PEDOT:PSS-Based Disposable Humidity Sensor for Skin Moisture Monitoring

This letter presents a flexible and disposable humidity sensor based on Poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS). The sensing layer is developed by drop casting PEDOT:PSS on screen printed graphene-carbon-ink-based interdigitated electrodes (IDEs) on paper substrate. The humidity sensing properties are investigated in a wide humidity range (25%RH–90%RH) at room temperature (RT; 27 °C ± 2 °C). The sensor exhibits substantial % response (118.5% at 90%RH) in the considered range with response/recovery time as 70/30 s. The applicability of the sensor has been demonstrated for skin moisture/humidity monitoring under normal and moist conditions. A read-out circuit is designed for demonstrating the real-time monitoring of skin moisture level. The obtained results indicate the suitability of the developed sensor for skin moisture monitoring, environmental humidity monitoring, and noncontact switching in areas such as healthcare and agriculture.