A joint team of French and German scientists have recently announced a major breakthrough in a renewable energy project. The scientists, from the Fraunhofer Institute for Solar Energy Systems ISE, Soitec, CEA-Let and the Helmholtz Center Berlin, worked together for years on a project which converts sunlight to energy through a photovoltaic (solar) cell. The project was directed toward producing the highest efficiency solar cell available, and the result is a solitary cell that is able to collect energy at an efficiency rate of 44.7%, equal to the concentration of 297 suns. The process works by collecting a percentage (in this case 44.7%) of the sun’s spectrum’s energy from ultraviolet to the infrared spectrum, which is converted into electrical energy. While they are still a little short of their ultimate goal of 50% efficiency, the scientists stated that this achievement was paving the way toward their goal.
Solar Cell Technology
“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,” Frank Dimroth, project leader in charge of the development work at Fraunhofer ISE, said in a statement.
The U.S. National Renewable Energy Laboratory held the previous record, with an efficiency rate of 43.5%, although the French-German team of scientists had already achieved a rating of 43.6% in May 2013. The new record took the team approximately three years to achieve.
“This world record increasing our efficiency level by more than 1 point in less than 4 months demonstrates the extreme potential of our four-junction solar cell design which relies on Soitec bonding techniques and expertise,” Soitec CEO Andre-Jacques Auberton-Herve said in a statement.
Solar technology came from space technology
Solar cells are used in concentrator photovoltaics (CPV), a technology which achieves more than twice the efficiency of conventional PV power plants in sun-rich locations. The new photovoltaic technology, known as III-V multi-junction solar cells, originally came from space technology and have continued to achieve the highest efficiencies for the conversion of sunlight to electricity. The solar cell is actually a comprised of four sub-cells using stacked “III-V” semiconductor materials. Each of the sub-cells absorb different wavelength ranges of the solar spectrum.