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DOE OSTI · 1615623

Hot-Carrier Relaxation in CdSe/CdS Core/Shell Nanoplatelets

Pelton, Matthew·Wang, Yana·Fedin, Igor·Talapin, Dmitri V.·O’Leary, Stephen K.
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Abstract

Here, we present time-resolved photoluminescence (PL) spectroscopy of a series of colloidal CdSe/CdS core/shell nanoplatelets with different core and shell thicknesses. Exciton numbers are determined from the integrated PI, intensities, and carrier temperatures are determined from the high-energy exponential tail of the PL spectra. For times between 10 and 1000 ps, the measured carrier relaxation dynamics are well described by a simple model of Auger reheating: biexcitonic Auger recombination continually increases the average energy of the carriers (while decreasing their number), and this reheating sets a bottleneck to cooling through electron-phonon coupling. For times between 1 and 10 ps, the relaxation dynamics are consistent with electron-phonon coupling, where the bottleneck is now the decay of the longitudinal optical phonon population. Comparison of relaxation dynamics to recombination dynamics reveals changes in the carrier-phonon coupling for shell thicknesses greater than 4 monolayers.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRYAuger recombinationCdSecarrier coolingcarrier relaxationcore/shellnanoplateletstwo-dimensional materials

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Pelton, Matthew, Wang, Yana, Fedin, Igor, Talapin, Dmitri V., O’Leary, Stephen K.. 2019-12-11. Hot-Carrier Relaxation in CdSe/CdS Core/Shell Nanoplatelets. https://doi.org/10.1021/acs.jpcc.9b08006

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