Organic electroluminescent device with emission from hole transporting layer
AssigneeMotorola, Inc.
InventorsSong Q. Shi, Hsing-Chung Lee, Thomas B. Harvey, III, Franky So
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Abstract
An organic EL device comprises a cathode, an electron transporting layer (ETL), a hole transporting layer (HTL) and an anode which are laminated in sequence, wherein the materials making up the ETL and HTL are so selected that the energy barrier for hole injection from the HTL to the ETL is substantially higher than the energy barrier for electron injection from the ETL to the HTL. The organic EL device obtained has efficient light emission from the HTL layer when an efficient fluorescent dye as an emitter is doped in the HTL or the part of the HTL close to the ETL/HTL interface.
Claims17
An organic electroluminescent device comprising a cathode, an electron transporting layer, a hole transporting layer, and an anode positioned sequentially in overlying relationship, the electron and hole transporting layers being formed of organic electron and hole transporting materials, respectively, selected so that the following inequality holds:
- (E.sub.C1 -E.sub.C2)<(E.sub.V1 -E.sub.V2)
- where E.sub.C1 and E.sub.V1 respectively represent a conduction band level, and a valence band level of the material making up the hole transporting layer;
- and E.sub.C2 and E.sub.V2 respectively represent a conduction band level and a valence band level of the material making up the electron transporting layer, whereby light is emitted from the hole transporting layer in response to electron and hole recombinations therein.
An organic electroluminescent device comprising a cathode, an electron injecting layer, an electron transporting layer, a hole transporting layer and an anode which are laminated in sequence, the electron and hole transporting layers being formed of organic electron and hole transporting materials, respectively, selected so that the following inequality holds:
- (E.sub.C1 -E.sub.C2)<(E.sub.V1 -E.sub.V2)
- where E.sub.C1 and E.sub.V1 respectively represent a conduction band level and a valence band level of the material making up the hole transporting layer, E.sub.C2 and E.sub.V2 respectively represent a conduction band level and a valence band level of the material making up the electron transporting layer, and a fluorescent dye material capable of emitting light in response to hole-electron recombinations being located in the hole transporting layer or in a part of the hole transporting layer close to an interface of the hole transporting and electron transporting layers.
An organic electroluminescence device comprising a cathode, an electron transporting layer, a hole transporting layer, a hole injecting layer and an anode which are laminated in sequence, the electron and hole transporting layers being formed of materials selected so that the following inequality holds:
- (E.sub.C1 -E.sub.C2)<(E.sub.V1 -E.sub.V2)
- where E.sub.C1 and E.sub.V1 respectively represent a conduction band level, and a valence band level of the material making up hole transporting layer;
- E.sub.C2 and E.sub.V2 respectively represent a conduction band level and a valence band level of the material making up the electron transporting layer;
- and
- a fluorescent dye material capable of emitting light in response to hole-electron recombinations located in the hole transporting layer or in a part of the hole transporting layer close to the interface of the hole transporting and electron transporting layers.
An organic electroluminescence device comprising a cathode, an electron injecting layer, an electron transporting layer, an hole transporting layer, a hole injecting layer and an anode which are laminated in sequence, the electron and hole transporting layers being formed of organic electron and hole transporting materials, respectively, selected so that the following inequality holds:
- (E.sub.C1 -E.sub.C2)<(E.sub.V1 -E.sub.V2)
- where E.sub.C1 and E.sub.V1 respectively represents a conduction band level, and a valence band level of the material making up hole transporting layer;
- E.sub.C2 and E.sub.V2 respectively represents a conduction band level and a valence band level of the material making up the electron transporting layer;
- and a fluorescent dye material capable of emitting light in response to hole-electron recombinations being located in the hole transporting layer or in a part of hole transporting layer close to an interface of the hole transporting and electron transporting layers.
Dependencies are inferred from the claim text.