▎ 摘　　要

Bilayer thin film humidity sensors based on graphene and polystyrene sulfonic sodium (NaPSS) has been prepared, and their electrical and humidity sensing properties have been investigated in the range of relative humidity (11-95% RH). The results showed that the bilayer thin film humidity sensors exhibited lower impedance at very low humidity (11% RH), which was suitable for detection of low humidity. The graphene/NaPSS bilayer thin film sensors show over three orders of change and smaller hysteresis in the impedance verse the relative humidity variation from 11 to 95% RH. The humidity sensitive mechanism in the graphene/NaPSS bilayer thin film sensors is discussed.