Unravelling the ultrafast charge dynamics in PbS quantum dots through resonant Auger mapping of the sulfur K-edge.

Autor:	Sloboda T; Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology SE-100 44 Stockholm Sweden fjson@kth.se., Johansson FOL; Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology SE-100 44 Stockholm Sweden fjson@kth.se.; Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP F-75005 Paris France., Kammlander B; Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology SE-100 44 Stockholm Sweden fjson@kth.se., Berggren E; Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University Box 516 751 20 Uppsala Sweden., Svanström S; Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University Box 516 751 20 Uppsala Sweden., Fernández AG; Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology SE-100 44 Stockholm Sweden fjson@kth.se., Lindblad A; Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University Box 516 751 20 Uppsala Sweden., Cappel UB; Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology SE-100 44 Stockholm Sweden fjson@kth.se.
Jazyk:	angličtina
Zdroj:	RSC advances [RSC Adv] 2022 Nov 04; Vol. 12 (49), pp. 31671-31679. Date of Electronic Publication: 2022 Nov 04 (Print Publication: 2022).
DOI:	10.1039/d2ra06091d
Abstrakt:	There is a great fundamental interest in charge dynamics of PbS quantum dots, as they are promising for application in photovoltaics and other optoelectronic devices. The ultrafast charge transport is intriguing, offering insight into the mechanism of electron tunneling processes within the material. In this study, we investigated the charge transfer times of PbS quantum dots of different sizes and non-quantized PbS reference materials by comparing the propensity of localized or delocalized decays of sulfur 1s core hole states excited by X-rays. We show that charge transfer times in PbS quantum dots decrease with excitation energy and are similar at high excitation energy for quantum dots and non-quantized PbS. However, at low excitation energies a distinct difference in charge transfer time is observed with the fastest charge transfer in non-quantized PbS and the slowest in the smallest quantum dots. Our observations can be explained by iodide ligands on the quantum dots creating a barrier for charge transfer, which reduces the probability of interparticle transfer at low excitation energies. The probability of intraparticle charge transfer is limited by the density of available states which we describe according to a wave function in a quantum well model. The stronger quantum confinement effect in smaller PbS quantum dots is manifested as longer charge transfer times relative to the larger quantum dots at low excitation energies. Competing Interests: There are no conflicts to declare. (This journal is © The Royal Society of Chemistry.)
Databáze:	MEDLINE
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