Solar PV R&DProject Tandem PV Micro Concentrator
This report discusses the project results and lessons learnt through to the end of the Australian National University’s Tandem PV Micro Concentrator project.
The project funded the development of a novel tandem solar photovoltaic (PV) micro concentrator module. The lightweight, thin form linear PV tandem micro concentrators are capable of being mounted on standard PV single axis tracking support systems that are being deployed in large quantities around the world.
The best commercial and laboratory silicon-only solar cells have efficiencies in the range 23-27%. In order to reach efficiencies of 30% and beyond, tandem solar cells comprising of two or more different materials must be used. Silicon (Si) is often used as the rear cell in tandem devices along with a higher bandgap top cell.
III-V materials such as gallium arsenide (GaAs) are promising candidates as high bandgap top cell due to their excellent efficiency and stability. However, these materials are expensive. In order to develop a commercially competitive GaAs/Si tandem solar cell system, the cost of the GaAs component must be reduced. This project aims to achieve this by using the ANU developed Sliver technique for creating GaAs solar cells, in conjunction with a micro concentrator system.
Individual measurements of the GaAs solar cells under concentrated light, combined with simulated performance measurements of the underlying silicon cell, indicate a tandem efficiency ≥ 30 % could be achieved using this system.