Conjugated Alkylamine by Two-Step Surface Ligand Engineering in CsPbBr3 Perovskite Nanocrystals for Efficient Light-Emitting Diodes

Long alkyl-chain capped ligands are prerequisites for preserving high photoluminescence quantum yield (PLQY) in perovskite nanocrystals (NCs). Unfortunately, the insulating feature of surface ligands potentially hinders carrier transport in light-emitting diode (LED) devices, which will degenerate the LED performance. To overcome this shortcoming, we introduce a conjugated molecule, 3-phenyl-2-propen-1-amine (PPA), into CsPbBr3 NCs through a two-step surface ligand engineering process. Owing to excellent electrical conductivity of PPA, PPA-capped CsPbBr3 NCs LEDs exhibit a maximum current efficiency of 23.53 cd A(-1), and a maximum luminance of 26,475 cd m(-2) at the wavelength of 517 nm. This work offers a new strategy to improve the quality of CsPbBr3 NCs and LEDs by introducing conjugation molecular ligands into the all-inorganic perovskite nanocrystals.