Controlled synthesis and luminescence properties of core-shell-shell structured SiO₂@AIPA-S-Si-Eu@SiO₂ and...

Two novel core-shell structured SiO₂@AIPA-S-Si-Eu and SiO₂@AIPA-S-Si-Eu-phen nanocomposites have been synthesized by a bifunctional organic ligands ((HOOC)₂C₆H₃NHCONH(CH₂)₃Si(OCH₂CH₃)₃) (defined as AIPA-S-Si) connected with Eu³⁺ ions and silica via covalent bond. And the corresponding core-shell-shell structured SiO₂@AIPA-S-Si-Eu@SiO₂ and SiO₂@AIPA-S-Si-Eu-phen@SiO₂ nanocomposites with enhanced luminescence have been synthesized by tetraethyl orthosilicate (TEOS) hydrolysis co-deposition method. The composition and micromorphology of the nanocomposites were characterized by means of Fourier-transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX) and X-ray photoelectron spectroscopy (XPS). The as-synthesized core-shell and core-shell-shell structured nanocomposites have excellent luminescence intensity and long lifetime. The nanocomposites show bright red light under ultraviolet lamp. However, the core-shell-shell structured nanocomposites have stronger luminescence intensity than the corresponding core-shell structured nanocomposites. Meanwhile, the core-shell-shell structured nanocomposites still exhibit good luminescence stability in aqueous solution. In addition, a large number of Si-OH on the surface of the core-shell-shell structured nanocomposites can be attached to many biomacromolecules. Therefore, they have potential applications in the fields of biology and luminescence.