Dendron engineering in self-host blue iridium dendrimers towards low-voltage-driving and power-efficient nondoped
Yang Wang1, Shumeng Wang1, Junqiao Ding2
1State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China. junqiaod@ciac.ac.cn lixiang@ciac.ac.cn and University of the Chinese Academy of Sciences, Beijing 100049, P. R. China.
Abstract:
Dendron engineering in self-host blue Ir dendrimers is reported to develop power-efficient nondoped electrophosphorescent devices for the first time, which can be operated at low voltage close to the theoretical limit (Eg/e: corresponding to the optical bandgap divided by the electron charge). With increasing dendron's HOMO energy levels from B-POCz to B-CzCz and B-CzTA, effective hole injection is favored to promote exciton formation, resulting in a significant reduction of driving voltage and improvement of power efficiency. Consequently, the nondoped device of B-CzTA achieves extremely low driving voltages of 2.7/3.4/4.4 V and record high power efficiencies of 30.3/24.4/16.3 lm W-1 at 1, 100 and 1000 cd m-2, respectively. We believe that this work will pave the way to the design of novel power-efficient self-host blue phosphorescent dendrimers used for energy-saving displays and solid-state lightings.
