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Physical Chemistry Chemical Physics

Modulation of electronic and mechanical properties of phagraphene via hydrogenation and fluorination

Authors: Dong-Hai Wu; Shuaiwei Wang; Jin-Yun Yuan; Baocheng Yang; Houyang Chen

Publication Date: -0001-11-30  Article ASAP

Recently, a new carbon sheet, phagraphene, was proposed by theoretical calculations [Nano Lett. 2015, 15, 6182]. In this paper, the hydrogenated and fluorinated phagraphene (denoted as H-PHA and F-PHA) sheets have been systematically studied using first-principles calculations. The results of formation energy, ab initio molecular dynamics, phonon dispersion and elastic constants confirm that the modified phagraphene sheets are thermodynamically and dynamically as well as mechanically stable. We find that hydrogenation or fluorination is an effective way to modulate the bandgap, and we also find that adsorption-induced semimetal-semiconductor transition and adsorption-induced semimetal-insulator transition occur. Configuration-dependent bandgap for partially H-PHA and configuration-independent bandgap for fully H-PHA are determined. Adsorption-ratio-dependent bandgaps of H-PHA and F-PHA are also identified. Calculated bandgaps from HSE06 and PBE functionals of fully H-PHA are larger than those of F-PHA, and they are comparable to the hydrogenated/fluorinated penta-graphene while they are larger than their corresponding graphene. Dependence of bandgaps of fully H-PHA and F-PHA on the tensile strain is investigated, and our calculations show that an insulator-semiconductor transition occurs upon increasing the tensile strain. Our results also determined that the mechanical properties are controllable by using hydrogenation and fluorination. The calculations of Young’s modulus and Poisson’s ratio reveal the functionalized phagraphene sheets possess suitable stiffness and resistance to volume deformation, and both are smaller than the pristine phagraphene.  Read more