Enhanced fluorescence from Dy 3+ owing to surface plasmon resonance of Au colloid nanoparticles

Abstract

Gold colloidal containing rare earth ions Dy 3+ were prepared at room temperature. Fluorescence spectra of Dy 3+ ions and Au colloid containing Dy 3+ were measured. For solution containing Dy 3+, fluorescence emission occurs at visible light wavelength region. Two emission peaks are observed at 480 nm and 570 nm respectively when the corresponding excitation wavelength is at 350 nm. When Au colloids were added to the solution containing Dy 3+, both these two fluorescence peaks were enhanced. Furthermore, with the increasing Au content, the fluorescence increases first and then decreases. We believe that this increased fluorescence are due to the local field enhancement around Dy 3+ ions owing to the induced higher orders of surface plasmon resonance.