$\pi$-bonding-dominated energy gaps in graphene oxides

TL;DR

This study uses first-principle calculations to explore how various oxygen concentrations affect the electronic energy gaps in graphene oxides, revealing that orbital hybridizations and different $\pi$ bondings dominate their electronic properties.

Contribution

It uncovers the detailed relationship between oxygen concentration, $\pi$ bonding types, and energy gaps in graphene oxides, providing new insights into their electronic behavior.

Findings

Energy gaps are mainly influenced by orbital hybridizations in C-C, O-O, and C-O bonds.

Five types of $\pi$ bondings are identified during oxygen variation.

Electronic properties are dominated by chemical bondings affecting band structures and density of states.

Abstract

Chemical bondings of graphene oxides with oxygen concentration from 1\% to 50\% are investigated using first-principle calculations. Energy gaps are mainly determined by the competition of orbital hybridizations in C-C, O-O, and C-O bonds. They are very sensitive to the changes in oxygen concentration and distributions. There exists five types of $\pi$ bondings during the variation from the full to vanishing adsorptions, namely the complete termination, the partial suppression, the 1D bonding, the deformed planar bonding, and the well-behaved one. They can account for the finite and gapless characteristics, corresponding to the O-concentrations of $>$25\% and $<$3\%, respectively. The feature-rich chemical bondings dominate band structures and density of states, leading to diverse electronic properties.