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

Patent metadata

Field	Value
Publication number	US-9299947-B2
Application number	US-201013257163-A
Country	US
Kind code	B2
Filing date	Mar 25, 2010
Priority date	Mar 31, 2009
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

Provided is an organic electroluminescent device (organic EL device), which has improved luminous efficiency, shows sufficiently ensured driving stability, and has a simple construction. The organic electroluminescent device includes an anode, a cathode, and organic layers including a hole-transporting layer and a light-emitting layer, the organic layers being interposed between the anode and the cathode, in which the light-emitting layer contains a phosphorescent light-emitting material and the hole-transporting layer and the light-emitting layer have an electron- and/or exciton-blocking layer therebetween, the electron- and/or exciton-blocking layer being adjacent to the light-emitting layer and containing an indolocarbazole compound represented by the general formula (2). In the formula, a ring B represents a heterocycle represented by the formula (1c) to be fused with adjacent rings, Z represents an n-valent aromatic hydrocarbon group or an aromatic heterocyclic group, and n represents 1 or 2.

First claim

The invention claimed is:

1. An organic electroluminescent device, comprising:
an anode;
a cathode; and
organic layers comprising at least:
a hole-injecting layer;
a hole-transporting layer;
a single light-emitting layer, and
an electron-transporting layer,
the organic layers being interposed between the anode and the cathode,
wherein:
the single light-emitting layer comprises a phosphorescent light-emitting material and a host material;
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
the hole-transporting layer and the single light-emitting layer have an electron- and/or exciton-blocking layer therebetween, the electron- and/or exciton-blocking layer being adjacent to the single light-emitting layer and containing an indolocarbazole compound represented by the following general formula (1):

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

2. An organic electroluminescent device according to claim 1 , wherein the host material is an electron-transporting host material.

3. An organic electroluminescent device according to claim 1 , wherein the electron-transporting layer further comprises at least one material or materials having an electron transfer rate of 1×10 −7 cm 2 N/V·s or more.

4. An organic electroluminescent device according to claim 1 , wherein the indolocarbazole compound represented by the general formula (1) comprises an indolocarbazole compound represented by the following general formula (2):

in the general formula (2): a ring B represents a heterocycle represented by the formula (1c) to be fused with adjacent rings; Z, Ar, R 1 , and R 2 have the same meanings as those in the general formula (1); R 3 represents a hydrogen atom, an aliphatic hydrocarbon group having a total of 1 to 10 carbon atoms, an aromatic hydrocarbon group having a total of 6 to 12 carbon atoms, or an aromatic heterocyclic group having a total of 3 to 11 carbon atoms; and n represents 2.

5. An organic electroluminescent device according to claim 1 , wherein the indolocarbazole compound represented by the general formula (1) is selected from indolocarbazole compounds represented by the following general formulae (3) to (6):

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

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 2 ,
wherein the electron-transporting host material has an electron transfer rate of 1×10 cm 2 /V·s or more.

8. An organic electroluminescent device according to claim 1 ,
wherein the single light-emitting layer is not adjacent to any other light-emitting layer.

9. 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.

10. An organic electroluminescent device, comprising:
an anode;
a cathode; and
organic layers comprising at least:
a hole-injecting layer;
a hole-transporting layer;
a single light-emitting layer; and
an electron-transporting layer,
the organic layers being interposed between the anode and the cathode,
wherein:
the single light-emitting layer comprises a phosphorescent light-emitting material and a host material;
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
the hole-transporting layer and the single light-emitting layer have an electron- and/or exciton-blocking layer therebetween, the electron- and/or exciton-blocking layer being adjacent to the single light-emitting layer and containing an indolocarbazole compound represented by one of the following general formulae (3)-(5):

wherein in the formulae (3)-(5): Z represents an n-valent aromatic hydrocarbon group having a total of 6 to 50 carbon atoms or an aromatic heterocyclic group having a total of 3 to 50 carbon atoms;
R 1 and R 2 each independently represent a hydrogen atom, an aliphatic hydrocarbon group having a total of 1 to 10 carbon atoms, an aromatic hydrocarbon group having a total of 6 to 12

Assignees

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

Inventors

• Kai Takahiro
• Yamamoto Toshihiro
• Komori Masaki
• Yoshimura Kazuaki
• Tsuji Taishi
• Takahashi Yasuhiro

Classifications

• H10K50/18

  Carrier blocking layers · CPC title

• H10K85/654

  comprising only nitrogen as heteroatom (H10K85/652 takes precedence) · CPC title

• H10K50/181

  Electron blocking layers · CPC title

• C09K11/06 Primary

  containing organic luminescent materials · CPC title

• H01L51/0081

  Electricity · mapped topic