36.1% Efficiency For Multijunction Solar Cell

• Fraunhofer ISE has announced achieving 36.1% efficiency for a multijunction silicon solar cell 
• It used GalnP and GalnAsP semiconductor layers for an in-house developed TOPCon cell to which AMOLF added a nanocoating to achieve the efficiency  
• The team claims this is a promising step towards future deployment of III-V/Si tandem solar cells  

Germany's Fraunhofer Institute for Solar Energy Research ISE and the Netherlands' NWO-Institute AMOLF have achieved 36.1% efficiency for a multijunction solar cell. They claim this to be the highest efficiency ever reached for a solar cell based on silicon.  

The cell was fabricated with Fraunhofer using its in-house developed new silicon TOPCon cell that combines semiconductor layers of gallium indium phosphide (GalnP) and gallium indium arsenide phosphide (GalnAsP). AMOLF supplied a specially designed metal/polymer nanocoating and the cell was fabricated jointly by both the teams. 

"The back reflector improves the trapping of light inside the solar cell, which enables the efficiency to be increased for the first time beyond 36%," claim the duo. 

In comparison, conventional solar cells can reach up to 27% efficiency. Even as the new ultra-high efficiency solar cells are expensive to fabricate, adding materials to make it a multijunction cell has its benefits in terms of improving cell efficiency. 

Researchers see the potential applications of this multijunction cell in locations with space crunch as solar-powered electric cars, consumer products and drones, as well as for silicon-perovskite multijunction solar cells.  

According to the researchers, "Given the established long-term stability of III-V and silicon based solar cells these results are promising steps towards the future employment of III-V/Si tandem solar cells." 

The team of researchers presented their findings at the recently concluded European Photovoltaic Solar Energy Conference (EU PVSEC) 2023 in Portugal. The conference paper is available on Fraunhofer's website. 

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