelength of the peak located on the longest wavelength side of the absorption spectrum. ４ Lmol －１ cm －１ The dye material for an imaging photoelectric conversion element is characterized by satisfying the above requirements: the half-width of the peak located on the longest wavelength side of the absorption spectrum is 50 nm or less, and ΔEst is 0.50 eV or less. Thus, a dye material for an imaging photoelectric conversion element that absorbs light of a specific wavelength at a level equal to or greater than that of conventional dye materials, is more likely to cause charge separation than conventional materials, and has a smaller half-width of the absorption spectrum than conventional materials, and an imaging photoelectric conversion element using the same have not been publicly known until now. An imaging photoelectric conversion element using a dye material with a small half-width can detect not only the three primary colors of red, green, and blue light, but also colors such as orange, yellow, blue-green, and purple without color mixing. Therefore, an image sensor composed of elements in which four or more colors (four layers) of elements absorbing these different colors are stacked can provide an image sensor with unprecedented high color resolution while solving the problems of high sensitivity and high resolution.

[0014] To advance the application of imaging photoelectric conversion elements to digital cameras, smartphone cameras, surveillance cameras, automotive sensors, and other applications, organic materials are key to achieving even higher sensitivity and resolution. To achieve pixel miniaturization (higher resolution) while maintaining imaging capabilities in dark environments and a certain level of sensitivity, high sensitivity is required for the element itself, necessitating dye materials with high photocurrent values. Furthermore, as technological developments such as machine learning progress, adding more information to image data, which is important as training data, will enable more advanced learning and image processing. For example, further advances in autonomous driving technology require more sophisticated object recognition within images. To achieve this, improving the color resolution of image sensors will enable clearer object boundaries and lead to accurate image recognition. In light of this current situation, the present invention aims to provide materials that achieve higher sensitivity and resolution in imaging photoelectric conversion elements, imaging photoelectric conversion elements using such materials, and image sensors that use stacked photoelectric conversion elements.

[0015] As a result of intensive research, the present inventors have found that by using the compound of the present invention, it is possible to control the absorption of light in a photoelectric conversion element and the behavior of excitons, holes, and electrons, thereby realizing a photoelectric conversion element that absorbs light in a narrow band and exhibits a high photocurrent. Furthermore, they have found that an image sensor constructed by stacking such photoelectric conversion elements has excellent color resolution, and have thus completed the present invention.

[0016] That is, the present invention provides a dye material for a photoelectric conversion element for imaging, which satisfies all of the following conditions 1 to 3: 1. The molar absorption coefficient of the maximum absorption wavelength of the peak located on the longest wavelength side of the absorption spectrum is 10 ４ Lmol －１ cm －１ or more. 2. The half-width of the peak located on the longest wavelength side of the absorption spectrum is 50 nm or less. 3. ΔEst is 0.50 eV or less. It is preferable that the dye material further satisfies the following condition 4: 4. The radiative rate constant from the lowest singlet excited state is 2.0 × 10 ７ s －１ That's all.

[0017] The dye material for the photoelectric conversion element for imaging is B, P, P=O, P=S, C=O, Al, Ga, As, Si—R ２ or Ge-R ２ and a multiple resonance type fused ring compound containing one or more selected from the group consisting of N, O, S, and Se as acceptors and N, O, S, and Se as donors.

[0018] The dye material for a photoelectric conversion element for imaging preferably comprises a compound represented by the following general formula (1a) or (1b). Here, ring J, ring K, ring C, ring D, ring E, ring F, ring G, and ring H are each independently a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 carbon atoms, or a substituted or unsubstituted aromatic heterocycle having 2 to 30 carbon atoms. １ ~Y ３ are each independently N, B, P, P=O, P=S, Al, Ga, As, Si—R ２ or Ge-R ２ and preferably N, B, P, or P=O, and more preferably B. ２ are each independently an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms. １ ~X ６ are each independently O, C═O, or N—Ar ５ , S or Se, preferably O, C═O, N—Ar ５ or S, more preferably O, C═O, or N—Ar ５ Also, X １ and X ２ are preferably compounds represented by different elements, and X １ and X ２ At least one of the following is N-Ar ５ It is preferable that X ３ ~X ６ At least one of the following is N-Ar ５ It is preferable that the Ar ５are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 8 of these. １ ~X ６ are each independently the N-Ar ５ When Ar ５ may be bonded to any of ring J, ring K, ring C, ring D, ring E, ring F, ring G, or ring H to form a heterocycle containing N. ３ ~R １０ are each independently a cyano group, deuterium, a diarylamino group having 12 to 44 carbon atoms, an arylheteroarylamino group having 12 to 44 carbon atoms, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms; R ３ , R ４ , R ５ , R ６ , R ７ , R ８ , R ９ , and R １０ may bond with the ring J, ring K, ring C, ring D, ring E, ring F, ring G, and ring H to which they are bonded to form a ring. In this case, condensation may occur via an oxygen, carbon, nitrogen, or sulfur atom acting as a bridging group. p to t represent the number of substitutions, and p, q, and t each independently represent an integer of 0 to 4, preferably an integer of 0 to 2, r, u, and w each independently represent an integer of 0 to 3, preferably an integer of 0 to 2, r is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. v represents an integer of 0 to 2, preferably an integer of 0 or 1, and is also preferably 2.

[0019] The polycyclic aromatic compound having a structure represented by the formula (1a) or (1b) is preferably a polycyclic aromatic compound represented by any one of the following formulas (2a), (2b), (1c), and (1d): In the above general formulas (2a) and (2b), X １ ~X ６ , R３ ~R １０ , Ar ５ , p, q, r, s, t, u, v, and w have the same meanings as in the general formula (1a) or (1b). In the general formulas (1c) and (1d), ring I and ring M are each independently a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 carbon atoms, or a substituted or unsubstituted aromatic heterocycle having 2 to 30 carbon atoms. Ring A represents a heterocycle represented by formula (1c-2) which is fused with an adjacent ring at any position, and X ７ ~X ９ are each independently O, C═O, or N—Ar ５ , S or Se, preferably O, C═O, N—Ar ５ or S, more preferably O, C═O, or N—Ar ５ Also, X ７ ~X ９ At least one of the following is N-Ar ５ It is also preferred that Ar ５ has the same meaning as in the general formula (1a) or (1b). ７ , and X ８ are each independently the N-Ar ５ When Ar ５ may be bonded to either ring I or ring M to form a heterocycle containing N. In this case, condensation may be effected via an oxygen, carbon, nitrogen, or sulfur atom as a bridging group. ９ is N-Ar ５ When Ar ５ may be fused with the ring A and the adjacent ring to form a ring. In this case, the fusion may be via an oxygen, carbon, nitrogen, or sulfur atom as a bridging group. １１ ~R ２０are each independently a cyano group, deuterium, a diarylamino group having 12 to 44 carbon atoms, an arylheteroarylamino group having 12 to 44 carbon atoms, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms. a to j represent the number of substitutions, b, d, e, f, h, and j each independently represent an integer of 0 to 4, preferably an integer of 0 to 2, c and g each independently represent an integer of 0 or 1, preferably 0, and a and i represent an integer of 0 to 3, preferably an integer of 0 to 2. In the above general formulas (2a), (2b), (1c), and (1d), B represents a boron atom.

[0020] The present invention also relates to an imaging photoelectric conversion element having a photoelectric conversion layer and an electron blocking layer between two electrodes, characterized in that either layer contains a dye material for an imaging photoelectric conversion element that satisfies all of the above conditions 1 to 3. The dye material for a photoelectric conversion element contained in the imaging photoelectric conversion element preferably further satisfies condition 4. The dye material for a photoelectric conversion element is preferably a polycyclic aromatic compound represented by formula (1a) or (1b), more preferably a polycyclic aromatic compound represented by any of formulas (2a), (2b), (1c), or (1d), and even more preferably a polycyclic aromatic compound represented by formula (1c) or (1d).

