A computational insight into the intrinsic, Si-decorated and vacancy-defected γ-graphyne nanoribbon towards adsorption of CO2 and O2 molecules

Abstract

In this study, the effects of decorating a silicon (Si) atom and applying a single vacancy defect on an armchair γ-graphyne nanoribbon (A-γ-GyNR) are investigated toward CO2 and O2 molecules adsorption. The magnetic and electronic transport properties, including the calculation of adsorption energy, charge transfer, magnetic moment, band structure, phonon dispersion and density of state (DOS), have been studied using the spin-polarized density functional theory (DFT) method. The stability of the proposed substrates is measured and different positions for gas molecules are considered. The results reveal that the highest amounts of adsorption energy of CO2 (0.63 eV) and O2 (2.2 eV) molecules belong to the substrate decorated with the Si atom in the 12-membered ring (H1) and acetylene linkage (B3), respectively. In addition, the removal of a carbon atom with sp hybridization improves the O2 molecule adsorption by 3.34 times compared to the primary substrate (P-GyNR). According to the recovery time calculations, the most appropriate desorption time is related to T1-M1 model. The current–voltage characteristic confirms that the resistance of the introduced sensors fully changed after sensing. This work can be considered as an effective step toward understanding and developing A-γ-GyNR-based gas sensors.