Remarkably high tensile strength and lattice thermal conductivity in wide band gap oxidized holey graphene C2O nanosheet.

Abstract

Recently, the synthesis of oxidized holey graphene with the chemical formula C₂O has been reported (J. Am. Chem. Soc. 2024, 146, 4532). We herein employed a combination of density functional theory (DFT) and machine learning interatomic potential (MLIP) calculations to investigate the electronic, optical, mechanical and thermal properties of the C₂O monolayer, and compared our findings with those of its C₂N counterpart. Our analysis shows that while the C₂N monolayer exhibits delocalized π-conjugation and shows a 2.47 eV direct-gap semiconducting behavior, the C₂O counterpart exhibits an indirect gap of 3.47 eV. We found that while the C₂N monolayer exhibits strong absorption in the visible spectrum, the initial absorption peaks in the C₂O lattice occur at around 5 eV, falling within the UV spectrum. Notably, we found that the C₂O nanosheet presents significantly higher tensile strength compared to its C₂N counterpart. MLIP-based calculations show that at room temperature, the C₂O nanosheet can exhibit remarkably high tensile strength and lattice thermal conductivity of 42 GPa and 129 W/mK, respectively. The combined insights from DFT and MLIP-based results provide a comprehensive understanding of the electronic and optical properties of C₂O nanosheets, suggesting them as mechanically robust and highly thermally conductive wide bandgap semiconductors.