[0021] In the imaging photoelectric conversion element, the dye material for the imaging photoelectric conversion element is preferably contained in a photoelectric conversion layer. The photoelectric conversion layer preferably further contains an electron transport material, which is preferably a fullerene derivative. The photoelectric conversion layer preferably contains a hole transport material having at least two thiophene rings in its skeleton.

[0022] In addition, in the imaging photoelectric conversion element, the photoelectric conversion layer of which contains a dye material for the imaging photoelectric conversion element and an electron transport material, when the lowest unoccupied molecular orbital (LUMO) of the dye material for the imaging photoelectric conversion element is defined as LUMO(D) and the LUMO of the electron transport material contained in the photoelectric conversion layer is defined as LUMO(EM), it is preferable that the value [LUMO(D)-LUMO(EM)] obtained by subtracting LUMO(EM) from LUMO(D) is 1.0 eV or more.

[0023] Furthermore, in the absorption spectrum of the electron transport material contained in the photoelectric conversion layer, the difference between the maximum absorption wavelength of the peak located on the longer wavelength side than 400 nm and the maximum emission wavelength of the emission spectrum of the dye material for photoelectric conversion elements is preferably ±100 nm or less, and further, the difference between the maximum emission wavelength of the emission spectrum of the dye material for photoelectric conversion elements and the wavelength of the absorption edge on the longer wavelength side of the absorption spectrum of the hole transport material contained in the photoelectric conversion layer is preferably ±10 nm or more.

[0024] Furthermore, the present invention provides an image sensor comprising two or more stacked photoelectric conversion elements for imaging, each containing the dye material for a photoelectric conversion element for imaging. The image sensor preferably comprises three or more stacked photoelectric conversion elements for imaging, and more preferably four or more stacked photoelectric conversion elements for imaging. Furthermore, the image sensor is preferably an image sensor comprising a stacked photoelectric conversion element for imaging, each containing the dye material for a photoelectric conversion element for imaging that absorbs green light, and a stacked photoelectric conversion element for imaging, each containing the dye material for a photoelectric conversion element for imaging that absorbs blue light.

[0025] By using the dye material for photoelectric conversion elements for imaging of the present invention, it is possible to control the absorption of light and the behavior of excitons, holes, and electrons within the photoelectric conversion element, thereby realizing a photoelectric conversion element that absorbs light in a narrow bandwidth (small half-width) and exhibits a high photocurrent. Furthermore, photoelectric conversion elements for imaging using dye materials with small half-widths such as those of the present invention can detect not only the three primary colors of red, green, and blue light, but also colors such as orange, yellow, blue-green, and purple without color mixing. Therefore, image sensors stacked with elements absorbing these different colors are expected to solve the problems of high sensitivity and high resolution and have unprecedentedly high color resolution. Therefore, the material of the present invention is useful as a material for photoelectric conversion elements in photoelectric conversion film-stacked imaging devices.

[0026] 1 is a cross-sectional view showing an example of the structure of a photoelectric conversion element used in the present invention; 2 is a diagram showing the absorption spectrum of compound 5-98; 3 is a diagram showing the absorption spectrum of fullerene; and 4 is a diagram showing the absorption spectrum of 2Ph-BTBT.

[0027] The present invention relates to a dye material for a photoelectric conversion element for imaging, which satisfies all of the above conditions 1 to 3, and to an image sensor comprising two or more stacked photoelectric conversion elements, the photoelectric conversion element having a photoelectric conversion layer and an electron blocking layer between two electrodes, the photoelectric conversion layer containing the dye material for a photoelectric conversion element, and the image sensor. Here, it is preferable that the dye material further satisfies the above condition 4.

[0028] Photoelectric conversion elements for imaging devices must efficiently convert light into electrical signals. Therefore, dye materials responsible for absorbing light are required to have physical properties that promote efficient photoelectric conversion. For efficient photoelectric conversion, it is important to have a high molar absorption coefficient and to easily absorb light. Unlike photoelectric conversion materials for solar cells, dye materials (photoelectric conversion materials) for imaging photoelectric conversion devices must have a narrow absorption band because they need to distinguish the color of the light source. In other words, the half-width of the absorption spectrum of dye materials for imaging photoelectric conversion devices is preferably small. By stacking elements that absorb light of different colors, imaging devices using dye materials with such narrow half-width absorption spectra can distinguish the color of ambient light without arranging imaging elements side by side as in conventional devices, thereby enabling higher-resolution images to be captured even within an imaging module of the same area. Furthermore, a smaller half-width enables finer color discrimination, thereby enabling image sensors with higher color resolution than conventional devices. Furthermore, it is preferable that the dye material used in the photoelectric conversion element for imaging absorbs light and enters an excited state, and then rapidly separates charges, transferring holes and electrons to the hole transport material and electron transport material, respectively. This makes it possible to suppress a decrease in photoelectric conversion efficiency due to charge recombination. Charge separation in the dye material is more likely to occur the more spatially separated the HOMO and LUMO of the dye material are. This is synonymous with a small ΔEst of the dye material.

[0029] As described above, in order to obtain an image sensor with high color separation and high resolution while maintaining high photoelectric conversion efficiency, the dye material for the photoelectric conversion element used for imaging must be a material that satisfies all of the above conditions 1 to 3. By satisfying all of the above conditions 1 to 3, a photoelectric conversion element thinner than conventional elements can maintain a high photoelectric conversion efficiency equal to or higher than conventional elements, and because of its thinness, an image sensor can be constructed in which these photoelectric conversion elements are stacked in multiple colors, and it is also possible to suppress color mixing when stacking multiple colors. Specifically, condition 1 is that, in the absorption spectrum exhibited by the dye material having multiple peaks, the molar extinction coefficient of the maximum absorption wavelength of the peak located on the longest wavelength side must be 10 ４ Lmol －１ cm－１ More preferably, the ratio is 2.5×10 ４ Lmol －１ cm －１ More preferably, 4.0 × 10 ４ Lmol －１ cm －１ These are the above. By satisfying these conditions, it is possible to easily absorb light and promote efficient photoelectric conversion. Furthermore, as condition 2, when the absorption spectrum of the dye material has multiple peaks, the half-width of the peak located on the longest wavelength side is preferably 50 nm or less. More preferably, it is 40 nm or less, and even more preferably, it is 35 nm or less. By using a dye material with a small half-width that satisfies this condition, an image sensor with high color separation and high resolution can be realized. Furthermore, as condition 3, it is preferable that ΔEst, which is the energy difference between the excited singlet state (S1) and the excited triplet state (T1), is 0.50 eV or less. More preferably, it is 0.45 eV or less. A dye material that satisfies these conditions can quickly separate charges after absorbing light and becoming excited, and can transfer holes and electrons to the hole transport material and the electron transport material, thereby suppressing a decrease in photoelectric conversion efficiency due to charge recombination.

[0030] Furthermore, in a photoelectric conversion element, not only do dye molecules absorb light and cause charge separation on the dye molecules, but energy may also be transferred to molecules surrounding the dye molecules, such as an electron transport material, followed by charge separation on the electron transport material. Prompt initiation of this process is also useful for improving photoelectric conversion efficiency, and the larger the radiative rate constant (kr) from the lowest excited singlet state of the dye molecules, the more efficiently this energy transfer occurs. Therefore, in addition to the above conditions 1 to 3, condition 4 is that the dye material for a photoelectric conversion element for imaging must have a radiative rate constant from the lowest excited singlet state of 2.0 × 10 ７ s －１ It is preferable that the above ratio is satisfied. More preferably, it is 3.0 × 10 ７ s －１ More preferably, it is 3.5×10 ７ s －１ That's all.

