Spectroscopic analysis of Eu³⁺ doped silica-titania-polydimethylsiloxane hybrid ORMOSILs

Eu³⁺ doped silica-titania-polydimethylsiloxane hybrid ORMOSILs were synthesized via a non-hydrolytic sol-gel route. The structural and thermal analyses of the samples confirmed that the matrix structure remains unaffected by doping with different concentrations of Eu³⁺ ions. Photoluminescence (PL) studies performed at 394 nm on Eu³⁺ doped ORMOSILs imply that they emit broad blue host emission and the characteristic Eu³⁺ red emissions simultaneously. Also, the samples were excited at the charge transfer (CT) band and this confirmed the existence of an energy transfer path from the host to the Eu³⁺ ions via Ti⁴⁺-O^2--Eu³⁺ bonds. The phonon energy of the host matrix was estimated by phonon sideband (PSB) analysis and the results were substantiated by Raman analysis. Judd-Ofelt (JO) parameters were also evaluated which give details about the local surroundings of the Eu³⁺ ions in the system and these parameters were further used for predicting the radiative properties of ⁵D₀ → ⁷F_1,2,4 transitions of Eu³⁺ ions. Furthermore, the quantum efficiency and CIE co-ordinates were evaluated and it was found that Eu³⁺ doped silica-titania-polydimethylsiloxane ORMOSIL has an intense pinkish red emission with a quantum efficiency of 30.7%.