Ag colloidal nanoparticles coated with Eu(TTA)(3) (.) 2H(2)O complexes were prepared, and it was found that Eu(TTA)(3) (.) 2H(2)O complexes J-aggregate was formed on the surface of Ag nanoparticles according to a red shift (18.2 nm) in UV-Vis spectra. However, there had similar excitation wavelength, which was attributed to existence of Ag nanoparticles. Highly luminescent properties of Ag colloidal nanoparticles were observed, and it was believed to result from low energy transfer between Eu(III) complexes and Ag and the large electromagnetic field arising from the excitation of surface plasmon polariton of Ag nanoparticles. (c) 2005 Elsevier B.V. All rights reserved.