Acid-free bidentate ligand passivation enables high-performance perovskite nanocrystals for X-ray imaging and display

Perovskite nanocrystals (NCs) have attracted much attention in the fields of laser, color conversion and X-ray imaging. However, the poor photophysical properties and stability of NCs due to the proton exchange of traditional X-type ligands such as the pair of oleic acid and oleylamine as well as their easy detachment after purification or long-time storage, have become the major bottleneck for practical applications. Herein, we exploit an in-situ passivation strategy for CsPbBr3 NCs by merely using a L-type bidentate ligand, namely 1,3-bis(3-aminopropyl) tetramethyldisiloxane (BAPTRDS). Theoretical calculations indicate that this double bridging of BAPTRDS on the surface of NCs can achieve a much larger binding energy (-1.86 eV) in comparision to single chelated 3-aminopropyl-triethoxysilane (APTES) (-1.05 eV). The BAPTRDS passivated NCs exhibit a high photoluminescence quantum yield of 71 %. Besides, the X-ray imaging detector and white light-emitting diodes (WLEDs) were separately obtained by BAPTRDS capped NCs, both of which possess the impressive performance. This work not only can provide deep understanding for surface chemistry of perovskite NCs, but also acquire high-quality CsPbBr3 NCs for dual applications in X-ray imaging and display.