Quantitative analysis of valence photoemission spectra and quasiparticle excitations at chromophore-semiconductor interfaces

Abstract

Investigating quasiparticle excitations of molecules on surfaces through photoemission spectroscopy forms a major part of nanotechnology research. Resolving spectral features at these interfaces requires a comprehensive theory of electron removal and addition processes in molecules and solids which captures the complex interplay of image charges, thermal effects and configurational disorder. We here develop such a theory and calculate the quasiparticle energy-level alignment and the valence photoemission spectrum for the prototype biomimetic solar cell interface between anatase TiO2 and the N3 chromophore. By directly matching our calculated photoemission spectrum to experimental data we clarify the atomistic origin of the chromophore peak at low binding energy. This case study sets a new standard in the interpretation of photoemission spectroscopy at complex chromophore/semiconductor interfaces.

4 figures. Article published by in Phys. Rev. Lett. by the American Physical Society (2012)

References in corpus (6)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Renormalization of Molecular Electronic Levels at Metal-Molecule Interfaces
• First-principles GW calculations for fullerenes, porphyrins, phtalocyanine, and other molecules of interest for organic photovoltaic applications
• Band Offsets at the Si/SiO${}_2$ Interface from Many-Body Perturbation Theory
• GW quasiparticle bandgaps of anatase TiO2 starting from DFT+U
• Ab initio simulation of photoemission spectroscopy in solids: Plane-wave pseudopotential approach, with applications to normal-emission spectra of Cu(001) and Cu(111)

Cited by in corpus (5)

• The GW compendium: A practical guide to theoretical photoemission spectroscopy
• Quasiparticle level alignment for photocatalytic interfaces
• 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