| 摘要 |
PROBLEM TO BE SOLVED: To improve high efficiency of emission efficiency and durability of an organic electroluminescent element. SOLUTION: In the organic electroluminescent element which has a laminated of at least a hole transfer layer 5, a light emitting layer 6, and an electron transfer layer 7 across a pair of electrodes 3, 8, the layer 6 is formed of a material of both hole mobility and electron mobility each lower than the former of the layer 5 and the latter of the layer 7. Preferably, the layer 6 is formed of the material where the hole mobility and electron mobility are balanced. Recombination probability of electron and hole is increased to increase luminous efficiency because carrier holding time is longer in the layer 6. In addition, durability is also improved because carriers that are not recombined scarcely enter the counter transfer layer. COPYRIGHT: (C)2007,JPO&INPIT
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