Improved Efficiency of Red Phosphorescent Organic Light-Emitting Diodes with Combination of Heterojunction and Mixed Host Structure

Abstract

We report an improvement of efficiency in red phosphorescent organic light-emitting diodes (PHOLEDs) based on a combination of heterojunction (HJ) structure and mixed host (MH) system using a phosphorescent red emitter: bis(2-phenylquinolinato)-acetylacetonate iridium III [Ir(pq)2(acac)] doped in 4,4,N,N'-dicarbazolebiphenyl (CBP) of hole transport type host material and 1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBi) of electron transport …