HAN Xiaodong ¹, ZHOU Shulan ¹, ZHAO Xian ², JIANG Xiangping ¹
(1. Department of Material Science and Engineering, Jingdezhen Ceramics Institute, Jingdezhen 333403, Jiangxi, China; 2. State Key
Laboratory of Crystal Material, Institute of Crystal Material, Shandong University, Jinan 250100, Shandong, China)

Abstract: The crystal structure, electronic structure, formation energy and relative positions of F-doped, N-doped and F+N codoped NaNbO₃ were investigated employing the first principle method based on the density functional theory. The study results of the crystal structure indicate the lattice distortion and expansion of F-doped, N-doped and F+N codoped NaNbO₃. The formation energy of F+N codoped NaNbO₃ is lower than that of N-doped NaNbO₃, which indicates that the concentration of the N impurity in the host lattice can be enhanced in the presence of F doping. For F-doped NaNbO₃, the low shift of the conduction band is only 0.46 eV without altering the valence band. While for N-doped NaNbO₃, N doping creates a partially occupied impurity band in the band gap of the host due to electron deficiency on N₂p levels,which makes the light absorption shift to visible region. The F+N codoping can eliminate the local trapping, which improves the carrier mobility. Hence, F+N codoped NaNbO₃ would be a promising visible-light-driven photocatalyst for water splitting.

Key words: electronic structure; F+N codoping; first principle; relative position of band edge; defect formation energy