Probing Ion Motion in Perovskite Solar Cells

The University of Bath Institute of Sustainability and Climate Change is inviting applications for the following PhD project which is part of a joint PhD programme between the University of Bath and Monash University in Australia. 

This project is one of a number that are in competition for up to two funded studentships. 

 Home institution: Monash University

Supervisor(s) at Bath: Prof Petra Cameron, Prof Alison Walker

Supervisor(s) at Monash: Dr Felipe Garcia

Lead Halide Perovskite solar cells have been intensively studied in the last ten years. Perovskite Solar Cells (PSC) show impressive efficiencies of over 25% and the stability has been improved to give measured lifetimes of between 1 and 2 years. Life cycle assessment suggests that PSC have the lowest CO2 footprint per kWhDC of electricity generated when compared to current commercial PV modules. Lead halide perovskites are mixed ionic-electronic conductors, which means that the movement of electrons through the perovskite material is closely linked to the motion of mobile ions such as the movement of iodide from vacant site to vacant site in the crystal lattice. Mobile ions in perovskites have been linked to lower stability, but they can also be used as probes to better understand the behaviour of the solar cells. Recently the assembled team used modelling and experiment to show that we can harness mobile ions to measure the band offsets in perovskite devices

(Adv. Mater. 2023, 35, 2302146). This project will focus on two areas: (1) making solar cells and understanding how mobile ions are linked to the measured efficiency and (2) making new perovskite materials to probe how ions move in mixed 2D-3D and non-stoichiometric perovskite materials.

The first year in Monash will focus on a new solvent free method of making high quality perovskite materials, mechanochemistry. Mechanochemical reactions are chemical reactions triggered by the input of mechanical

energy (e.g., shear, impact, etc.). Traditionally, the synthesis of perovskite materials for energy-related applications suffers from the fact that very subtle variations in the precursors, solvents, reaction times, and temperatures could lead to non-perovskite phases or dramatically poorer quality products. Mechanosynthesis offers a significant advance compared to well-established solution-based methods since it avoids the use of bulk solvents, shortens reaction times, provides phase-pure products in high yield, and displays a high degree of batch-to-batch consistency. The project will look at making a range of perovskite materials using mechanochemistry, including non-stoichiometric phases where the motion of ions inside the material can be

varied. The year in Bath will focus on learning how to make and measure solar cells with a wide range of perovskite materials. We will work to understand how mobile ions impact on highly efficient solar cells and how they can be used to give detailed information about loss pathways inside the cells.

On the last year, we will probe ion motion in mechanosynthesised perovskite powders and then make solar cells with the phase-pure mechanosynthesised perovskite powders. We will link the materials properties of the new materials with the properties of the solar cells. We will attempt to systematically vary the

stoichiometry of the perovskite films to give new insight into the interplay between ions and cell performance. The Monash-Bath team have extensive complementary expertise in this area. Dr García is an expert in mechanochemistry and has experience in synthesizing a range of perovskite materials using this technique (iScience 16, 312–325). Prof. Cameron and Prof. Walker have long standing expertise in the characterization and modelling of perovskite solar cells respectively. This combination of skills puts us in an excellent position to co-supervise a truly collaborative research project that makes real progress in understanding what ions can tell us about perovskite solar cells.

To apply:

We invite applications from Science and Engineering graduates who have, or expect to obtain, a first or upper second class degree and have a strong interest in Sustainable & Circular Technologies. 

You may express an interest in up to three projects in order of preference. 

Please submit your application to the Home institution of your preferred project. You should note, however, that you are applying for a joint PhD programme and applications will be processed as such.

If this is your preferred project, please fill out the Monash Expression of Interest form.

Studentship eligibility

Funding for Monash-based projects, such as the one advertised here, is available to candidates of any nationality. 

Please see the Monash website for a full list of projects where Monash is the Home institution.