  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.
