Picosecond energy transfer in oligo(p-phenylene vinylene) capped gold nanoparticles

Photophysical processes in gold nanoparticles functionalized with oligo(p-phenylene vinylene) (OPV) chromophores linked via a disulfide moiety are investigated using fluorescence and photoinduced absorption (PIA) spectroscopy. Binding of OPV to nanosized gold particles reduces the quantum yield for fluorescence by an order of magnitude. PIA spectroscopy monitoring the lowest excited state of the OPV (S1) bound to the gold particle reveals a very short lifetime (ps) much shorter than the lifetime of the unbound OPV (1.3 ns). The reduction of the S1 lifetime is ascribed to resonance energy transfer between the OPV and the nanoparticle via the Fِrster mechanism.