Details
| Original language | English |
|---|---|
| Article number | 2207101 |
| Journal | SMALL |
| Volume | 19 |
| Issue number | 23 |
| Early online date | 9 Mar 2023 |
| Publication status | Published - 7 Jun 2023 |
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.
Keywords
- colloidal synthesized 2H-MoS, differential pulse voltammetry, potential-dependent conductivity, potential-modulated absorption spectroscopy, thin films
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Biotechnology
- Chemistry(all)
- Materials Science(all)
- Biomaterials
- Materials Science(all)
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In: SMALL, Vol. 19, No. 23, 2207101, 07.06.2023.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Electronic Structure of Colloidal 2H-MoS2 Mono and Bilayers Determined by Spectroelectrochemistry
AU - Wurst, Kai M.
AU - Strolka, Onno
AU - Hiller, Jonas
AU - Keck, Jakob
AU - Meixner, Alfred J.
AU - Lauth, Jannika
AU - Scheele, Marcus
N1 - Funding Information: The authors thank André Niebur, excellence cluster PhoenixD, and the Institute of Physical Chemistry and Electrochemistry, Hannover for performing TEM measurements. Distilled solvents used for electrochemical experiments were kindly provided by Florian Fetzer and Andreas Schnepf, Institute of Inorganic Chemistry, University of Tübingen. The authors thank Elke Nadler, Institute of Physical and Theoretical Chemistry, University of Tübingen, for performing SEM/EDX measurements using a Hitachi SU 8030 SEM, which was funded by the DFG under the contract INST 37/829‐1 FUGG. The glass and metal workshops of the Central Chemistry Institute, University of Tübingen, are acknowledged for the fabrication of many components used in the measurement setups. J.L. is thankful for funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy within the Cluster of Excellence PhoenixD (EXC2122, Project ID 390833453). Financial support for this work was provided by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No 802822), as well as the DFG under grant SCHE1905/9‐1.
PY - 2023/6/7
Y1 - 2023/6/7
N2 - 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.
AB - 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.
KW - colloidal synthesized 2H-MoS
KW - differential pulse voltammetry
KW - potential-dependent conductivity
KW - potential-modulated absorption spectroscopy
KW - thin films
UR - http://www.scopus.com/inward/record.url?scp=85150489205&partnerID=8YFLogxK
U2 - 10.1002/smll.202207101
DO - 10.1002/smll.202207101
M3 - Article
AN - SCOPUS:85150489205
VL - 19
JO - SMALL
JF - SMALL
SN - 1613-6810
IS - 23
M1 - 2207101
ER -