Exploration of Nontoxic Cs<sub>3</sub>CeBr<sub>6</sub> for Violet Light-Emitting Diodes
Liang Wang, Qingxun Guo, Jiashun Duan, Weiwei Xie, Guoqi Ji, Shunran Li, Chao Chen, Jinghui Li, Longbo Yang, Zhifang Tan, Ling Xu, Zewen Xiao, Jiajun Luo, Jiang Tang
Abstract
Violet light-emitting diodes (LEDs) are widely utilized for solid-state lighting, bacteria sterilization, and so on. Herein, the nontoxic and earth-abundant Ce3+ ion with intrinsic strong violet emission is introduced to substitute Pb2+ in CsPbBr3 perovskite for electrically driven PeLEDs. Cs3CeBr6 possesses a zero-dimensional photoactive site with a high photoluminescence quantum yield of ≈90% for both crystals and films. The excited-state lifetime of ≈28 ns enabled by the spin- and parity-allowed Ce-5d → Ce-4f transition is considerably faster than other lanthanide-based luminescent centers. The violet LEDs based on thermally evaporated Cs3CeBr6 films display color-stable spectra with a maximum EQE of 0.46%, representing the first Cs3CeBr6 LED and one of the most efficient violet PeLEDs. Moreover, a white LED with standard color coordinates of (0.339, 0.343) is constructed by combining Cs3CeBr6-based violet PeLEDs with yellow phosphor downconverters. Our work will motivate further exploration of diverse lanthanide-based perovskites for LEDs and other optoelectronics.