Effective Doping of Rare-earth Ions in Silica Gel: A Novel Approach to Design Active Electronic Devices

Abstract

Eu³⁺ luminescence spectroscopy has been used to investigate the effective doping of alkoxide-based silica (SiO₂) gels using a novel pressure-assisted sol-gel method. Our results pertaining to intense photoluminescence (PL) from gel nanospheres can be directly attributed to the high specific surface area and remarkable decrease in unsaturated dangling bonds of the gel nanospheres under pressure. An increased dehydroxylation in an autoclave resulted in enhanced red (∼611 nm) PL emission from europium and is almost ten times brighter than the SiO₂ gel made at atmospheric pressure and ∼50°C using conventional Stöber-Fink-Bohn process. The presented results are entirely different from those reported earlier for SiO₂:Eu³⁺ gel nanospheres and the origin of the enhanced PL have been discussed thoroughly.