Journal of Inorganic Materials ›› 2021, Vol. 36 ›› Issue (3): 269-276.DOI: 10.15541/jim20200070

Special Issue: 能源材料论文精选(2021) 【虚拟专辑】计算材料

• RESEARCH PAPER • Previous Articles     Next Articles

First Principles Study of Electronic Structure and Optical Properties of ZnNb2O6 with Vacancy Defects

YAN Yuxing1(), WANG Fan1, ZHANG Juexuan2, LI Fushao1   

  1. 1. College of Chemistry and Environmental Science, Qujing Normal University, Qujing 655011, China
    2. College of Teacher Education, Qujing Normal University, Qujing 655011, China
  • Received:2020-02-15 Revised:2020-03-29 Published:2021-03-20 Online:2020-08-28
  • About author:YAN Yuxing(1980-), male, PhD, lecturer. E-mail: 58536437@qq.com
  • Supported by:
    Science and Research Program of Yunnan Education Department(2017ZDX148)

Abstract:

Niobate materials, such as LiNbO3, KNbO3, LnNbO4 (Ln=Pr, La, Ga, Y), etc. have attracted wide attention due to their excellent photosensitivity. However, the transition metal niobate is rarely studied, and the relationship between its photoelectric properties and vacancy defects has not been thoroughly explored. Here, the effect of vacancy defect on electro-optical characteristics of ZnNb2O6 system was studied based on first-principles of density function theory. Its geometric structure, electronic structure, and optical spectrum clearly revealed the effect of electro- negativity and geometric position of atoms on the structure and electronic energy level. At the center of the octahedron, atoms, such as Zn and Nb, contributed similarly to the energy band, and had relatively fixed positions on the valance band when they formed vacancy defects. However, Nb atoms with larger electro-negativity generated larger lattice distortions, more obvious negative shifts of the conduction band, and red shifts of the absorption edge upon the formation of vacancy defects, which are conducive to improving electro-optical characteristics. Atom O at the vertices of the octahedron generated smaller lattice distortions when vacancy defects formed. However, negative shifts occurred at the conduction and valance bands, and impurity energy levels emerged on the Fermi surface, which induced the formation of “capture traps” on the charge carriers. This in turn exerted a larger influence on the redistribution of charge, resulting in a blue shift of the system in whole, and an all-round enhancement of optical spectrum intensity.

Key words: ZnNb2O6, vacancy defect, optical-electrical characteristic, first-principles

CLC Number: