Effects of thermal treatment on the structure and luminescent properties of Eu3+ doped SiO2-PMMA hybrid nanocomposites prepared by a sol-gel process

Hybrid nanocomposites are multifunctional materials and their properties are the consequence of molecular interaction between inorganic and organic phases. These materials are interesting hosts for lanthanide ions, such as Eu3+. The purpose of this research was to synthesize Eu3+ doped SiO2-PMMA hybrid nanocomposites by a sol-gel process and to study the effects of thermal treatment on the structure and luminescent properties of the material. Structural characterization was carried out using the FTIR, TG and 29Si NMR techniques, however, the luminescence studies were more sensitive to detect the slight structural changes resulting from the thermal treatment. The Eu3+ ions inserted into the matrix behaved as a structural probe and make it possible to notice the symmetry change from Eu3+ site, the decrease in the number of hydroxyl coordinated groups and the improvement in quantum efficiency as a result of the thermal treatment. In addition, the Judd-Ofelt intensity parameters were obtained and supported the interaction between the rare earth and hybrid material. The hybrid was obtained as a stable material until 200 °C and the high sensitivity of the Eu3+ ions in the system may be used in future applications as thermal sensors, for example.