Fast response humidity sensor based on chitosan/graphene oxide/tin dioxide composite.

In this paper, Chitosan(CS)/graphene oxide(GO)/SnO 2 composite is proposed as the sensing material of an impedance-type humidity sensor. The composite was synthesized via a facile solution mixing method. And it was formed by adding CS and SnO 2 to GO aqueous solution. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectrometer (FT-IR) were executed to characterize the structure and morphology of the composite. At room temperature, the CS/GO/SnO 2 composite shows more favorable humidity-sensing properties compared with the CS, CS/GO, and CS/SnO 2 material. The resulted sensor exhibits high response (72683%), high sensitivity (402.5 kΩ/%RH), rapid response and recovery time (8 s/8 s). Moreover, small humidity hysteresis value (<7%) under maximum impedance difference, good repeatability and long-term stability are demonstrated. Therefore, the CS/GO/SnO 2 composite is a promising candidate for humidity sensing. • Impedance humidity sensor based on chitosan/graphene oxide/SnO 2 composite is prepared. • Graphene oxide and SnO 2 can obviously improve the response of chitosan. • Chitosan/graphene oxide/SnO 2 composite exhibits a high response, rapid response and recovery time and good repeatability. • Chitosan/graphene oxide/SnO 2 composite is easily recycled. [ABSTRACT FROM AUTHOR]