Photofunctional Eu3+/Tb3+ hybrids through sulfoxide linkages: coordination bonds construction, characterization and luminescence

Abstract

New kinds of organic–inorganic hybrid materials consisting of rare earth (Eu³⁺, Tb³⁺) complexes covalently bonded to a silica-based network have been obtained by a sol–gel approach. Three novel versatile molecular building blocks containing sulfoxide organic units have been synthesized by methylene modification reaction, which are used as the ligands of rare earth ions and also as siloxane network precursors. The obtained hybrids are characterized by chemical analysis and spectroscopic methods such as FTIR and UV; XRD and SEM. Photoluminescence measurements on the prepared hybrids were performed showing the intra-4fⁿ emission in the visible (Eu³⁺, Tb³⁺) region and in all the cases being sensitized by the sulfoxide ligands. The emission quantum efficiency and the Judd–Ofelt intensity parameters of Eu³⁺ hybrid materials were also investigated in detail.