Zinc-halide/phenylbutyrate co-passivation of CsPbX₃ nanocrystals toward efficient and robust luminescence

Cesium lead halide perovskite nanocrystals (IPNCs) exhibit excellent optoelectronic properties but are susceptible to degradation in practical environments due to their ionic surface and unstable ligand capping. Here, we propose a post-synthesis surface passivation strategy for CsPbX₃ (X = Br, I) IPNCs by employing combined zinc halide and zinc phenylbutyrate (Zn(PA)₂) as surface ligands. ZnBr₂ fills surface halide vacancies on IPNCs, resulting in high photoluminescence efficiency, whereas Zn(PA)₂ stabilizes IPNCs by substituting surface ammonium ligands. Additionally, the -PA capping endows IPNCs with high solubility in polystyrene (PS), enabling the direct fabrication of highly efficient and uniform IPNCs-PS color conversion films through in situ polymerization of the IPNC-styrene solution. The resulting IPNCs-PS films displayed significantly enhanced stability, retaining excellent PL persistence after 1000 h of photoaging. This novel ligand and modification method presents a promising strategy for improving the efficiency and stability of IPNCs, facilitating their potential applications in display backlight and other optoelectronic applications.