Spontaneous chemical functionalization via coordination of Au single atoms on monolayer MoS2

INTRODUCTION

Chemical surface functionalization has been used to tune the electronic, optical, and catalytic properties of two-dimensional (2D) transition metal dichalcogenides (TMDs) (1–3). Chemical functionalization commonly relies on the presence of lattice defects and physisorption methods to circumvent the chemical inertness of pristine semiconducting TMDs (4). Unfortunately, such routes inevitably modify the surface characteristics as well as the optical, thermal, and transport properties of the atomically thin layers (5–9). Most of the proposed MoS₂ functionalization routes are based on liquid exfoliated flakes, which have reduced and more reactive lateral sizes. In addition, this exfoliation route is not ideal for scaling up processes in the electronics and optoelectronics industries (10). For example, Voiry et al. (6) reported covalent functionalization using chemically exfoliated MoS₂, WS₂, and MoSe₂ with organohalides…