Fabrication of single crystalline WO₃ nano-belts based photoelectric gas sensor for detection of high concentration ethanol gas at room temperature

WO3 gas sensing material was synthesized by hydrothermal process, exhibiting a belt-like surface morphology. By comparing and analysing the UV-vis absorption spectra, it is shown that the band gap of WO3 nano-belts (NBs) is 0.56 eV larger than that of WO3 nano-particles (NPs). Surface photo-voltage (SPV) spectra and SPV phase spectra indicate that the direction of the surface built-in electric field is from the surface to the bulk of WO3 NBs and the surface band bending is upwards. WO3 NBs based photoelectric gas sensor was assembled for detecting high concentration of C2H5OH at room temperature. The results demonstrate that the WO3 NBs based photoelectric sensor exhibits higher sensitivity and resolution to high concentration (1000 ppm-20000 ppm) of ethanol at room temperature than WO3 NPs based photoelectric sensor. WO3 NBs are promising candidates of gas sensing material used to fabricate photoelectric gas sensor for high concentration C2H5OH detection operating at room temperature. (C) 2020 Elsevier B.V. All rights reserved.