Energy transfer in nanostructured films containing poly(p-phenylene vinylene) and acceptor species.

Abstract

The combination of luminescent polymers and suitable energy-accepting materials may lead to a molecularlevel control of luminescence in nanostructured films. In this study, the properties of layer-by-layer (LbL) films of poly(p-phenylene vinylene) (PPV) were investigated with steady-state and time-resolved fluorescence spectroscopies, where fluorescence quenching was controlled by interposing inert polyelectrolyte layers between the PPV donor and acceptor layers made with either Congo Red (CR) or nickel tetrasulfonated phthalocyanine (NiTsPc). The dynamics of the excited state of PPV was affected by the energy-accepting layers, thus confirming the presence of resonant energy transfer mechanisms. Owing to the layered structured of both energy donor and acceptor units, energy transfer varied with the distance between layers, r, according to 1/rn with n ) 2 or 3, rather than with 1/r6 predicted by the Fo¨rster theory for interacting point dipoles.