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

Abstract

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 1,10phenanthroline. The functionalized materials display strong red or blue emission at UV-excitation, coming from the formation of [Eu(phen) 2 ](NO 3) 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 1,10phenanthroline and the Eu 3+ ion.

Luminescence of Binary-Doped Silica Aerogel Powders: A Two-Step Sol-Gel Approach

“…In the first stage, we observe the formation of an inorganic silica aerogel matrix with a selected degree of hydrophobicity. Here, the aerogel matrix properties (hydrophobicity and pore architecture) can be tuned in order to obtain a suitable carrier for optically active species [2][3][4].…”

“…The first known publication that we encountered with optical composites based on silica hydrophobic aerogels shows the possibility of obtaining composites with the composition SiO 2 (aerogel):[Eu(phen) 2 ](NO 3 ) 3 using a two-step sol-gel process [2].…”

Real-Time Tracking of Highly Luminescent Mesoporous Silica Particles Modified with Europium β-Diketone Chelates in Living Cells

“…For this reason, the decoration of MSP by functional ligands has had significant consideration. In general, direct incorporation of europium complex into silica aerogel was attempted without any covalent bond [ 28 , 29 ].…”

Spectral and Texture Properties of Hydrophobic Aerogel Powders Obtained from Room Temperature Drying

“…The subcritical synthesis of oxide aerogels from alcoxydes consists of few main steps: the hydrolysis of the alcoxide species in acidic conditions until oligomers form, alkaline polycondensations, gelation, and drying subcritical conditions. Choosing hydrocarbon-containing silica precursors for treating wet gel with surface-modifying agents such as trimethyl chlorosilane (TMCS) leads to the production of hydrophobic gels, granules, powders, and coatings with different degrees of hydrophobicity [ 7 , 11 ]. In this way, significant amounts of highly porous powders can be prepared depending on the drying capacity.…”

“…In addition to the classical aerogel-based thermal and sound insulation materials, optical materials with sensory [4] and biological applications [5,6] constitute a new, fastgrowing field of aerogel development. In a recent paper, the possibilities for the incorporation of optically active hybrid molecules in hydrophobic aerogel granules were discussed [7]. In the same paper, a useful approach for the impregnation of hydrophobic aerogel granules with [Tb(phen) 2 ](NO 3 ) 3 complexes was described using high-porosity aerogel granules and powders, at about 95%.…”