Synthesis, luminescent and thermometric properties of the Tb3+ doped Gd2TeO6 phosphor

Gadolinium tellurate phosphor Gd2TeO6 pure and Tb3+ doped were successfully synthesized by solid-state reaction. The crystal structure and photoluminescence properties were characterized by X-ray powder diffraction (XRD) and fluorescence spectroscopy. The influence of Tb3+ concentration on the behaviour of the relative emission intensity and chromaticity coordinates were systematically investigated as a function of energy excitation and temperature. From the Tb3+ emission spectra the CIE (x,y) values and G/B = I(5D4 → 7F5)/I(5D4 → 7F6) ratio were calculated. While the G/B ratio is found temperature independent for all samples, the CIE runs from reddish to greenish region. The thermometric properties are also determined and a good relative thermal sensitivity Sr value 0.98%K-1 was obtained. The investigation results show that these phosphors could be potentially interesting for use in white light-emitting devices as well as noncontact temperature sensors.