Probing Excitons in Ultrathin PbS Nanoplatelets with Enhanced Near-Infrared Emission

Journal Article (2021)
Authors

Francisco Vázquez (Student TU Delft)

Qianli Yu (Student TU Delft)

Lars F. Klepzig (Leibniz Universität)

L.D.A. Siebbeles (TU Delft - ChemE/Opto-electronic Materials)

Ryan W. Crisp (TU Delft - ChemE/Opto-electronic Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg)

Jannika Lauth (TU Delft - ChemE/Opto-electronic Materials, Leibniz Universität)

Research Group
ChemE/Opto-electronic Materials
Copyright
© 2021 Francisco Manteiga Vázquez, Qianli Yu, Lars F. Klepzig, L.D.A. Siebbeles, R.W. Crisp, J.D. Lauth
To reference this document use:
https://doi.org/10.1021/acs.jpclett.0c03461
More Info
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Publication Year
2021
Language
English
Copyright
© 2021 Francisco Manteiga Vázquez, Qianli Yu, Lars F. Klepzig, L.D.A. Siebbeles, R.W. Crisp, J.D. Lauth
Research Group
ChemE/Opto-electronic Materials
Issue number
1
Volume number
12
Pages (from-to)
680-685
DOI:
https://doi.org/10.1021/acs.jpclett.0c03461
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Abstract

Colloidal PbS nanoplatelets (NPLs) are highly interesting materials for near-infrared optoelectronic applications. We use ultrafast transient optical absorption spectroscopy to study the characteristics and dynamics of photoexcited excitons in ultrathin PbS NPLs with a cubic crystal structure. NPLs are synthesized at near room temperature from lead oleate and thiourea precursors; they show an optical absorption onset at 680 nm (1.8 eV) and photoluminescence at 720 nm (1.7 eV). By postsynthetically treating PbS NPLs with CdCl2, their photoluminescence quantum yield is strongly enhanced from 1.4% to 19.4%. The surface treatment leads to an increased lead to sulfur ratio in the structures and associated reduced nonradiative recombination. Additionally, exciton-phonon interactions in pristine and CdCl2 treated NPLs at frequencies of 1.96 and 2.04 THz are apparent from coherent oscillations in the transient absorption spectra. This study is an important step forward in unraveling and controlling the optical properties of IV-VI semiconductor NPLs.

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