Type

Journal Article

Authors

Jonathan N Coleman
Thomas M Higgins
Ronan J Smith
Andrew Harvey
Beata M Szydlowska
Damien Hanlon
Claudia Backes

Subjects

Chemistry

Topics
chemistry nanostructures graphite sonication surface active agents microscopy atomic force tungsten compounds molybdenum disulfides molybdenum disulfide microscopy electron transmission

Preparation of Liquid-exfoliated Transition Metal Dichalcogenide Nanosheets with Controlled Size and Thickness: A State of the Art Protocol. (2016)

Abstract We summarize recent advances in the production of liquid-exfoliated transition metal dichalcogenide (TMD) nanosheets with controlled size and thickness. Layered crystals of molybdenum disulphide (MoS2) and tungsten disulphide (WS2) are exfoliated in aqueous surfactant solution by sonication. This yields highly polydisperse mixtures containing nanosheets with broad size and thickness distributions. However, for most purposes, specific sizes (in terms of both lateral dimension and thickness) are required. For example, large and thin nanosheets are desired for (opto) electronic applications, while laterally small nanosheets are interesting for catalytic applications. Therefore, post-exfoliation size selection is an important step that we address here. We provide a detailed protocol on the efficient size selection in large quantities by liquid cascade centrifugation and the size and thickness quantification by statistical microscopic analysis (atomic force microscopy and transmission electron microscopy). The comparison of MoS2 and WS2 shows that both materials are size-selected in a similar way by the same procedure. Importantly, the dispersions of size-selected nanosheets show systematic changes in their optical extinction spectra with size due to edge and confinement effects. We show how these optical changes are related quantitatively to the nanosheets dimensions and describe how mean nanosheets length and layer number can be extracted reliably from the extinction spectra. The exfoliation and size selection protocol can be applied to a broad range of layered crystals as we have previously demonstrated for graphene, gallium sulphide (GaS) and black phosphorus.
Collections Ireland -> Trinity College Dublin -> PubMed

Full list of authors on original publication

Jonathan N Coleman, Thomas M Higgins, Ronan J Smith, Andrew Harvey, Beata M Szydlowska, Damien Hanlon, Claudia Backes

Experts in our system

1
Jonathan Coleman
Trinity College Dublin
Total Publications: 217
 
2
Thomas M Higgins
Trinity College Dublin
Total Publications: 7
 
3
Ronan J Smith
Trinity College Dublin
Total Publications: 11
 
4
Andrew Harvey
Trinity College Dublin
Total Publications: 17
 
5
Damien Hanlon
Trinity College Dublin
Total Publications: 13
 
6
Claudia Backes
Trinity College Dublin
Total Publications: 20