Effects of glycerin volume ratios and annealing temperature on the characteristics of nanocrystalline tin dioxide thin films

Nanocrystalline (NC) tin dioxide thin films have been synthesized via sol–gel spin coating method. The sol solution produces thin films that suffer from cracking at room temperature and at different annealing temperatures. Hence, the determination of the smallest value of glycerin is necessary to solve the cracking problem. Glycerin was added to the sol solutions with different volume ratios (0:1, 1:12, 1:8) at low temperature to enhance film porosity and to eliminate cracks. Temperature affects on the characteristics of NC SnO₂ thin films, particularly particle size where the crystallization of SnO₂ thin films obtained after annealing at 400 °C is a NC tetragonal rutile structure. With the increase of annealing temperature the crystallinity has enhanced, the crystallite size increased, and it was observed that both of the intensity and a blue shift of the A_1g phonon peak increased at constant volume ratio of glycerin. Hence, these results indicated that (1:12) of glycerin volume ratio to sol solution volume ratio represents the optimum value for the fabrication of SnO₂ thin films without cracks.