The effects of GeO2 adulterant on the luminescence properties of Tb-doped silicate glasses

Abstract The GeO 2 -doped, Tb 4 O 7 -doped, and GeO 2 and Tb 4 O 7 co-doped silicate glasses were synthesized by high-temperature melting method, and their optical spectra were analyzed. The effects of GeO 2 adulterant on the luminescence properties of Tb-doped silicate glasses were studied with ultraviolet–visible transmission, excitation and emission spectra. The results showed that the ratio of the absorption induced by Tb 3+ ions to that induced by Tb 4+ ions in Tb 4 O 7 -doped silicate glasses was increased by GeO 2 co-dopant. This implies that the Tb 3+ ions tend to exist in GeO 2 and Tb 4 O 7 co-doped silicate glasses. It was found that the Ge 2+ centers could exist in the co-doped silicate glasses, and moreover, there was energy transfer from T 1 level of Ge 2+ centers to 5 D 3 level of Tb 3+ ions under UV excitation. The way of the transfer was nonradiative energy resonance transfer, and its efficiency increased with increasing the concentration of GeO 2 .