A team of researchers of the Fraunhofer Institute for Solar Energy Research ISE and NWO-Institute AMOLF (Amsterdam) have fabricated a multijunction solar cell with an efficiency of 36.1 percent, the highest efficiency ever reached for a solar cell based on silicon. The team presented the new record at the European Photovoltaic Solar Energy Conference (EU PVSEC) in Lisbon on Thursday, September 21, 2023. The research project was funded through the Fraunhofer ICON program.

Researchers from Fraunhofer ISE and AMOLF have achieved a significant breakthrough in solar cell efficiency by collaborating on a project focused on multijunction solar cells. The collaboration leveraged Fraunhofer's expertise in fabricating high-efficiency solar cells based on silicon and III-V semiconductors, as well as AMOLF's knowledge in optimizing light management within solar cells.

Solar cells based on silicon, while widely used, face a fundamental efficiency limitation of 29.4 percent. This limitation can be surpassed by creating multijunction solar cells, where multiple light absorption layers are stacked to effectively absorb different parts of the sunlight's spectrum. The researchers achieved a new efficiency record by combining a state-of-the-art silicon solar cell with semiconductor layers composed of gallium indium phosphide (GaInP) and Gallium Indium Arsenide Phosphide (GaInAsP). A specialized metal/polymer nanocoating designed at AMOLF was applied to enhance light absorption, and a back reflector was incorporated to improve light trapping, resulting in an efficiency beyond 36 percent.

While these ultra-high-efficiency solar cells are currently more expensive to produce than conventional silicon solar cells, their suitability for applications where space is limited and high power generation is essential makes them valuable. Potential applications include solar-powered electric cars, consumer products, drones, and scenarios where a large amount of solar power needs to be generated within a confined area. Additionally, the new light management design holds promise for application in other types of solar cells beyond silicon-based ones, extending its potential impact across various solar technologies.

Find the original press release here.