Self-powered, ultrasensitive, room temperature humidity sensors using SnS nanofilms.

Humidity monitoring has become extremely vital in various technological fields such as environment control, biomedical engineering, and so on. Therefore, a substantial interest lies in the development of fast and highly sensitive devices with high figures of merit. Self-powered and ultrasensitive humidity sensors based on SnS nanofilms of different film thicknesses have been demonstrated in this work. The sensing behavior has been investigated in the relative humidity (RH) range of 2-99%. The observed results reveal a remarkable response and ultrafast detection even with zero applied bias (self-powered mode), with response and recovery times of ~ 10 and ~ 0.7 s, respectively. The self-powered behavior has been attributed to the inhomogeneities and the asymmetry in the contact electrodes. The highest sensitivity of ~ 5.64 × 10% can be achieved at an applied bias of 5 V. This approach of fabricating such highly responsive, self-powered and ultrafast sensors with simple device architectures will be useful for designing futuristic sensing devices.