Photoluminescence from terbium doped silica–titania prepared by a sol–gel method

Terbium doped (0.5 at.%) TiO2–SiO2 (30%/70%) was prepared by a sol–gel method. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the powder calcined at two different temperatures. At a low temperature of 550 °C an amorphous phase was obtained, but at a higher temperature of 1000 °C, the anatase TiO2 phase was crystallized in the amorphous SiO2 phase. Green photoluminescence from ultraviolet excitation was detected after heating to either temperature, but the amorphous sample heated to 550 °C exhibited a higher intensity. X-ray diffraction and photoluminescence excitation data are discussed to explain these observations.