A facile and one step synthesis of W doped SnO₂ nanopowders with enhanced humidity sensing performance

High sensitivity and fast response humidity sensor based W doped SnO₂ nanopowders were prepared by hydrothermal method. The structural, morphological and optical properties of the films nanopowders were analysed by using powder X-ray diffraction (XRD), Transmission electron microscope (TEM), UV–Vis transmission spectra, Fourier transform infra-red spectra and photoluminescence spectra analysis. XRD results suggest that both pure and W doped samples had a tetragonal rutile type structure and the results are in good agreement with the standard JCPDS data (card no# 41-1445). The uniform distribution and well crystalline elongated spherical shaped rod like morphology was observed by TEM micrographs. UV and PL results confirmed the optical property of pristine SnO₂ was significantly improved by W doping. Humidity sensor set up was fabricated and tested for relative humidity (RH) variation from 10 to 90%. The 10 wt% doped W sample showed high sensitivity fast response and recovery time as compared to other samples. The humidity sensing results showed that W–SnO₂ can be used as active nanostructures for humidity sensors. The humidity sensing mechanism was also discussed in detail.