A new world record of 46% for the direct conversion of sunlight into electricity was recently established by Soitec, Leti and the Fraunhofer Institute for Solar Energy Systems ISE (read the press release here). Multi-junction cells are used in concentrator photovoltaic (CPV) systems to produce low-cost electricity in photovoltaic power plants, in regions with a large amount of direct solar radiation.
Multi-junction solar cells are based on a selection of III-V compound semiconductor materials. The world record cell is a four-junction cell, and each of its sub-cells converts precisely one quarter of the incoming photons in the wavelength range between 300 and 1750 nm into electricity. When applied in concentrator PV, a very small cell is used with a Fresnel lens, which concentrates the sunlight onto the cell. The new record 46.0% efficiency was measured at a concentration of 508 suns and has been confirmed by the Japanese AIST.
Jocelyne Wasselin, Vice President Solar Cell Product Development for Soitec, predicts that they’ll reach the holy grail of 50% efficiency in the near future.