Controlled Förster energy transfer in emissive polymer Langmuir-Blodgett structures

Abstract

We have investigated the effect of the guest-host separation on F\"orster transfer rate between two fluorescent polymers grown as layered nanostructures by the Langmuir-Blodgett technique. Precise variation of chromophore separation achieved by the monolayer deposition of an inert spacer layer between guest and host molecules allows control over the transfer rate. By fitting theoretical models to the observed data we find that an inverse square relationship (i.e., energy transfer rate ${k}_{\mathrm{ET}}\ensuremath{\propto}{R}^{\ensuremath{-}2},$ where $R$ is the distance between the layers) exists for the two-dimensional layered nanostructures, as opposed to the more widely quoted ${k}_{\mathrm{ET}}\ensuremath{\propto}{R}^{\ensuremath{-}6}$ dependence assumed for point-like dipole-dipole interactions.