ORGANIC ELECTROLUMINESCENCE DEVICE AND MATERIAL FOR ORGANIC ELECTROLUMINESCENCE DEVICE

• US 20090045730A1
• Filed: 07/03/2008
• Published: 02/19/2009
• Est. Priority Date: 07/07/2007
• Status: Active Grant

• Current Assignee: Idemitsu Kosan Company Limited
• Original Assignee: Idemitsu Kosan Company Limited
• Inventors: Iwakuma, Toshihiro, Fukuoka, Kenichi, Hosokawa, Chishio, Ito, Mitsunori, Kawamura, Masahiro, Nishimura, Kazuki, Ogiwara, Toshinari, Takashima, Yoriyuki
• Granted Patent: US 8,779,655 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1011 Condensed systems
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: H05B 33/20 characterised by the chemical or physical composition or the arrangement of the material in which the electroluminescent material is embedded
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 2102/103 comprising indium oxides, e.g. ITO
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/14 Carrier transporting layers
• CPC Class Codes: H10K 50/171 Electron injection layers
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/346 comprising platinum
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• CPC Class Codes: H10K 85/626 containing more than one polycyclic condensed aromatic rings, e.g. bis-anthracene
• CPC Class Codes: H10K 85/657 Polycyclic condensed heteroaromatic hydrocarbons
• CPC Class Codes: H10K 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole

Abstract

An organic electroluminescence device includes: a cathode; an anode; and a single-layered or multilayered organic thin-film layer provided between the cathode and the anode. The organic thin-film layer includes at least one emitting layer. The at least one emitting layer contains at least one phosphorescent material and a host material represented by the following formula (1).

Ra-Ar¹-Rb  (1)

In the formula, Ar¹, Ra and Rb each represent a substituted or unsubstituted benzene ring or a condensed aromatic hydrocarbon ring selected from a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted chrysene ring, a substituted or unsubstituted fluoranthene ring, a substituted or unsubstituted phenanthrene ring, a substituted or unsubstituted benzophenanthrene ring, a substituted or unsubstituted dibenzophenanthrene ring, a substituted or unsubstituted triphenylene ring, a substituted or unsubstituted benzo[a]triphenylene ring, a substituted or unsubstituted benzochrysene ring, a substituted or unsubstituted benzo[b]fluoranthene ring and a substituted or unsubstituted picene ring. Substituents for Ra and Rb are not aryl groups.

Claims

1. An organic electroluminescence device, comprising:

a cathode;

an anode; and

a single-layered or multilayered organic thin-film layer provided between the cathode and the anode, wherein

the organic thin-film layer comprises at least one emitting layer, and

the at least one emitting layer comprises;

at least one phosphorescent material;

and a host material represented by a formula (1) as follows,

Ra-Ar¹-Rb 

 

(1)

where;

Ar¹, Ra and Rb each represent a substituted or unsubstituted benzene ring or a condensed aromatic hydrocarbon ring selected from a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted chrysene ring, a substituted or unsubstituted fluoranthene ring, a substituted or unsubstituted phenanthrene ring, a substituted or unsubstituted benzophenanthrene ring, a substituted or unsubstituted dibenzophenanthrene ring, a substituted or unsubstituted triphenylene ring, a substituted or unsubstituted benzo[a]triphenylene ring, a substituted or unsubstituted benzochrysene ring, a substituted or unsubstituted benzo[b]fluoranthene ring and a substituted or unsubstituted picene ring;

substituents for Ra and Rb are not aryl groups;

Ra and Rb do not concurrently represent a substituted or unsubstituted triphenylene ring; and

, when Ar¹ represents a substituted or unsubstituted triphenylene ring, Ra and Rb represent substituted or unsubstituted condensed aromatic hydrocarbon groups that are mutually different.

2. The organic electroluminescence device according to claim 1, wherein when Ar¹ represents a substituted or unsubstituted benzene ring or a substituted or unsubstituted 2,7-phenanthrenediyl group, Ra and Rb represent substituted or unsubstituted condensed aromatic hydrocarbon groups that are mutually different.

3. The organic electroluminescence device according to claim 1, wherein when Ra, Rb or Ar¹ in the formula (1) has a single or plural substituent(s), the single or plural substituent(s) is an alkyl group having 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 18 carbon atoms, a silyl group having 3 to 20 carbon atoms, a cyano group or a halogen atom, while a substituent for Ar¹ is further allowed to be an aryl group having 6 to 22 carbon atoms.

