Preparation and luminescent properties of lanthanide (Eu3+ and Tb3+) complexes grafted to 3-aminopropyltriethoxysilane by covalent bonds

• Aromatic acids/bridged polysilsesquioxanes have been synthesized by sol–gel method.
• As-prepared compounds in sol condition were coated on quartz plates to form a layer of thin film.
• The obtained materials enhanced thermal stability, mechanical resistances, waterproofness as well as machining properties.

A novel precursor PMA–Si was synthesized by modifying 1,2,4,5-benzene-tetracarboxylic acid (PMA) with 3-aminopropyltriethoxysilane (APTES). Then the hybrids were prepared by PMA–Si coordinating to lanthanide ions (Eu3+ and Tb3+) in sol–gel process. In order to improve luminescent efficiency, 1,10-Phenanthroline (Phen) was introduced to the system as the second ligand. As-prepared compounds in sol condition were coated on quartz plates to form a layer of thin film, which was different from other similar hybrids. The properties of the hybrids were characterized by FT-IR, fluorescence spectra, TG and SEM. The results showed that the obtained materials enhanced thermal stability, mechanical resistances, waterproofness as well as machining properties.