Synthesis of CsPbBr3 decorated ZIF-8 nanocomposite for enhanced photocatalytic performance

Abstract

CsPbBr₃ (CPB) perovskite nanocrystals (NCs) have attracted considerable interest due to their outstanding charge carrier mobility, long diffusion lengths, and efficient visible light absorption, making them ideal candidates for photocatalysis, light-emitting diodes (LEDs), solar cells, and photodetectors. However, their practical applications are limited by poor environmental stability. To address this challenge, we employ a zeolitic imidazolate framework (ZIF), specifically ZIF-8, as a stabilizing matrix for its exceptional thermal and chemical stability, high surface area, and versatile synthesis routes. The CPB/ZIF-8 nanocomposite was synthesized by integrating hot-injection-produced CPB NCs with ZIF-8 using an optimized mixing approach, ensuring a uniform NCs distribution. Electron microscopy (EM) analysis confirmed the well-controlled and uniform distribution of the NCs on the surface of the ZIF-8. Moreover, the Fourier-transform infrared spectroscopy (FTIR) revealed ligand exchange, where the imidazole linkers of the ZIF-8 structure replace the NCs ligands. The process advances almost epitaxial attachment of the latter, thus promoting effective charge interactions in the integration process. Indeed, we observe that upon formation of the composite, there is a 92% quenching in the photoluminescence (PL) of the NCs. This finding further indicates efficient charge separation and reduced electron–hole recombination. To gain deeper insight into the charge transfer mechanisms, we conducted electron paramagnetic resonance (EPR) measurements to compare the radical generation capabilities of CPB and ZIF with those of the CPB/ZIF composite. The composite exhibited superior radical generation capabilities, particularly hydroxyl radicals (˙OH), indicating enhanced charge transfer. These findings suggest that the composite is a highly promising candidate for photocatalysis. Building on these findings, we explored the photocatalytic abilities of the composite through dye degradation experiments, using methyl orange (MO) and bromocresol green (BCG) as model dyes. The CPB/ZIF nanocomposite demonstrated significantly enhanced photocatalytic performance compared to pristine ZIF and CPB NCs. Specifically, its degradation rates were 1.48× and 1.75× higher for MO and BCG, respectively, than those of CPB NCs. This improvement highlights the effective interaction between CPB NCs and ZIF, establishing the CPB/ZIF nanocomposite as a promising material for photocatalysis and optoelectronic applications.