Density functional study on electronic and optical properties of C (or N)-doped cubic cerium dioxide

Density functional calculations were performed on electronic and optical properties of C (or N)-doped cubic cerium dioxide (CeO2). When O is replaced by C (or N) in CeO2, obvious band-gap (Eg) reduction is observed. Meanwhile, it is interesting to find that the substitutional doping of C (or N) in CeO2 obviously increases the O 2p–Ce 4f transition intensity and also the refractive index. The increase in the O 2p–Ce 4f transition intensity on going from undoped, N-doped and C-doped CeO2 was related to the covalent character of the Ce–O bond. Compared with the undoped CeO2, the C (or N)-doped CeO2, with steep absorption peaks at lower energy, can be used for visible-light absorption applications.