The effect of silica content on the luminescence properties of Tb3+-doped calcium aluminosilicate glasses

Abstract Tb 3+ doped materials exhibit strong emission in the green ( 5 D 4 ) and weak emission in the UV-blue ( 5 D 3 ) regions. The blue emission can occur from direct UV excitation or by excited state absorption, through 5 D 4 metastable level. In this paper, we investigate the effect of silica content on the spectroscopic properties of the Tb 3+ doped calcium aluminosilicate glasses. The low silica calcium aluminosilicate glass (LSCAS) and calcium aluminosilicate glass (CAS) doped with 0.5 wt% of Tb 3+ were prepared and characterized through absorption, excitation, Stokes emission, upconversion emission and 5 D 4 lifetime decay measurements. The green luminescence in the LSCAS glass presented a fast quenching. The silica influence on this behavior was discussed and a comprehensive interpretation is presented, correlating the Tb 3+ luminescence behavior with the silica concentration. Additionally, we analyze the excited state absorption effect on fluorescence transients to 5 D 4 energy level lifetimes.