| Abstract
| - We present a combined experimental and theoretical study on energy transfer processes in awell-defined three-dimensional host−guest system, which allows for high chromophore concentrations whilemaintaining the highly luminescent properties of the molecules in solution. The self-assembled, nanostructured system with a defined ratio of included donor and acceptor molecules is amenable to quantitativecomparison between experiment and theory. Experimentally, energy migration is monitored by steady-state and time-resolved fluorescence spectroscopy. From the theoretical side, the energy transfer processis modeled by a Monte Carlo approach including homo and hetero transfer steps with multi-acceptordistribution. In this dense system, the classical Förster point-dipole approach for energy transfer breaksdown, and the hopping rates are therefore calculated on the basis of a quantum-chemical description ofthe donor and acceptor excited states. Thereby, the true directionality of the excitation diffusion is revealed.Excellent agreement with experimental donor and acceptor decays and overall transfer efficiencies is found.Even at low acceptor concentrations (down to 0.1%), efficient energy transfer over distances as large as25 nm was observed due to rapid energy migration through a series of homo-transfer steps with preferencealong one direction of the structure.
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