Three-dimensional energy transport in highly luminescent host-guest crystals: a quantitative experimental and theoretical study.
We present a combined experimental and theoretical study on energy transfer processes in a well-defined three-dimensional host-guest system, which allows for high chromophore concentrations while maintaining 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 quantitative comparison between experiment and theory. Experimentally, energy migration is monitored by steady-state and time-resolved fluorescence spectroscopy. From the theoretical side, the energy transfer process is modeled by a Monte Carlo approach including homo and hetero transfer steps with multi-acceptor distribution. In this dense system, the classical Förster point-dipole approach for energy transfer breaks down, and the hopping rates are therefore calculated on the basis of a quantum-chemical description of the 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 as 25 nm was observed due to rapid energy migration through a series of homo-transfer steps with preference along one direction of the structure.
Poulsen
Lars
L
Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
Jazdzyk
Mikael
M
Communal
Jean-Edouard
JE
Sancho-García
Juan Carlos
JC
Mura
Andrea
A
Bongiovanni
Giovanni
G
Beljonne
David
D
Cornil
Jérôme
J
Hanack
Michael
M
Egelhaaf
Hans-Joachim
HJ
Gierschner
Johannes
J