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Project overview
  • Lead Organisation

    Australian National University (ANU)


    Canberra, Australian Capital Territory

    ARENA Program

    Research and Development

  • Start date

    5 December 2017

    End date

    2 May 2021

  • Project Partners
    National Renewable Energy Laboratory (​NREL), Solar Energy Research Institute of Singapore (SERIS)
    This solar PV project was completed on 02 May 2021.


One method we use to reduce the cost of the GaAs cells is to place it at the focus of a thin plastic solar concentrator that produces tenfold concentration of sunlight on the cell. This reduces the amount of GaAs that we need by ten times. The concentrator which are the cells are mounted on a standard one-axis solar tracker – the same that is used in most large PV systems these days.

Key results

The project has the potential to benefit the Australian energy system through the introduction of a novel, high efficiency solar cell system. The system is designed to be easily integrated into existing single-axis tracking system for simple large-scale deployment.

A prototype tandem PV micro concentrator module was developed with a GaAs/Si underlying cell efficiency of 30%. This demonstrates the potential of the novel combination of non-imaging micro concentrators with GaAs and silicon cells for single-axis tracking systems. Further work could improve the overall efficiency of the tandem module.

The fabrication of GaAs SLIVER cells was demonstrated, which is a pathway to decrease the cost of GaAs cells. Improvements in GaAs SLIVER cell design and fabrication methods could further improve the efficiency. Use of the SLIVER process in combination with optical concentration has the potential to significantly reduce the cost of high efficiency GaAs/Si tandem PV systems.

Project innovation

The Tandem PV Micro Concentrator Project aims to develop a commercially competitive high efficiency photovoltaic (PV) tandem system. A tandem PV system contains one type of cell that absorbs visible light and another that absorbs infrared light. Because each cell can be optimized to convert only part of the sunlight, the combined efficiency can be higher than using a single cell type – albeit at higher cost. The best infrared-absorbing cell is a conventional silicon solar cell. Silicon solar cells comprise 94% of the worldwide solar market, and have very low cost because they come from vast production facilities. The best visible light absorbing cell is made from gallium arsenide (GaAs) which is highly efficient but rather expensive. The main goal of the project is to reduce the effective cost of the GaAs cell.


If the Tandem PV Micro Concentrator Project proceeds well, then an efficiency above 30% could be achieved at affordable cost. This compares with 26% for the record efficiency silicon solar cell. The advantage of high efficiency is that it leverages overall cost reductions throughout the value chain by reducing the area needed for a given amount of solar energy production.

Last updated 02 March 2022
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