Investigating the influence of nano film depositions on the metal surface on the solid-liquid interfacial work function

Abstract

Most physical and chemical processes occur at the interface. Accordingly, the construction of a metal surface dielectric film to control the work function of the solid-liquid interface is an effective method to improve the properties of materials, which has attracted a lot of interest recently. Here, we report a DFT method is applied to explore the influence of the SiO2 film on the work functions of the Cu and Fe surface in the liquid. Then the charge transfer characteristics of the solid-liquid interface are analyzed. The obtained results show that liquid molecules slightly affect the interface electronic density of states, while the metal electrode keeps the metallic properties after SiO2 film deposition. Electrons near the Fermi level mainly originate from the d-orbital of Cu and Fe. Moreover, the SiO2 thin film bends the energy band at the solid-liquid interface and increases the work function by 0.57 eV-0.94 eV, indicating that the charge injected by the electrode into the liquid is bound in the SiO2 layer, which inhibits the interface charge transfer. Accordingly, the work function of the solid-liquid interface increases, and the seed charge of the liquid breakdown reduces, thereby improving the dielectric strength of the liquid. The effective regulation of the work function of the metal surface through the dielectric film also has a broader application space.