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Explaining the Unusual Photoluminescence of Semiconductor Nanocrystals Doped Via Cation Exchange

Freyer, Abigail R. and Sercel, Peter C. and Hou, Zhentao and Savitzky, Benjamin H. and Kourkoutis, Lena F. and Efros, Alexander L. and Krauss, Todd D. (2019) Explaining the Unusual Photoluminescence of Semiconductor Nanocrystals Doped Via Cation Exchange. Nano Letters, 19 (7). pp. 4797-4803. ISSN 1530-6984. doi:10.1021/acs.nanolett.9b02284.

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Aliovalent doping of CdSe nanocrystals (NCs) via cation exchange processes has resulted in interesting and novel observations for the optical and electronic properties of the NCs. However, despite over a decade of study, these observations have largely gone unexplained, partially due to an inability to precisely characterize the physical properties of the doped NCs. Here, electrostatic force microscopy was used to determine the static charge on individual, cation-doped CdSe NCs in order to investigate their net charge as a function of added cations. While the NC charge was relatively insensitive to the relative amount of doped cation per NC, there was a remarkable and unexpected correlation between the average NC charge and PL intensity, for all dopant cations introduced. We conclude that the changes in PL intensity, as tracked also by changes in NC charge, are likely a consequence of changes in the NC radiative rate caused by symmetry breaking of the electronic states of the nominally spherical NC due to the Coulombic potential introduced by ionized cations.

Item Type:Article
Related URLs:
URLURL TypeDescription
Freyer, Abigail R.0000-0001-8256-3488
Sercel, Peter C.0000-0002-1734-3793
Efros, Alexander L.0000-0003-1938-553X
Krauss, Todd D.0000-0002-4860-874X
Additional Information:© 2019 American Chemical Society. Received: June 4, 2019; Revised: June 13, 2019; Published: June 14, 2019. This work was supported by the National Science Foundation (NSF) (CHE-1609365). This work was supported in part by the PARADIM Materials Innovation Platform (DMR-1539918) and made use of the Cornell Center for Materials Research with funding from the NSF MRSEC program (DMR-1719875). B.H.S. was supported by NSF GRFP DGE-1144153. A.L.E. acknowledges support from the U.S. Office of Naval Research through the U.S. Naval Research Laboratory’s core research program. We thank David Norris and Ayash Sahu for assistance with the doping process and for useful discussions. We would like to thank Chiara Borrelli and Dustin Trail for help with the ICP-MS measurements and Christine Pratt for performing the X-ray diffraction measurements. The ICP-MS instrument is partially supported by a grant from the NSF (EAR-1545637). The authors declare no competing financial interest.
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE-1144153
Office of Naval Research (ONR)UNSPECIFIED
Subject Keywords:semiconductor nanocrystals, aliovalent doping, cation exchange, electrostatic force microscopy, nanocrystal charge, symmetry breaking
Issue or Number:7
Record Number:CaltechAUTHORS:20190614-111555452
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Official Citation:Explaining the Unusual Photoluminescence of Semiconductor Nanocrystals Doped via Cation Exchange. Abigail R. Freyer, Peter C. Sercel, Zhentao Hou, Benjamin H. Savitzky, Lena F. Kourkoutis, Alexander L. Efros, and Todd D. Krauss. Nano Letters 2019 19 (7), 4797-4803. DOI: 10.1021/acs.nanolett.9b02284
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96445
Deposited By: George Porter
Deposited On:17 Jun 2019 14:50
Last Modified:16 Nov 2021 17:21

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