Ultrafast Charge Transfer at a Quantum Dot/2D Materials Interface Probed by Second Harmonic Generation
Name
1806.03764.pdf
Description
Submitted version
Size
1.55 MB
Format
Adobe PDF
Checksum (MD5)
a8596df1907daf8a7acc9d04db76e72c
Author(s)
Goodman, Aaron J.
Dahod, Nabeel S.
Tisdale, William
Date Issued
July 2018
Journal
Journal of Physical Chemistry Letters
Publisher
American Chemical Society (ACS)
Citation
Goodman, Aaron J. et al. “Ultrafast Charge Transfer at a Quantum Dot/2D Materials Interface Probed by Second Harmonic Generation.” The Journal of Physical Chemistry Letters 9, 15 (August 2018): 4227–32.
Version
Original manuscript
Abstract
Hybrid quantum dot (QD)/transition metal dichalcogenide (TMD) heterostructures are attractive components of next generation optoelectronic devices, which take advantage of the spectral tunability of QDs and the charge and exciton transport properties of TMDs. Here, we demonstrate tunable electronic coupling between CdSe QDs and monolayer WS[subscript 2] using variable length alkanethiol ligands on the QD surface. Using femtosecond time-resolved second harmonic generation (SHG) microscopy, we show that electron transfer from photoexcited CdSe QDs to single-layer WS2 occurs on ultrafast (50 fs to 1 ps) time scales. Moreover, in the samples exhibiting the fastest charge transfer rates (≤50 fs) we observed oscillations in the time-domain signal corresponding to an acoustic phonon mode of the donor QD, which coherently modulates the SHG response of the underlying WS2 layer. These results reveal surprisingly strong electronic coupling at the QD/TMD interface and demonstrate the usefulness of time-resolved SHG for exploring ultrafast electronic-vibrational dynamics in TMD heterostructures.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
Massachusetts Institute of Technology. Department of Chemical Engineering
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DOI of Published Version
https://doi.org/10.1021/acs.jpclett.8b01606
