Synthesis and application of non-agglomerated ITO nanocrystals via pyrolysis of indium-tin stearate without using additional organic solvents

Indium-tin stearate precursor was successfully synthesized by a direct reaction between metals (indium and tin) and molten stearic acid under a nitrogen atmosphere at 260°C for 3 h for the first time. Nearly, monodisperse ∼7 nm indium tin oxide (ITO) nanocrystals without any agglomeration were efficiently synthesized by pyrolysis of the as-synthesized precursors without using additional organic solvents under different conditions. It was found that both pyrolysis temperature and Sn doping level significantly influenced the particle size and size distribution of the ITO nanocrystals. A lower pyrolysis temperature and a higher Sn doping level resulted in a smaller particle size of the ITO nanocrystals. Addition of 1-octadecene solvent in the pyrolysis reaction could lead to a narrow particle size distribution of the ITO nanocrystals. In addition, all the as-synthesized ITO nanocrystals could be dispersed homogeneously in non-polar solvents such as n-hexane and chloroform without using surfactants forming optically clear solutions, which were used to prepare ITO/PVB nanocomposite film as interlayer for making laminated glass in solar control glazing.