Phase dependent selectivity shifting behavior of Cd2SnO4 nanoparticles based gas sensor towards volatile organic compounds (VOC) at low operating temperature

Abstract

Orthorhombic as well as cubic phase Cd2SnO4 nanoparticles have been synthesized by one step solution combustion method. X-ray diffraction result confirms the high crystallinity and phase purity of the synthesized nanoparticles. TEM images reveals, the synthesized nanoparticles have spherical morphology with an average diameter of 30 nm for both phases. EDS spectra affirms the stoichiometric Cd2SnO4 nanoparticles. Further, the gas sensors were fabricated using thick film, deposited on alumina substrate by doctor blade method, of the synthesized nanoparticles. In order to determine the sensitivity and detection limit, 1 μL of diluted VOCs was inserted into the sensing chamber at atmospheric pressure and the variation of resistance with respect to time has been monitored. The sensing result suggests that cubic and orthorhombic phase nanoparticles are highly sensitive (S ̴ 65%) and selective towards isopropanol and methanol vapors, respectively, at 170 °C. The phase dependent selectivity and high sensitivity of the Cd2SnO4 spherical nanoparticles based sensors at low operating temperature towards diluted isopropanol and methanol at atmospheric pressure are the important findings of the present work.