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 degrees 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.