Electrochemical Surface Modification of a 2D MoS2 Semiconductor

TL;DR

This paper demonstrates a novel electrochemical method to modify the basal plane of 2D MoS2 semiconductors using aryl-diazonium salt grafting, enabling high spatial selectivity for potential applications in nanostructure surface engineering.

Contribution

It introduces a new electrochemical grafting technique for basal plane modification of MoS2, overcoming previous inertness limitations and allowing nanoscale spatial control.

Findings

Successful electrochemical grafting on MoS2 basal plane.

High spatial selectivity achieved on nanoscale.

Potential applicability to other 2D semiconductors.

Abstract

The surface modification of 2D semiconducting materials, such as transition metal dichalcogenides (TMDCs), is becoming important for a diverse range of applications, such as biosensing, catalysis, energy generation and energy storage. Due to the chemical inertness of their basal plane, the surface modification of 2D TMDCs is mainly limited to their defective sites, or it requires a conversion of TMDC from its semiconducting into a metallic phase. In this work, we show that the basal plane of a 2D semiconductor molybdenum disulfide (MoS2) can be modified by electrochemical grafting of aryl-diazonium salt, such as 3,5-bis(trifluoromethyl)benzenediazonium tetrafluoroborate. To investigate the applicability of this method, we perform electrografting on MoS2 nanoribbons by addressing them individually via a different electrode. High spatial selectivity of this method on the nanoscale opens the possibility for specific surface modification of neighboring 2D layers and nanostructures that are contacted by electrodes. This method could be potentially applicable to other 2D semiconducting materials that are active in the same potential window in which the electrochemical reduction of aryl diazonium salts occurs.