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Picosecond energy transfer in quantum dot Langmuir-Blodgett nanoassemblies

Marc Achermann·Melissa A. Petruska·Scott A. Crooker·Victor I. Klimov
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Abstract

We study spectrally resolved dynamics of Forster energy transfer in single monolayers and bilayers of semiconductor nanocrystal quantum dots assembled using Langmuir-Blodgett (LB) techniques. For a single monolayer, we observe a distribution of transfer times from ~50 ps to ~10 ns, which can be quantitatively modeled assuming that the energy transfer is dominated by interactions of a donor nanocrystal with acceptor nanocrystals from the first three shells surrounding the donor. We also detect an effective enhancement of the absorption cross section (up to a factor of 4) for larger nanocrystals on the red side of the size distribution, which results from strong, inter-dot electrostatic coupling in the LB film (the light-harvesting antenna effect). By assembling bilayers of nanocrystals of two different sizes, we are able to improve the donor-acceptor spectral overlap for engineered transfer in a specific (vertical) direction. These bilayers show a fast, unidirectional energy flow with a time constant of ~120 ps.

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Marc Achermann, Melissa A. Petruska, Scott A. Crooker, Victor I. Klimov. 2003-10-06. Picosecond energy transfer in quantum dot Langmuir-Blodgett nanoassemblies. https://arxiv.org/abs/cond-mat/0310127

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