Covalently Bonded Assembly of Lanthanide/Silicon−Oxygen Network/Polyethylene Glycol Hybrid Materials through Functionalized 2-Thenoyltrifluoroacetone Linkage

2-Thenoyltrifluoroacetone (TTA) used as the organic ligand and the poly(ethylene glycol) (PEG400 with the molecular weight of 380-430) used as the network precursor were grafted onto the coupling agent 3-(triethoxysilyl)-propyl isocyanate (TEPIC), respectively, to construct two precursors TTA-Si and PEG-Si. Then the precursor TTA-Si and the terminal ligand 1,10-phenanthroline (Phen) have coordinated to the rare earth ions by the carbonyl group or nitrogen atom to obtain binary or trinary hybrid polymeric materials after hydrolysis and copolycondensation between the tetraethoxysilane (TEOS), water molecules, and the network precursor PEG-Si via the sol-gel process. The terminal ligand 1,10-phenanthroline (Phen) was used to investigate the difference of photophysical and luminescent properties between binary and trinary hybrid materials, and the network precursor PEG-Si was induced to show its influence on microstructure and thermal properties. The results have revealed that the hybrid materials containing organic ligands bonded with PEG400 showed more efficient intramolecular energy transfer between the europium ion and the ligands (TTA-Si and Phen) and more excellent characteristic emission of the europium ion under UV irradiation with higher (5)D(0) luminescence quantum efficiency than the hybrid materials without PEG400, while less uniformity in the microstructure.