[0031] The dye material for the photoelectric conversion element for imaging is B, P, P=O, P=S, C=O, Al, Ga, As, Si—R ２ or Ge-R ２ and a multiple-resonance fused ring compound containing one or more atoms selected from the group consisting of N, O, S, and Se as an acceptor and one or more atoms selected from the group consisting of N, O, S, and Se as a donor. In the multiple-resonance fused ring compound, a LUMO orbital is localized in an electron orbital not involved in bonding on the acceptor atom, and a HOMO orbital is localized in an electron orbital not involved in bonding on the donor atom. Therefore, molecular vibrations have little effect on the molecular energy level, resulting in a narrow absorption spectrum. Meanwhile, π-conjugation is large, and sufficient interaction with the hole transport material and electron transport material used in the photoelectric conversion layer is obtained, thereby facilitating the transfer of charge-separated holes to the hole transport material and the transfer of charge-separated electrons to the electron transport material. Furthermore, the HOMO-LUMO is largely localized in the electron orbital on each atom, and the overlap between the HOMO-LUMO orbitals is small, increasing the distance between holes and electrons and facilitating charge separation. Furthermore, the small overlap of the HOMO-LUMO orbitals is quantitatively expressed by a small ΔEst.

[0032] The dye material for a photoelectric conversion element for imaging is preferably a polycyclic aromatic compound represented by the general formula (1a) or (1b), and the polycyclic aromatic compound represented by (1a) or (1b) is more preferably a polycyclic aromatic compound represented by any one of the formulas (2a), (2b), (1c), or (1d).

[0033] The compounds represented by the general formula (1a), (1b), (2a), (2b), (1c), or (1d) will be explained below.

[0034] Ring J, ring K, ring C, ring D, ring E, ring F, ring G, ring H, ring I, and ring M each independently represent a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic ring having 2 to 30 carbon atoms. Preferably, they represent a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic ring having 2 to 20 carbon atoms. More preferably, they are a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 10 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic ring having 2 to 20 carbon atoms.

[0035] Specific examples of unsubstituted aromatic hydrocarbon rings and unsubstituted aromatic heterocycles for ring J, ring K, ring C, ring D, ring E, ring F, ring G, ring H, ring I, and ring M include benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, chrysene, pyrene, phenanthrene, triphenylene, fluorene, benzo[a]anthracene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazo Examples of suitable benzophenones include benzophenone, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, dibenzofuran, dibenzothiophene, dibenzoselenophene, and carbazole. Preferred are benzene, naphthalene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, dibenzofuran, dibenzothiophene, dibenzoselenophene, and carbazole. More preferred are benzene, naphthalene, pyridine, pyrimidine, pyrazine, quinoline, isoquinoline, quinoxaline, quinazoline, indole, benzofuran, dibenzofuran, dibenzothiophene, and carbazole.

[0036] Ring A represents a heterocycle represented by formula (1c-2) fused to an adjacent ring at any position, and B represents a boron atom.

[0037] Y １ ~Y３ are each independently N, B, P, P=O, P=S, Al, Ga, As, Si—R ２ or Ge-R ２ and preferably N, B, P, or P═O, and more preferably B.

[0038] R ２ are each independently an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, and are preferably a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms.

[0039] R ２Specific examples of when represents an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms or an unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms include benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, chrysene, pyrene, phenanthrene, triphenylene, fluorene, benzo[a]anthracene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, Examples include groups formed by removing one hydrogen atom from isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, dibenzofuran, dibenzothiophene, dibenzoselenophene, and carbazole. Preferred examples include groups formed by removing one hydrogen atom from benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, chrysene, pyrene, phenanthrene, fluorene, benz[a]anthracene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, dibenzofuran, dibenzothiophene, dibenzoselenophene, or carbazole.

[0040] R ２is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a phenyl group, a biphenyl group, a terphenyl group, and a naphthyl group. A methyl group, an ethyl group, a propyl group, or a butyl group is preferred.

[0041] X １ ~X ９ are each independently O, C═O, or N—Ar ５ , S or Se, and O, C═O, N—Ar ５ or S is preferred, and O, C=O, or N-Ar ５ More preferably, X １ ~X ６ At least one of the following is N-Ar ５ In formula (1c) or (1d), N-Ar ５ is the Ar ５ may be bonded to either the ring to which it is bonded or an adjacent ring to form a heterocyclic ring containing N. 1 and X 2 In addition, in the general formula (1b), X is preferably a compound represented by a different element. ３ ~X ６ Preferably, at least one of X is represented by O or S, ３ ~X ６ At least one of is N and X ３ ~X ６ It is also preferred that at least one of the groups is S.

[0042] Ar ５are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 8 of these, preferably a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 6 of these, more preferably a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 4 of these.

[0043] Ar ５is an unsubstituted aromatic hydrocarbon ring having 6 to 18 carbon atoms, an unsubstituted aromatic heterocycle having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 8 of these, specific examples thereof include benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, chrysene, pyrene, phenanthrene, triphenylene, fluorene, benzo[a]anthracene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine ... benzo[a]anthracene, pyridine, pyrimidine, triazine, thiophene, benzo[a]anthracene, pyridine, pyrimidine, triazine, thiophene, benzo[a]anthracene, pyridine, pyrimidine, triazine, thiophene, benzo[a]anthracene, pyridine, pyrimidine, triazine, thiophene, benzo[a]anthracene, pyridine, pyridine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, fluorene, benzo[a]anthracene, pyridine, pyridine, benzo[a]anthracene, pyridine, pyridine, benzo[a]anthracene, pyridine, pyridine, benzo[a]anthracene, benzo[a]anthracene, pyridine, pyridine, benzo[a]anthracene, benzo[a]anthracene, benzo[ Examples of such groups include oran, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, dibenzofuran, dibenzothiophene, dibenzoselenophene, carbazole, and a group formed by removing one hydrogen atom from a compound formed by linking 2 to 8 of these. Preferred examples include benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, chrysene, pyrene, phenanthrene, fluorene, benzo[a]anthracene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, dibenzofuran, dibenzothiophene, dibenzoselenophene, carbazole, and a group formed by removing one hydrogen atom from a compound formed by linking 2 to 6 of these.More preferred examples include benzene, naphthalene, azulene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, or a group formed by removing one hydrogen from a compound formed by linking 2 to 4 of these.

[0044] X １ ~X ８ are each independently the N-Ar ５ When Ar ５ is the Ar ５ is bonded to the ring to which N-Ar is bonded or to any of the adjacent rings J, K, C, D, E, F, G, H, I, and M, ５ In addition, X may form a heterocyclic ring containing N. ９ is N-Ar ５ When Ar ５ may be fused with the ring A and the adjacent ring to form a ring.

[0045] R ３ ~R ２０are each independently a cyano group, deuterium, a diarylamino group having 12 to 44 carbon atoms, an arylheteroarylamino group having 12 to 44 carbon atoms, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, and preferably represent deuterium, a substituted or unsubstituted diarylamino group having 12 to 24 carbon atoms, an aliphatic hydrocarbon group having 1 to 8 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms. More preferably, represent a substituted or unsubstituted diarylamino group having 12 to 18 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 10 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 12 carbon atoms. ３ , R ４ , R ５ , R ６ , R ７ , R ８ , R ９ , and R １０ may be bonded to the ring J, ring K, ring C, ring D, ring E, ring F, ring G, or ring H to form a ring.

[0046] R ３ ~R ２０ Specific examples of when represents a diarylamino group having 12 to 44 carbon atoms, an arylheteroarylamino group having 12 to 44 carbon atoms, or an aliphatic hydrocarbon group having 1 to 10 carbon atoms include diphenylamino, dibiphenylamino, phenylbiphenylamino, naphthylphenylamino, dinaphthylamino, dianthranylamino, diphenanthrenylamino, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl. Preferred are diphenylamino, dibiphenylamino, phenylbiphenylamino, naphthylphenylamino, dinaphthylamino, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl. More preferred are diphenylamino and phenylbiphenylamino.

