Fabrication and Optimization of CdS/MoS2 Heterostructure Thin Films for Visible-Light Photocatalytic Applications

CdS/MoS2 heterostructure thin films were fabricated on glass substrates using the chemical bath deposition method. To optimize crystalline quality and enhance the light absorption of the CdS/MoS2 heterostructure thin films, aiming to improve the visible-light photocatalytic activity, we controlled the thickness of the CdS thin film deposited on the MoS2 thin film by changing the deposition time. The results revealed that the optimal CM15 heterostructure thin film (deposition time of 15 min, CdS thickness ~186 nm on a 28 nm MoS2 thin film) exhibited excellent light absorption in the range of 400 to 700 nm. Furthermore, the CM15 sample demonstrated a remarkable degradation efficiency of 95.46% and a degradation rate constant (kapp) of 0.020307 min–1 for rhodamine 6G (R6G) dye after 150 min of visible-light irradiation. This high performance can be ascribed to: (1) the improved crystalline quality of the CdS thin film grown on MoS2 thin film, which reduced defects and minimized charge carrier trapping; (2) the band alignment at the CdS/MoS2 interface, facilitating efficient charge carrier separation.