First-principles study of electronic structure and optical properties of (Zr-Al)-codoped ZnO

The Heyd-Scuseria-Ernzerhof (HSE) hybrid density functional was used to investigate the electronic structure and optical properties of (Zr-Al)-codoped ZnO. The calculated results show that the formation energy of (Zr-Al)-codoped ZnO is low, indicating that it is the energetically favorable structure and the first absorption peak of optical absorption spectra for (Zr-Al)-codoped ZnO has a red-shift compared with pure ZnO, which may lead to the improvement on the visible-light photocatalytic ability. The zinc and oxygen vacancies introduced by (Zr-Al)-codoped ZnO have also been investigated. Through analysis the main absorption peaks of the imaginary part of the dielectric function on polarization vectors perpendicular or parallel to the Z axis, we think that oxygen vacancy introduced by (Zr-Al) codoping can also improve the visible-light photocatalytic ability and zinc vacancy has weak effect to enhance the optical photocatalytic ability compared with (Zr-Al)-codoped ZnO.