Colloidal 2D Mo_1−xW_xS₂ nanosheets

an atomic- to ensemble-level spectroscopic study

verfasst von

Markus Fröhlich, Marco Kögel, Jonas Hiller, Leo Kahlmeyer, Alfred J. Meixner, Marcus Scheele, Jannika Lauth, Jannik C. Meyer

Abstract

Composition dependent tuning of electronic and optical properties in semiconducting two-dimensional (2D) transition metal dichalcogenide (TMDC) alloys is promising for tailoring the materials for optoelectronics. Here, we report a solution-based synthesis suitable to obtain predominantly monolayered 2D semiconducting Mo_1−xW_xS₂ nanosheets (NSs) with controlled composition as substrate-free colloidal inks. Atomic-level structural analysis by high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) coupled with energy dispersive X-ray spectroscopy (EDXS) depicts the distribution of individual atoms within the Mo_1−xW_xS₂ NSs and reveals the tendency for domain formation, especially at low molar tungsten fractions. These domains cause a broadening in the associated ensemble-level Raman spectra, confirming the extrapolation of the structural information from the microscopic scale to the properties of the entire sample. A characterization of the Mo_1−xW_xS₂ NSs by steady-state optical spectroscopy shows that a band gap tuning in the range of 1.89-2.02 eV (614-655 nm) and a spin-orbit coupling-related exciton splitting of 0.16-0.38 eV can be achieved, which renders colloidal methods viable for upscaling low cost synthetic approaches toward application-taylored colloidal TMDCs.

Organisationseinheit(en)

PhoenixD: Simulation, Fabrikation und Anwendung optischer Systeme

Externe Organisation(en)

Eberhard Karls Universität Tübingen

Typ

Artikel

Journal

Physical Chemistry Chemical Physics

Band

26

Seiten

13271-13278

Anzahl der Seiten

8

ISSN

1463-9076

Publikationsdatum

2024

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Physik und Astronomie (insg.), Physikalische und Theoretische Chemie

Elektronische Version(en)

https://doi.org/10.1039/d4cp00530a (Zugang: Offen)