Influence of an External Electric Field on Electronic and Optical Properties of a g-C 3 N 4 /TiO 2 Heterostructure: A First-Principles Perspective.

In this study, calculations based on density functional theory (DFT) were utilized to examine how electrostatic fields affect the electrical and optical characteristics of g-C 3 N 4 /TiO 2 heterostructures. The binding energy, density of states, difference in charge density, and optical absorption spectra of the heterostructure were calculated and analyzed to reveal the mechanism of the influence of the external electric field (EF) on the properties of the heterostructure. The results show that the binding energy of the heterogeneous structure is reduced due to the imposed electric field in X - and Y -directions, and the optical absorption spectrum is slightly enhanced, but the BG and charge transfer number are basically unchanged. On the contrary, applying the electric field in the Z -direction increases the binding energy of the heterogeneous structure, decreases the BG, increases the number of charge transfers, and red shifts the optical absorption spectrum, which improves the photocatalytic ability of the g-C 3 N 4 /TiO 2 heterostructure.