Organic electroluminescent device

• US 5,821,003 A
• Filed: 09/20/1996
• Issued: 10/13/1998
• Est. Priority Date: 03/16/1994
• Status: Expired due to Fees

• Current Assignee: Chemipro Kasei Kaisha, Ltd.
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Okuda, Nobuyuki, Uemura, Takashi, Kimura, Hiroya, Ueba, Yoshinobu, Osaka, Hajime, Okuda, Yasuko
• Primary Examiner(s): NOLD, CHARLES R
• Application Number:
  US08/716,871
• Time in Patent Office: 753 Days
• Field of Search: 428/690, 428/917, 313/504
• US Class Current: 428/690
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces
• 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: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 85/10 Organic polymers or oligomers
• CPC Class Codes: H10K 85/111 comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/631 Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine
• CPC Class Codes: H10K 85/649 Aromatic compounds comprising a hetero atom
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

An organic electroluminescent device having the hole-transport layer in which the hole-transport material is dispersed in the resin binder having a glass transition temperature of not less than 170° C.

Since the above organic electroluminescent device has the hole-transport layer exhibiting sufficient durability and higher hole-transport property, it is excellent in luminous efficiency, luminance and stability.

Claims

1. An organic electroluminescent device having a hole-transport layer, which is formed by applying and drying a coating solution in which a hole-transport material and a resin binder having a glass transition temperature of not less than 170°

C. are dissolved in a solvent from which dissolved gas is previously removed.

2. An organic electroluminescent device according to claim 1, wherein the resin binder is at least one member selected from the group consisting of a polyethersulfone having a repeating unit of the formula:

##STR11## and a polysulfone having a repeating unit of the formula;

##STR12##

3. An organic electroluminescent device according to claim 1, wherein the hole-transport material is an N,N'"'"'-diphenyl-N,N'"'"'-bis(3-methylphenyl)-1,1'"'"'-biphenyl-4,4'"'"'-diamine of the formula:

##STR13##

4. An organic electroluminescent device according to claim 1, wherein the hole-transport material is present in an amount of 40 to 60% by weight with respect to an entire hole-transport layer.

5. An organic electroluminescence device according to claim 1, further including an electro-transport layer formed by depositing by vacuum deposition an electron-transport material onto the hole-transport layer.

6. An organic electroluminescence device according to claim 5, wherein the electron-transport material constituting the electron-transport layer is a tris(8-quinolinolato)aluminum (III) complex of the formula:

##STR14##

7. An organic electroluminescent device comprising:

a hole-transport layer having a layer structure that a hole-transport material is dispersed in a resin binder having a glass transition temperature of not less than 170°

C.; and

an electron-transport layer which is formed by depositing by vacuum deposition an electron-transport material onto the hole-transport material onto the hole-transport layer.

8. An organic electroluminescent device according to claim 7, wherein

the resin binder constituting the hole-transport layer is at least one member selected from the group consisting of a polyethersulfone having a repeating unit of the formula:

##STR15## and a polysulfone having a repeating unit of the formula;

##STR16## the hole-transport material is an N,N'"'"'-diphenyl-N,N'"'"'-bis(3-methylphenyl)-1,1'"'"'-biphenyl-4,4'"'"'-diamine of the formula;

##STR17## the electron-transport material constituting the electron-transport layer is a tris(8-quinolinolato)aluminum (III) complex of the formula;

##STR18##

9. An organic electroluminescent device according to claim 7, wherein the hole-transport material is present in an amount of 40 to 60% by weight with respect to the entire hole-transport layer.

10. An organic electroluminescence device having a hole-transport layer in which a hole-transport material and at least one fluorescent dye are dispersed in a resin binder having a glass transition temperature of not less than 170°

C.

11. An organic electroluminescent device according to claim 10, wherein

the resin binder constituting the hole-transport layer is at least one member selected from the group consisting of a polyethelsulfone having a repeating unit of the formula:

##STR19## and a polysulfone having a repeating unit of the formula;

##STR20## the hole-transport material is an N,N'"'"'-diphenyl-N,N'"'"'bis(3-methylphenyl)-1,1'"'"'-biphenyl-4,4'"'"'-diamine of the formula;

##STR21##

12. An organic electroluminescent device according to claim 10, wherein the hole-transport material is present in an amount of 40 to 60% by weight with respect to the entire hole-transport layer.

13. An organic electroluminescent device according to claim 10, wherein

(a) a tetraphenylbutadiene of the formula:

##STR22## (b) a coumarine 6 of the formula;

##STR23## (c) a 4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran of the formula;

##STR24## are employed with respect to the fluorescent dye.

14. An organic electroluminescent device according to claim 10, wherein a first electron-transport layer composed of an electron-transport material excellent in hole-blocking property and a second electron-transport layer composed of an electron-transport material are laminated in this order on the hole-transport layer.

15. An organic electroluminescent device according to claim 14, wherein the electron-transport material for the first electron-transport layer is a triazole compound of the formula:

##STR25## and the electron-transport material for the second electron-transport layer is a tris(8-quinolinolato)aluminum (III) complex of the formula;

##STR26##