Me-graphane: tailoring the structural and electronic properties of Me-graphene by hydrogenation

TL;DR

This study uses first-principles calculations and molecular dynamics simulations to demonstrate how hydrogenation can effectively tune the structural and electronic properties of Me-graphene, a non-zero bandgap graphene derivative.

Contribution

It provides a detailed analysis of hydrogenation effects on Me-graphene's electronic bandgap and structural stability, revealing new insights into controllable property modification.

Findings

Hydrogenation significantly increases the bandgap from 0.64 eV to 2.81 eV.

Hydrogenated Me-graphene exhibits strong C-H bonds and a stable boat-like conformation.

Hydrogenation is temperature-dependent and occurs via island growth, with specific sites acting as triggers.

Abstract

Graphene-based materials (GBMs) constitute a large family of materials which has attracted great interest for potential applications. In this work, we apply first-principles calculations based on density functional theory (DFT) and fully atomistic reactive molecular dynamics (MD) simulations to study the structural and electronic effects of hydrogenation in Me-graphene, a non-zero bandgap GBM composed of both $sp^2$ and $sp^3$-hybridized carbon. Our DFT results show a substantial tuning of the electronic properties of Me-graphene by hydrogenation, with the bandgap varying from $0.64$ eV to $2.81$ eV in the GGA-PBE approach, passing through metallic ground-states and a narrower bandgap state depending on the hydrogen coverage. The analyses of structural properties and binding energies have shown that hydrogenated Me-graphene presents strong and stable \ce{C-H} bonds, and all of the carbon atoms are in $sp^3$ hybridization resulting in a boat-like favorable conformation for fully-hydrogenated Me-graphene. Our MD simulations have indicated that the hydrogenation of Me-graphene is temperature-dependent, and the covalent adsorption tends to grow by islands. Those simulations also show that the most favorable site, predicted by our DFT calculations, acts as trigger adsorption for the extensive hydrogenation.