Reducing the impact of Auger recombination in quasi-2D perovskite light-emitting diodes
Yuanzhi Jiang, Minghuan Cui, Saisai Li, Changjiu Sun, Yanmin Huang, Keyu Wei, Li Zhang, Mei Lv, Chaochao Qin, Yufang Liu, Mingjian Yuan
Abstract
Abstract Rapid Auger recombination represents an important challenge faced by quasi-2D perovskites, which induces resulting perovskite light-emitting diodes’ (PeLEDs) efficiency roll-off. In principle, Auger recombination rate is proportional to materials’ exciton binding energy ( E b ). Thus, Auger recombination can be suppressed by reducing the corresponding materials’ E b . Here, a polar molecule, p -fluorophenethylammonium, is employed to generate quasi-2D perovskites with reduced E b . Recombination kinetics reveal the Auger recombination rate does decrease to one-order-of magnitude lower compared to its PEA + analogues. After effective passivation, nonradiative recombination is greatly suppressed, which enables resulting films to exhibit outstanding photoluminescence quantum yields in a broad range of excitation density. We herein demonstrate the very efficient PeLEDs with a peak external quantum efficiency of 20.36%. More importantly, devices exhibit a record luminance of 82,480 cd m −2 due to the suppressed efficiency roll-off, which represent one of the brightest visible PeLEDs yet.