Modulation of the Electronic Structure of Ti3C2Tx MXene via Thiol Functionalization Induced by a Click Reaction

Abstract

The functionalization of MXenes through chemical modifications offers unprecedented opportunities for tailoring their electronic properties. In this study, we investigate the effects of thiol functionalization by a radical-induced click reaction on a Ti3C2Tx-MXene nanosheet, explicitly focusing on the modulation of its electronic properties. Through comprehensive characterization techniques, including spectroscopy and microscopy, it was demonstrated that the chemical modification effectively modifies the surface chemistry of MXenes while concurrently altering their work function and electronic band structure. The thiol functionalization in the MXene results in a notable opening of the electronic band gap of (0.45 ± 0.05) eV revealed from scanning tunneling spectroscopy data. Moreover, the Kelvin probe force microscopy measurement exhibited a significant increase in the work function of the MXene from −4.44 eV to −4.28 eV after functionalization, indicative of enhanced electron transport properties, which are crucial to improving photovoltaic device efficiencies as estimated by SCAPS 1D software. This work highlights the utility of thiol functionalization in MXene, emphasizing its applicability in advanced electronic applications where precise control of electronic properties is essential.