High‐Efficiency Formamidinium Lead Bromide Perovskite Nanocrystal‐Based Light‐Emitting Diodes Fabricated via a Surface Defect Self‐Passivation Strategy

• DOI: 10.1002/adom.201901390
• Publication Date: 2020-01-15T09:08:10Z
• Authors: Hongting Chen; Lianwei Fan; Rui Zhang; Chunxiong Bao; Haifeng Zhao; Wei Xiang; Wei Liu; Guangda Niu; Runda Guo; Louwen Zhang; Lei Wang
• Keywords: Formamidinium; Passivation; Quantum yield; Quantum Efficiency

Abstract Formamidinium lead bromide (FAPbBr 3 ) nanocrystals (NCs) demonstrate great potential in light‐emitting diode (LED) applications due to their pure green emission and excellent stability. However, the abundant defects at surface of NCs act as charge trapping centers significantly increase trap‐assisted nonradiative recombination channels, hampering performance improvement LEDs based on FAPbBr NCs. Herein, a facile self‐passivation strategy is developed by introducing excess formamidinium (FABr) during colloidal synthesis NCs, leading much improved photoluminescence quantum yield (PLQY) obtained In addition, enhanced transport property measured assembled films owing simultaneously declined insulating ligands The molar ratio FABr PbBr 2 rationally optimized high‐efficient green‐emissive are fabricated with champion current efficiency 76.8 cd A −1 , corresponding an external 17.1%, which among best‐performing perovskite so far.