[0047] R ３ ~R ２０Specific examples of when R represents an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms or an unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms include ２ The specific examples are the same as those in the case where represents an unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms or an unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms. Preferred examples include groups formed by removing one hydrogen atom from benzene, naphthalene, acenaphthene, acenaphthylene, azulene, anthracene, chrysene, pyrene, phenanthrene, fluorene, benzo[a]anthracene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, chromone, dibenzofuran, dibenzothiophene, dibenzoselenophene, and carbazole. More preferred are groups formed by removing one hydrogen atom from benzene, naphthalene, azulene, pyridine, pyrimidine, triazine, thiophene, isothiazole, thiazole, pyridazine, pyrrole, pyrazole, imidazole, triazole, thiadiazole, pyrazine, furan, isoxazole, quinoline, isoquinoline, quinoxaline, quinazoline, thiadiazole, phthalazine, tetrazole, indole, benzofuran, benzothiophene, benzoxazole, benzothiazole, indazole, benzimidazole, benzotriazole, benzisothiazole, benzothiadiazole, purine, pyranone, coumarin, isocoumarin, or chromone.

[0048] p to w represent the number of substitutions, p, q, s, and t each independently represent an integer of 0 to 4, preferably an integer of 0 to 2, r, u, and w each independently represent an integer of 0 to 3, u and w are preferably an integer of 0 to 2, r is preferably 1 to 3, more preferably 1 or 2, and even more preferably 1. v represents an integer of 0 to 2, preferably 0 or 1, and also preferably 2. a to j represent the number of substitutions, b, d, e, h, and j each independently represent an integer of 0 to 4, preferably an integer of 0 to 2, c represents an integer of 0 or 1, preferably 0, a, f, and i represent an integer of 0 to 3, preferably an integer of 0 to 2, g represents an integer of 0 to 2, preferably 0 to 1, and c represents an integer of 0 or 1, preferably 0.

[0049] In this specification, the aromatic hydrocarbon group, aromatic heterocyclic group, or linking aromatic group may each have a substituent. When substituted, the substituent is a cyano group, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a diarylamino group having 12 to 30 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, or an arylthio group having 6 to 18 carbon atoms. The number of substituents is 0 to 5, preferably 0 to 2. When the aromatic hydrocarbon group or aromatic heterocyclic group has a substituent, the number of carbon atoms in the substituent is not included in the calculation of the carbon number. However, it is preferable that the total number of carbon atoms, including the carbon atoms in the substituent, satisfies the above range.

[0050] Specific examples of the substituent include cyano, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, diphenylamino, naphthylphenylamino, dinaphthylamino, dianthranylamino, diphenanthrenylamino, methoxy, ethoxy, phenol, diphenyloxy, methylthio, ethylthio, thiophenol, and diphenylthio. Preferred are cyano, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, diphenylamino, naphthylphenylamino, dinaphthylamino, phenol, and thiophenol.

[0051] Specific examples of the dye materials represented by the general formulae (1a) to (1d), (2a), and (2b) are shown below, but the dye materials are not limited to these exemplary compounds.

[0052] The compound represented by general formula (1) of the present invention can be obtained by synthesizing it using commercially available reagents as raw materials through various organic synthesis reaction methods established in the field of organic synthetic chemistry, including coupling reactions such as Suzuki coupling, Stille coupling, Grignard coupling, Ullmann coupling, Buchwald-Hartwig reaction, and Heck reaction, followed by purification using known methods such as recrystallization, column chromatography, and sublimation purification, but is not limited to these methods.

[0053] The dye material for a photoelectric conversion element of the present invention preferably has an energy level of the highest occupied molecular orbital (HOMO) obtained by a structure optimization calculation using density functional theory calculation B3LYP / 6-31G(d) of −4.3 eV or less, more preferably in the range of −5.5 eV to −4.5 eV, and even more preferably in the range of −5.2 eV to −4.8 eV.

[0054] The dye material for photoelectric conversion elements of the present invention preferably has an energy level of the lowest unoccupied molecular orbital (LUMO) obtained by a structural optimization calculation using density functional theory calculation B3LYP / 6-31G(d) of -2.5 eV or higher, more preferably in the range of -2.0 eV to -0.50 eV, and even more preferably in the range of -1.5 eV to -0.50 eV. By satisfying this range, electrons that have moved from the dye material to the electron transport material are less likely to return to the dye material, allowing electrons to move efficiently to the electrode.

[0055] In the material for photoelectric conversion elements of the present invention, the difference (absolute value) between the HOMO energy level and the LUMO energy level is preferably in the range of 2.0 eV to 5.0 eV, more preferably in the range of 2.5 eV to 4.7 eV, and even more preferably in the range of 3.5 eV to 4.5 eV.

[0056] The material for a photoelectric conversion element of the present invention has a hole mobility of 1×10 －６ cm ２ / Vs or more, and more preferably 1×10 －５ cm ２ / Vs ~ 1 × 10 －１ cm ２ / Vs, more preferably 8×10 －５ cm ２ / Vs~1×10 －２ cm ２ The hole mobility can be evaluated by known methods such as a method using a FET transistor element, a time-of-flight method, or an SCLC method.

[0057] The dye material for a photoelectric conversion element of the present invention is preferably amorphous. The amorphous nature can be confirmed by various methods, for example, by detecting no peaks in an XRD method or no endothermic peaks in a DSC method.

[0058] Next, an imaging photoelectric conversion element using the dye material for a photoelectric conversion element of the present invention will be described, but the structure of the imaging photoelectric conversion element of the present invention is not limited thereto. The description will be made with reference to the drawings. FIG. 1 is a cross-sectional view schematically illustrating an example structure of an imaging photoelectric conversion element of the present invention, in which 1 represents an electrode, 2 represents a hole blocking layer, 3 represents a photoelectric conversion layer, 4 represents an electron blocking layer, 5 represents an electrode, and 6 represents a substrate. Note that the configuration excluding the substrate may be reversed from that of FIG. 1 , i.e., 1 represents a substrate, 2 represents an electrode, 3 represents an electron blocking layer, 4 represents a photoelectric conversion layer, 5 represents a hole blocking layer, and 6 represents an electrode. The structure of FIG. 1 is not limited thereto, and layers can be added or omitted as necessary.

[0059] - Electrode - The electrode used in an imaging photoelectric conversion element using the dye material for an imaging photoelectric conversion element of the present invention has the function of collecting holes and electrons generated in the photoelectric conversion layer. It also needs to have the function of allowing light to enter the photoelectric conversion layer. Therefore, it is desirable that at least one of the two electrodes is transparent or semi-transparent. In addition, the material used as the electrode is not particularly limited as long as it is conductive, but examples thereof include ITO, IZO, SnO, and the like. ２ , ATO (antimony-doped tin oxide), ZnO, AZO (Al-doped zinc oxide), GZO (gallium-doped zinc oxide), TiO ２Examples of the conductive material include transparent conductive materials such as fluorine-containing tetrahydrofuran (FTO), metals such as gold, silver, platinum, chromium, aluminum, iron, cobalt, nickel, and tungsten, inorganic conductive materials such as copper iodide and copper sulfide, and conductive polymers such as polythiophene, polypyrrole, and polyaniline. A mixture of these materials may be used as needed. Two or more layers may also be laminated.

[0060] Photoelectric Conversion Layer: The photoelectric conversion layer is a layer in which holes and electrons are generated by charge separation of excitons generated by incident light. It may be formed of a single photoelectric conversion material, or may be formed in combination with a P-type organic semiconductor material, which is a hole-transporting material, or an N-type organic semiconductor material, which is an electron-transporting material. Two or more P-type organic semiconductors may be used, or two or more N-type organic semiconductors may be used. It is desirable that one or more of these P-type organic semiconductors and / or N-type semiconductors be made of a dye material that has the function of absorbing light of a desired wavelength in the visible range. The dye material may be a compound represented by general formula (1a) or (1b) of the present invention.

