Electronic Structure of Colloidal 2H-MoS₂ Mono and Bilayers Determined by Spectroelectrochemistry

authored by

Kai M. Wurst, Onno Strolka, Jonas Hiller, Jakob Keck, Alfred J. Meixner, Jannika Lauth, Marcus Scheele

Abstract

The electronic structure of mono and bilayers of colloidal 2H-MoS₂ nanosheets synthesized by wet-chemistry using potential-modulated absorption spectroscopy (EMAS), differential pulse voltammetry, and electrochemical gating measurements is investigated. The energetic positions of the conduction and valence band edges of the direct and indirect bandgap are reported and observe strong bandgap renormalization effects, charge screening of the exciton, as well as intrinsic n-doping of the as-synthesized material. Two distinct transitions in the spectral regime associated with the C exciton are found, which overlap into a broad signal upon filling the conduction band. In contrast to oxidation, the reduction of the nanosheets is largely reversible, enabling potential applications for reductive electrocatalysis. This work demonstrates that EMAS is a highly sensitive tool for determining the electronic structure of thin films with a few nanometer thicknesses and that colloidal chemistry affords high-quality transition metal dichalcogenide nanosheets with an electronic structure comparable to that of exfoliated samples.

Organisation(s)

PhoenixD: Photonics, Optics, and Engineering - Innovation Across Disciplines
Laboratory of Nano and Quantum Engineering

External Organisation(s)

University of Tübingen

Type

Article

Journal

SMALL

Volume

19

ISSN

1613-6810

Publication date

07.06.2023

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Biotechnology, Chemistry(all), Biomaterials, Materials Science(all)

Electronic version(s)

https://doi.org/10.1002/smll.202207101 (Access: Open)