Organic electroluminescent element

a technology of electroluminescent elements and organic materials, applied in the direction of discharge tube luminescnet screens, natural mineral layered products, transportation and packaging, etc., can solve the problems of poor stability, storage stability and stability, and the stability of charge-transporting materials, etc., to achieve the effect of increasing luminescent intensity and stable characteristics

Inactive Publication Date: 2002-04-11
MINOLTA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

0016] In light of the aforesaid information, an object of the present invention is to provide an organic electroluminescent element which possesses increased luminescent intensity and exhibits stable characteristics even with repeated use.

Problems solved by technology

Although organic electroluminescent elements have high luminance characteristics, they also are unstable when luminescing and have poor stability during storage so as to be impractical for use.
One disadvantage of the aforesaid elements regarding storage stability and stability during luminescence pertains to the stability of the charge-transporting material.
Further disadvantages arise, however when metals other than aluminum are used, inasmuch as the layer formation conditions become more difficult, oxidation may occur during layer formation, black spots become prevalent when luminescing.

Method used

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Examples

Experimental program
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example 2

[0067] A thin hole injecting / transporting layer was formed on a glass substrate coated with indium-tin oxide via vacuum deposition using N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-diphenyl-4,4'-diamine to form a layer 60 nm in thickness.

[0068] A thin layer of aluminum trisoxine 60 nm in thickness was superimposed over the aforesaid hole injecting / transporting layer via vacuum deposition to form an organic luminescing layer.

[0069] Then, magnesium and silver were co-deposited via vacuum deposition to form a thin layer 50 nm in thickness with an atomic ratio of 10:1 to form a negative electrode. A thin layer of magnesium and silver about 100 nm in thickness was then co-deposited over the aforesaid layer via resistance heating at an atomic ratio of 1:5.

[0070] The organic electroluminescent element was produced in this manner.

[0071] The magnesium used has a work function of 3.66 eV.

[0072] The silver used had a work function of 4.26 eV.

example 3

[0073] A thin hole injecting / transporting layer was formed on a glass substrate coated with indium-tin oxide via vacuum deposition using N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-diphenyl-4,4'-diamine to form a layer 60 nm in thickness.

[0074] A thin layer of aluminum trisoxine 60 nm in thickness was superimposed over the aforesaid hole injecting / transporting layer via vacuum deposition to form an organic luminescing layer.

[0075] Then, magnesium and indium were vacuum deposited together to form a thin layer 60 nm in thickness with an atomic ratio of 10:1 to form a negative electrode. A thin layer of magnesium and indium about 140 nm in thickness was then co-deposited over the aforesaid layer via resistance heating at an atomic ratio of 1:5.

[0076] The organic electroluminescent element was produced in this manner.

[0077] The magnesium used has a work function of 3.66 eV.

[0078] The indium used had a work function of 4.09 eV.

reference example 1

[0079] An organic electroluminescent element was prepared in the same manner as in Example 1 with the exception that the negative electrode was formed by co-depositing magnesium and silver via resistance heating at an atomic ratio of 10:1 and layer thickness of 100 nm.

[0080] The magnesium used has a work function of 3.66 eV.

[0081] The silver used had a work function of 4.26 eV.

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Abstract

The object of the invention is to provide an organic electroluminescent element which reduces the luminescence starting voltage, increases the luminescence brightness, and has excellent stability with repeated use. The invention achieves these objects by providing an organic electroluminescent element comprising at least a positive electrode, luminescing layer, and negative electrode, wherein said negative electrode is a compound layer of magnesium and a metal having a higher work function than magnesium, and the exterior surface side of said compound layer has a higher percentage of metal having a high work function.

Description

[0001] This application is based on Application No. HEI 9-267036 filed in Japan, the content of which is hereby incorporated by reference.[0002] 1. Field of the Invention[0003] The present invention relates to an organic electroluminescent element.[0004] 2. Description of the Related Art[0005] Organic electroluminescent elements are elements constructed using organic compounds as luminescent materials which emit light in response to electric signals.[0006] Organic electroluminescent elements have a basic structure of an organic luminescent layer interposed between a pair of opposing electrodes.[0007] Electroluminescence is a phenomenon wherein electrons are injected from one electrode and holes are injected from another electrode so as to excite an illuminant within the luminescent layer to a higher energy level, and excess energy is discharged as light when the illuminant returns to its original base state.[0008] In addition to the aforesaid basic structure, a hole injecting layer ...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C09K11/06H01L51/50H05B33/26H01L51/52H05B33/12
CPCY10T428/24942H01L51/5221Y10T428/31678H10K50/82H10K2101/80
Inventor UEDA, HIDEAKIFURUKAWA, KEIICHITERASAKA, YOSHIHISA
Owner MINOLTA CO LTD
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