Optical activation of Eu3+ions by Ag nanoparticles in ion exchanged silica-gel films

Thin films of silica containing 0.15 at.% Eu and 3.5 to 7 at.% Na were prepared by sol–gel chemistry and annealed at 600 ° C in air, then submitted to ion–exchange treatments in NaNO3 : AgNO3 for studying the effect of the plasmon resonance of Ag nanoparticles on the excitation of Eu3+ ions. When excited at other wavelengths in the UV other than that corresponding to the 7F0–5L6 transitions of the Eu3+ ions, the yield of the 5D0–7F2 emission is increased by a factor of the order of 10 in films containing Ag particles with respect to that in non-exchanged films.