Advanced multilayer materials for efficient and durable solar fuel photo-electrodes using atomic layer deposition guided by an artificial intelligence research advisor. (Reference Potter LRC125)

Solar energy is an abundant but under-utilized resource, primarily due to its intermittency. Using sunlight to drive the production of chemical fuel which can be stored for prolonged periods would overcome this barrier. Sometimes referred to as ‘artificial leaves’, photoelectrochemical systems use solar energy to convert abundant, or waste, feedstocks such as water and CO2 into carbon neutral fuels such as hydrogen or synthetic hydrocarbons such as CH4 or CH3OH. Solar fuels are potentially a green, energy dense way of storing solar energy and they are also transportable, making them a viable alternative to battery storage. While electrode technology is an active area of research, there remain issues relating to efficiency, durability and cost to overcome to be commercially viable.

A shared feature of all major solar-to-fuel systems under investigation is the need to oxidise water. State-of-the-art water oxidation photoanodes typically consist of a light absorbing semiconductor which is modified with thin (<10 nm) overlayers to improve charge separation, impart catalytic activity and to improved endurance. Atomic layer deposition (ALD) offers a route to forming these overlayers with atomic accuracy, while also being highly scalable for mass manufacturing. ALD is a cyclic thin film deposition process related to chemical vapour deposition (CVD), however, unlike conventional CVD, ALD relies on self-limiting surface reactions, which leads to exceptional process control.

This studentship builds, but goes well beyond, our existing expertise using single ALD overlayers on hematite (α-Fe2O3) light absorbers to passivate surface states (Chem Sci., 2015, 6, 4009). The project aims to design novel high efficiency photoanodes with multi-layer structures that achieve the rapid cascade of photogenerated holes towards an outer catalytic overlayer.

The overall experimental parameter space to control is vast, alongside the chemical composition of each overlayer it is possible to vary thickness, microstructure and density. The interplay between overlayers can be complex with modification of device activity through multiple routes including changes in optical properties, band alignment, development of trapping sites, modifications of catalytic activity and modification of charge mobility. Using current “master craftsman” approaches and ‘trial-and-error’ science this would be an extremely challenging, potentially impossible goal. Working within the Leverhulme research centre (LRC) the studentship will explore a new way of developing photoelectrodes. You will initially generate a small series of samples, measuring not only the overall device efficiency but also fundamental properties such as: microstructure, electronic structure, kinetic parameters and catalytic activity using leading facilities available to the project such as x-ray diffraction transient absorption spectroscopy, XPS and dual working electrode studies. This alone will provide valuable information to the solar fuels community, but on a small subset of materials. The project will use the initially generated “sparse data” sets as an input into the material design engine that is under-development in the LRC. It is anticipated that the engine will enable us to use artificial intelligence to identify potential emerging trends in both our own and literature data sets which can in turn be validated through further experimental tests, greatly reducing the experimental hours required to deliver the breakthrough in photoanode design.

Qualifications: The candidate should have a degree in Physics, Chemistry, Materials Science or a related discipline with at least a 2:1 classification.

Please apply by completing the online postgraduate research application form here, https://www.liverpool.ac.uk/study/postgraduate-taught/applying/online/

Please ensure you quote the following reference on your application: Advanced multilayer materials for efficient and durable solar fuel photo-electrodes using atomic layer deposition guided by an artificial intelligence research advisor. (Reference Potter LRC125)