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EP-3822278-B1 - ELECTRON-ACCEPTING COMPOUND, COMPOSITION FOR CHARGE TRANSPORT FILM, AND LIGHT-EMITTING ELEMENT USING SAME

EP3822278B1EP 3822278 B1EP3822278 B1EP 3822278B1EP-3822278-B1

Inventors

  • GOROHMARU, HIDEKI
  • OKABE, KAZUKI
  • IIDA, KOICHIRO
  • UMEMOTO, TOMOKAZU
  • BANDO, YOSHIMASA
  • ISHIBASHI, KOICHI
  • KAJIYAMA, YOSHIKO
  • ABE, TOMOHIRO

Dates

Publication Date
20260506
Application Date
20170323

Claims (20)

  1. A charge-transporting ion compound composed of a cation radical of a hole-transporting compound and a counter anion represented by the following formula (6): wherein Ar is each independently an aromatic ring group which may have a substituent or a fluorine-substituted alkyl group, wherein the substituent that Ar has is a hydrogen atom, a halogen atom, a cyano group, an aromatic ring group composed of 1 to 5 aromatic rings, a hydrocarbon ring group, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an alkyloxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkyl ketone group, or an aryl ketone group, F 4 represents a substitution with four fluorine atoms, F (5-a) represents a substitution with (5-a) fluorine atom(s), k each independently represents an integer of 0 to 5, a each independently represents an integer of 0 to 5, k+a is 1 or more, wherein the cation radical of the hole-transporting compound is a cation radical of an aromatic tertiary amine compound.
  2. The charge-transporting ion compound according to claim 1, wherein the above k is 0, the above a is 1, and the above Ar is each independently an aromatic ring group which may have a substituent.
  3. The charge-transporting ion compound according to claim 1 or 2, wherein Ar of the above formula (6) has four or more fluorine atoms as substituents.
  4. The charge-transporting ion compound according to any one of claims 1 to 3, wherein at least one Ar of the above formula (6) is represented by the following formula (3): wherein Ar 7 is a substituent and F 4 represents a substitution with four fluorine atoms, wherein Ar 7 is the same as the substituent that Ar has in claim 1.
  5. The charge-transporting ion compound according to claim 4, wherein Ar 7 of the above formula (3) is represented by the following formula (4):
  6. The charge-transporting ion compound according to any one of claims 1 to 5, wherein at least one Ar of the above formula (6) has a crosslinkable group.
  7. The charge-transporting ion compound according to any one of claims 1 to 6, wherein the hole-transporting compound is polymer compound.
  8. The charge-transporting ion compound according to claim 7, wherein the cation radical of the hole-transporting compound is an aromatic tertiary amine compound having a partial structure represented by the following formula (10): wherein y represents an integer of 1 to 5, Ar 81 to Ar 84 each independently represents a group represented by the following formula (13). wherein q and r represent each an integer of 0 or more; Ar 21 and Ar 23 each independently represent a divalent aromatic ring group; Ar 22 represents a monovalent aromatic ring group, and R 13 represents a divalent group derived from an alkyl group, an aromatic ring group, or an alkyl group and an aromatic ring group; Ar 32 represents a monovalent aromatic ring group or a monovalent crosslinkable group, ; the asterisk (*) represents a bonding hand with the nitrogen atom of the general formula (11); R 81 to R 84 each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an amino group, an aromatic hydrocarbon group, or an aromatic heterocyclic group.
  9. A composition for a charge-transporting film, comprising the charge-transporting ion compound according to any one of claims 1 to 8 and a solvent.
  10. The composition for a charge-transporting film according to claim 9, wherein the solvent contains at least one solvent selected from the group consisting of ether-based solvents and ester-based solvents.
  11. The composition for a charge-transporting film according to claim 10, which further comprises aromatic hydrocarbon-based solvents..
  12. A method for preparing the charge-transporting ion compound according to any one of claims 1 to 8, comprising a step of dissolving an electron-accepting compound having a structure of the following formula (1) and the hole-transporting compound in a solvent, followed by mixing: wherein Ar is each independently an aromatic ring group which may have a substituent or a fluorine-substituted alkyl group, wherein the substituent that Ar has is a hydrogen atom, a halogen atom, a cyano group, an aromatic ring group composed of 1 to 5 aromatic rings, a hydrocarbon ring group, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an alkyloxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkyl ketone group, or an aryl ketone group, F 4 represents a substitution with four fluorine atoms, F (5-a) represents a substitution with (5-a) fluorine atom(s), k each independently represents an integer of 0 to 5, a each independently represents an integer of 0 to 5, k+a is 1 or more, and X + represents a counter cation having a structure of the following formula (2): wherein Ar 5 and Ar 6 are each independently an aromatic ring group which may have a substituent, wherein the substituent that Ar 5 and Ar 6 have are a hydrogen atom, a halogen atom, an aromatic ring group composed of 1 to 5 aromatic rings, a hydrocarbon ring group, an alkyl group, an aralkyl group, an alkyloxy group, an aryloxy group, and a hydroxy group.
  13. The method for preparing the charge-transporting ion compound according to claim 12, comprising a step of heating a solution in which the electron-accepting compound and the hole-transporting compound are dissolved in a solvent.
  14. A method for preparing the charge-transporting ion compound according to any one of claims 1 to 8, comprising a step of heating a mixture of an electron-accepting compound having a structure of the following formula (1) and the hole-transporting compound: wherein Ar is each independently an aromatic ring group which may have a substituent or a fluorine-substituted alkyl group, wherein the substituent that Ar has is a hydrogen atom, a halogen atom, a cyano group, an aromatic ring group composed of 1 to 5 aromatic rings, a hydrocarbon ring group, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an alkyloxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkyl ketone group, or an aryl ketone group, F 4 represents a substitution with four fluorine atoms, F (5-a) represents a substitution with (5-a) fluorine atom(s), k each independently represents an integer of 0 to 5, a each independently represents an integer of 0 to 5, k+a is 1 or more, and X + represents a counter cation having a structure of the following formula (2): wherein Ar 5 and Ar 6 are each independently an aromatic ring group which may have a substituent, wherein the substituent that Ar 5 and Ar 6 have are a hydrogen atom, a halogen atom, an aromatic ring group composed of 1 to 5 aromatic rings, a hydrocarbon ring group, an alkyl group, an aralkyl group, an alkyloxy group, an aryloxy group, and a hydroxy group.
  15. The method for preparing the charge-transporting ion compound, according to claim 14, comprising a step of heating a film formed by applying a solution obtained by dissolving the mixture of the electron-accepting compound and the hole-transporting compound in a solvent.
  16. A charge-transporting film, comprising the charge-transporting ion compound according to any one of claims 1 to 8.
  17. An organic electroluminescent element comprising a hole injection layer and a luminescent layer between an anode and a cathode and emitting light by electric energy, wherein the hole injection layer contains the charge-transporting ion compound according to any one of claims 1 to 8.
  18. A display using the organic electroluminescent element according to claim 17.
  19. A lighting device using the organic electroluminescent element according to claim 17.
  20. A light-emitting device using the organic electroluminescent element according to claim 17.

