Solar cells have a hard life in space from particle bombardment, so the efficiency at the end of life is more prized than their initial efficiency. The next generation solar cell developed for the European Space Agency has a starting efficiency of up to 30.9% and end of life efficiency at 27.5%, and the designers expect to push this figure above 30%.
The 0.1mm thick, 30 sq cm cell was developed for ESA by a consortium led by German solar cell maker Azur Space, CESI in Italy, Germany’s Fraunhofer Institute for Solar Energy Systems, Qioptiq in the UK, Umicore in Belgium, tf2 devices in the Netherlands and Finland’s Tampere University of Technology. It uses a ‘four-junction’ design containing four layers of different materials (AlGaInP, AlGaInAs, GaInAs,Ge) to absorb separate wavelengths of sunlight.
The design was developed in ESA’s Technology Research Programme with further development and qualification testing supported through the Agency’s ARTES, Advanced Research in Telecommunications Systems, programme. It is currently intended to fly with ESA’s next generation Neosat telecom satellites.