| 摘要 |
PROBLEM TO BE SOLVED: To obtain an EL element stably emitting light in green-red orange color by including quinoxalinobenzothiazine derivative as a luminescent material in an electron hole transport layer or an electronic transport layer. SOLUTION: In an electron hole transport layer or an electronic transport layer provided between a pair of electrodes, a quinoxalinobenzothiazine derivative is made to be included as a dopant by about 0.01 to 40 wt.%. As quinoxalinobenzothiazine derivative, derivative having 12H-Quinoxalino [z, 3-b][1, 4] benzothiazine shown by formula I as a skelton can be cited, for example. When compound in the formula I is irradiated with ultraviolet ray in the solid state, strong thuorescence in yellow and green color is displayed. An alkyl group or an aryl group is introduced into 12-th rank nitride atom in the formula I, electron-attracting groups such as a nitro group, a nitryl group and a perfluoroalkyl group are introduced into an aromatic ring, green-red orange luminescence is given in a solid state, as a result of the extension of the aromatic ring and the quinoxalinobenzothiazine derivative which has high heat resistance and is shown by formula II can be obtained.
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