The size effect of exfoliated MoS₂ based thin film humidity sensor

Layered two-dimensional nanomaterials such as MoS₂ show great potential for sensor application owing to their distinct nature that most atoms are surface atoms. The difficult in mass production of exfoliated MoS₂ hinders its practical application. In this study, we investigate the ultrasound assisted liquid method to efficiently exfoliate MoS₂ into nanosheets and nanoparticles. The dependence of ultrasonic dosing, e.g., ultrasonic time, on the morphology and yield of final products are studied. The exfoliated MoS₂ nanomaterials are fabricated into thin film sensors and examined with humidity gas. The sensors exhibit excellent and quick response toward humidity gas. We find the sensor prepared with longer ultrasonic treatment presents higher response owing to that the longer ultrasonic irradiation exposes more active edge sites.