Competing Energy Transfer Pathways in a Five-Chromophore Perylene Array

Abstract

A perylene (donor–dimer)–acceptor–(donor–dimer) pentamer array is synthesized to investigate the competition between excimer formation and Förster resonance energy transfer. Using time-resolved fluorescence, we show that, upon excitation, the isolated perylene dimer forms an excimer with a time constant of 4.3 ns. However, in the pentamer array, when either of two constituent dimers donate their energy to the acceptor fluorophore, the excimer energy trap is eliminated. The pentamer macromolecule shows broad absorption and reduced self-absorption, at some cost to fluorescence quantum yield.