[0061] The P-type organic semiconductor material may be any material having hole transport properties, and examples thereof include compounds having a condensed polycyclic aromatic group such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, triphenylene, perylene, fluoranthene, fluorene, and indene; compounds having a π-excess aromatic group such as cyclopentadiene derivatives, furan derivatives, thiophene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, dinaphthothienothiophene derivatives, indole derivatives, pyrazoline derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, and indolocarbazole; aromatic amine derivatives, styrylamine derivatives, benzidine derivatives, porphyrin derivatives, phthalocyanine derivatives, and quinacridone derivatives, and preferably materials having at least two thiophene rings in their skeletons.

[0062] The P-type organic semiconductor material may be a polymer-type P-type organic semiconductor material. Specific examples include polyphenylene vinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinyl carbazole derivatives, and polythiophene derivatives. Furthermore, two or more compounds selected from the P-type organic semiconductor materials and the polymer-type P-type organic semiconductor materials may be mixed and used.

[0063] The N-type organic semiconductor material may be any material having electron transport properties, such as naphthalene tetracarboxylic acid diimide, perylene tetracarboxylic acid diimide, fullerenes, and azole derivatives such as imidazole, thiazole, thiadiazole, oxazole, oxadiazole, and triazole. Two or more compounds selected from these N-type organic semiconductor materials may be mixed and used. Fullerene derivatives are preferred.

[0064] Examples of the dye material include compounds represented by general formula (1a) or (1b) of the present invention, and other examples include quinacridone derivatives, subphthalocyanine derivatives, phthalocyanine derivatives, porphyrin derivatives, squarylium derivatives, naphthalene or perylene derivatives, cyanine derivatives, merocyanine derivatives, rhodamine derivatives, diphenylmethane or triphenylmethane derivatives, xanthene derivatives, acridine derivatives, phenoxazine derivatives, quinoline derivatives, oxazole derivatives, thiazole derivatives, oxazine derivatives, thiazine derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, indigo or thioindigo derivatives, pyrrole derivatives, pyridine derivatives, dipyrrine derivatives, and indole derivatives. , diketopyrrolopyrrole derivatives, coumarin derivatives, fluorene derivatives, fluoranthene derivatives, anthracene derivatives, pyrene derivatives, triarylamine derivatives such as triphenylamine, naphthylamine and styrylamine, carbazole derivatives, phenylenediamine derivatives, benzidine derivatives, phenanthroline derivatives, imidazole derivatives, oxazoline derivatives, thiazoline derivatives, triazole derivatives, thiadiazole derivatives, oxadiazole derivatives, thiophene derivatives, selenophene derivatives, silole derivatives, germole derivatives, stilbene derivatives, phenylenevinylene derivatives, pentacene derivatives, rubrene derivatives, thienothiophene derivatives, benzodithiophene derivatives, or xanthenoxanthene derivatives. Preferred are compounds represented by general formula (1a) or (1b) of the present invention.

[0065] -Electron Blocking Layer- The electron blocking layer is provided to suppress dark current generated by injection of electrons from one electrode into the photoelectric conversion layer when a bias voltage is applied between the two electrodes. The electron blocking layer also functions as a hole transport layer, transporting holes generated by charge separation in the photoelectric conversion layer to the electrode. A single layer or multiple layers may be arranged as needed. A P-type organic semiconductor material, which is a hole transport material, may be used for the electron blocking layer. Specific examples of the P-type organic semiconductor are the same as the specific examples of the P-type semiconductor of the photoelectric conversion layer.

[0066] -Hole Blocking Layer- The hole blocking layer is provided to suppress dark current generated by holes being injected from one electrode into the photoelectric conversion layer when a bias voltage is applied between the two electrodes. It also functions as an electron transport layer, transporting electrons generated by charge separation in the photoelectric conversion layer to the electrode, and a single layer or multiple layers may be disposed as needed. An N-type organic semiconductor having electron transport properties may be used for the hole blocking layer. The N-type organic semiconductor material may be any material having electron transport properties, and examples thereof include polycyclic aromatic polycarboxylic anhydrides and imidized products thereof, such as naphthalene tetracarboxylic diimide and perylene tetracarboxylic diimide, fullerenes such as C60 and C70, azole derivatives such as imidazole, thiazole, thiadiazole, oxazole, oxadiazole, and triazole, tris(8-quinolinolato)aluminum(III) derivatives, phosphine oxide derivatives, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, bipyridine derivatives, quinoline derivatives, and indolocarbazole derivatives. Two or more of these N-type organic semiconductor materials may also be used in combination.

[0067] The hydrogen atoms in the dye material for a photoelectric conversion element of the present invention may be deuterium atoms. That is, in addition to the hydrogen atoms on the aromatic rings in general formulae (1a) to (1d), (2a), and (2b), some or all of the hydrogen atoms in the substituents may be deuterium atoms. Furthermore, some or all of the hydrogen atoms in the compounds used as the N-type organic semiconductor material and the P-type organic semiconductor material may be deuterium atoms.

[0068] When producing the imaging photoelectric conversion element of the present invention, the method for forming each layer is not particularly limited, and the layer may be produced by either a dry process or a wet process. The organic layer containing the dye material for a photoelectric conversion element of the present invention may be a multi-layer layer, if necessary.

[0069] In the photoelectric conversion element of the present invention, the photoelectric conversion layer contains the dye material for photoelectric conversion elements for imaging and the electron transport material. When the lowest unoccupied molecular orbital (LUMO) of the dye material for photoelectric conversion elements for imaging is defined as LUMO(D) and the LUMO of the electron transport material is defined as LUMO(EM), the value obtained by subtracting LUMO(EM) from LUMO(D) [LUMO(D) - LUMO(EM)] is preferably 1.0 eV or more. It is more preferably 1.4 eV or more, and even more preferably 1.7 eV or more. Under the above conditions, the large LUMO energy difference allows the electron transport material to exhibit strong electron trapping properties in the photoelectric conversion layer, efficiently inducing electron migration from the dye material to the electron transport material, and electrons trapped in the electron transport material are less likely to migrate back to the dye material with a large energy difference. This suppresses charge recombination due to electrons returning to the dye material, thereby improving photoelectric conversion efficiency on both sides.

[0070] Furthermore, in the photoelectric conversion element of the present invention, in which the photoelectric conversion layer contains the dye material for photoelectric conversion elements for imaging and the electron transport material, the difference between the maximum absorption wavelength of the peak located on the wavelength side longer than 400 nm in the absorption spectrum of the electron transport material and the maximum emission wavelength of the emission spectrum of the dye material for photoelectric conversion elements is preferably ±100 nm or less, more preferably ±80 nm or less, and even more preferably ±50 nm or less. It is known that energy transfer of excitons is caused by Förster energy transfer. Since Förster energy transfer is caused by the resonance of molecular vibrations, energy transfer is possible when the energy donor and energy acceptor have excitation levels with the same energy level. The energy level of the excitation level is represented by the emission wavelength in the emission spectrum in the case of an energy donor, and by the absorption wavelength in the absorption spectrum in the case of an energy acceptor. Therefore, when the maximum absorption wavelength of the peak located on the longer wavelength side of 400 nm in the visible light region in the absorption spectrum of the electron transport material as an energy acceptor and the maximum emission wavelength of the emission spectrum of the dye material for a photoelectric conversion element as an energy donor are in a band of ±100 nm or less, the dye material and the electron transport material can have excitation levels of the same energy level, and energy transfer from the dye material to the electron transport material can be efficiently induced.

