First-Principles Calculation of Electronic Energy Level Alignment at Electrochemical Interfaces

Abstract

Energy level alignment at solid-solvent interfaces is an important step in determining the properties of electrochemical systems. The positions of conduction and valence band edges of a semiconductor are affected by its environment. In this study, using first-principles DFT calculation, we have determined the level shifts of the semiconductors TiO${}_2$ and ZnO at the interfaces with MeCN and DMF solvent molecules. The level shifts of semiconductor is obtained using the potential difference between the clean and exposed surfaces of asymmetric slabs. In this work, neglecting the effects of present ions in the electrolyte solution, we have shown that the solvent molecules give rise to an up-shift for the levels, and the amount of this shift varies with coverage. It is also shown that the shapes of density of states do not change sensibly near the gap. Molecular dynamics simulations of the interface have shown that at room temperatures the semiconductor surface is not fully covered by the solvent molecules, and one must use intermediate values in an static calculations.

8 pages, 7 figures

References in corpus (4)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• First-Principles Approach for Energy Level Alignment at Aqueous Semiconductor Interfaces
• Theoretical description of the efficiency enhancement in DSSC sensitized by newly synthesized heteroleptic Ru complexes
• Efficiency enhancement of black dye-sensitized solar cell by newly synthesized D-$\pi$-A coadsorbents: A theoretical study