Abstract:
Precursor gel for preparation of nanocrystalline BaSnO3
powder was synthesised by aqueous sol-gel method
using Ba(OH)2
· 8 H2O and Na2
SnO3
· 3 H2O as raw materials. Thermogravimetric and differential scanning
calorimetric analyses of the raw materials, precursor gel and a mechanical mixture of raw materials were
carried out to understand the mechanisms involved in the formation of the single phase BaSnO3
. Based on the
thermal analysis, the precursor gel was calcined at 400, 800 and 1400 °C for 4 h to obtain pure phase BaSnO3
powder. X-ray diffraction pattern of the powder calcined at 1400 °C was refined for atomic coordinate, lattice
parameter (a = 4.1117(2) Å) and occupancies using Rietveld refinement analysis. The average crystallite size
calculated from the Scherrer formula is ∼35 nm. Transmission electron micrograph of the powders confirmed
that particle sizes are in range of 20–40 nm. The phase purity of the powder calcined at 1400 °C was further
examined by Fourier transform infrared spectroscopy. Optical properties of the BaSnO3
powder were studied
by UV-visible absorption and photoluminescence (PL) spectra. The band gap energy (3.09 eV) obtained from
the Tauc plot confirmed the semiconductor nature of the powder. The CIE coordinate corresponding to PL
spectrum exhibited an intense emission in the visible region.
