Journal article

Robustness of Size Selection and Spectroscopic Size, Thickness and Monolayer Metrics of Liquid-Exfoliated WS2



Publication Details
Authors:
Ueberricke, L.; Coleman, J.; Backes, C.
Publisher:
WILEY-V C H VERLAG GMBH

Publication year:
2017
Journal:
physica status solidi (b) – basic solid state physics
Pages range :
1700443
Volume number:
254
Issue number:
11
Number of pages:
9
ISSN:
0370-1972
DOI-Link der Erstveröffentlichung:


Abstract
Liquid exfoliation and centrifugation based size selection has emerged as widely applied technique to produce nanosheets in a solution-processable form. Quantitative spectroscopic metrics to extract nanosheet size, thickness and monolayer content from optical spectra have previously been established. Such metrics are extremely useful and can be used to optimise the production technique (for example on scale-up) and size selection. However, it is not clear whether exfoliation, size selection, and spectroscopic metrics are robust or whether the result depends on the starting material or subtle details of the processing and analysis. By comparing two batches of WS2 exfoliated and size-selected in aqueous surfactant solution using different starting materials, protocols and equipment in each step, we show that the nanosheet size obtained after different steps in a cascade centrifugation is highly reproducible. A detailed statistical analysis on the nanosheet dimensions revealed well-defined relationships between nanosheet mean thickness and monolayer content. Spectroscopic metrics for nanosheet layer number, lateral size (from extinction) and monolayer content (from Raman/photoluminescence) do not depend on sample type and measurement conditions, albeit the data analysis may require adjustment as discussed.


Keywords
centrifugation, layered materials, liquid exfoliation, optical properties, transition metal dichalcogenides, WS2


Authors/Editors

Last updated on 2022-20-04 at 14:50