Effect of Al2O3 and La2O3 on structure and spectroscopic properties of Nd-doped sol-gel silica glasses

Nd3+-doped sol-gel silica glasses with enhanced spectroscopic properties via co-doped Al2O3 and La2O3 are reported. Co-doped Al2O3 and La2O3 not only significantly increases the fluorescence intensity and prolongs the fluorescence lifetimes of Nd3+, but also has a large σems × τf of the Nd-doped sol-gel silica glasses. The Judd-Ofelt parameters were evaluated from the absorption spectrum of Nd3+-doped glass, and these were used to predict the effects of various Al2O3 and La2O3 contents. The structures resulting from co-doping Al3+, La3+, and Nd3+ ions in silica glass were analyzed by using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). It showed that La2O3 could change the chemical environment of Nd3+ ion and depolymerize the silica glass network. These results suggest that La/Al/Nd co-doped silica glass is a potentially useful material for developing optical devices and an ideal choice for lasers.