Europium 4 Gels 4 Luminescence 4 Organic precursor 4 Sol-gel 4 Sol-gel process 4 Sol-gel technique Sol-gels 4 Sols 4 Acid media 2 Amides 2 Aminopropyltriethoxysilane 2 Ammonium compounds 2 Aqueous media 2 Bromine compounds 2 Cetyltrimethylammonium bromide 2 Crosslinker 2 Cu(II) sensor 2 Differential thermal analysis 2 Esters 2 Europium complex 2 Europium(III) 2 Europium(III) complexes 2 Glass slides 2 Glass transition 2 Hybrid materials 2 Hybrid matrix 2 Hybrid organic-inorganic materials 2 Hydrolysis 2 In-situ 2