Solar Junction, a San Jose-based manufacturer of concentrating photovoltaic (CPV) cells, announced Monday that it had broken the world record for energy efficiency of a production solar cell. According to the company, it measured a record 44% rate of conversion of sunlight to electrical energy in its cells, a result that has been verified by the National Renewable Energy Laboratory.
CPV modules use optics such as lenses or mirrors to concentrate the sun's light on small, highly efficient photovoltaic cells. The 44% efficiency achieved by Solar Junction's cells is about twice that in readily available flat-panel PV modules. The previous record of 43.5% set in April 2011, was also held by Solar Junction's cells.
"Breaking our own world record cements Solar Junction as an innovator and leader in the multi-junction cell space," Vijit Sabnis, VP Technology at Solar Junction, said in a press release. "We continue to push technological boundaries to further drive CPV costs down."
The PV component of Solar Junction's solar cells use "multijunction" technology, in which several layers of photovoltaic material are stacked, each one sensitive to a different band of light wavelengths. The cells are made with III-V semiconductors as the photovoltaic element: III-V semiconductors are those made of compounds of elements in the boron and nitrogen "families."
Though flat-panel photovoltaics are hard to compete with on price alone, SolarJunction aims to bring its products power conversion efficiency to the point where it can compete on a dollars-per-kilowatt basis with thin film PV, which offer real-world efficiencies as low as 1/3 that of Solar Junction's products. Other CPV companies like Amonix have learned this the hard way. Solar Junction points out that converting more sun into electricity could mean less land use for PV arrays -- though cheaper, more efficient modules could just as easily mean more land converted to PV power production. Still Solar Junction's breakthrough offers the possibility of better integration of power generation into more fragmented urban landscapes. As Solar Junction has just acquired a new round of financing, and plans to launch a manufacturing plant in the Bay Area in 2013, it may well make the possibility a reality.