Europium(III) complexes 4 Luminescence 4 Acid media 2 Crystal structures 2 Differential thermal analysis 2 Esters 2 Europium 2 Europium complex 2 Gels 2 Hybrid matrix 2 Hybrid organic-inorganic materials 2 Hydrolysis 2 Infrared spectroscopy 2 Lanthanides 2 Luminescence and DCCA 2 Organic moiety 2 Organic precursor 2 Oxydiacetic acid 2 Scanning electron microscopy 2 Sol-gel 2 Sol-gel process 2 Sol-gel technique 2 Sol-gels 2 Sols 2 Spectral feature 2 Spectroscopic analysis 2 Structural characterization 2 TEOS 2 Terbium(III) complexes 2 Tetraethoxysilanes 2