Engineers at Sharp Corp. recently set a new record for the efficiency of non-concentrating solar cells. They did this by building a three-layer compound cell which had a conversion efficiency of 36.9%. The record was confirmed by the National Institute of Advanced Industrial Science and Technology.
The cell stacks three photo-absorption layers - indium gallium phosphate, gallium arsenide, and indium gallium arsenide - atop a silicon substrate. Each layer absorbs photons with different wavelengths, letting the compound cell convert a wide spectrum of sunlight into electricity.
Two years ago, Sharp set a record of 35.8% with a three-junction cell. The new cell improves on that figure by reducing the resistance of the connections between each layer, thereby boosting the maximum power output.
Sharp Corp., sharp-world.com