4. The organic electroluminescence device according to claim 1, wherein excited triplet energy of the host material is in a range of 2.0 eV to 2.8 eV.

5. The organic electroluminescence device according to claim 1, wherein

the phosphorescent material comprises a metal complex, and

the metal complex comprises:

a metal atom selected from Ir, Pt, Os, Au, Cu, Re and Ru; and

a ligand.

6. The organic electroluminescence device according to claim 5, wherein the ligand has an ortho-metal bond.

7. The organic electroluminescence device according to claim 1, wherein a maximum wavelength of light emission of the at least one phosphorescent material contained in the emitting layer is in a range of 500 nm to 720 nm.

8. The organic electroluminescence device according to claim 1, wherein

the organic thin-film layer comprises an electron transporting layer or an electron injecting layer between the cathode and the emitting layer, and

the electron transporting layer or the electron injecting layer comprises an aromatic ring having a nitrogen-containing six-membered or five-membered ring skeleton, or a condensed aromatic cyclic compound having a nitrogen-containing six-membered or five-membered ring skeleton.

9. The organic electroluminescence device according to claim 1, wherein a reductive dopant is present at an interfacial region between the cathode and the organic thin-film layer.

10. A material for an organic electroluminescence device, comprising a host material represented by a formula (2) as follows,

Ra-Ar¹-Rb 

 

(2)

where;

Ar¹, Ra and Rb each represent a substituted or unsubstituted benzene ring or a condensed aromatic hydrocarbon ring selected from a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted chrysene ring, a substituted or unsubstituted fluoranthene ring, a substituted or unsubstituted phenanthrene ring, a substituted or unsubstituted benzophenanthrene ring, a substituted or unsubstituted dibenzophenanthrene ring, a substituted or unsubstituted triphenylene ring, a substituted or unsubstituted benzo[a]triphenylene ring, a substituted or unsubstituted benzochrysene ring, a substituted or unsubstituted benzo[b]fluoranthene ring and a substituted or unsubstituted picene ring;

substituents for Ra and Rb are not aryl groups;

Ra and Rb do not concurrently represent a triphenylene ring; and

, when Ar¹ represents a substituted or unsubstituted benzene ring, an unsubstituted naphthalene ring, a substituted or unsubstituted 2,7-phenanthrenediyl group or a substituted or unsubstituted triphenylene ring, Ra and Rb represent substituted or unsubstituted condensed aromatic hydrocarbon groups that are mutually different.

11. The material for an organic electroluminescence device according to claim 10, wherein when Ra, Rb or Ar¹ in the formula (2) has a single or plural substituent(s), the single or plural substituent(s) is an alkyl group having 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 18 carbon atoms, a silyl group having 3 to 20 carbon atoms, a cyano group or a halogen atom, while a substituent for Ar¹ is further allowed to be an aryl group having 6 to 22 carbon atoms.

12. A material for an organic electroluminescence device, comprising a host material represented by a formula (3) as follows,

Ra-Ar¹-Rb 

 

(3)

where;

Ar¹ represents a divalent benzene ring bonded with two adjacent groups in meta positions or a naphthalene ring bonded with two adjacent groups respectively in the second and seventh positions;

Ra and Rb each represent a condensed aromatic hydrocarbon ring selected from a substituted or unsubstituted chrysene ring, a substituted or unsubstituted fluoranthene ring, a substituted or unsubstituted phenanthrene ring, a substituted or unsubstituted benzophenanthrene ring, a substituted or unsubstituted dibenzophenanthrene ring, a substituted or unsubstituted triphenylene ring, a substituted or unsubstituted benzo[a]triphenylene ring, a substituted or unsubstituted benzochrysene ring, a substituted or unsubstituted benzo[b]fluoranthene ring and a substituted or unsubstituted picene ring;

substituents for Ra and Rb are not aryl groups; and

Ra and Rb do not concurrently represent a triphenylene ring.

13. The material for an organic electroluminescence device according to claim 12, wherein when Ra, Rb or Ar¹ in the formula (3) has a single or plural substituent(s), the single or plural substituent(s) is an alkyl group having 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 5 to 18 carbon atoms, a silyl group having 3 to 20 carbon atoms, a cyano group or a halogen atom, while a substituent for Ar¹ is further allowed to be an aryl group having 6 to 22 carbon atoms.