Wide-Range, Fast-Responsive Humidity Sensor Based on In₂Se₃/PEDOT:PSS Nanocomposite

Due to their exceptional properties, two-dimensional (2D) materials have received remarkable interest recently in environmental sensing devices. In the presented study, a humidity sensor was developed, featuring a nanocomposite of indium(III) selenide (In 2 Se 3 ) nanoflakes (for high responsivity to low humidity levels) and poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) polymer (for high responsivity to higher humidity levels). The developed sensor exhibited a robust and repeatable response to a wide operating range of humidity levels. By combining these two sensing elements in a nanocomposite configuration, we fabricated a single humidity sensing device, demonstrating the capability to detect a broad range of relative humidity levels with exceptional sensitivity. Two-dimensional In 2 Se 3 nanoflakes were synthesized through the aqueous exfoliation of pristine In 2 Se 3 . PEDOT:PSS was utilized to disperse these 2D In 2 Se 3 nanoflakes by using a well-established sol–gel process. The obtained results showed high performance of the fabricated sensor including a capacitive sensitivity of 0.177 μF/%RH and response/recovery time of 1.2 s/1.9 s over a wide operating range of 5–95%RH. We used our sensor for the practical applications of noncontact skin humidity detection, real-time environmental monitoring, and breathing tests.