Ultra-sensitive and responsive capacitive humidity sensor based on graphene oxide

Humidity sensors have attracted extensive attentions due to their various applications in environment monitoring, health care and internet of things. Graphene oxide has recently been exploited as a humidity sensing material because of its good hydrophilicity and excellent sensitivity. Here we report an ultra-sensitive and responsive capacitive humidity sensor using graphene oxide as sensing material. A capacitance change of ten times is observed when the relative humidity changes from 50% to 90%. The response and recovery time of the sensor are measured to be 0.066 and 0.154 s, respectively, which are several orders of magnitude shorter than conventional humidity sensors. Furthermore, its responses to flow rate, temperature and other vapors are also characterized.