Ab initio study of electronic structure, quantum transport and optical absorption properties of polyacene quinone radical polymers

摘要

Semiempirical quantum mechanical calculations have been implemented to study the molecular structure, electronic structure, optical properties of polyacene quinone radical polymers, and the quantum transport properties are also been calculated through combination of the numerical atomic orbitals basis set method based on density functional theory with the non-equilibrium Green¿¿s function formalism. The polyacene quinone radical polymers exhibit similar elastic modulus to the carbon nanotubes. The electronic molecular orbitals and energy bands of polyacene quinone radical polymers show insulator features, with the great conjugated bonds formed in polymer molecules resulting in extreme high polarization and dielectric constants, and the Fermi energy and band-gaps of ultraviolet range are static with the variation of polymerization degree. The aluminum electrodes with crystallographic (001) surfaces have been used in the electronic transport calculations, which indicate the quantum conductance spectrum changes with the varied strain and polymerization degree, however appears no explicit change, representing large open-gap feature of insulators. Ultraviolet-visible absorption spectra show a few characteristic peaks, the positions and number of which varying with polymerization degree, predicting that polyacene quinone radical polymers, as high dielectric functional materials, could be applied to ultraviolet optoelectronic nanoscale quantum devices.