Chemical modification of 2D materials using molecules and assemblies of molecules

Abstract

In this article, we discuss the recent progress on controlled structural modification of 2D materials by means of molecular functionalization, with a focus on scanning probe microscopy techniques for their characterization. For many practical applications of these novel materials, it is necessary to tune their electronic and optical properties, and molecule-based functionalization is a powerful approach to reach this. We discuss recent covalent and non-covalent approaches, for functionalization of graphene, transition metal dichalcogenides, black phosphorus, and hexagonal boron nitride. Nanostructuring approaches and their impact on 2D materials' properties are highlighted.

Boosting and Balancing Electron and Hole Mobility in Single- and Bilayer WSe2 Devices via Tailored Molecular Functionalization

“…In order to improve the device performances, the engineering of the energy levels of the 2DM through functionalization with molecules represents a valuable alternative to the use of diverse metals. 9,[23][24][25][26][27][28][29] In this context, self-assembled monolayers (SAMs), i.e. ultra-thin molecular layers that are covalently attached to the target surfaces, 30 are particularly appealing since their ordered structure, framed by the self-assembly, ensures a parallel out-of-plane alignment of molecular dipoles, causing a profound change of surface energy and electronic properties of the functionalized surface.…”

Prospects of Observing Ionic Coulomb Blockade in Artificial Ion Confinements

“…Moreover, the standard method of wetting all nanoscale devices uses prewetting with water-ethanol mixtures, a procedure known to produce nanobubbles on hydrophobic surfaces and which has been linked to the same effect on mildly hydrophobic 2D material surfaces [ 25 ]. In addition, remnants of bound ethanol, or other molecules, have been shown to modify surface properties and can persist after subsequent flushing [ 62 ]. Differentiating these effects from ICB nonlinear IV curves requires additional probes and separate gating control.…”

Highly Selective Non‐Covalent On‐Chip Functionalization of Layered Materials

“…[ 8–10 ] Additionally, the tailorable surface makes chemical functionalization an essential tool to access the full potential of these materials. As a consequence, many studies target the modification of the surface of TMDs via covalent [ 11–15 ] or non‐covalent [ 16–19 ] functionalization. Noticeably, both paths can be conducted in solution, for example, for liquid‐phase exfoliated TMDs, [ 20 ] as well as on substrate‐supported layers from chemical vapor deposition (CVD) growth or mechanical exfoliation.…”