Far-field modulation of fluorescence decay rates in pairs of oriented semiconducting polymer nanostructures

We report on the observation of far-field dipole-dipole coupling in pairs of uniformly z-oriented polymer nanostructures manifested as a fluorescence lifetime modification (both enhancement and suppression relative to isolated particles) modulated by interparticle separation. The observed oscillatory modulation in the fluorescence decay rate as a function of interparticle distance (ranging from 200 to approximate to 2000 nm) results from modification of the vacuum field at the position of the probe dipole by the presence of the second radiating dipole. These results provide observation of a dipole-dipole interaction in the "inductance" interparticle distance scale between the near field (approximate to 200 nm) and far field (> 500 nm), important for the realization of efficient active nanophotonic devices.