Structural Features Dictate the Photoelectrochemical Activities of Two-Dimensional MoSe 2 and WSe 2 Nanostructures.

Autor: Tóth PS; MTA Premium Post Doctorate Research Program, University of Szeged, Szeged 6720, Hungary.; Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Center, University of Szeged, Szeged 6720, Hungary., Szabó G; Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Center, University of Szeged, Szeged 6720, Hungary., Janáky C; Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Center, University of Szeged, Szeged 6720, Hungary.
Jazyk: angličtina
Zdroj: The journal of physical chemistry. C, Nanomaterials and interfaces [J Phys Chem C Nanomater Interfaces] 2021 Apr 15; Vol. 125 (14), pp. 7701-7710. Date of Electronic Publication: 2021 Mar 31.
DOI: 10.1021/acs.jpcc.1c01265
Abstrakt: The exfoliation of layered materials into two-dimensional (2D) semiconductors creates new structural domains, for example, basal planes, defect-rich in-planes, and edge sites. These surface species affect the photoelectrochemical (PEC) performance, which in turn determines their applicability in solar energy conversion technologies. In this study, a custom-designed microdroplet cell-based spatially resolved PEC approach was employed to identify the structural parts and to measure the PEC activity of the mechanically exfoliated MoSe 2 and WSe 2 nanosheets for bulk, few-layer, and monolayer specimens. The PEC performance decreased with the decreasing thickness of nanoflakes, and the relative PEC activity (photo/total current) reduced by introducing more defects to the 2D flakes: 1-3% loss was found for in-plane defects and 30-40% for edge defects. While edge sites act as charge carrier recombination centers, their electrocatalytic activity is higher than that of the basal planes. The comparison of PEC activity of micromechanically and liquid phase exfoliated bulk and few-layer MoSe 2 and WSe 2 flakes further confirmed that the PEC performance of 2D flakes decreases with an increasing number of edge sites.
Competing Interests: The authors declare no competing financial interest.
(© 2021 The Authors. Published by American Chemical Society.)
Databáze: MEDLINE
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