Surface Depletion Effects in Bromide-Ligated Colloidal Cadmium Selenide Nanoplatelets: Toward Efficient Emission at High Temperature

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Surface Depletion Effects in Bromide-Ligated Colloidal Cadmium Selenide Nanoplatelets: Toward Efficient Emission at High Temperature
Title:
Surface Depletion Effects in Bromide-Ligated Colloidal Cadmium Selenide Nanoplatelets: Toward Efficient Emission at High Temperature
Other Titles:
The Journal of Physical Chemistry Letters
Publication Date:
14 September 2021
Citation:
Zhang, Z., Thung, Y. T., Wang, L., Chen, X., Ding, L., Fan, W., & Sun, H. (2021). Surface Depletion Effects in Bromide-Ligated Colloidal Cadmium Selenide Nanoplatelets: Toward Efficient Emission at High Temperature. The Journal of Physical Chemistry Letters, 12(37), 9086–9093. https://doi.org/10.1021/acs.jpclett.1c02623
Abstract:
The colloidal semiconductor nanoplatelet (NPL) with broad ligand-semiconductor interface is an ideal system for surface science investigation, but the study regarding depletion effects in NPLs remains lacking. Herein we explore such effects in colloidal CdSe NPLs through Br ligation. Apart from improved brightness and red-shifted optical features, we also experimentally observed abnormal negative thermal quenching phenomena in bromide-ligated CdSe NPLs over 200 K under a cryogenic environment and up to 383 K under an ambient environment, which was absent in pristine NPLs. We speculate that the surface depletion effect shall account for these anomalous phenomena due to the susceptibility of the surface depletion region on photoexcited carrier concentration and surface condition. The existence of the depletion layer in NPLs is also validated quantitatively with k·p simulation. Besides offering an alternative explanation on the red-shifted optical properties of CdSe NPLs by Br-ligation, our findings pave the new route toward solution-processed NPLs-based optoelectronics with boosted thermal resistance.
License type:
Publisher Copyright
Funding Info:
This research / project is supported by the National Research Foundation - Competitive Research Programme
Grant Reference no. : NRF-CRP21-2018-0092

This research / project is supported by the National Research Foundation - Competitive Research Programme
Grant Reference no. : NRFCRP23-2019-0007

This research / project is supported by the A*STAR - Advanced manufacturing programme -individual research grant
Grant Reference no. : A20E5c0083

This research / project is supported by the Ministry of Education Singapore - Academic Research Fund Tier 1
Grant Reference no. : RG95/19 (S)
Description:
This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see doi.org/10.1021/acs.jpclett.1c02623
ISSN:
1948-7185
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