Highly proton conducting MoS2/graphene oxide nanocomposite based chemoresistive humidity sensor

Abstract

This paper reports the development of MoS₂/GO nanocomposite based sensing layers for resistive humidity sensors. The MoS₂ nanoflakes were synthesized through liquid exfoliation and GO was synthesized using modified Hummers method. The nanocomposite was drop-cast on a Si/SiO₂ substrate containing aluminium electrodes to fabricate the sensor device. The best performance was shown by the 1 : 4 (MoS₂/GO) composite. Various characterization techniques like Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), and Fourier Transform Infrared Spectroscopy (FTIR) were used to verify the composite formation. The sensing response was found to lie between 55 times at 35% RH and 1600 times at 85% RH. Such a high response is believed to be because of proton conductivity in the water layer for both MoS₂ and GO. The sensor performance was found to be repeatable even after three months of the first measurement with quick response and recovery. Thus the authors believe that the excellent sensitivity coupled with low cost synthesis and resistive sensing will make their work useful to develop new generation humidity sensors.