Optical properties of Eu-doped hybrid materials prepared from dimethyl and methyl alkoxides precursors

The sol–gel methodology allows for the attainment of hybrids with controlled doping, which cannot be achieved via other methods. In this work, a europium (III) dipicolinate complex has been incorporated into hybrid materials prepared from alkoxides modified with methyl groups, obtained via the sol–gel process, aiming at the preparation of hydrophobic hybrids. The photoluminescence analysis showed that the europium (III) complex was not affected during its incorporation into the hybrid materials, since its spectroscopic properties were maintained. The X-ray diffraction analysis revealed that the synthesized silica was amorphous, whereas the alkoxides dimethyldimethoxysilane and methyltriethoxysilane displayed diffraction halos centered at 2θ=10°, which disappeared after heating, as well as halos centered at 2θ=20°, typical of silica. The scanning electron microscopy analysis provided evidence of different morphologies for the hybrids. The thermal analysis demonstrated variations in the curves of the hybrids prepared with europium (III) chloride and those obtained in the presence of the europium (III) dipicolinate complex.