New solar cell records

The Energy Department's National Renewable Energy Lab [Myles Steiner] has announced a world record of 31.1% conversion efficiency for a two-junction solar cell under one sun of illumination. (...) The previous record of 30.8% efficiency was held by Alta Devices. The tandem cell was made of a gallium indium phosphide cell atop a gallium arsenide cell, has an area of about 0.25 square centimeters and was measured under the AM1.5 global spectrum at 1,000 W/m2. It was grown inverted, similar to the NREL-developed inverted metamorphic multi-junction (IMM) solar cell -- and flipped during processing. The cell was covered on the front with a bilayer anti-reflection coating, and on the back with a highly reflective gold contact layer.

More info: Conversion-efficiency record for a two-junction solar cell measured under one-sun illumination

Sharp Corporation has achieved the world's highest solar cell conversion efficiency of 44.4%, using a concentrator triple-junction compound solar cell. These solar cells are used in a lens-based concentrator system that focuses sunlight on the cells to generate electricity. (...) Sharp's concentrator triple-junction compound solar cells use a proprietary technology that enables the efficient conversion of sunlight into electricity by means of a stack of three photo-absorption layers, the bottommost of which is made from InGaAs (indium gallium arsenide).To achieve a concentrating conversion efficiency of 44.4%, Sharp worked to widen the effective concentrator cell surface and ensure uniformity of width at the interface of the connecting concentrator cell and electrodes.

More info: Sharp Develops Concentrator Solar Cell with World's Highest Conversion Efficiency of 44.4%