Quasiparticle level alignment for photocatalytic interfaces

Abstract

Electronic level alignment at the interface between an adsorbed molecular layer and a semiconducting substrate determines the activity and efficiency of many photocatalytic materials. Standard density functional theory (DFT) based methods have proven unable to provide a quantitative description of this level alignment. This requires a proper treatment of the anisotropic screening, necessitating the use of quasiparticle (QP) techniques. However, the computational complexity of QP algorithms has meant a quantitative description of interfacial levels has remained elusive. We provide a systematic study of a prototypical interface, bare and methanol covered rutile TiO${}_2$(110) surfaces, to determine the type of many-body theory required to obtain an accurate description of the level alignment. This is accomplished via a direct comparison with metastable impact electron spectroscopy (MIES), ultraviolet photoelectron spectroscopy (UPS) and two-photon photoemission (2PP) spectra. We consider GGA DFT, hybrid DFT and $G_0{W}_0$, $\mathrm{scQP}GW1$, $\mathrm{scQP}G{W}_0$, and $\mathrm{scQP}GW$ QP calculations. Our results demonstrate that $G_0{W}_0$, or our recently introduced $\mathrm{scQP}GW1$ approach, are required to obtain the correct alignment of both highest occupied and lowest unoccupied interfacial molecular levels (HOMO/LUMO). These calculations set a new standard in the interpretation of electronic structure probe experiments of complex organic molecule-semiconductor interfaces.

10 pages, 11 figures

References in corpus (4)

• Renormalization of Molecular Electronic Levels at Metal-Molecule Interfaces
• Quasiparticle and Optical Properties of Rutile and Anatase TiO${}_2$
• Trends in Metal Oxide Stability for Nanorods, Nanotubes, and Surfaces
• Quantitative analysis of valence photoemission spectra and quasiparticle excitations at chromophore-semiconductor interfaces

Cited by in corpus (5)

• Energy Level Alignment at Molecule-Metal Interfaces from an Optimally-Tuned Range-Separated Hybrid Functional
• Comparing quasiparticle H${}_2$O level alignment on anatase and rutile TiO${}_2$
• Quasiparticle interfacial level alignment of highly hybridized frontier levels: H${}_2$O on TiO${}_2$(110)
• Coverage Dependence of the Level Alignment for Methanol on TiO${}_2$(110)
• Using surface plasmonics to turn on fullerene's dark excitons