Surface Treatment of Inorganic CsPbI3 Nanocrystals with Guanidinium Iodide for Efficient Perovskite Light-Emitting Diodes with High Brightness

• 作者: Minh Tam Hoang Amandeep Singh Pannu Yang Yang Sepideh Madani Paul Shaw Prashant Sonar Tuquabo Tesfamichael Hongxia Wang
• 来源期刊: 纳微快报（英文版）
• 年，卷（期）: 2022,（4）
• 页码范围: 277-288
• 页数: 12页
• 语种: 英文

摘要

The remarkable evolution of metal halide perovskites in the past dec-ade makes them promise for next-generation optoelectronic material.In particular,nanocrystals(NCs)of inorganic perovskites have demonstrated excellent performance for light-emitting and display applications.However,the presence of surface defects on the NCs negatively impacts their performance in devices.Herein,we report a com-patible facial post-treatment of CsPbI3 nanocrystals using guanidinium iodide(GuI).It is found that the GuI treatment effectively passivated the halide vacancy defects on the surface of the NCs while offering effective surface protection and exciton con-finement thanks to the beneficial contribution of iodide and guanidinium cation.As a consequence,the film of treated CsPbI3 nanocrystals exhibited significantly enhanced luminescence and charge transport properties,leading to high-performance light-emitting diode with maximum external quantum efficiency of 13.8％with high bright-ness(peak luminance of 7039 cd m-2 and a peak current density of 10.8 cd A-1).The EQE is over threefold higher than performance of untreated device(EQE:3.8％).The operational half-lifetime of the treated devices also was significantly improved with T50 of 20 min(at current density of 25 mA cm-2),outperforming the untreated devices(T50～6 min).