Monolayer-enriched production of Au-decorated WS 2 Nanosheets via Defect Engineering
- PDF / 1,206,259 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 96 Downloads / 157 Views
MRS Advances © 2018 Materials Research Society DOI: 10.1557/adv.2018.350
Monolayer-enriched production of Au-decorated WS2 Nanosheets via Defect Engineering Jeremy R. Dunklin,1 Paul Lafargue,2 Thomas M. Higgins,2 Gregory T. Forcherio,3 Mourad Benamara,4 Niall McEvoy,5 D. Keith Roper,4 Jonathan N. Coleman,5 Yana Vaynzof,2 Claudia Backes2 1
National Renewable Energy Laboratory, Golden, CO, USA
2
Ruprecht-Karls University Heidelberg, Heidelberg, DE
3
U.S. Army Research Laboratory, Adelphi, MD, USA
4
University of Arkansas, Fayetteville, AR, USA
5
Trinity College Dublin, Dublin 2, IE
ABSTRACT
Layered transition metal dichalcogenides (TMDs) represent a diverse, emerging source of twodimensional (2D) nanostructures with broad application in optoelectronics and energy. Chemical functionalization has evolved into a powerful tool to tailor properties of these 2D TMDs; however, functionalization strategies have been largely limited to the metallic 1Tpolytype. The work herein illustrates that 2H-semiconducting liquid-exfoliated tungsten disulfide (WS2) undergoes a spontaneous redox reaction with gold (III) chloride (AuCl 3). Au nanoparticles (NPs) predominantly nucleate at nanosheet edges with tuneable NP size and density. AuCl3 is preferentially reduced on multi-layer WS2 and resulting large Au aggregates are easily separated from the colloidal dispersion by simple centrifugation. This process may be exploited to enrich the dispersions in laterally large, monolayer nanosheets. It is proposed that thiol groups at edges and defects sides reduce the AuCl3 to Au0 and are in turn oxidized to disulfides. Optical emission, i.e. photoluminescence, of the monolayers remained pristine, while the electrocatalytic activity towards the hydrogen evolution reaction is significantly improved. Taken together, these improvements in functionalization, fabrication, and catalytic activity represent an important advance in the study of these emerging 2D nanostructures.
Downloaded from https://www.cambridge.org/core. Access paid by the UCSB Libraries, on 10 Apr 2018 at 10:04:22, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/adv.2018.350
INTRODUCTION Layered two-dimensional (2D) transition metal dichalcogenides (TMDs) nanostructures have received significant recent interest in energy and optoelectronic applications [1,2]. The lack of scalable, reproducible fabrication techniques has limited implementation of TMDs due to difficulty, scalability, or cost. Liquid exfoliation presents an accessible, potentially scalable method of producing TMD nanosheets [3]. Several distinct liquid exfoliation techniques are available, with the simplest being liquid-phase exfoliation (LPE). A key advantage of LPE is that the semiconducting 2H-polytype is retained, whereas n-BuLi chemical exfoliation (CE) yields the metastable metallic 1Tpolytype. A significant disadvantage of LPE over other techniques is the broad size and thickness distributions obtained. Size selection can be ach
Data Loading...
