Enhancement and Concurrence of Emissions from Multiple Fluorophores in a Single Emitting Layer of Micellar Nanostructures

Abstract

For concurrent emission of multiple fluorophores from a single emitting layer with a highly efficient energy transfer from antenna molecules to emitting molecules by fluorescence resonance energy transfer (FRET), a paradoxical requirement in an emitting layer is necessary, that is, close placement of an emitting fluorophore and a harvesting molecule, and isolation of emitting fluorophores. Here we demonstrate how to overcome this paradox by full utilization of a micellar nanostructure consisting of a core and a corona, that is, the core is used as a place for FRET between light-collecting donors and light-emitting fluorophores, and the corona is used as a barrier for FRET between light-emitting fluorophores. Enhancement of light emission from fluorophores was achieved by locating emitting fluorophores and light-harvesting molecules at the same core of micelles. Moreover, with the same micellar nanostructure, concurrent emission of multiple fluorophores with enhanced intensity was induced by isolating them in independent micelles, the corona structure of which worked as an effective blockade for FRET.