Two-dimensional molecular aggregate (2DMA), a thin sheet of strongly interacting dipole molecules self-assembled at close distance on an ordered lattice, is a fascinating fluorescent material. It is distinctively different from the conventional (single or colloidal) dye molecules and quantum dots. In this paper, we verify that when a 2DMA is placed at a nanometric distance from a metallic substrate, the strong and coherent interaction between the dipoles inside the 2DMA dominates its fluorescent decay at a picosecond timescale. Our streak-camera lifetime measurement and interacting lattice–dipole calculation reveal that the metal-mediated dipole–dipole interaction shortens the fluorescent lifetime to about one-half and increases the energy dissipation rate by 10 times that expected from the noninteracting single-dipole picture. Our finding can enrich our understanding of nanoscale energy transfer in molecular excitonic systems and may designate a unique direction for developing fast and efficient optoelectronic devices.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Sep 5 2017|
Bibliographical noteKAUST Repository Item: Exported on 2022-06-08
Acknowledged KAUST grant number(s): OSR-2016-CRG5-2950-03
Acknowledgements: Q.H. thanks Tresback Jason in the Center for Nanoscale Systems at Harvard University for his help on AFM characterization. D.J. thanks Steven Kooi in the Institute for Soldier Nanotechnologies at Massachusetts Institute of Technology (MIT), Cambridge, MA for his help on photoluminescence measurement. N.X.F., Q.H., D.J., and S.H.N. acknowledge financial support by the National Science Foundation (NSF) (Grant CMMI-1120724) and Air Force Office of Scientific Research (AFOSR) Multidisciplinary Research Program of the University Research Initiative (MURI) (Award FA9550-12-1-0488). N.X.F. and S.H.N. are also supported by the Cooperative Agreement between the Masdar Institute of Science and Technology (Masdar Institute), Abu Dhabi, United Arab Emirates and MIT, Reference 2/MI/MI/CP/11/07633/GEN/G/00. X.Z., J.X., and X.L. acknowledge financial support from AFOSR MURI (Award FA9550-12-1-0488), “Light-Material Interactions in Energy Conversion” Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences (Award DE-AC02-05CH11231) (for fluorescence lifetime measurement), and the King Abdullah University of Science and Technology Office of Sponsored Research (OSR) (Award OSR-2016-CRG5-2950-03). Y.L. acknowledges the financial support of the NSF under Grant DMR-1654192 and the support of the 3M Non-Tenured Faculty Award.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
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