Effect of Mg concentration on structural, optical and humidity sensing performance of SnO2 nanoparticles prepared by one step facile route

Pure and magnesium (Mg) doped SnO2 nanoparticles were successfully synthesized by one step facile hydrothermal method. The effect of Mg dopant on structural, morphological, optical and humidity sensing properties of the samples 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. Powder XRD results suggest that SnO2 nanoparticles reveal that polycrystalline structure with tetragonal phase and no structural changes was observed for the Mg dopants. TEM pictures confirm the spherical shape morphology with uniform distribution of nanoparticles. The optical transmittance of samples was measured and the optical band gap Eg values were found in the range of 3.65–3.23 eV, using the Tauc relation. The sensing test reveals that Mg doped SnO2 sensor exhibit excellent humidity sensing performance such as high sensitivity fast response time (32 s) and recovery time (15 s) at room temperature. Moreover, the improved mechanism of Mg doped SnO2 nanosensors were also proposed in this study. The samples were further characterized by photoluminescence and Energy dispersive spectra (EDS) analysis.