The role of functional thiolated molecules on the enhanced electronic transport of interconnected MoS$_2$ nanostructures

TL;DR

This study uses first-principles calculations to explore how thiol molecular linkers enhance electronic transport in interconnected MoS₂ nanostructures, revealing mechanisms that could improve 2D electronic devices.

Contribution

It provides a microscopic understanding of how thiol functionalization improves electronic transport in MoS₂ nanostructures, combining theoretical and experimental insights.

Findings

Thiol linkers create electronic states near the Fermi level facilitating transport.

Molecular linkers lower potential barriers for thermally activated hopping.

Experimental verification shows improved conductivity with functionalization.

Abstract

Molecular linkers have emerged as an effective strategy to improve electronic transport properties on solution-processed layered materials via defect functionalization. However, a detailed discussion on the microscopic mechanisms behind the beneficial effects of functionalization is still missing. Here, by first-principles calculations based on density functional theory, we investigate the effects on the electronic properties of interconnected MoS$_2$ model flakes systems upon functionalization with different thiol molecule linkers, namely thiophenol, 1,4-benzenedithiol, 1,2-ethanedithiol, and 1,3-propanedithiol. The bonding of benzene- and ethanedithiol bridging adjacent armchair MoS$_2$ nanoflakes leads to electronic states just above or at the Fermi level, thus forming a molecular channel for electronic transport between flakes. In addition, the molecular linker reduces the potential barrier for thermally activated hopping between neighboring flakes, improving the conductivity as verified in experiments. The comprehension of such mechanisms helps in future developments of solution-processed layered materials for use on 2D electronic devices.