Grain Size Control of Calcined SnO_2 Nanocrystals: Raman Study and Room Temperature Ethanol Sensing Properties

摘要

SnO_2 nanoparticles were prepared via a sol-gel method by heating the mixture of hydrous SnO_2 nanoparticles and SiO_2 nanospheres at 600℃. The average particle size of the obtained SnO_2 nanoparticles is 3.3 nm, smaller than that of the SnO_2 nanoparticles (～6.4 nm) prepared by calcining the pure hydrous SnO_2 at 600℃. The restricting effect of SiO_2 on the growth of SnO_2 nanoparticles was discussed by Raman spectra. A blue shift of A_(1g) and B_(2g) Raman modes in SnO_2/SiO_2 composite was observed, and it was considered to be a compressive stress effect. The obtained SnO_2 nanoparticles with a size of about 3.3 nm exhibit enhanced ethanol response at room temperature, and their recovery time is much shorter than that of the SnO_2 nanocrystals with a size of about 6.4 nm.