Solvent-Directed Femtosecond Laser Ablation: Tuning Phase and Defect Engineering in Hybrid CdPS 3 /CdS Nanostructures

Abstract

The limited visible-light absorption of wide-bandgap van der Waals crystals fundamentally restricts their utility in solar energy conversion. Here, we report the application of a surfactant-free, solvent-directed laser synthesis strategy to engineer the phase and optoelectronic properties of Cadmium Phosphorus Trisulfde (CdPS3). By exploiting the non-equilibrium thermodynamics of femtosecond pulsed laser ablation in liquid (fs-PLAL), we demonstrate a tunable transition from the stoichiometric ternary phase to a highly active binary-rich heterostructure. While ablation in water preserves the monoclinic CdPS3 lattice, the reducing environment of isopropanol triggers the formation of CdS quantum dots and metallic cadmium defect sites. This solvent-induced phase engineering transforms the ultraviolet-active host into a robust visible-light photocatalyst. The resulting hybrid CdPS3/CdS nanocolloids exhibit superior charge separation efciency, driven by Schottky-like metalsemiconductor junctions, achieving ∼ 90% degradation of Methylene Blue under 532 nm irradiation within 30 minutes. This work establishes fs-PLAL as a scalable defect-engineering tool for complex ternary layered materials, offering a new design of high-performance metal-thiophosphate-based photocatalysts.