Preparation and luminescence of silica aerogel composites containing an europium (III) phenanthroline nitrate complex

A simple two step procedure for the functionalization of hydrophobic silica aerogel microgranules with europium ions and/or 1,10 - phenanthroline is demonstrated. The activation procedure is based on soaking aerogels in a europium nitrate solution, followed by functionalization with 1,10 - phenanthroline. The functionalized materials display strong red or blue emission at UV-excitation, coming from the formation of [Eu(phen)(2)](NO3)(3) or Si(IV)- 1,10-phenathroline complexes in the porous system of the aerogels. The most probable site symmetry of the europium cation is C-2v confirmed by luminescence spectra analysis. Room temperature diffuse reflectance spectra and excitation/luminescence spectra are used to describe the optical properties of the hybrid composites. Excitation spectra prove an efficient energy transfer between 1,10 - phenanthroline and the Eu3+ ion. (C) 2016 Elsevier B.V. All rights reserved.