| 摘要 |
PROBLEM TO BE SOLVED: To provide an organic EL element having high luminous characteristics, good durability and excellent in actual usage. SOLUTION: In an organic EL element having an anode 30, a cathode 22 and an organic layers 24 comprising one or plural layers sandwiched between them, a transparent electrode or a metal electrode with large work function such as ITO and Au, for example, is used for the anode 30, and an (n) type semiconductor material which has a large gap, is transparent in a visible light region and has a small work function is used for the cathode 22. In the band gap of the semiconductor material used for the cathode 22 is not less than 3.0 eV, it is transparent in the visible light region and can be used for the transparent electrode. In addition, if the semiconductor material has almost the same level of electron affinity as electron affinity of the adjacent organic layer 24, an energy spike of the cathode 22 on the boundary surface between the cathode and the organic layer 24 can be made small. If the work function of the semiconductor material is smaller than the work function of the adjacent organic layer 24, an energy barrier is prevented from being formed between the organic layer 24 and the cathode 22. Semiconductor or GaN compound is suitable for the (n) type semiconductor material.
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