Novel nanobelts constructed from hexagonal graphene quantum dots: Electronic, optical, and sensing properties

Abstract

New nanobelts and nanoribbons are built from zigzag-hexagonal graphene quantum dots. Their stability, electronic, optical, and sensing properties are studied using density functional theory calculations. The infrared spectra's real vibrational frequencies and positive binding energy prove the stability of the constructed structures. The thermal stability at 600 K is also confirmed by molecular dynamics simulations. The nanobelts have a significantly low energy gap compared to the planer single quantum dots or the extended nanoribbons based on these nanodots. This is a result of the wrapping of the graphene nanodots which raises the π-overlapping between adjacent rings that decreases the energy gap. Interactive electronic states localized at the zigzag edges characterize both nanobelts and nanoribbons. Thus these systems are promising candidates for sensing and catalytic applications. Their sensing capability is tested by studying the adsorption of selected volatile organic compounds such as chloromethane and trichloroethylene. The findings indicate that these gases are effectively adsorbed with moderate adsorption energy and charge transfer, opening the door toward gas sensor applications.

Keywords

• Graphene quantum dots
• Nanobelts and nanoribbons
• DFT
• Electronic and optical properties
• Volatile organic compounds
• Sensors