XPS for energy materials: development of methods for the chemical speciation of transition metals

X-ray photoelectron spectroscopy (XPS) is a mature surface analytical technique, with its use increasing exponentially year-on-year. This increased use is accompanied by a growing presence of significantly flawed results. A strength of XPS is its ability to provide quantitative chemical state information of mixed-valence compounds of the same element. For the transition metals, this requires a significant amount of prior knowledge. With the increasing importance of such elements (e.g. Ti, Co, Fe, Mn, Ni) in energy applications, and the challenge of the extraction of chemical state information for the inexperienced user, this project aims to establish a new approach for such activities. The goal is an unsupervised method to unravel the complexity of chemical states that will be more objective than the current, subjective, method of operator definition of individual components. This will ensure the increased reliability of XPS spectra in energy related, and other, research.

This project will achieve a paradigm shift in which peak fitting for the extraction of chemical states can be achieved. Standard, well characterised, transition metal compounds will be employed to provide high-quality XPS data recorded at high spectral resolution. The meat of the project will be the development of AI-based procedures such as machine learning (ML) to carry out unsupervised fitting of mixed valence state spectra using the spectra from the standard compounds. These will be used to “teach” the ML routine the characteristics of each oxidation state thus enabling the precise speciation of the “unknown” compounds. In this way, the quality of data produced from complex electron spectra, such as the 3d transition metals, will be widely available and not just limited to a relatively small group of experts which (includes the supervisors of this project). In this manner, the quality of XPS data in the literature will become enhanced.

Open to candidates who pay UK/home rate fees. See UKCISA for further information.

Candidates must meet Surrey graduate entry requirements which include holding at least an upper second-class degree or equivalent qualifications in a relevant subject area such as physics, chemistry, materials science or engineering. A masters degree in a relevant discipline and additional research experience would be an advantage

We are committed to supporting Female, Black, Asian, or minoritised ethnic communities (sometimes referred to as BAME) that are currently under-represented. All candidates must be permanent UK resident for fee purposes.

Further details can be found under the entry requirements tab on the Engineering Materials PhD course page.

Centre for Engineering Materials