Highly Stable Red-Light-Emitting Electrochemical Cells

摘要

The synthesis and characterization of a series of new cyclometalated iridium(Ⅲ) complexes [Ir(ppy)_2(N^N)] [PF_6] in which Hppy = 2-phenylpyridine and N^N is (pyridin-2-yl)benzo[d]thiazole (Ll), 2-(4-(tert-butyl)pyridin-2-yl)benzo-[d] thiazole (L2), 2-(6-phenylpyridin-2-yl)benzo[d]thiazole (L3), 2-(4-(tert-butyl)-6-phenylpyridin-2-yl)benzo[d] thiazole (L4), 2,6-bis(benzo[d]thiazol-2-yl)pyridine (L5), 2-(pyridin-2-yl)benzo[d]oxazole (L6), or 2,2'-dibenzo[d]thiazole (L7) are reported. The single crystal structures of [Ir(ppy)_2(Ll)][PF_6]•1.5CH_2Cl_2, [Ir-(ppy)_2(L6)][PF_6]•CH_2Cl_υ, and [Ir(ppy)_2(L7)][PF_6] have been determined. The new complexes are efficient red emitters and have been used in the active layers in light-emitting electrochemical cells (LECs). The effects of modifications of the 2-(pyridin-2-yl)benzo [d] thiazole ligand on the photoluminescence and LEC perform-ance have been examined. Extremely stable red-emitting LECs are obtained, and when [Ir(ppy)_2(Ll)][PF_6], [Ir(ppy)_2(L2)]-[PF_6], or [Ir(ppy)_2(L3)] [PF_6] are used in the active layer, device lifetimes greater than 1000, 6000, and 4000 h, respectively, are observed