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US 7,888,865 B2Granted
Organic electroluminescent device and display having multiple emitting layers
AssigneeIdemitsu Kosan Co., Ltd.
InventorsToshihiro Iwakuma, Masahide Matsuura, Hiroshi Yamamoto, Hisayuki Kawamura, Chishio Hosokawa
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Abstract
An organic electroluminescent device including at least an anode, a first emitting layer, a hole barrier layer, a second emitting layer and a cathode in this order. The first emitting layer and the second emitting layer both include a hole transporting material. The organic EL device is small in chromaticity change and has high efficiency.
Claims10
An organic electroluminescent device comprising, in order:
- an anode;
- a first emitting layer;
- a hole barrier layer;
- a second emitting layer;
- and
- a cathode;
- wherein:
- the first emitting layer and the second emitting layer both comprise a hole transporting material;
- a difference in affinity level between the hole barrier layer and the first emitting layer is 0.2 eV or less;
- a difference in affinity level between the hole barrier layer and the second emitting layer is 0.2 eV or less;
- affinity levels of the hole barrier layer, the first emitting layer and the second emitting layer are determined using ionization potential values obtained with a photoelectron spectrometer at atmospheric pressure with a UV source.
8 more elements
Dependencies are inferred from the claim text.