Organic electroluminescent device having an electron- and/or exciton-blocking layer comprising an indolocarbazole compound

Patent metadata

Field	Value
Publication number	US-9290498-B2
Application number	US-201013502520-A
Country	US
Kind code	B2
Filing date	Oct 19, 2010
Priority date	Oct 23, 2009
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

Disclosed is an organic electroluminescent device (organic EL device) which is improved in luminous efficiency, fully secure of driving stability, and of a simple configuration. The organic EL device comprises organic layers comprising a hole-transporting layer and a light-emitting layer sandwiched between an anode and a cathode. The light-emitting layer contains a fluorescent light-emitting material and an electron- and/or exciton-blocking layer containing an indolocarbazole derivative represented by general formula (2) is disposed between the hole-transporting layer and the light-emitting layer so as to be adjacent to the light-emitting layer. In general formula (2), ring B is a heterocyclic ring fused to the adjacent rings and represented by formula (1c), Z is an n-valent aromatic hydrocarbon group or aromatic heterocyclic group, and n is 1 or 2.

First claim

The invention claimed is:

1. An organic electroluminescent device comprising organic layers comprising at least a hole-injecting layer, a hole-transporting layer, and a light-emitting layer sandwiched between an anode and a cathode,
wherein the hole-transporting layer consists essentially of one or more compounds selected from the group consisting of a triazole derivative, an oxadiazole derivative, an imidazole derivative, a carbazole derivative, a polyarylalkane derivative, a pyrazoline derivative, a pyrazolone derivative, a phenylenediamine derivative, an arylamine derivative, an amino-substituted chalcone derivative, an oxazole derivative, a styrylanthracene derivative, a fluorenone derivative, a hydrazone derivative, a stilbene derivative, a silazane derivative, an aniline-based copolymer, and a thiophene oligomer; and
wherein the light-emitting layer contains a fluorescent light-emitting material, and an electron- and/or exciton-blocking layer containing an indolocarbazole compound represented by general formula (1) is disposed between the hole-transporting layer and the light-emitting layer so as to be adjacent to the light-emitting layer:

in general formula (1), Z is an n-valent aromatic hydrocarbon group of 6 to 50 carbon atoms or an n-valent aromatic heterocyclic group of 3 to 50 carbon atoms; Y is a group represented by formula (1a); n is an integer of 2 to 6; Y's may be identical with or different from each other when n is 2 or more,
in formula (1a), ring A is an aromatic or heterocyclic ring fused to the adjacent rings and represented by formula (1b) and ring B is a heterocyclic ring fused to the adjacent rings and represented by formula (1c); each of R 1 and R 2 is independently a hydrogen atom, an aliphatic hydrocarbon group of 1 to 10 carbon atoms, an aromatic hydrocarbon group of 6 to 12 carbon atoms, or an aromatic heterocyclic group of 3 to 11 carbon atoms,
in formula (1b), X is a methine group or a nitrogen atom; R 3 is a hydrogen atom, an aliphatic hydrocarbon group of 1 to 10 carbon atoms, an aromatic hydrocarbon group of 6 to 12 carbon atoms, or an aromatic heterocyclic group of 3 to 11 carbon atoms; R 3 may be fused to a ring containing X to form a fused ring, and
in formula (1c), Ar is an aromatic hydrocarbon group of 6 to 50 carbon atoms or an aromatic heterocyclic group of 3 to 50 carbon atoms, and
wherein the LUMO energy of the indolocarbazole compound contained in the electron- and/or exciton-blocking layer is higher than the LUMO energy of the fluorescent light-emitting material contained in the light-emitting layer, the LUMO energy in eV of the indolocarbazole compound being greater than or equal to −1.2, and
wherein the HOMO energy of the hole-transporting material contained in the hole-transporting layer is higher than the HOMO energy of the indolocarbazole compound contained in the electron- and/or exciton-blocking layer, the HOMO energy in eV of the hole-transporting material being greater than or equal to −4.8.

2. An organic electroluminescent device as described in claim 1 wherein the light-emitting layer contains a fluorescent light-emitting material and an electron-transporting host material.

3. An organic electroluminescent device as described in claim 1 wherein the indolocarbazole compound represented by general formula (1) is an indolocarbazole compound represented by the following general formula (2):

In general formula (2), ring B is a heterocyclic ring fused to the adjacent rings and represented by formula (1c); Z, Ar, R 1 , and R 2 have the same meaning as those in general formula (1); R 3 is a hydrogen atom, an aliphatic hydrocarbon group of 1 to 10 carbon atoms, an aromatic hydrocarbon group of 6 to 12 carbon atoms, or an aromatic heterocyclic group of 3 to 11 carbon atoms; n is an integer of 2.

4. An organic electroluminescent device as described in claim 1 wherein the indolocarbazole compound represented by general formula (1) is selected from indolocarbazole compounds represented by general formulas (3) to (6):

In general formulas (3) to (6), Z, Ar, R 1 , R 2 , R 3 , and n have the same meaning as those in general formula (1).

5. An organic electroluminescent device as described in claim 1 wherein the organic layers further comprise an electron-transporting layer and at least one of the materials used in the said electron-transporting layer has an electron mobility of 1×10 −7 cm 2 /V·s or more.

6. An organic electroluminescent device according to claim 1 ,
wherein the hole-transporting layer consists essentially of one or more compounds selected from the group consisting of a porphyrin compound, an aromatic tertiary amine compound, and a styrylamine compound.

7. An organic electroluminescent device according to claim 1 ,
wherein the light-emitting layer is a single layer.

8. An organic electroluminescent device according to claim 1 ,
wherein the LUMO energy and the HOMO energy are determined by a structure optimization calculation at the B3LYP/6-31G* level.

9. An organic electroluminescent device according to claim 2 ,
wherein the electron-transporting host material has an electron transfer rate of 1×10 −6 cm 2 /V·s or more.

Assignees

• Kai Takahiro
• Yamamoto Toshihiro
• Komori Masaki
• Yoshimura Kazuaki
• Tsuji Taishi
• Takahashi Yasuhiro
• Yuki Toshinao
• Nakajima Yusuke
• Nippon Steel & Sumikin Chem Co
• Pioneer Corp
• Pioneer Tohoku Corp

Inventors

• Kai Takahiro
• Yamamoto Toshihiro
• Komori Masaki
• Yoshimura Kazuaki
• Tsuji Taishi
• Takahashi Yasuhiro
• Yuki Toshinao
• Nakajima Yusuke

Classifications

• H10K50/181

  Electron blocking layers · CPC title

• H10K85/6572 Primary

  comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole · CPC title

• C07D487/04 Primary

  Ortho-condensed systems · CPC title

• H01L51/0072

  Electricity · mapped topic

• H01L51/5096

  Electricity · mapped topic