Down-conversion luminescence and optical thermometric performance of Tb3+/Eu3+ doped phosphate glass

Tb3+/Eu3+ co-doped phosphate glasses were successfully synthesized by conventional melt-quenching method. The transmittance spectra and down-conversion optical properties were investigated by using UV-visible spectrophotometer and fluorescence spectrometer. All the glass samples show light transmittance of about 90%, and the color of luminescence could be tuned by altering the concentrations of Eu3+ ions. The decrease of the Tb3+ emission decay time in presence of Eu3+ ascertained that Tb3+ → Eu3+ non-radiative energy transfer happened. The research of energy transfer between Tb3+ and Eu3+ based on the Inokuti-Hirayama model revealed that an electric dipole-dipole interaction might be the predominant mechanism. Under the excitation of 378 nm, the temperature dependent luminescence of Tb3+/Eu3+ co-doped glasses was carefully investigated in the temperature range of 303-753 K. Impressively, a high absolute sensitivity Sa of 1.0% K−1 and a high relative sensitivity Sr of 11.67 × 10−3 K−1 at 753 K could be obtained. It is expected that the investigated glasses might be a promising candidate for solid-state lighting and optical thermometry.