Effect of solvent on crystallographic, morphological and optical properties of SnO2 nanoparticles

SnO2 nanoparticles were synthesized by co-precipitation method using different solvent media (Methanol:Water: 100:0; 80:20; 60:40; and 0:100). X-ray diffraction (XRD) patterns showed highly crystalline single phase tetragonal structure, with predominant (110) plane in all samples. High resolution transmission electron microscopy (HR-TEM) images indicated the decrease in the particle size of nanoparticles with an increase in methanol to water ratio. The Raman shifts revealed that with increase in the water content as solvent, the intensity of A(1g) and B-2g Raman modes decreases, indicating the distortion in crystal structure, which is in agreement with HR-TEM results. Fourier transform infrared (FTIR) spectroscopy spectra confirmed Sn-O stretching mode and also complemented Raman spectroscopy results. The optical band gap of SnO2 decreased from 3.66 eV to 3.54 eV with a decrease in methanol to water solvent ratio, thereby implying that the optical properties of these materials are affected by the synthesis medium, used during synthesis. (C) 2016 Elsevier Ltd. All rights reserved.