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

verfasst von

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

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.

Organisationseinheit(en)

Institut für Physikalische Chemie und Elektrochemie
PhoenixD: Simulation, Fabrikation und Anwendung optischer Systeme

Externe Organisation(en)

Delft University of Technology
Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU Erlangen-Nürnberg)

Typ

Artikel

Journal

Journal of Physical Chemistry Letters

Band

12

Seiten

680-685

Anzahl der Seiten

6

ISSN

1948-7185

Publikationsdatum

14.01.2021

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Werkstoffwissenschaften (insg.), Physikalische und Theoretische Chemie

Elektronische Version(en)

https://doi.org/10.48550/arXiv.2011.07174 (Zugang: Offen)
https://doi.org/10.1021/acs.jpclett.0c03461 (Zugang: Geschlossen)