Zinc-methacrylate passivation enables an efficient and stable perovskite nanocrystal-polymer composite for LED applications

Abstract

Lead halide perovskite nanocrystals (PNCs) are emerging as promising light-conversion materials for light-emitting diode (LED) display applications. However, the practical application of PNCs is hindered by their labile surface and dynamic ionic ligand binding. Here, we report a post-synthetic surface passivation strategy to stabilize the CsPbBr₃ PNCs by zinc methacrylate (ZnMA) and trioctylphosphine oxide (TOPO) co-passivation. Surface analyses reveal that the ZnMA stabilizes the PNCs by replacing the surface ammonium ligands, and TOPO further coordinates to the ZnMA to provide a high photoluminescence quantum yield (PLQY) of the PNCs. Moreover, the ZnMA capping on the PNC surface could participate in the polymerization of MMA to form a crosslinked polymer shell around the PNCs. The resultant PNCs–PMMA film presents a PLQY of 74% and maintains a constant PL intensity under continuous UV irradiation in air, while the PNCs–PMMA film made of classical PNCs quickly degrades. The prepared PNCs–PMMA film was tested as the light down-conversion layer in LED backlighting and presented photostability comparable to classical CdSe/ZnS NCs–PMMA under continuous illumination. This surface passivation strategy avoids the use of ionic ligands for the surface passivation of PNCs in polymer matrices, and we expect related surface chemistry to promote the performance enhancement of diverse PNCs–polymer composites for LEDs and other optoelectronic applications.