8 February 2011

EPIR and NREL achieve 77.6% fill factor for CdTe single-junction PV cell

EPIR Technologies Inc of Bolingbrook (a suburb of Chicago), IL, USA, which develops infrared sensor, biosensor and solar photovoltaic products, says that it has repeatedly fabricated high-efficiency polycrystalline single-junction cadmium telluride (CdTe) solar cells on commercial glass substrates.

The firm was founded in 1997 by CEO Dr Sivalingam Sivananthan who, at the University of Illinois at Chicago, pioneered the growth of single-crystal II-VI materials such as mercury cadmium telluride (HgCdTe) on silicon for infrared night-vision applications. EPIR is now building on this to also develop and manufacture high-efficiency, low-cost multi-junction solar cells for concentrated photovoltaic (CPV) applications.

“EPIR has been collaborating closely with a team of scientists from National Renewable Energy Laboratory (NREL),” says Sivananthan. “The combination of EPIR’s expertise in CdTe materials and NREL’s expertise in CdTe solar cell device technology has empowered us to achieve these excellent results in a short timeframe,” he adds.

“Our champion-cell efficiency was officially verified by NREL at 15.2%. The high efficiency was driven by a fill factor of 77.6%, which is one of the highest fill factor values ever recorded for this type of solar cell,” says EPIR’s CdTe Solar Cell Technical Lead Dr Chollada Gilmore. “These results are significant because our solar cells were fabricated using inexpensive commercial TEC-series glass substrates as opposed to technical-grade glass which is commonly used in champion cell fabrication,” he adds.

“This achievement elevates EPIR to the very small group of solar companies and research facilities that have reproducibly fabricated CdTe solar cells with greater than 15% efficiency,” comments Dr Timothy Coutts, NREL Fellow Emeritus and founder of the Device Development Group at NREL. “This clearly validates EPIR’s expertise in CdTe solar cell growth and fabrication,” he adds.

“This is an important advancement for CdTe thin-film PV technology because it not only surpasses the previous best result that was published for commercial soda-lime glass by a clear margin (14.4% was the previous best result on commercial soda-lime glass), but all the layers incorporated into this new device structure are consistent with present commercial manufacturing processes,” notes Dr Timothy Gessert, principal scientist & group manager of the NREL CdTe Research Group.

Tags: EPIR NREL CdTe single-junction PV cell

Visit: www.epir.com

Visit: www.nrel.gov

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