Microstructures and optical, electrical and photocatalytic properties of sonochemically and hydrothermally synthesized SnO2 nanoparticles

Rutile SnO2 nanocrystals have been synthesized by sonochemical and hydrothermal methods. Sonochemically obtained crystals possess compressive strain and hydrothermally prepared crystals have tensile strain. Polyethylene glycol 20,000 provides spherical shape to the particles in hydrothermal synthesis but fails to give finite shape to the particles in sonochemical synthesis. The direct band gap of sonochemically prepared SnO2 is much larger than that of hydrothermally obtained one. However, the indirect band gaps of the oxides do not differ significantly. The photoluminescence spectra of both the oxides are similar. The solid state complex impedance spectra of sonochemically and hydrothermally synthesized SnO2 are different; while the former displays a depressed semicircular arc the latter shows a linear relationship between Z '' and Z'. Hydrothermally prepared SnO2 is more photocatalytic than sonochemically obtained SnO2. However, the two oxides do not differ in their bactericidal activities. (c) 2012 Elsevier B.V. All rights reserved.