Phase quantification of heterogeneous surfaces using DFT-simulated valence band photoemission spectra

DOI: 10.1021/acsami.3c06638

Authors: Roxy Lee (University College London) , Raul Quesada-Cabrera (University College London; Universidad de Las Palmas de Gran Canaria (ULPGC)) , Joe Willis (University College London; Diamond Light Source) , Asif Iqbal (McGill University) , Ivan P. Parkin (University College London) , David O. Scanlon (University College London) , Robert G. Palgrave (University College London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Applied Materials & Interfaces , VOL 73

State: Published (Approved)
Published: August 2023

Abstract: Quantifying the crystallographic phases present at a surface is an important challenge in fields such as functional materials and surface science. X-ray photoelectron spectroscopy (XPS) is routinely employed in surface characterization to identify and quantify chemical species through core line analysis. Valence band (VB) spectra contain characteristic but complex features that provide information on the electronic density of states (DoS) and thus can be understood theoretically using density functional theory (DFT). Here, we present a method of fitting experimental photoemission spectra with DFT models for quantitative analysis of heterogeneous systems, specifically mapping the anatase to rutile ratio across the surface of mixed-phase TiO2 thin films. The results were correlated with mapped photocatalytic activity measured using a resazurin-based smart ink. This method allows large-scale functional and surface composition mapping in heterogeneous systems and demonstrates the unique insights gained from DFT-simulated spectra on the electronic structure origins of complex VB spectral features.

Journal Keywords: XPS phase quantification; DFT; valence band; surface mapping; heterogeneous surfaces; polymorphs; photocatalysis; TiO2

Diamond Keywords: Photocatalysis

Subject Areas: Materials, Chemistry, Physics


Technical Areas:

Added On: 09/08/2023 14:51

Documents:
acsami.3c06638.pdf

Discipline Tags:

Surfaces Technique Development - Materials Science Physics Physical Chemistry Catalysis Chemistry Materials Science

Technical Tags: