Pb−S Anchored CsPbBr3 Nanorods with Preserved 1D Morphology and Enhanced Stability in Water for Visible-Light Photocatalysis

Abstract

Achieving water stability in lead halide perovskites while preserving accessible surfaces for photocatalysis remains a major challenge due to rapid ligand desorption and structural degradation in polar media. Here, we report morphology-retained, water-stable CsPbBr3 nanorods (CPB NRs) achieved via Pb−S surface anchoring with (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide (MUTAB). CsPbBr3 nanorods synthesized via cation exchange from Cs2CuBr4 templates preserve their one-dimensional morphology, crystal structure, and optical properties after transfer to water. Strong thiol−Pb interactions, together with amphiphilic ligand protection, effectively suppress water-induced degradation and enable stable aqueous dispersions for extended periods. Time-resolved spectroscopy reveals prolonged excited-state lifetimes in the MUTAB-passivated nanorods compared with similarly passivated nanocubes, suggesting reduced nonradiative relaxation and improved surface passivation. The water-stable nanorods further exhibit enhanced visible-light-driven oxidation of 3,3′,5,5′-tetramethylbenzidine in aqueous media. Microscopy and spectroscopic analyses suggest that the retained anisotropic nanorod morphology contributes to the improved photocatalytic performance. This work demonstrates that combining morphology engineering with strong Pb−S interfacial binding provides an effective strategy for developing water-tolerant perovskite photocatalysts for aqueous-phase applications.