Blue-shift and intensity enhancement of photoluminescence in lead-zirconate-titanate-doped silica nanocomposites.

Transparent PbZr(0.52)Ti(0.48)O(3) (PZT)-doped silica nanocomposites were fabricated via a modified sol-gel process. The nanocomposites were annealed at different temperatures between 740 and 800 °C in order to produce PZT crystallites with different particle sizes. X-ray diffraction analysis indicated that the embedded PZT nanoparticles were crystallized with a perovskite structure while the SiO(2) matrix was still in an amorphous state. Transmission electron microscopy confirmed that the PZT particles were of nanosize with perovskite structure and dispersed within the SiO(2) matrix. Photoluminescence spectra of the samples were measured between 10 and 290 K. The pure silica matrix showed an emission band at 3.20 eV and a weak emission band at 2.65 eV. They were noticeably suppressed in the PZT/SiO(2) nanocomposites. An additional emission band at ∼2.30 eV, due to transition within the PZT crystallites, was identified. This emission band showed a large blue-shift with decreasing PZT crystallite size and a substantially enhanced intensity as compared with that of bulk PZT ceramics. Our studies demonstrate the typical quantum size effect of ferroelectric-doped nanocomposites and the large influence of the silica matrix on the PL intensity of the embedded PZT particles.