| 摘要 |
PROBLEM TO BE SOLVED: To provide a hole transporting material and its layer suppressing decrease of light-emission luminance of an organic EL element; to provide an organic electroluminescent element; and also to provide a purification method of the hole transportation material. SOLUTION: In this organic EL element 1, when a voltage is applied across a positive electrode 3 and a negative electrode 5, holes are moved in a hole transportation layer 41, electrons are moved in an electron transportation layer 43, and the holes and the electrons are recombined in a light emitting layer 42. In the light emitting layer 42, excitons are produced by energy released upon the recombination, and the excitons release (emit) energy (fluorescence or phosphorescence) when returning to the ground state. This hole transportation material is used for the hole transportation layer 41, in which the content of nonionic impurities having a molecular weight of 5,000 or less is adjusted to be small. Thereby, the decrease of light-emission luminance of the organic EL device 1 is suppressed. COPYRIGHT: (C)2005,JPO&NCIPI
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