PBCF‐Graphene: A 2D Sp² Hybridized Honeycomb Carbon Allotrope with a Direct Band Gap

Abstract Inspired by the synthesis of graphene with benzene as the precursor, a novel all‐sp² hybridized two‐dimensional (2D) carbon allotrope is proposed in this work. This 2D carbon allotrope is a poly‐butadiene‐cyclooctatetraene‐framework and displays a P6/mmm space group with 24 carbon atoms in a hexagonal unit cell (denoted as PBCF‐graphene). First‐principles calculations show the presence of a honeycomb structure along the c‐axis that possesses two kinds of holes with diameters of 4.88 and 2.39 Å. PBCF‐graphene has a direct band gap of 1.355 eV at the Γ point as determined using the HSE06 hybrid functional. This structure is energetically preferable over E‐graphene, C₃₃‐carbon sheets, cyclo[18]carbon and C₂₀ fullerenes and is the same to PCF‐graphene. Its dynamical, thermal and mechanical stabilities are proven from the phonon dispersion, ab initio molecular dynamics (AIMD simulations and elastic constants, respectively. It can not only withstand equi‐biaxial tensile strains as high as 17.6% but can also withstand temperatures at least 1000 K. PBCF‐graphene exhibits a high, room temperature, in‐plane, electron mobility, which is higher than the electron mobility of monolayer black phosphorus and 5.9 times higher than the hole mobility of monolayer MoS₂. In addition, PBCF‐graphene can absorb photons from the visible to near‐ultraviolet regimes, giving it potential value in applications for nanoelectronic and optoelectronic devices.