Inspenet, October 8, 2023.
Germany’s renowned Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE), in collaboration with the Dutch research institute AMOLF, has achieved a significant milestone in the field of solar energy by developing a solar cell of multiple junctions that has achieved an unprecedented efficiency of 36.1%, surpassing any previous record for silicon-based solar cells.
Although silicon is widely used in solar technology, its efficiency has a natural limit of 29.4%. However, the Fraunhofer Institute ISE suggests that there are ways to overcome this limitation. The key is to apply additional layers of materials to these solar cells, transforming them into what are known as “multifunction” solar cells. These have multiple layers designed to absorb different parts of the sunlight spectrum, allowing for more efficient use of solar energy.
Albert Polman, who is leading the project on behalf of AMOLF, emphasized the importance of the collaboration between both institutes, which began in 2020 and has culminated in this unprecedented achievement. The combination of the specialties of each team has been fundamental: while Fraunhofer is known for developing highly efficient solar cells based on silicon and semiconductors such as GaInP or GaAs, AMOLF has accumulated experience in optimizing light management in solar cells .
Multifunction solar cell: How did they do it?
The manufacturing process involved the use of a TOPCon silicon solar cell, which was combined with two semiconductor layers, one of gallium indium phosphorus (GaInP) and another of gallium indium arsenide phosphorus (GaInAsP), both developed by the Fraunhofer ISE Institute. . This assembly was then coated with a special metal-polymer composite nanocoating, designed by the Dutch research institute in collaboration with Fraunhofer ISE.
Likewise, an important additional component was the reflector located at the back of the solar cell, which amplifies the collection of light inside, allowing it to achieve an unprecedented efficiency of more than 36%.
Although these next-generation solar cells may have a higher price, the Fraunhofer Institute ISE sees great potential for their use in places with limited space where a large amount of solar energy needs to be generated. The possible applications in the future are diverse, ranging from powering electric vehicles through solar energy to consumer electronics devices and drones.
Frank Dimroth of the Fraunhofer ISE Institute celebrates this achievement and emphasizes the contribution of both the new rear reflector developed by AMOLF and the improvement in Fraunhofer’s GaInAsP cell that led to this exceptional result. Without a doubt, this advance marks the beginning of a new chapter in the history of solar energy and how it will be used for a more sustainable world.