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Project overview
  • Lead Organisation

    University of New South Wales


    Kensington, New South Wales

    ARENA Program

    Research and Development

  • Start date

    18 September 2020

    End date

    30 November 2023

  • Project Partners
    University of Science and Technology of China, Eastern China Normal University, Open Instrument, California Technology Centre, First Solar, The University of Alabama, Jinko Solar Holding, Daeyeon C&I Co.


This project aims to reduce the cost of silicon (Si) based tandem solar cells by developing an earth-abundant, restriction of hazardous substances (RoHS)-compliant antimony chalcogenide top cell.


The power conversion efficiency of Si photovoltaic (PV) technology has reached its practical limit in the lab. Reducing Si PV costs further requires technological evolution beyond theoretical Shockley-Queisser efficiency limits. Tandem cells with appropriate thin-film PV technology on crystalline Si bottom cells offer the most compelling option for Levelised Cost of Electricity (LCOE) reduction. Despite progress on the high bandgap top cells, there is no affirmed top cell solution for Si-based tandem cells that meets all key requirements of high-efficiency, stability, cost-effectiveness and limited environmental impact.


This project aims to ease this transition by using an antimony chalcogenide top cell for Si tandem cells, offering performance gains without sacrificing other requirements. UNSW will work with project partners to maximise the potential of antimony chalcogenide and provide an appealing alternative top cell with excellent merits for Si-based tandems.

Starting from the UNSW research team’s recent 10% world-record efficiency antimony selenosulfide cells, progress towards beyond 20% efficiency Sb2(S,Se)3/Si tandem cells will be realised by implementing a bottom-up research and development approach, with combined experimental and theoretical exploration, identified key-step change processing strategies regarding the design of absorber, interfaces and architectures.


This project is expected to deliver an alternative top cell technology for Si-based tandem cells, promoting the deployment of tandem PV technology for cost reduction. It will bring new findings, identify step change strategies, achieve key technological milestones, generate record efficiency antimony chalcogenide cells, and build the commercialisation roadmap for upscaling this developed technology.

This completion of this project will maximise chances of success and establish Australia at the forefront internationally for the next generation Si tandem cells technology.

Additional impact

The project will increase knowledge about RoHS-compliant and earth-abundant semiconductors suitable for stacking onto silicon for tandem cells. If successful, it will accelerate the transition for commercial use and future terawatt-scale deployment, as well as manufacturing sequences for high efficiency Si-based tandem cells using this material. The project will employ three full-time equivalent positions across UNSW, including two new research associate/assistant positions.

Last updated 01 June 2023


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