Investigation of spectroscopic properties of Sm-Eu codoped phosphate glasses

Abstract

Phosphate glasses with chemical compositions of 74.5NaH2PO4–20ZnO–5Li2O–0.5Sm2O3 and 74NaH2PO4–20ZnO–5Li2O–0.5Sm2O3–0.5Eu2O3 were synthetized by melt quenching method. We investigated the influence of Sm3+/Eu3+ doping on the optical properties of phosphate glasses. X-ray Diffraction indicates that the samples have an amorphous structure. DSC measurements show a good thermal stability of phosphate glasses. Using the absorption spectra, Judd–Ofelt analysis was applied to absorption bands of Sm3+ (4f5) to carry out the three phenomenological parameters of Judd–Ofelt (JO). According to the obtained values of Ω2, Ω4 and Ω6, some radiative properties were theoretically determined. We report both the photoluminescence (PL) and the PL lifetime measurements of a prominent emission transition 4G5/2→6H5/2 (604nm) of Sm3+ both in absence and in presence of Eu3+. It is shown that Eu3+ ions act as sensitizers for Sm3+ ions and contribute largely to the improvement of the radiative properties of phosphate glasses. An improvement of the PL lifetime value after adding Eu3+ ions (4.58ms) is reported. The predicted lifetime (τrad) calculated by Judd–Ofelt theory and the experimental lifetime (τmeas) for the prepared phosphate glasses were compared with those of other works. Photoluminescence (PL) intensity of 4G5/2→6H5/2 (604nm), 4G5/2→6H7/2 (567nm), 4G5/2→6H9/2 (650nm) and 4G5/2→6H11/2 (706nm) and the quantum efficiency (η) for the excited 4G5/2 level were enhanced after adding Eu3+. The radiative properties obtained for (Sm, Eu) codoped phosphate glasses suggest that the present material can be a potential candidate for the development of color display devices.