Join the Group
We are always keen to hear from driven and enthusiastic students and postdocs looking to work at the forefront of optoelectronic materials development. We offer a dynamic, interdisciplinary working environment with links across the world. Contact Dr Robert Hoye if you are interested in joining us as a postdoc, PhD or Masters student.
Funded vacancies will be regularly advertised here. In addition, we can support applicants to join our group through the schemes listed below.
Postdoc Vacancy: Instilling defect tolerance in ABZ2 photovoltaic materials
Applications are invited for a Research Associate position to join the Department of Materials. The overarching goal of the project is to pinpoint defect-tolerant ABZ2 materials and develop them into efficient thin film photovoltaics (PVs) processed at low temperature using scalable methods. In ABZ2 materials, A = monovalent cation, B = Bi3+ or Sb3+, and Z = divalent anion (e.g., S2-, Se2-). This position will involve developing vapour- and solution-based synthesis routes for these materials, and characterising their crystal structure, composition, electronic structure, charge-carrier lifetime and photoluminescence quantum efficiency. New insights into the role of electronic, composition and structural properties on defect tolerance will be generated, and these used to identify promising ABZ2 materials, which will be developed into photovoltaics. The performance and stability of the devices will be systematically improved by identifying and mitigating limiting factors.
The project is funded by EPSRC, No. EP/V014498/1, and a summary of the aims and background can be found online: https://gow.epsrc.ukri.org/NGBOViewGrant.aspx?GrantRef=EP/V014498/1
Job listing information
- Reference ENG01493
- Date posted 2 December 2020
- Closing date 4 January 2021
PhD Vacancy: Defect Tolerant Ternary Chalcogenides for Efficient, Low-Cost Photovoltaics
Photovoltaics (PVs) convert sunlight to electricity without carbon-based by-products, providing a vital source of renewable energy. Accelerating the deployment of PVs will be necessary to meet net-zero CO2 emissions targets, as well as to provide sustainable energy to the billion people worldwide living off-grid. This urgently requires new thin film PV materials. Such materials can be integrated with standard commercial silicon solar cells to increase efficiencies, used for energy-harvesting windows and façades in buildings, or used indoors to power autonomous electronic devices.
Critically, thin film PVs will need to achieve efficient performance when manufactured with low capital-intensity methods. A limiting factor is the effect of point defects, such as vacancies, which are always present in thin films grown at room temperature. Such defects cause non-radiative recombination, which decreases PV efficiencies. It has been found that these effects could be mitigated through defect tolerance, in which the majority of traps are shallow within the band gap and have low capture cross-sections. This leads to low non-radiative recombination rates despite high defect densities. Defect tolerance is primarily found in lead-halide perovskites and has enabled these materials to rapidly achieve commercially-relevant efficiencies despite being made using low-temperature, simple fabrication methods. Recently, defect tolerance has also been found to occur in ternary chalcogenides based on bismuth and antimony, which have the advantages of substantially lower toxicity and improved stability over lead-halide perovskites.
This project will focus on developing scalable routes to manufacture thin films of newly identified ternary bismuth and antimony chalcogenides (e.g., NaBiS2). Growth methods include chemical vapour deposition and nanocrystal synthesis. Single-junction devices will be developed from these materials. Optical and electronic loss-analyses will be performed to rationally improve PV performance. Device stability will be measured in collaboration with industry. The main degradation processes will be identified through in-depth characterisation of interfaces, and mitigation routes developed.
The studentship is funded by the Department of Materials and is part of a wider project “ABZ2-PV” funded by the Engineering and Physical Sciences Research Council. The student will be mentored by Dr. Hoye, as well as a postdoctoral researcher working on ABZ2-PV. In addition, the student will be able to interact with the diverse group of PhD students in the Energy Materials and Devices Group. The lab facilities will primarily be based on the new Royce@Imperial space in the Sir Michael Uren Building in the White City Campus.
The project will be of 3.5 yr duration. It is open to all, including overseas and EU students, as well as UK students. The studentship will fully cover tuition fees plus the standard maintenance stipend of £17,285 per annum, which will increase each year with inflation.
Applicants should have a Masters degree (or equivalent) with First Class Honours or Upper Second Class Honours in Materials Science, Physics, Chemistry, Electrical Engineering, Chemical Engineering, or a related discipline. Applicants from under-represented groups are particularly encouraged to apply.
Applicants who are interested should make informal enquiries to Dr. Robert Hoye , and should include their CV and transcript with their enquiry. Formal applications can be made online . The PhD prospectus, entry requirements and application form are available the Postgraduate Study pages . For further information on how to apply, please contact Dr. Alba Maria Matas Adams . Information on the Department can be found by following this link.
Closing date: 29 January 2021 or earlier if the position is filled