Electronic and optical properties of C-N-codoped TiO2: A first-principles GGA+U investigation

摘要

Electronic structures and optical properties of C-N-codoped anatase TiO2 werecalculated by using GGA+U method based on the density functional theory. Thecalculated results showed that the N-doped, C-doped, and C-N-codoped TiO2produced 2p states in band gap, and the band gaps of the three doped systemsdecreased compared with the pure TiO2. According to the optical results, theband edges of the three doped systems shifted to the long wavelength region,and the visible optical absorption from 450 to 800 nm was observed. Moreover,the visible light response of C-N-codoped TiO2 was better than the C or Nsingle doped TiO2, indicating that there was a synergistic effect for theC-N-codoped TiO2, which offseted the deficiencies of C or N-doped TiO2.