Enhanced linear and nonlinear optical response in CuS/Ag2S nanocomposites

Nonlinear optical (NLO) materials are crucial candidates for growing optical technologies as they can broaden the range of wavelengths achieved by common laser sources. However, the essential requirements for a real-life NLO material are precise. Here, we reported a simple chemical method used to prepare pure copper sulfide (CuS) and its composite with silver sulfide (Ag2S) at room temperature by changing the concentration of Ag source. Their structural properties, UV-Vis absorption and photoluminescence properties were studied thoroughly, and the optical limiting ability is investigated by employing open aperture Z-scan technique with 532 nm laser pulses (10 ns, 10 Hz). We optimized the wt% of AgNO3 content for which the composite CuS/Ag2S(6) shows the highest third-order nonlinear response. These results suggest that the composite sample can be used as a promising material to design high-quality optical limiters by varying the concentration of constituent nanoparticles. Additionally, the photocatalytic experiment is performed for pure CuS and CuS/Ag2S(9) composite, using their strong visible absorption properties.