| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an organic EL element having a high luminous efficiency by means of mixed luminescence. Ž<P>SOLUTION: This organic electroluminescent element includes: a pair of electrodes constituted of a positive electrode and a negative electrode; and at least a luminescent layer arranged between the pair of electrodes, a hole transport layer arranged between the positive electrode and the luminescent layer, and an electron transport layer arranged between the negative electrode and the luminescent layer. In the organic electroluminescent element, (1) the luminescent layer contains an electron transporting luminescent material and a hole transporting host material; (2) the concentration of the electron transporting luminescent material in the luminescent layer is gradually reduced toward the positive electrode side of the luminescent layer from the negative electrode side thereof; and (3) at least one kind of a luminescent material low in triplet energy level relative to the electron transporting luminescent material is included in a region reduced in the electron transporting luminescent material concentration in the luminescent layer and in a region having a thickness of 1/100-1/2 of the total thickness of the luminescent layer. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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