Water Dispersible, Positively and Negatively Charged MoS2 Nanosheets: Surface Chemistry and the Role of Surfactant Binding

Gupta, Amit and Arunachalam, Vaishali and Vasudevan, Sukumaran (2015) Water Dispersible, Positively and Negatively Charged MoS2 Nanosheets: Surface Chemistry and the Role of Surfactant Binding. In: JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 6 (4). pp. 739-744.

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Abstract

Stable aqueous dispersions of atomically thin layered MoS2 nanosheets have been obtained by sonication in the presence of ionic surfactants. The dispersions are stabilized by electrostatic repulsion between the sheets, and we show that the sign of the charge on the MoS2 nanosheets, either positive or negative, can be can be controlled by the choice of the surfactant. Using techniques from solution NMR, we show that the surfactant chains are weakly bound to the MoS2 sheets and undergo rapid exchange with free surfactant chains present in the dispersion. In situ nuclear Overhauser effect spectroscopic measurements provide direct evidence that the surfactant chains lie flat, arranged randomly on the basal plane of the MoS2 nanosheets with their charged headgroup exposed. These results provide a chemical perspective for understanding the stability of these inorganic nanosheets in aqueous dispersions and the origin of the charge on the sheets.

Item Type:	Journal Article
Publication:	JOURNAL OF PHYSICAL CHEMISTRY LETTERS
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copy right for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Keywords:	TRANSITION-METAL DICHALCOGENIDES; SINGLE-LAYER MOS2; EXFOLIATED MOS2; GRAPHENE; LIQUID; NANOCRYSTALS
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	20 Apr 2015 07:13
Last Modified:	20 Apr 2015 07:13
URI:	http://eprints.iisc.ac.in/id/eprint/51241

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