Constructing Low-Triplet-Energy Hosts for Highly Efficient Blue PHOLEDs: Controlling Charge and Exciton Capture in Doping Systems

• DOI: 10.1021/cm403160p
• Publication Date: 2013-11-25T13:16:42Z
• Authors: Chunmiao Han; Fangchao Zhao; Zhen Zhang; Liping Zhu; Hui Xu; Jing Li; Dongge Ma; Pengfei Yan
• Keywords: Triphenylamine; Charge carrier

With the aim to rationally figure out significance of charge and exciton capture in electrophosphorescent processes low-triplet-energy hosts involved doping systems, frontier molecular orbital (FMO) energy levels a series with diphenylphosphine oxide (DPPO) triphenylamine (TPA), collectively named DPExPOTPAn, were successfully gradually tuned on basis their constant triplet (T1) 2.63 eV get rid interference from host-dopant transfer. It was showed that device efficiencies directly proportional depths carrier traps formed dopants inversely ability hosts, which evidenced by highest external quantum efficiency ∼15% FIrpic-based PHOLED DPESPOTPA deepest hole electron weakest among DPExPOTPAn. This work not only demonstrated great advantages potential this kind host materials for low-driving-voltage application but also clarified determinants highly efficient blue PHOLEDs, are consequentially referable purposeful design.