First-principles study of electronic and optical properties of defective sawtooth penta-graphene nanoribbons

We present first-principles calculations of the structural, electronic, transport, and optical properties of defective sawtooth penta-graphene nanoribbons (D-SSPGNRs), promising candidates as building units of future optoelectronic devices. The calculated results of the binding energy and phonon band structure show that the single- and double-vacancy SSPGNR structures with four various chain widths may stabilize with different topologies in the vacancies. Electronic structure calculations denote that the semiconducting D-SSPGNRs appear confined electronic states in the band gap. The electronic transmission spectrum through the D-SSPGNRs is attenuated. Optical properties are investigated by calculating complex dielectric function and optical absorption coefficient with different polarization directions. The imaginary parts of the dielectric function and the absorption coefficient of D-SSPGNR structures expose the new peaks and redshift. Optical polarization occurs in all structures and occurs strongly with the SSPGNRs which are vacated at the sp3-hybrid carbon atom. These diverse optoelectronic properties indicate a great possibility for applying D-SSPGNR materials in the future optoelectronics field.