RoseStreet Labs Energy says it has demonstrated the first known nitride/silicon tandem solar cell. Using the same nitride material technology as solid-state lighting and blue lasers, the Phoenix-based company fabricated and tested a working photovoltaic device that couples a silicon cell with a nitride thin film.
RSLE says the hybrid cell should achieve practical conversion efficiencies of 25-30%. The company, which has a 0.5MW pilot line featuring a molecular beam epitaxy (MBE) tool, plans to begin production of this technology in the fourth quarter of 2010.
The company (a unit of RoseStreet Labs) explains that its proprietary full spectrum technology is primarily based on nitride alloys, specifically indium-gallium-nitrides, which have a direct bandgap spanning almost the entire solar spectrum. Their large absorption coefficients facilitate the complete absorption of the photons in PV devices with a film thickness of 1 µm.
“We are quite excited about this new hybrid solar cell that marries low-cost nitride thin film with the massive infrastructure of silicon solar cells,” said CEO Bob Forcier. “Our target market for this hybrid device is the high-performance sector for photovoltaics, which we estimate to be over 1% of the $34B solar cell global market. This high-performance market is especially sensitive to applications which have constrained areas, such as industrial rooftops and mobile devices.”
CTO Wladek Walukiewicz added that the “nitrides have plenty of upside opportunity for higher efficiencies where most competing technologies are very near to their maximum practical efficiencies.”