Organic electroluminescent element
AssigneeMinolta Co., Ltd.
InventorsHideaki Ueda, Yoshihisa Terasaka, Keiichi Furukawa
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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, electron injecting layer, and negative electrode, wherein said electron injecting layer is a compound layer comprising an electron transporting material and metal, and the negative electrode side of said compound layer has a higher percentage of metal.
Claims21
An organic electroluminescent element comprising:
- a positive electrode;
- a luminescing layer;
- an electron injecting layer;
- and
- a negative electrode;
- wherein said electron injecting layer is interposed between the luminescing layer and the negative electrode and is composed of an electron transporting material and a metal, said electron injecting layer having a higher concentration of the metal in a negative electrode side of the electron injecting layer than that in a luminescing layer side of the electron injecting layer,
- said metal having a work function of less than 4.0 eV and being at least one type selected from the group consisting of magnesium, calcium, titanium, yttrium, lithium, gadolinium, ytterbium and ruthenium.
An organic electroluminescent element comprising:
- a positive electrode;
- a luminescing layer;
- an electron injecting layer;
- and
- a negative electrode;
- wherein said electron injecting layer is interposed between the luminescing layer and the negative electrode and is composed of an electron transporting material and a metal, said electron injecting layer having a higher concentration of the metal in a negative electrode side of the electron injecting layer than that in a luminescing layer side of the electron injecting layer, a volume ratio of metal/electron transporting material in the luminescing layer side of the electron injecting layer being more than 1/5.
Dependencies are inferred from the claim text.