N,F-monodoping and N/F-codoping effects on the electronic structures and optical performances of Zn2GeO4

Abstract

First-principles density-functional calculation has been performed to investigate the synergistic effects of N and F doping on the photocatalytic properties of Zn₂GeO₄. Our results indicate that the presence of F facilitates the introduction of N by reducing the formation energy significantly. As N and F is codoped into Zn₂GeO₄, the mobility of the charge carriers is more rapid due to the dispersive levels above the valence band. And with the narrowed band gap the optical absorption spectrum red-shifts into the ideal visible-light region. Thus, we propose that the codoping of N and F can be a promising strategy to promote the photocatalytic performances of Zn₂GeO₄ under visible light.