The world record for solar cell efficiency has apparently been broken after a team of researchers created a cell (pictured) that can convert 44.7% of the energy in sunlight to electricity, by stacking materials that absorb different wavelengths of light on top of each other.
The development was jointly announced by the Fraunhofer Institute for Solar Energy Systems ISE, Soitec, CEA-Leti and the Helmholtz Center Berlin. The German-French team has been working on the project for three years and in May announced they had developed a cell with 43.6% efficiency.
The catchily named ‘III-V multi-junction solar cells’ are used in concentrator photovoltaics (CPV), a technology which is more than twice as efficient as conventional PV cells in sun-rich environments. CPV began life in the space industry before being used on terra firma.
Frank Dimroth, Department Head and Project Leader at Fraunhofer ISE said: “Besides improved materials and optimization of the structure, a new procedure called wafer bonding plays a central role.
“With this technology, we are able to connect two semiconductor crystals, which otherwise cannot be grown on top of each other with high crystal quality. In this way we can produce the optimal semiconductor combination to create the highest efficiency solar cells.”
In July the US Department of Energy announced it was spending nearly £20 million on research to make solar power more cost effective.