Structure and composition-dependent optical properties of (PbxSr1–x)TiO3 (x=0.4, 0.6) nanotube arrays

Lead strontium titanate (PbxSr1–x)TiO3 (x=0.4, 0.6) nanotubes were synthesized by sol-gel template method via spin coating. The structures and morphology of the as-prepared samples were characterized by X-ray diffractometry, scanning electron microscopy and transmission electron microscopy. X-ray photoelectron spectroscopy was used to determine the chemical composition of the sample and the valence state of elements. Raman spectroscopy of the as-prepared (PbxSr1–x)TiO3 (x=0.4, 0.6) nanotubes at room temperature was also investigated. The results indicate that as-prepared (PbxSr1–x)TiO3 (x=0.4, 0.6) nanotubes are perfectly crystallized and there is a trend of structure change from PST40 to PST60. A weak peak at 508 cm−1 assigned to E(3TO) mode can be seen in the Raman spectrum of (Pb0.6Sr0.4)TiO3 sample. Photoluminescence spectra of samples at room temperature reveal three intense emission bands centered at 356, 400 nm for (Pb0.4Sr0.6)TiO3 and 413, 433, 451 nm for (Pb0.6Sr0.4)TiO3 nanotubes, respectively. The peak positions of the emission band have a significant blue shift as Pb content increases.