Luminescent sintered silica glass prepared by adsorbing Pr ions into mesoporous SiO₂-PVA nanocomposite

A monolithic silica glass doped with Pr³⁺ was prepared by immersing a mesoporous SiO₂-polyvinly alcohol (PVA) nanocomposite in a Pr nitrate solution and then sintering it at 1100°C in air. The sintered glass exhibited pink emission when excited by ultraviolet irradiation. The photoluminescence intensity of the glass depended on the total concentration of Pr ions, which was adjusted by changing the concentration of the Pr nitrate solution and the immersion time. The glass with the highest photoluminescence intensity was prepared by using a 1- or 10-mM Pr solution at an immersion time of 60 min. To reveal how the immersion conditions affected the photoluminescence intensity, we analyzed and discussed the adsorption kinetics of the Pr ions onto the surface of the mesoporous nanocomposite. At immersion times below 60 min, the Pr ions diffused into pores of the nanocomposite without aggregating. To prepare Pr³⁺-doped silica glass with high photoluminescence, both the concentration of the Pr solution and the immersion time must be controlled.