Organic electroluminescent element

• US 5,429,884 A
• Filed: 10/15/1992
• Issued: 07/04/1995
• Est. Priority Date: 01/17/1992
• Status: Expired due to Term

• Current Assignee: Pioneer Electronics (USA) Incorporated (Pioneer Corporation)
• Original Assignee: Pioneer Electronics (USA) Incorporated (Pioneer Corporation)
• Inventors: Shinkai, Masanao, Sato, Hitoshi, Nagayama, Kenichi, Watanabe, Teruichi, Namiki, Tohru
• Primary Examiner(s): Nold, Charles R.
• Application Number:
  US07/961,506
• Time in Patent Office: 992 Days
• Field of Search: 428/690, 428/691, 428/917, 313/503, 313/504, 313/509
• US Class Current: 428/690
• CPC Class Codes: H05B 33/26 characterised by the composition or arrangement of the conductive material used as an electrode
• CPC Class Codes: H10K 50/82 Cathodes
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

Disclosed are organic EL elements having high environmental stability as well as high luminous efficiency and luminance. In an organic EL element comprising a transparent anode, a hole-carrying layer, a light-emitting layer and an alloy cathode consisting of a first metal Li and a stabilizing second metal Al, all laminated on a substrate, the concentration of the first metal Li contained in the alloy region with a predetermined thickness from the interface between the alloy cathode and the organic layer is controlled to a minute amount ranging from 0.005 wt. % to 0.3 wt. %. In another organic EL element comprising a transparent anode, a hole-carrying layer, a light-emitting layer and an alloy cathode consisting of a first metal Sr and a stabilizing second metal Mg, all laminated on a substrate, the concentration of the first metal Sr contained in the alloy region with a predetermined thickness from the interface between the alloy cathode and the organic layer (light-emitting layer or electron-carrying layer) is controlled to a minute amount ranging from 10 wt. % to 40 wt. %.

Claims

1. An organic EL element comprising an anode, a hole-carrying layer formed of an organic compound, a light-emitting layer formed of an organic compound and a cathode, laminated in order on a substrate,

said cathode being made of lithium and aluminum and having an alloy region contacting an interface between said light-emitting layer and said cathode,

said alloy region containing said lithium with a concentration in a weight ratio of 0.005 to 0.3 parts by weight to 100 parts by weight of said aluminum.

2. The organic EL element according to claim 1, wherein said alloy region lies within a thickness range from above 0 Å

to 1500 Å

from said interface between said light-emitting layer and said alloy cathode.

3. The organic EL element according to claim 1, further comprising a protective electrode laminated on said alloy cathode.

6. The organic EL element according to claim 1, further comprising a protective electrode laminated on said alloy cathode.

4. An organic EL element comprising an anode, a hole-carrying layer formed of an organic compound, a light-emitting layer formed of an organic compound and a cathode, laminated in order on a substrate,

said cathode being made of strontium and magnesium and having an alloy region contacting an interface between said light-emitting layer and said cathode,

said alloy region containing said strontium with a concentration in a weight ratio of 10 to 40 parts by weight to 100 parts by weight of said magnesium.

5. The organic EL element according to claim 4, wherein said alloy region lies within a thickness range from above 0 Å

to 1500 Å

from said interface between said light-emitting layer and said alloy cathode.

7. An organic EL element comprising an anode, a hole-carrying layer formed of an organic compound, a light-emitting layer of an organic compound and an alloy cathode, laminated in order on a substrate,

said alloy cathode comprising lithium and a second metal capable of stabilizing said lithium,

further comprising a protective electrode laminated on said alloy cathode.

8. The organic EL element according to claim 7, wherein a weight ratio of said lithium to said second metal of said alloy cathode is 50 parts by weight to 1000 parts by weight.

9. The organic EL element according to claim 7, wherein said second metal is selected from the group consisting of aluminum and magnesium.

10. The organic EL element according to claim 7, wherein said protective electrode comprises said second metal.

11. An organic EL element comprising an anode, an organic hole-carrying layer formed of an organic compound, a light-emitting layer formed of an organic compound and a cathode, laminated in order on a substrate, said cathode being made of indium and lithium and having an alloy region contacting an interface between said light-emitting layer and said cathode, said alloy region containing said lithium with a concentration in a weight ratio of 0.005 to 0.11 part by weight to 100 parts by weight of said indium.

12. The organic EL element according to claim 11, wherein said alloy region lies within a thickness range from above 0 Å

to 10000 Å

from said interface between said light-emitting layer and said cathode.

13. An organic EL element comprising an anode, a hole-carrying layer formed of an organic compound, a light-emitting layer formed of an organic compound, an organic electron-carrying layer and a cathode, laminated in order on a substrate,

said cathode being made of lithium and aluminum and having an alloy region contacting an interface between said organic electron-carrying layer and said cathode,

said alloy region containing said lithium with a concentration in a weight ratio of 0.005 to 0.3 parts by weight to 100 parts by weight of said aluminum.

14. The organic EL element according to claim 13, wherein said alloy region is present within a thickness range from above 0 Å

to 1500 Å

from said interface between said organic electron-carrying layer and said cathode.

15. The organic EL element according to claim 13, further comprising a protective electrode laminated on said cathode.

16. An organic EL element comprising an anode, a hole-carrying layer formed of an organic compound, a light-emitting layer formed of an organic compound, an organic electron-carrying layer and a cathode, laminated in order on a substrate,

said cathode being made of strontium and magnesium and having an alloy region contacting an interface between said organic electron-carrying layer and said cathode,

said alloy region containing said strontium with a concentration in a weight ratio of 10 to 40 parts by weight to 100 parts by weight of said magnesium.

17. The organic EL element according to claim 16, wherein said alloy region is present within a thickness range from above 0 Å

to 1500 Å

from said interface between said organic electron-carrying layer and said cathode.

18. The organic EL element according to claim 16, further comprising a protective electrode laminated on said cathode.

19. An organic EL element comprising an anode, a hole-carrying layer formed of an organic compound, a light-emitting layer of an organic compound, an organic electron-carrying layer and an alloy cathode, laminated in order on a substrate,

said alloy cathode comprising lithium and a second metal capable of stabilizing said lithium,

further comprising a protective electrode laminated on said alloy cathode.

20. The organic EL element according to claim 19, wherein a weight ratio of said lithium to said second metal of said alloy cathode is 50 parts by weight to 1000 parts by weight.

21. The organic EL element according to claim 19, wherein said second metal is selected from the group consisting of aluminum and magnesium.

22. The organic EL element according to claim 19, wherein said protective electrode comprises said second metal.

23. An organic EL element comprising an anode, an organic hole-carrying layer formed of an organic compound, a light-emitting layer formed of an organic compound, an organic electron-carrying layer and cathode, laminated in order on a substrate,

said cathode being made of indium and lithium and having an alloy region contacting an interface between said organic electron-carrying layer and said cathode,

said alloy region containing said lithium with a concentration in a weight ratio of 0.005 to 0.11 part by weight to 100 parts by weight of said indium.

24. The organic EL element according to claim 23, wherein said alloy region is present within a thickness range from above 0 Å

to 10000 Å

from said interface between said organic electron-carrying layer and said cathode.