CuO nanoparticles-decorated femtosecond laser-irradiated WS2-WO3 heterojunctions to realize selective H2S gas sensor

Femtosecond (FS) laser irradiation is an easy and highly effective strategy for enhancing the sensing properties of resistive gas sensors. In this study, we applied this technique to WS2 nanosheets (NSs) to generate WS2-WO3 heterojunctions. Subsequently, they were decorated with CuO nanoparticles (NPs). Different characterization techniques demonstrated the formation of CuO-decorated WS2-WO3 heterojunction NSs with the desired morphology, phase, and chemical composition. Based on H2S gas-sensing studies, while non-irradiated WS2 sensors exhibited poor sensing performance, a combination of FS laser irradiation and CuO decoration led to significant performance improvement for H2S sensing in terms of response and selectivity. Enhanced performance is related to the formation of plenty of WS2-WO3 heterojunctions, oxygen vacancies, and the conversion of CuO to CuS with high metallic conductivity. We believe that the strategy used in this work can pave the way for the realization of low-temperature, sensitive, and selective H2S gas sensors.