Enhancement of luminescence of Rhodamine B by gold nanoparticles in thin films on glass for active optical materials applications

Fluorescent dyes in solid matrices have many potential applications provided that their high optical efficiencies are achieved. We present here gold nanoparticles formed and incorporated together with fluorescent dye Rhodamine B into a film of polyvinyl alcohol (PVA). The increase of fluorescence of the dye results from its interaction with surface plasmons. The electric charge on the gold nanoparticles and the distance between them and the dye molecules has a significant effect on the fluorescence intensity. Fluorescence enhancement of 74% was achieved for the negatively charged particles. Dynamic measurements reveal decrease of fluorescent lifetimes of the dye in presence of gold nanoparticles. Our findings enable utilization of films with enhanced fluorescence in optical materials such as luminescence solar concentrators, solid state tunable laser and active waveguides.