Data_Po-graphene: A Two-Dimensional Carbon Sheet as a Quantum Capacitor
Description
Po-graphene: A Two-Dimensional Carbon Sheet as a Quantum Capacitor: Advanced two-dimensional (2D) carbon allotropes for quantum-capacitor applications require structural stability, mechanical robustness, and a finite density of states (DOS) near the Fermi level. This combination is difficult to achieve in pristine graphene because of its vanishing DOS at the Dirac point, while many non-hexagonal allotropes require precise energetic and dynamical stability. In this work, we report a first-principles investigation of PO-graphene, a 2D carbon allotrope com posed of pentagonal and octagonal carbon rings, as a strain-tunable quantum-capacitive material. Density functional theory (DFT) confirms the energetic, dynamical, and mechanical stability of the proposed monolayer through cohesive-energy analysis, phonon dispersion, and strain-dependent total-energy calculations. Electronic-structure analysis demonstrates metallic behavior with a fi nite DOS near the Fermi level, providing an intrinsic advantage for quantum capacitance without the need for chemical doping or defect engineering. The optical response displays pronounced strain-dependent modulation in the near-infrared region. Furthermore, applying a 6% compressive biaxial strain increases the quantum capacitance to 170Fg−1. Meanwhile, surface charge analysis shows that PO-graphene possesses the largest positive-voltage charge-storage area among the car bon allotropes evaluated. These results identify PO-graphene as a stable and mechanically tunable 2D carbon platform for next generation quantum capacitor and flexible optoelectronic applications