Synthesis and optical properties of Eu3+-doped inorganic–organic hybrid materials based on siloxane networks

Abstract

Transparent polydimethylsiloxane–metal oxide (PDMS–M_xO_y) hybrid materials have been studied as host matrices of Eu³⁺ ions for their application as optical devices. The versatility of these nanocomposites and the different nature of the metal–oxo domains allow the modulation of the emitting ion coordination and, therefore, of its luminescent response. The optical characterization of Eu³⁺-doped PDMS–metal oxide hybrid materials (where the metal, M = Al(III), Ge(IV), Sn(IV), Ti(IV), Zr(IV), Nb(V) and Ta(V)) is reported. UV-Vis absorption, excitation and emission spectra, lifetime-resolved measurements, selective excitation experiments and the effect on the optical properties of a post-curing of the doped-nanocomposites are discussed. From the optical results and taking into account the structure of the nanocomposites, the capability of the matrices for encapsulating and dispersing the rare earth ions is analyzed. In this sense, the matrix which contains Ta(V) as cross-linking metal allows the dispersion of the emitting ion in a very effective way, and consequently, its luminescence is highly enhanced (long lifetime value and high emission intensity), even before heat treatment.