[0071] In the photoelectric conversion element of the present invention, in which the photoelectric conversion layer contains the dye material for photoelectric conversion elements for imaging, the electron transport material, and the hole transport material, the difference between the maximum emission wavelength of the emission spectrum of the dye material for photoelectric conversion elements and the wavelength of the long-wavelength absorption edge of the absorption spectrum of the hole transport material contained in the photoelectric conversion layer is preferably ±10 nm or more, more preferably ±20 nm or more, and even more preferably ±30 nm or more. To increase the photoelectric conversion efficiency of the element, electrons must be rapidly transferred from the photoelectric conversion layer to the electron transport layer. Electrons move between molecules by exciton energy transfer or LUMO-to-LUMO hopping of multiple molecules. To rapidly transfer electrons to the electron transport layer, it is effective to localize electrons in the electron transport material in the photoelectric conversion layer. Since a hole transport material is also present in the photoelectric conversion layer and there is a concern that charge recombination may occur, the difference between the maximum emission wavelength of the emission spectrum of the dye material for photoelectric conversion elements and the wavelength of the absorption edge on the long-wavelength side of the absorption spectrum of the hole transport material is ±10 nm or more, and as described above, due to the difference in energy levels of the excitation levels, energy transfer from the dye to the hole transport material can be suppressed, and the transfer of excitons and electrons can be preferentially induced to the electron transport material, thereby improving the photoelectric conversion efficiency. Note that the absorption edge on the long-wavelength side of the absorption spectrum of the hole transport material is determined by drawing a tangent to the falling edge on the long-wavelength side of the absorption spectrum of the hole transport material, and the wavelength value at the intersection of the tangent and the horizontal axis.

[0072] The present invention also provides an image sensor comprising two or more stacked photoelectric conversion elements for imaging, each containing the dye material for a photoelectric conversion element for imaging. The image sensor may comprise a stack of photoelectric conversion elements for imaging, each containing the dye material for a photoelectric conversion element for imaging of the present application that absorbs green light and the dye material for a photoelectric conversion element for imaging of the present application that absorbs blue light.

[0073] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0074] Synthesis Example 1 A 500 mL three-neck flask was charged with 5.0 g (6.7 mmol) of precursor 5-98T, 7.2 g (53.8 mmol) of aluminum chloride, and 100 mL of o-dichlorobenzene (ODCB) and stirred under a nitrogen atmosphere. Subsequently, 5.10 mL (53.8 mmol) of BBr3 was slowly added using a 10 mL syringe in a water bath. The mixture was then heated and stirred at 90 °C for 3 hours. After the reaction was complete, the mixture was allowed to cool to room temperature and quenched by slowly adding the reaction solution to 600 mL of water in an Erlenmeyer flask in a water bath. The mixture was then extracted with dichloromethane, and the organic layer was recovered. The dichloromethane was then removed using an evaporator. The resulting crude product was subjected to silica gel column chromatography to obtain 5-98. The yield was 13.4%.

[0075] Synthesis Example 2 A 500 mL three-neck flask was charged with 5.0 g (7.7 mmol) of precursor 5-89T, 8.2 g (61.6 mmol) of aluminum chloride, and 100 mL of o-dichlorobenzene (ODCB) and stirred under a nitrogen atmosphere. Subsequently, 5.84 mL (61.6 mmol) of BBr3 was slowly added using a 10 mL syringe in a water bath. The mixture was then heated and stirred at 90 °C for 3 hours. After the reaction was complete, the mixture was allowed to cool to room temperature and quenched by slowly adding the reaction solution to 600 mL of water in a conical flask in a water bath. The mixture was then extracted with dichloromethane, and the organic layer was recovered. The dichloromethane was then removed using an evaporator. The resulting crude product was subjected to silica gel column chromatography to obtain 5-89. The yield was 8.6%.

[0076] Measurement method of absorption spectrum The synthesized compound was －５The compound was dissolved in a toluene solvent to a concentration of 1000 mol / L, and the toluene solution containing the dissolved compound was subjected to measurement of its absorption spectrum at room temperature using an ultraviolet-visible absorption spectrometer (V-560ST, manufactured by JASCO). The absorption spectrum was obtained by subtracting the spectrum obtained by measuring only toluene from the spectrum of the toluene solution containing the dissolved compound, thereby removing the influence of the absorption spectrum of the toluene solvent. Next, the maximum absorption wavelength of the peak located on the longest wavelength side in the obtained absorption spectrum was identified, and the molar extinction coefficient (L mol －１ cm －１ The absorption spectrum of each compound was used to determine the peak wavelength (nm) and the half-width (nm) of the peak. The color of light absorbed by the compound was classified as follows: Specifically, when the maximum absorption wavelength located on the longest wavelength side of the absorption spectrum was 400 nm to 439 nm, the color of light absorbed by the compound was classified as purple; when it was 440 nm to 469 nm, the color of light absorbed by the compound was classified as blue; when it was 470 nm to 499 nm, the color of light absorbed by the compound was classified as blue-green; and when it was 500 nm to 559 nm, the color of light absorbed by the compound was classified as green.

[0077] The compounds used in the examples and comparative examples are listed below.

[0078] Example 1: Using the method described above, a toluene solvent was used to prepare a solution with a concentration of 10 －５ The absorption spectrum of Compound 5-98 was measured using a toluene solution of Compound 98 adjusted to 100 mol / L. The results are shown in Figure 2. In the obtained absorption spectrum, the maximum absorption wavelength of the peak located on the longest wavelength side was at a vertex near 460 nm, and the molar extinction coefficient at this time was 4.5 x 10 ４ Lmol －１ cm －１ The half-width was 25 nm. Furthermore, when the color absorbed by the compound was classified based on the absorption spectrum using the criteria described above, the color of light absorbed by compound 5-98 was blue. These results are shown in Table 1.

[0079] Examples 2 to 10 and Comparative Examples 1 and 2 Absorption spectra were measured in the same manner as in Example 1, except that the compounds used were those listed in Table 1. The molar absorption coefficients (Lmol －１ cm －１ The color of light absorbed by each compound was classified based on the wavelength (nm) and the half-width (nm) of the peak. The results are shown in Table 1.

[0080]

[0081] Photoluminescence quantum yield (PLQY) measurement method: First, the compound of the present invention was deposited on a quartz substrate by vacuum deposition at a vacuum degree of 4.0 × 10 －５ An organic thin film having a thickness of 100 nm was prepared by vapor deposition at 100 Pa. Next, the photoluminescence quantum yield (PLQY) of the organic thin film was measured using an Absolute PL Quantum Yield Measurement C9920-03G system (Hamamatsu Photonics K.K.). Using the C9920-03G system, photoexcitation and emission spectra of the organic thin film can be measured continuously, and the PLQY of the organic thin film can be calculated by calculating the energy balance at this time. The PLQY (%) was determined using software U6039-05 version 3.6.0. The excitation wavelength in the PLQY measurement was 340 nm.

[0082] The excited singlet energy (S1) and excited triplet energy (T1) are calculated by drawing a tangent to the rising edge on the short wavelength side of the emission spectrum of the organic thin film obtained during the PLQY measurement, and substituting the wavelength value λedge [nm] at the intersection of the tangent and the horizontal axis into the following formula (i) to calculate S1: S1 [eV] = 1239.85 / λedge (i) On the other hand, T1 is calculated by drawing a tangent to the rising edge on the short wavelength side of the phosphorescence spectrum of the organic thin film obtained during the PLQY measurement, and substituting the wavelength value λedge [nm] at the intersection of the tangent and the horizontal axis into formula (ii) to calculate T1: T1 [eV] = 1239.85 / λedge (ii) ΔEST is calculated by subtracting T1 from S1 calculated above.

[0083] The radiative rate constant (kr) from the lowest excited singlet state is calculated using the following formula: kr [s-1] = PLQY / tau The luminescence lifetime tau [s] is measured using a compact fluorescence lifetime measurement device C11367 (Hamamatsu Photonics K.K.) and determined using software U11487-01 version 2.1.0.

