Prace Call: 17th
ID: 2018184457, Leader: Aron Walsh
Affiliation: Imperial College London, UK
Research Field: Chemical Sciences and Materials
Resource Awarded: 25 Mil. core hours on Piz Daint
Photovoltaics constitute one of the main technologies to achieve the targets defined by the EU Energy Roadmap 2050. The major technologies, however, are based on several Critical Raw Materials listed by the European Commission. It is essential to overcome this constraint for the consolidation of independent and secure European photovoltaic technology to meet our greenhouse and energy supply commitments. Kesterites are formed from low toxicity metals, which are abundant in the earth’s crust. For applications in solar energy conversion, material properties of quaternary I2-II-IV-VI4 compounds have been investigated, and a Cu2ZnSn(S,Se)4 solar cell with the maximum efficiency of 12.6 % was made relatively recently. The solar cell can be solution processed at low cost, showing the potential to support a terawatt photovoltaic industry. To foster further research and development and to meet the engineering requirements, deeper knowledge of the physical properties of kesterites including their defects and interfaces is necessary. The aim of this proposal is to harness atomistic simulations to understand the large voltage losses that limit the efficiency of kesterite solar cells to less than 15% sunlight to electricity and find a means to overcome them. We will study (I) the non-radiative deep level recombination process limiting the carrier lifetime, (II) the secondary phase emerging under the off-stoichiometry condition and (III) the electronic and optical properties of kesterite alloys as alternative absorber materials. These calculations, involving first-principles electronic structure and electron-phonon coupling analysis, will be carried out in close collaboration with experiment. The supporting experiments are being performed as part of the EU H2020 STARCELL project (http://www.starcell.eu). A successful collaboration with experiment requires access to large computational resources supported by the PRACE Tier 0 system.