Controlling the Particle Size of Calcined Sn0₂ Nanocrystals

Smaller SnO₂ nanocrystals are prepared by a novel method. In this method, hydrous tin oxide nanoparticles are precipitated by dropping ammonium hydroxide into tin salt solution under sonication. Further calcination is conducted after the hydrous tin oxide nanoparticles are adsorbed onto the surface of SrCO₃ nanoparticles. Calcination at 600°C yields SnO₂ particles with an average particle size of 3.5 nm. This compares with 5.9 nm for the sample prepared by the conventional method. The band gap of SnO₂ nanocrystals increases from 3.65 eV with a particle size 5.9 nm to 3.97 eV with a particle size 3.5 nm.