[0084] Example 11: Compound 5-98 was used to prepare an organic thin film having a thickness of 100 nm by the method described above. The difference (ΔEST) between the excited singlet energy (S1) and the excited triplet energy (T1) and the radiative rate constant (kr) from the lowest excited singlet state were calculated by the method described above. The results are shown in Table 2.

[0085] Examples 12 to 20 and Comparative Examples 3 to 4 ΔEST and the radiative rate constant (kr) from the lowest excited singlet were calculated in the same manner as in Example 11, except that the compounds used were those listed in Table 2. The results are shown in Table 2.

[0086]

[0087] From the results of Examples 1 to 20 in Tables 1 and 2, it can be seen that the dye material for a photoelectric conversion element of the present invention has a molar absorption coefficient of 10 at the maximum absorption wavelength of the peak located on the longest wavelength side of the absorption spectrum. ４　 Lmol －１ cm －１The above (condition 1), the half-width of the peak located on the longest wavelength side of the absorption spectrum is 50 nm or less (condition 2), and ΔEST, an index of the likelihood of charge separation, is 0.50 eV or less (condition 3), indicating that all of the above conditions 1 to 3 are satisfied. In particular, the half-width of the absorption spectrum is narrower (smaller) by about half in Example Compounds 5-98 and 5-54, which absorb the same blue light, compared to TBPe, a comparative example compound, which is a known dye material for photoelectric conversion elements for imaging, thereby enabling finer color discrimination. In other words, by using the dye material for photoelectric conversion elements of the present invention that satisfies all of conditions 1 to 3, it is possible to realize an image sensor with high color separation and high resolution while maintaining high photoelectric conversion efficiency. Furthermore, Table 2 shows that the compounds of the present invention, compared to TBPe, a known dye material for photoelectric conversion elements for imaging, exhibit a high molar absorption coefficient, a small (narrow) half-width, and a small ΔEST, as described above, as well as a large kr, indicating their usefulness as dye materials for use in photoelectric conversion elements for imaging. Furthermore, a material with a high molar absorption coefficient can accommodate the amount of light that the photoelectric conversion layer of the element needs to absorb with a smaller film thickness, which is also effective in reducing the amount of material used in the element and increasing the response speed of the element.

[0088] Example 21 A vacuum chamber was placed on an electrode made of ITO with a thickness of 70 nm formed on a glass substrate. －５ A film of compound PB0001 was formed at 10 Pa as an electron blocking layer to a thickness of 10 nm. Next, as a photoelectric conversion layer, 2Ph-BTBT, compound 5-98 (dye), and fullerene (C60) were co-deposited at a deposition rate ratio of 4:4:2 to form a film of 200 nm. Subsequently, dpy-NDI was deposited to a thickness of 10 nm to form a hole blocking layer. Finally, a film of aluminum was formed to a thickness of 70 nm as an electrode to prepare a photoelectric conversion element. When a voltage of 5.0 V was applied using ITO and aluminum as electrodes, the current in the dark (dark current) was 2.5 × 10 －１０ A / cm ２ When a voltage of 5.0 V was applied and the ITO electrode side was irradiated with light from a height of 10 cm using an LED adjusted to 1.6 μW and a wavelength of 460 nm, the current (light current) was 3.3×10 －７A / cm ２ The light-dark ratio when a voltage of 5.0 V was applied was 1.3 × 10 ３ These results are shown in Table 3. An LED with an emission wavelength of 410 nm was used to evaluate the device using a material absorbing violet light, an LED with an emission wavelength of 460 nm was used to evaluate the device using a blue material, an LED with an emission wavelength of 480 nm was used to evaluate the device using a blue-green material, and an LED with an emission wavelength of 550 nm was used to evaluate the device using a green material.

[0089] Examples 22 to 30 Photoelectric conversion elements were prepared in the same manner as in Example 1, except that the compounds shown in Table 3 were used as dyes, and LEDs with different emission wavelengths were used depending on the color of light absorbed by the compound when measuring the current value upon light irradiation (light current value), and the current value upon light irradiation was measured. The results are shown in Table 3.

[0090] Comparative Examples 5 to 8 Photoelectric conversion elements were prepared in the same manner as in Example 21 except for using the compounds shown in Table 3 as dyes, and the current values ​​upon light irradiation were measured. The results are shown in Table 3.

[0091]

[0092] It can be seen from Table 3 that the photoelectric conversion elements fabricated using the materials of the present invention that satisfy the above conditions 1 to 4 have superior current values ​​(light currents) upon light irradiation compared to photoelectric conversion elements that use the compounds of the comparative examples. In other words, the dye material for photoelectric conversion elements of the present invention has a high photoelectric conversion efficiency, which is thought to be due to the fact that the materials of the present invention have a large molar absorption coefficient, a small ΔEst, and a large kr.

[0093] Here, when the lowest unoccupied molecular orbital (LUMO) of the dye material for a photoelectric conversion element for imaging of the present invention is defined as LUMO(D) and the LUMO of fullerene, which is an electron transport material, is defined as LUMO(EM), LUMO(D)-LUMO(EM) and the difference therebetween are shown in Table 4 below.

[0094]

[0095] As can be seen from Table 4, the dye materials for photoelectric conversion elements of the present invention all have a LUMO(D)-LUMO(EM) of 1.0 eV or more relative to fullerene, which is an electron transport material, and therefore have a large LUMO energy difference. This allows for efficient transfer of electrons from the dye material to the fullerene, and also makes it possible to suppress charge recombination caused by electrons trapped in the fullerene returning to the dye material, which is thought to also improve photoelectric conversion efficiency.

[0096] Table 5 shows the maximum absorption wavelength (lmax(EM)) located on the longer wavelength side than 400 nm in the absorption spectrum of fullerene, which is the electron transport material contained in the photoelectric conversion layer, the maximum emission wavelength (lmax(D)) in the emission spectrum of the dye material of the present invention, and the difference therebetween (lmax(EM) - lmax(D)).

[0097]

[0098] From the above, it can be seen that the material of the present invention has an emission spectrum in a band of ±100 nm or less as a difference from the absorption spectrum of fullerene, which is an electron transport material, and can thereby efficiently induce energy transfer from the dye to the fullerene.

[0099] The maximum emission wavelength (lmax(D)) of the emission spectrum of the dye material of the present invention, the wavelength of the absorption edge on the long wavelength side of the absorption spectrum of 2Ph-BTBT, which is a hole transport material contained in the photoelectric conversion layer (ledge(HM)), and the difference therebetween (lmax(D) - ledge(HM)) are shown in Table 6. Ledge(HM) was calculated by drawing a tangent to the falling edge on the long wavelength side of the absorption spectrum of 2Ph-BTBT, and the value of the wavelength at the intersection of this tangent and the horizontal axis was taken as ledger(HM).

[0100]

[0101] Table 6 shows that the dye materials of the present invention generally have emission spectra in a band of ±10 nm or more from the absorption edge on the long-wavelength side of the absorption spectrum of the hole-transporting material, 2Ph-BTBT. As described above, electrons move between molecules by exciton energy transfer or by LUMO-to-LUMO hopping between multiple molecules. To rapidly transfer electrons to the electron-transporting layer and thereby improve photoelectric conversion efficiency, it is effective to localize electrons in the electron-transporting material in the photoelectric conversion layer. As described above, by having an emission spectrum in a band of ±10 nm or more from the absorption edge on the long-wavelength side of the absorption spectrum of the hole-transporting material, 2Ph-BTBT, it is possible to suppress energy transfer from the dye to 2Ph-BTBT, and it is believed that the migration of excitons and electrons is preferentially induced to the fullerene, the electron-transporting material, thereby improving photoelectric conversion efficiency.

