Rare-earth (Eu3+, Tb3+) hybrids through amide bridge: Chemically bonded self-assembly and photophysical properties

This work focuses on the construction of a series of chemically bonded rare-earth/inorganic/organic hybrid materials (TCH–Si–Ln, TCH–Si–Ln–Phen and TCH–Si–Ln–Bipy: Phen = 1,10-phenanthroline, Bipy = 2,2′-bipyridyl) using TCH–Si as an organic bridge molecule that can both coordinate to rare-earth ions (Eu3+ and Tb3+) and form an inorganic Si–O–Si network with tetraethoxysilane (TEOS) after cohydrolysis and copolycondensation through a sol–gel process. All of these hybrid materials exhibit homogeneous microstructures and morphologies, suggesting the occurrence of self-assembly of the inorganic network and organic chain. Measurements of the photoluminescent properties of these materials show that the ternary europium systems present stronger luminescent intensities than the binary hybrids, indicating that the introduction of the second ligands can sensitize the luminescence emission of the europium hybrid systems. However, in the terbium systems, this phenomenon was not observed.