ORGANIC ELECTROLUMINESCENT DEVICE

• US 20120235136A1
• Filed: 12/21/2010
• Published: 09/20/2012
• Est. Priority Date: 12/28/2009
• Status: Active Grant

• Current Assignee: NIPPON STEEL Chemical & Material Co., Ltd. (Nippon Steel Corporation)
• Original Assignee: Nippon Steel & Sumikin Chemical Co., Ltd. (Nippon Steel Corporation)
• Inventors: Kai, Takahiro, Yamamoto, Toshihiro, Ogawa, Junya, Matsumoto, Megumi
• Granted Patent: US 9,461,250 B2
• Time in Patent Office: Days
• US Class Current: 257/40
• CPC Class Codes: C07D 209/86 with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to carbon atoms of the ring system
• CPC Class Codes: C07D 209/88 with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to carbon atoms of the ring system
• CPC Class Codes: C07D 409/14 containing three or more hetero rings
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1029 containing one nitrogen atom as the heteroatom
• CPC Class Codes: C09K 2211/1088 containing oxygen as the only heteroatom
• CPC Class Codes: C09K 2211/1092 containing sulfur as the only heteroatom
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole
• CPC Class Codes: H10K 85/6576 comprising only sulfur in the heteroaromatic polycondensed ring system, e.g. benzothiophene

Abstract

Disclosed is an organic electroluminescent device (organic EL device) which is improved in luminous efficiency, sufficiently secures driving stability, and has a simple configuration. The organic EL device of this invention comprises a light-emitting layer between an anode and a cathode piled one upon another on a substrate wherein the light-emitting layer contains a phosphorescent dopant and a 1,9-substituted carbazole compound as a host material. An example of the 1,9-substituted carbazole compound is represented by the following general formula (1). In formula (1), Ar is an aromatic hydrocarbon group or aromatic heterocyclic group; L is an aromatic hydrocarbon group or aromatic heterocyclic group; each of R₁ to R₃ is a hydrogen atom, an alkyl group, a cycloalkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group; n is an integer of 1 to 3.

Claims

1. An organic electroluminescent device comprising an anode, a plurality of organic layers, and a cathode piled one upon another on a substrate wherein the plurality of organic layers comprise an organic layer containing a carbazole compound having aromatic groups selected from aromatic hydrocarbon groups and aromatic heterocyclic groups, at least one of the said aromatic groups having a fused ring structure composed of two rings or more, as substituents at the 1 and 9 positions of the carbazole ring and having the total of 20 to 80 carbon atoms and the organic layer containing the carbazole compound is a light-emitting layer containing a phosphorescent dopant.

2. An organic electroluminescent device as described in claim 1 wherein the carbazole compound is represented by general formula (1) or (2).

3. An organic electroluminescent device as described in claim 2 wherein one or both of Ar and L are derived, the former as a monovalent organic group and the latter as an n-valent aromatic group, from an aromatic compound represented by the following general formula (3).

4. An organic electroluminescent device as described in claim 3 wherein, in general formula (3), Z is a direct bond.

5. An organic electroluminescent device as described in claim 2 wherein either Ar or L is a monovalent or n-valent aromatic group derived from an organic compound represented by the following general formula (4).

6. An organic electroluminescent device as described in claim 1 wherein light emitted from the phosphorescent dopant has a peak wavelength below 550 nm.

7. (canceled)

8. (canceled)