Optically transparent nanocomposites of strontium-barium-niobate (SBN) and silica were fabricated via a novel sol-gel method. The nanocomposites were annealed in temperatures of 600-800 °C to yield the nanometer-sized tetragonal tungsten-bronze phase of SBN crystallites. Photoluminescence studies at temperatures from 10 K to room temperature were performed. The undoped silica matrix showed a strong emission band at 3.2 eV and a weak emission band at 2.65 eV. They were noticeably suppressed in our SBN/SiO2 nanocomposites. Extra sharp peaks on top of the 3.2 eV band were seen. An additional emission band at 2.3 eV due to transitions within the NbO6 complex of SBN crystallites was also observed. This emission band showed a large blueshift with decreasing SBN crystallite size. This demonstrates that the photoluminescence spectra of ferroelectric-doped silica nanocomposites have a strong dependence on crystallite size.
Scopus Subject Areas
- Physics and Astronomy (miscellaneous)