Fabrication of polypyrrole/graphene oxide hybrid nanocomposite for ultrasensitive humidity sensing with unprecedented sensitivity

An ultrasensitive humidity sensor using polypyrrole/graphene oxide (PPy/GO) nanocomposite as sensing film was fabricated by chemical oxidative polymerization method. The nanostructural characteristics of the PPy/GO sample were examined by a series of characterization techniques. The capacitance and complex impedance spectra of the PPy/GO film sensor at different relative humidity and applied frequencies were measured at room temperature of 20 °C. An unprecedented response, outstanding repeatability and ultralow hysteresis were demonstrated by the PPy/GO film sensor. Furthermore, the equivalent circuits and Bode plots for the PPy/GO film sensor were employed to discover its humidity sensing mechanism. This work highlights that the PPy/GO film based sensor can achieve the ultrasensitive humidity detection over a wide range of 11–97% due to its hydrophilic properties and swell effect of polypyrrole.