  In this paper, the effects of changes in Sol concentration on the structural
and optical properties of SnO2 Nanoparticles are studied through the Sol-Gel
method. SnO2 Nanoparticles are produced from different SnO2 solution
concentrations (0.1, 0.3 and 0.5 mol/L) at room temperature. X-ray diffraction
(XRD) and scanning electron microscopy (SEM) analysis is used to investigate
the effects of changes in Sol concentration on the crystalline and surface
morphology of Nanoparticles. The XRD pattern shows that the particles are in
the standard tetragonal phase of SnO2. The crystallites size are 11.7nm,
18.8nm, and 74.8nm, for 0.1 M, 0.3M and 0.5 M of concentration respectively.
The average size of SnO2 particles decreases by a reduction in the Sol
concentration. The band gap value is 4.07ev, 4.28ev and 4.36ev for 0.1M, 0.3M
and 0.5M of concentration respectively. The UV-visible analysis shows that
decreasing the Sol concentration will cause the absorption edge shift to the
shorter wavelengths, because decreasing the Sol concentration will reduce the
Nanoparticles size, and smaller Nanoparticles size absorb shorter wavelengths
better and also increase the band gap.
