▎ 摘　　要

Inspired by the synthesis of graphene with benzene as the precursor, a novel all-sp(2) 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 angstrom. PBCF-graphene has a direct band gap of 1.355 eV at the Gamma point as determined using the HSE06 hybrid functional. This structure is energetically preferable over E-graphene, C-33-carbon sheets, cyclo[18]carbon and C-20 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.