A Nano-Silver Enhancement Effect on the Luminescence of a Ligand–Eu3+ Complex via a SiO2 Spacer

Abstract

Luminescent rare earth complex (REC) nanocomposites, Eu(TTA)3Phen attached onto Ag@SiO2 nanoshells, were fabricated by facile wet chemistry and self-assembly techniques. Transmission electron microscopy, and fourier transform infrared and UV–Vis spectroscopy were used to investigate the step-by-step fabrication. The luminescence of REC was significantly enhanced using a silver core (size: 45 nm) surrounded by a 20-nm thick silica shell. Thicker or thinner silica shells afforded tuning of the metal-enhanced luminescence. The thiophene-TTA-containing REC fluorophore was able to etch the silver core, resulting in hollow silica shells, consequently displaying no luminescence enhancing capabilities. The etching efficiency was proportional to the concentration of Eu(TTA)3Phen, and decreased with increasing shell thickness.