Suppressing Auger Recombination in Cesium Lead Bromide Perovskite Nanocrystal Film for Bright Light-Emitting Diodes

作者：Jisong Yao, Jia‐Chen Zhang, Li Wang, Kunhua Wang, Xue‐Chen Ru, Jun‐Nan Yang, Jingjing Wang, Xing Chen, Yong‐Hui Song, Yi‐Chen Yin, Yi‐Feng Lan, Qun Zhang, Hong‐Bin Yao · 发表于：The Journal of Physical Chemistry Letters · 年份：2020 · DOI：10.1021/acs.jpclett.0c02777 · 被引用次数：43 · 研究领域：Perovskite Materials and Applications、Quantum Dots Synthesis And Properties、Chalcogenide Semiconductor Thin Films

All-inorganic cesium lead halide perovskite colloidal nanocrystals are attractive for next-generation light-emitting diodes because of their high color purity, but the nonradiative Auger recombination in perovskite nanocrystal film limits the efficiency and brightness of the fabricated devices. Here, we introduce a surface-engineering process to exchange the original long-chain oleic acid/oleylamine ligands by the cerium–tributylphosphine oxide hybrid ligands to suppress nonradiative Auger recombination in CsPbBr 3 NC film for bright and low-efficiency roll-off light-emitting diodes. Using ultrafast transient absorption and time-resolved photoluminescence spectroscopy, we demonstrate that the hybrid ligand passivation can efficiently remove surface trap states to enhance radiative recombination and homogenize the exciton concentration to suppress nonradiative Auger recombination in the CsPbBr 3 nanocrystal thin film. Consequently, we fabricate a light-emitting diode with efficient charge injection into the CsPbBr 3 nanocrystal emitting layer, achieving a pronounced improvement of electroluminescence with an external quantum efficiency from 5.5% to 9.1%. More importantly, the efficiency roll-off characteristics of high-brightness light-emitting diodes is effectively mitigated. Our reported hybrid ligand passivation suppressed Auger recombination strategy shows a great potential for fabricating high-brightness cesium lead halide perovskite light-emitting diodes.