In2O3 and tin-doped In2O3 nanocrystals prepared by glass crystallization

Glasses in the system Na2O/B2O3/Al2O3/In2O3/(SnO2) were melted and subsequently tempered in the range from 540 to 700 °C. This led to the crystallization of In2O3, besides also NaBO2 and Na2Al2B2O7 were formed. The crystallite sizes were in the range from 12 to 34 nm, depending on the temperature of thermal treatment, as calculated from XRD-line broadening. Crystal sizes determined by TEM were in the same range. Particle size histograms show a narrow crystal size distribution. After crystallization, the glass matrices and the non indium-containing crystalline phases were dissolved in diluted acetic acid. Spectra of the obtained suspensions containing tin-doped In2O3 nanocrystals exhibited a sharp UV-cut off, high transmission in the visible range and strongly decreasing transmission at wavelengths >1000 nm.