Synthesis of nanosized BaSnO3 powders from metal isopropoxides

Nanocrystalline BaSnO₃ with a primary particle size of 40–60 nm was prepared through hydrolysis of a barium tin isopropoxide and following crystallization. The thermal decomposition, the crystallization and the microstructure of the obtained powders were investigated with the help of TG-DTA, IR, XRD, HRSEM and HRTEM. The organic rest groups in the as-prepared powder decompose thermally at 350°C, which is accompanied by the building of BaCO₃ that disappear again at 600°C. The crystallization of BaSnO₃ takes place at 500–600°C. Single-phase BaSnO₃ powders have been obtained at a temperature as low as 600°C. The amorphous as-prepared powder shows a cluster structure. Nucleation of BaSnO₃ beginning at 350°C was observed under HRTEM, and the spherical nano-particles of BaSnO₃ calcined at 760°C crystallize well and are strongly aggregated. The presented results indicate a heterogeneous nucleation and growth mechanism by the formation of BaSnO₃.