[0102] By using the dye material for photoelectric conversion elements for imaging of the present invention, it is possible to control the absorption of light and the behavior of excitons, holes, and electrons within the photoelectric conversion element, thereby realizing a photoelectric conversion element that absorbs light in a narrow bandwidth (small half-width) and exhibits a high photocurrent. Furthermore, photoelectric conversion elements for imaging using dye materials with small half-widths such as those of the present invention can detect not only the three primary colors of red, green, and blue light, but also colors such as orange, yellow, blue-green, and purple without color mixing. Therefore, image sensors stacked with elements absorbing these different colors are expected to solve the problems of high sensitivity and high resolution and have unprecedentedly high color resolution. Therefore, the material of the present invention is useful as a material for photoelectric conversion elements in photoelectric conversion film-stacked imaging devices.

[0103] REFERENCE SIGNS LIST 1 Electrode 2 Hole blocking layer 3 Photoelectric conversion layer 4 Electron blocking layer 5 Electrode 6 Substrate

Claims

1. A dye material for a photoelectric conversion element for imaging, which satisfies all of the following conditions 1 to 3:

1. The molar absorption coefficient of the maximum absorption wavelength of the peak located on the longest wavelength side of the absorption spectrum is 10 ４ Lmol －１ cm －１ 2. The half-width of the peak located on the longest wavelength side of the absorption spectrum is 50 nm or less.

3. ΔEst is 0.50 eV or less.

2. The dye material for a photoelectric conversion element for imaging according to claim 1, further satisfying the following condition 4:

4. The radiative rate constant from the lowest singlet excited state is 2.0 × 10 ７ s －１ End 3. The dye material for the photoelectric conversion element for imaging is a multiple resonance type fused ring compound, and is selected from the group consisting of B, P, P=O, P=S, C=O, Al, Ga, As, and Si—R. ２ or Ge-R ２ 2. The dye material for a photoelectric conversion element for imaging according to claim 1, wherein the dye material contains at least one selected from the group consisting of N, O, S, and Se as an acceptor and at least one selected from the group consisting of N, O, S, and Se as a donor.

4. The dye material for a photoelectric conversion element for imaging according to claim 1, characterized in that it comprises a compound represented by the following general formula (1a) or (1b): Here, ring J, ring K, ring C, ring D, ring E, ring F, ring G, and ring H are each independently a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 carbon atoms, or a substituted or unsubstituted aromatic heterocycle having 2 to 30 carbon atoms. １ ~Y ３ are each independently N, B, P, P=O, P=S, Al, Ga, As, Si—R ２ or Ge-R ２ It is. ２ are each independently an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms. １ ~X ６ are each independently O, C═O, or N—Ar ５ , S or Se. Ar ５ are each independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 8 of these. １ ~X ６ are each independently N-Ar ５ When Ar ５ may be bonded to any of ring J, ring K, ring C, ring D, ring E, ring F, ring G, or ring H to form a heterocycle containing N. ３ ~R １０ are each independently a cyano group, deuterium, a diarylamino group having 12 to 44 carbon atoms, an arylheteroarylamino group having 12 to 44 carbon atoms, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms; R ３ , R ４ , R ５ , R ６ , R ７ , R ８ , R ９ , and R １０ may be bonded to the ring J, ring K, ring C, ring D, ring E, ring F, ring G, and ring H to form a ring. p to w represent the number of substitutions, p, q, s, and t each independently represent an integer of 0 to 4, r, u, and w each independently represent an integer of 0 to 3, and v represents an integer of 0 to 2.

5. The dye material for a photoelectric conversion element for imaging according to claim 4, characterized in that it is a compound in which r is represented by 1 to 3 in the general formula (1a).

6. In the above general formula (1a), X 1 and X 2 and the dye material for a photoelectric conversion element for imaging according to claim 4, characterized in that the dye material for a photoelectric conversion element for imaging according to claim 4 is made of compounds represented by different elements.

7. In the above general formula (1b), X ３ ~X ６ 5. The dye material for a photoelectric conversion element for imaging according to claim 4, wherein at least one of the above is a compound represented by O or S.

8. A dye material for a photoelectric conversion element for imaging according to claim 4, characterized in that the polycyclic aromatic compound having a structure represented by general formula (1a) or (1b) is a polycyclic aromatic compound represented by any one of the following formulas (2a), (2b), (1c), or (1d): In the above general formulas (2a) and (2b), X １ ~X ６ , R ３ ~R １０ , Ar ５ , p, q, r, s, t, u, v, and w have the same meanings as in the general formula (1a) or (1b). In the general formulas (1c) and (1d), ring I and ring M are each independently a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 30 carbon atoms, or a substituted or unsubstituted aromatic heterocycle having 2 to 30 carbon atoms. Ring A represents a heterocycle represented by formula (1c-2) which is fused with an adjacent ring at any position, and X ７ ~X ９ are each independently O, C═O, or N—Ar ５ , S or Se. Ar ５ has the same meaning as in the general formula (1a) or (1b). ７ ~X ９ are each independently the N-Ar ５ When Ar ５ is the Ar ５ may be bonded to either the ring to which it is bonded or an adjacent ring to form a heterocyclic ring containing N. １１ ~R ２０ are each independently a cyano group, deuterium, a diarylamino group having 12 to 44 carbon atoms, an arylheteroarylamino group having 12 to 44 carbon atoms, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms. a to j represent the number of substitutions, b, d, e, h, and j each independently represent an integer of 0 to 4, a, f, and i represent an integer of 0 to 3, g represents an integer of 0 to 2, and c represents an integer of 0 or 1. In the above general formulas (2a), (2b), (1c), and (1d), B represents a boron atom.

9. A photoelectric conversion element for imaging, having a photoelectric conversion layer and an electron blocking layer between two electrodes, characterized in that either layer contains the dye material for photoelectric conversion elements described in any one of claims 1 to 8.

10. A photoelectric conversion element for imaging, having a photoelectric conversion layer and an electron blocking layer between two electrodes, characterized in that the photoelectric conversion layer contains the dye material for photoelectric conversion elements described in any one of claims 1 to 8.

11. The photoelectric conversion element for imaging according to claim 10, characterized in that the photoelectric conversion layer further contains an electron transporting material.

12. The photoelectric conversion element for imaging according to claim 11, characterized in that the electron transporting material contains a fullerene derivative.

13. The photoelectric conversion element for imaging according to claim 11, wherein the lowest unoccupied molecular orbital (LUMO) of the dye material for the photoelectric conversion element for imaging according to any one of claims 1 to 5 is LUMO(D), and the LUMO of the electron transport material is LUMO(EM), and the LUMO(D)-LUMO(EM) is 1.0 eV or more.

14. The photoelectric conversion element for imaging described in claim 11, characterized in that the difference between the maximum absorption wavelength of the peak located on the longer wavelength side than 400 nm in the absorption spectrum of the electron transport material and the maximum emission wavelength of the emission spectrum of the dye material for the photoelectric conversion element is ±100 nm or less.

15. The photoelectric conversion element for imaging according to claim 11, characterized in that the photoelectric conversion layer contains a hole transporting material having at least two thiophene rings in its skeleton.

16. The photoelectric conversion element for imaging described in claim 15, characterized in that the difference between the maximum emission wavelength of the emission spectrum of the dye material for the photoelectric conversion element and the wavelength of the absorption edge on the long wavelength side of the absorption spectrum of the hole transport material is ±10 nm or more.

17. An image sensor comprising two or more photoelectric conversion elements for imaging according to claim 9 stacked together.

18. The image sensor according to claim 17, wherein the photoelectric conversion element for imaging, which contains a dye material for the photoelectric conversion element that absorbs green light, and the photoelectric conversion element for imaging, which contains a dye material for the photoelectric conversion element that absorbs blue light, are stacked together.

Images