Effect of Pr3+ Doping on the OH Content of Silica Xerogels

Pr2O3-SiO2 xerogels doped with different Pr/Si concentrations were annealed at 900°C for 120 h and then investigated by FTIR, NIR absorption, Raman and luminescence spectroscopies. It is observed that the content of surface silanol groups is lower for higher Pr3+ concentrations. Luminescence measurements indicate that the amount of the residual OH plays an important role in the spectroscopic properties of the Pr3+ ion and in particular the quantum yield of the emission from the 3P0,1 and 1D2 states.