Synthesis, characterization and gas sensing studies of SnO2 nanoparticles
This project has been carried out with the aim of exploring the gas sensing behaviour of SnO2 nanoparticles and to find out the enhancement of its sensing characteristics with Ni doping. Undoped, 1% Ni doped, 2% Ni doped and 5% Ni doped SnO2 nanoparticles were synthesised by polyol method. The samples were annealed at 700°C for 5 hours in ambient atmosphere. The XRD (X-ray diffraction) patterns of the samples had a good agreement with the tetragonal structure of SnO2. The shifting and broadening of the diffraction peaks indicated the influences of Ni on the lattices of SnO2 nanoparticles. Using UV-Visible spectrometer, optical properties like absorbance and transmittance were analysed for the SnO2 nanoparticles. The optical bandgaps estimated by Tauc plot were 3.47 eV, 3.53 eV, 3.95 eV and 3.65 eV for undoped, 1%, 2% and 5% Ni doped SnO2 respectively. Gas sensors were fabricated by dropcasting the nanoparticles on inter-digitated electrodes (IDE) on glass substrate. Gas sensing studies of these sensors for different gases (SO2, H2S, NO2, etc) were carried out in a static gas sensing set up at room temperature. The studies revealed that sensor response for SO2, H2S and NO2 was strongly influenced by Ni doping. Among all the sensors, 2% Ni doped SnO2 showed highest sensitivity for SO2, H2S and NO2.