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US-20260130041-A1 - HOLE TRANSPORT BODY, PHOTOELECTRIC CONVERSION ELEMENT, AND COMPOSITION

US20260130041A1US 20260130041 A1US20260130041 A1US 20260130041A1US-20260130041-A1

Abstract

A hole transport body includes: an organic semiconductor; and a nonionic surfactant having a critical micelle concentration of 0.001 g/L or more and 0.080 g/L or less in pure water. A photoelectric conversion element includes a first electrode, a photoelectric conversion layer, a hole transport layer, and a second electrode, and the hole transport layer includes the hole transport body of the present disclosure. A composition for producing a hole transport body includes: an organic semiconductor; a nonionic surfactant having a critical micelle concentration of 0.001 g/L or more and 0.080 g/L or less in pure water; and a solvent.

Inventors

  • Maki HIRAOKA

Assignees

  • PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.

Dates

Publication Date
20260507
Application Date
20260105
Priority Date
20230707

Claims (20)

  1. 1 . A hole transport body comprising: an organic semiconductor; and a nonionic surfactant having a critical micelle concentration of 0.001 g/L or more and 0.080 g/L or less in pure water.
  2. 2 . The hole transport body according to claim 1 , further comprising a dopant.
  3. 3 . The hole transport body according to claim 1 , wherein the nonionic surfactant includes an alkyl hexyl ether in which the number of carbon atoms in an alkyl group is 1 or more and 5 or less.
  4. 4 . The hole transport body according to claim 3 , wherein the alkyl hexyl ether includes at least one selected from the group consisting of methyl hexyl ether, ethyl hexyl ether, normal propyl hexyl ether, normal butyl hexyl ether, and normal pentyl hexyl ether.
  5. 5 . The hole transport body according to claim 1 , wherein the nonionic surfactant includes an ester compound obtained by a condensation reaction between a sugar alcohol or an intramolecular dehydration condensation product of a sugar alcohol and a fatty acid.
  6. 6 . The hole transport body according to claim 5 , wherein the ester compound includes a fatty acid ester in which the number of carbon atoms in an alkyl group is 12 or more and 15 or less.
  7. 7 . The hole transport body according to claim 5 , wherein the ester compound includes a glycerin fatty acid ester.
  8. 8 . The hole transport body according to claim 5 , wherein the ester compound includes a sorbitan fatty acid ester.
  9. 9 . The hole transport body according to claim 5 , wherein the ester compound includes glycerin monolaurate.
  10. 10 . The hole transport body according to claim 5 , wherein the ester compound includes a fatty acid ester of an intramolecular dehydration condensation product of a sugar alcohol, the intramolecular dehydration condensation being modified with polyethylene glycol.
  11. 11 . The hole transport body according to claim 10 , wherein the polyethylene glycol includes 1 or more and 22 or less ethylene glycol units as constituent monomer units.
  12. 12 . The hole transport body according to claim 10 , wherein the fatty acid ester of the intramolecular dehydration condensation product of the sugar alcohol includes a monolaurate.
  13. 13 . The hole transport body according to claim 10 , wherein the fatty acid ester of the intramolecular dehydration condensation product of the sugar alcohol includes a monooleate.
  14. 14 . The hole transport body according to claim 1 , wherein the nonionic surfactant includes a copolymer of polyethylene glycol and polypropylene glycol.
  15. 15 . The hole transport body according to claim 14 , wherein the copolymer includes 6 or more and 53 or less ethylene glycol units and 42 or more and 69 or less propylene glycol units as constituent monomer units.
  16. 16 . The hole transport body according to claim 1 , wherein the nonionic surfactant includes a glucoside derivative.
  17. 17 . The hole transport body according to claim 16 , wherein the glucoside derivative is an alkyl glucoside derivative.
  18. 18 . The hole transport body according to claim 17 , wherein the alkyl glucoside derivative is n-octyl-α-D-glucopyranoside.
  19. 19 . The hole transport body according to claim 1 , wherein the organic semiconductor includes at least one selected from the group consisting of 2,2′,7,7′-tetrakis[N,N-di-P-methoxyphenylamino]-9,9′-spirobifluorene, poly[bis(4-phenyl)(2,4,6-triphenylmethyl)amine], poly(3-hexylthiophene-2,5-diyl), poly(3,4-ethylenedioxythiophene), copper phthalocyanine, a derivative of 2,2′,7,7′-tetrakis[N,N-di-P-methoxyphenylamino]-9,9′-spirobifluorene, a derivative of poly[bis(4-phenyl)(2,4,6-triphenylmethyl)amine], a derivative of poly(3-hexylthiophene-2,5-diyl), a derivative of poly(3,4-ethylenedioxythiophene), and a derivative of copper phthalocyanine.
  20. 20 . The hole transport body according to claim 2 , wherein the dopant includes at least one selected from the group consisting of lithium hexafluorophosphate, lithium borofluoride, lithium perchlorate, lithium bis(pentafluoroethanesulfonyl)imide, bis(trifluoromethanesulfonyl)amine, lithium bis(trifluoromethanesulfonyl)imide, zinc bis(trifluoromethanesulfonyl)imide, tris[2-(1H-pyrazole-1-yl)-4-tert-butylpyridine]cobalt, 4-isopropyl-4-methyl diphenyl iodonium tetrakis(pentafluorophenyl)borate, tris(pentafluorophenyl)borane, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-quinodimethane, and 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H,31H-phthalocyanine.