Description

The present invention relates to a charge-transporting ion compound and a composition for a charge-transporting film, and a charge-transporting film and an organic electroluminescent element using the same. Specifically, it relates to an excellent composition for a charge-transporting film and an electron-accepting compound, which can afford an organic electroluminescent element having excellent heat resistance and capable of operating at low voltage and also relates to a charge-transporting film using the same and a method for manufacturing the same. Further, it relates to an organic electroluminescent element using the same. Background Art In recent years, as electroluminescent (electroluminescence: EL) elements, electroluminescent elements employing organic materials (organic electroluminescent elements) in place of inorganic materials such as ZnS. In the organic electroluminescent element, high luminescent efficiency thereof is one important factor but the luminescent efficiency has been remarkably improved by an organic electroluminescent element provided with a hole-transporting layer containing an aromatic amine compound and a luminescent layer composed of an aluminum complex of 8-hydroxyquinoline. However, though the luminescent efficiency is improved, a big problem for expanding the demand for the organic electroluminescent element is a decrease in operating voltage. For example, in the display element of a portable device, operation at low voltage from the battery is requested. Also, in general uses other than the portable uses, the cost of operating IC (Integrated Circuit) depends on the operating voltage and lower operating voltage results in a lower cost. Moreover, a gradual increase in the operating voltage at continuous operation is also a big problem for maintaining stable display properties of the display element. For solving these problems, it is attempted to mix various electron-accepting compounds with a hole-transporting compound. When an electron-accepting compound is mixed with a hole-transporting compound, electrons transfer from the hole-transporting compound to the electron-accepting compound to form a charge-transporting ion compound composed of a cation radical of the hole-transporting compound and a counter anion derived from the electron-accepting compound. For example, Patent Document 1 discloses that an organic electroluminescent element capable of operation at low voltage is obtained by mixing tris(4-bromophenyl aminiumhexachloroanitmonate) (TBPAH) with a hole-transporting polymer compound. Specifically, in the case where TBPAH described in Patent Document 1 is used as an electron-accepting compound, the counter anion is SbCl6-. Moreover, Patent Document 2 discloses that iron(III) chloride (FeCl3) is mixed as an electron-accepting compound with a hole-transporting compound by a vacuum deposition method and is used. In the case where FeCl3 described in Patent Document 2 is used as an electron-accepting compound, the counter anion is Cl- (or FeCl4-). Furthermore, Patent Document 3 discloses that tris(pentafluorophenyl)borane (PPB) is mixed an electron-accepting compound with a hole-transporting polymer compound by a wet film formation method to form a hole injection layer. In the case where PPB described in Patent Document 3 is used as an electron-accepting compound, the counter anion is an anion radical represented by the following formula (I). Incidentally, the anion radical is a chemical species having an unpaired electron and negative charge. Moreover, the negative charge is considered to be spread all over the molecule but, in the above formula, there is shown a resonance structure that is considered to be the most contributing one. Moreover, Patent Document 4 discloses to use an ion compound composed of an aluminum cation radical and SbF6- or BF4- as a component of a charge-transporting film of a photovoltanic apparatus (organic solar battery). Furthermore, Patent Document 5 discloses to use an ion compound composed of an aluminum cation radical and a counter anion. As the counter anion, there are exemplified a halide ion such as I-, a polyhalide ion such as Br3-, an oxo acid ion such as ClO4- or PO3-, an ion composed of a center element and a halogen, such as BF4-, FeCl4-, SiF62-, or RuCl62-, a carboxylic acid ion such as CF3COO-, a sulfonic acid ion such as CF3SO2O-, an ate complex derived from a sulfonic acid ion, such as (CF3SO3)4Al-, C60-, C602-, or B12H122-. US 2015/079714 A1 relates to a composition for use in an organic device, wherein the composition at least contains two cross-linking compounds having different numbers of cross-linking groups. Further, said document relates to a polymer film produced by forming a film of the composition for use in an organic device and then polymerizing the cross-linking compounds. In addition, since an ion compound composed of an aluminum cation radical and a counter anion has absorption in a near-infrared region, Patent Docum