Surface defect passivation by ligand in polymeric melt encapsulated CsPbBr3 perovskite nanocrystals/PP composite with high X-ray imaging performance

Abstract

In-situ growth method has been widely used in the preparation of metal halide perovskite nanocrystals/polymer composites. However, the ligand-free process tends to bring surface defects which always deteriorate the photoluminescence. The passivation effect of surface ligands on the defects of nanocrystals, which is of benefit to promote the photoluminescence performance of the composites, is often neglected in the preparation of perovskite nanocrystals/polymers. Here, we report a facile post-passivation treatment of CsPbBr3/polypropylene (PP) composite film with octylamine solution, and surface engineering of CsPbBr3 nanocrystals in PP molecular chain by swelling effect to passivate the surface defects of nanocrystals. The composite film achieves a significant photoluminescence enhancement by 27 times under UV light. In addition, when used as a scintillator material, the passivated CsPbBr3/PP composite film has a enhanced significant light response to X-ray, and the X-ray imaging ability of the metal spring in the capsule is preliminarily realized. Moreover, this post-treatment passivation strategy is easy to apply and expected to be applied to the performance improvement of other perovskite nanocrystals/polymer composites. Overall, this approach has the potential to design a new generation of perovskite nanocrystals/polymer-based scintillator materials.