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Title: Elucidation of Two Giants: Challenges to Thick-shell Synthesis in CdSe/ZnSe and ZnSe/CdS Core/Shell Quantum Dots

Abstract

Core/thick-shell "giant" quantum dots (gQDs) possessing type II electronic structures exhibit suppressed blinking and diminished nonradiative Auger recombination. Here we investigate CdSe/ZnSe and ZnSe/CdS as potential new gQDs. We show theoretically and experimentally that both can exhibit partial or complete spatial separation of an excited-state electron–hole pair (i.e., type II behavior). However, we reveal that thick-shell growth is challenged by competing processes: alloying and cation exchange. We demonstrate that these can be largely avoided by choice of shelling conditions (e.g., time, temperature, and QD core identity). The resulting CdSe/ZnSe gQDs exhibit unusual single-QD properties, principally emitting from dim gray states but having high two-exciton (biexciton) emission efficiencies, whereas ZnSe/CdS gQDs show characteristic gQD blinking suppression, though only if shelling is accompanied by partial cation exchange.

Authors:
 [1];  [1];  [1];  [2];  [3];  [4];  [3];  [5];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Physics and Applications Division, Center for Integrated Nanotechnologies
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division, Physics of Condensed Matter & Complex Systems
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Earth & Environmental Science Division, Earth System Observations
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division, Physical Chemistry & Applied Spectroscopy
  5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Physics and Applications Division: Center for Integrated Nanotechnologies
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States
Sponsoring Org.:
USDOE
OSTI Identifier:
1329561
Report Number(s):
LA-UR-15-20906
Journal ID: ISSN 0002-7863
Grant/Contract Number:
AC52-06NA25396; 2009LANL1096
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 137; Journal Issue: 11; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Inorganic and Physical Chemistry; Material Science

Citation Formats

Acharya, Krishna P., Nguyen, Hue M., Paulite, Melissa, Piryatinski, Andrei, Zhang, Jun, Casson, Joanna Lee, Xu, Hongwu, Htoon, Han, and Hollingsworth, Jennifer Ann. Elucidation of Two Giants: Challenges to Thick-shell Synthesis in CdSe/ZnSe and ZnSe/CdS Core/Shell Quantum Dots. United States: N. p., 2015. Web. doi:10.1021/jacs.5b00313.
Acharya, Krishna P., Nguyen, Hue M., Paulite, Melissa, Piryatinski, Andrei, Zhang, Jun, Casson, Joanna Lee, Xu, Hongwu, Htoon, Han, & Hollingsworth, Jennifer Ann. Elucidation of Two Giants: Challenges to Thick-shell Synthesis in CdSe/ZnSe and ZnSe/CdS Core/Shell Quantum Dots. United States. doi:10.1021/jacs.5b00313.
Acharya, Krishna P., Nguyen, Hue M., Paulite, Melissa, Piryatinski, Andrei, Zhang, Jun, Casson, Joanna Lee, Xu, Hongwu, Htoon, Han, and Hollingsworth, Jennifer Ann. Fri . "Elucidation of Two Giants: Challenges to Thick-shell Synthesis in CdSe/ZnSe and ZnSe/CdS Core/Shell Quantum Dots". United States. doi:10.1021/jacs.5b00313. https://www.osti.gov/servlets/purl/1329561.
@article{osti_1329561,
title = {Elucidation of Two Giants: Challenges to Thick-shell Synthesis in CdSe/ZnSe and ZnSe/CdS Core/Shell Quantum Dots},
author = {Acharya, Krishna P. and Nguyen, Hue M. and Paulite, Melissa and Piryatinski, Andrei and Zhang, Jun and Casson, Joanna Lee and Xu, Hongwu and Htoon, Han and Hollingsworth, Jennifer Ann},
abstractNote = {Core/thick-shell "giant" quantum dots (gQDs) possessing type II electronic structures exhibit suppressed blinking and diminished nonradiative Auger recombination. Here we investigate CdSe/ZnSe and ZnSe/CdS as potential new gQDs. We show theoretically and experimentally that both can exhibit partial or complete spatial separation of an excited-state electron–hole pair (i.e., type II behavior). However, we reveal that thick-shell growth is challenged by competing processes: alloying and cation exchange. We demonstrate that these can be largely avoided by choice of shelling conditions (e.g., time, temperature, and QD core identity). The resulting CdSe/ZnSe gQDs exhibit unusual single-QD properties, principally emitting from dim gray states but having high two-exciton (biexciton) emission efficiencies, whereas ZnSe/CdS gQDs show characteristic gQD blinking suppression, though only if shelling is accompanied by partial cation exchange.},
doi = {10.1021/jacs.5b00313},
journal = {Journal of the American Chemical Society},
number = 11,
volume = 137,
place = {United States},
year = {Fri Mar 06 00:00:00 EST 2015},
month = {Fri Mar 06 00:00:00 EST 2015}
}

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Cited by: 21 works
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