Description

This application is a continuation of PCT/JP2024/022697 filed on Jun. 21, 2024, which claims foreign priority of Japanese Patent Application No. 2023-112590 filed on Jul. 7, 2023, the entire contents of both of which are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hole transport body, a photoelectric conversion element, and a composition. 2. Description of Related Art Semiconductor devices including silicon which is an inorganic semiconductor material need a high-temperature and high-vacuum process in formation thereof. That makes it difficult to increase the area and reduce the cost for semiconductor devices including silicon. Meanwhile, organic semiconductor devices including an organic semiconductor material are expected to be used in various applications because, for example, a production process temperature can be decreased and a film can be formed from an organic semiconductor material by a simple process, such as coating, owing to its high solubility in solvents, compared to conventional inorganic semiconductor devices including an inorganic semiconductor material. For example, JP 2019-175970 A discloses a photoelectric conversion element including a buffer layer formed of an organic semiconductor material, the buffer layer being positioned between an active layer and an electrode. SUMMARY OF THE INVENTION The present disclosure aims to provide a hole transport body suitable for increasing the power conversion efficiency of a photoelectric conversion element. A hole transport body of the present disclosure includes: an organic semiconductor; anda nonionic surfactant having a critical micelle concentration of 0.001 g/L or more and 0.080 g/L or less in pure water. The present disclosure provides a hole transport body suitable for increasing the power conversion efficiency of a photoelectric conversion element. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a photoelectric conversion element according to a third embodiment. FIG. 2 is a cross-sectional view showing a first modification of the photoelectric conversion element according to the third embodiment. FIG. 3 is a cross-sectional view showing a second modification of the photoelectric conversion element according to the third embodiment. DETAILED DESCRIPTION Findings on which the Present Disclosure is Based Organic semiconductor materials included in organic semiconductor devices are required to have high charge mobility. A polymer having a TT-conjugated molecular structure is selected, for example, as a material that transports holes and which can be included in a hole transport layer of a photoelectric conversion element. However, it is difficult to form a uniform film using IT-conjugated molecules because IT-conjugated molecules have highly anisotropic molecular structures and a steric higher-order structure is likely to be formed of anisotropically stacked TT-conjugated molecules. Hence, to drive a device including the above material, it is necessary to suppress formation of a higher-order structure and thereby improve interfacial adhesion between layers and prevent a layer short due to a gap. A dynamic drying process, such as spin coating, is generally effective in suppressing formation of a higher-order structure of a film and forming a flat film. According to this method, formation of a higher-order structure is suppressed to form a flat film by applying a solution in which a semiconductor material is dissolved and then quickly vaporizing the solvent of the solution under an in-plane stress. However, in the case of an area increasing process where adequate control over vaporization conditions is difficult, it is difficult to sufficiently improve the manufacturing reliability by adjusting processing conditions. An additive that promotes flattening may be added to an organic semiconductor material to facilitate flattening of a film independently of drying conditions. However, the additive can hinder electrical conduction of the semiconductor material, leading to degradation rather than improvement of the device performance. For example, in the case where an organic semiconductor material is included in a photoelectric conversion element such as a solar cell, it is difficult to increase the power conversion efficiency of the photoelectric conversion element. Conventionally, a hole transport material includes, for example, a dopant for increasing the hole mobility as well as an organic semiconductor which is a material that transports holes. A solvent is adjusted to disperse these two components. Therefore, an additive that suppresses formation of a higher-order structure of a film has not drawn attention. The present inventors focused on this and studied a relationship between a surfactant and properties of a photoelectric conversion element. As a result, the present inventors have newly found that a hole transport body produced using a n