Eu3+ photoluminescence enhancement due to thermal energy transfer in Eu2O3-doped SiO2–B2O3–PbO2 glasses system

In this work, Eu3+-doped lead borosilicate glasses (SiO2–B2O3–PbO2) synthesized by fusion method had their optical properties investigated as a function of temperature. Atomic Force Microscopy images obtained for a glass matrix annealed at 350 and 500 °C show a precipitated crystalline phase with sizes 11 and 21 nm, respectively. Besides, as the temperature increases from 350 to 300 K a strong Eu3+ photoluminescence (PL) enhancement takes place. This anomalous feature is attributed to the thermally activated carrier transfer process from nanocrystals and charged intrinsic defects states to Eu3+ energy levels. In addition, the PL peaks in this temperature range were assigned to the Eu3+ transitions 5D0→7F2, at 612 nm, 5D0→7F1, at 595 nm, and 5D0→7F0, at 585 nm. It was also observed that the 5D0→7F3 and 5D0→7F4 PL bands at 655 and 700 nm, respectively, show a continuous decrease in intensity as the temperature increases.