Novel sol-gel precursors for thin mesoporous Eu 3+-doped silica coatings as efficient luminescent materials.

Abstract

Europium(III) ions containing mesoporous silica coatings have been prepared via a solvent evaporation-induced self-assembly (EISA) approach of different single-source precursors (SSPs) in the presence of Pluronic P123 as a structure-directing agent, using the spin-coating process. A deliberate tailoring of the chemical composition of the porous coatings with various Si:Eu ratios was achieved by processing mixtures of tetraethylorthosilicate (TEOS) and Eu 3+-coordinated SSPs. Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) analyses demonstrate that the thin metal oxide-doped silica coatings consist of a porous network with a short-range order of the pore structure, even at high europium(III) loadings. Furthermore, luminescence properties were investigated at different temperatures and different degrees of Eu 3+ contents. The photoluminescence spectra clearly show characteristic emission peaks corresponding to the 5D 0→ 7F J (J = 0-5) transitions resulting in a red luminescence visible by the eyes, although the films have a very low thickness (150-200 nm). © 2012 American Chemical Society.