Structure, electronic and optical properties of Al, Si, P doped penta-graphene: A first-principles study

Penta-graphene, an irregular pentagon two-dimensional structure, has an intrinsic quasi-direct band gap. In the paper, first-principles calculations have been performed to study the geometrical structures, electronic and optical properties of pure and Al, Si, P doped penta-graphene. The doping of Al, Si or P atoms significantly reduce the band gap of penta-graphene. The gap value of Al-doped penta-graphene at C1 is the largest, 1.693eV, and P-doped penta-graphene at C2 is the smallest, 0.314eV. For doped penta-graphene, the fluctuations of the partial density of states in the full energy range are similar, indicating that the orbitals of C and other impurity atoms are hybridized into bonds. Furthermore, it is found that the change of the static dielectric constant will be affected by the different doping atoms and the different positions of doping atoms. The effective width of absorption spectrum becomes narrower than that of pure penta-graphene after the doping. Our findings indicate the possibility of tuning the bandgap and the optical properties of the material to make it suitable for optoelectronic and photovoltaic applications.