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

Francisco Manteiga Vázquez, Qianli Yu, Lars F. Klepzig, Laurens D.A. Siebbeles, Ryan W. Crisp, Jannika Lauth

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)
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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.

Original languageEnglish
Pages (from-to)680-685
JournalJournal of Physical Chemistry Letters
Volume12
Issue number1
DOIs
Publication statusPublished - 2021

Bibliographical note

Accepted Author Manuscript
Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

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