Highly Luminescent and Stable CsPbI3 Perovskite Nanocrystals with Sodium Dodecyl Sulfate Ligand Passivation for Red-Light-Emitting Diodes

CsPbI3 perovskite nanocrystals (NCs) have recently emerged as promising materials for optoelectronic devices because of their superior properties. However, the poor stability of the CsPbI3 NCs induced by easy ligand desorption represents a key issue limiting their practical applications. Herein, we report stable and highly luminescent black-phase CsPbI3 NCs passivated by novel ligands of sodium dodecyl sulfate (SDS). Theoretical calculation results reveal a stronger adsorption energy of SDS molecules at the CsPbI3 surface than that of commonly used oleic acid. As a result, the defect formation caused by the ligand loss during the purification process is greatly suppressed. The optimized SDS- CsPbI3 NCs exhibit significantly reduced surface defects, much enhanced stability, and superior photoluminescence efficiency. The red perovskite light-emitting diodes based on the SDS-CsPbI3 NCs demonstrate an external quantum efficiency of 8.4%, which shows a 4-fold improvement compared to the devices based on the oleic acid-modified CsPbI3 NCs.Funding Agencies|NSFCNational Natural Science Foundation of China (NSFC) [61774077]; Key Projects of Joint Fund of Basic and Applied Basic Research Fund of Guangdong Province [2019B1515120073, 2019B090921002]; Guangzhou Key laboratory of Vacuum Coating Technologies and New Energy Materials Open Projects Fund [KFVE20200006]; National Key R&D Program of China [2018YFA0209200]; National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [21574049]; China Postdoctoral Science FoundationChina Postdoctoral Science Foundation [2020M683191]; Swedish Research Council VetenskapsradetSwedish Research Council [2020-03564]; Guangdong Basic and Applied Basic Research Foundation [2020A1414010036, 2020A1515110527, 2020A1515110384]