Sixtron airs antireflective passivation coating that reduces light-induced degradation on PV cells

Sixtron Advanced Materials has introduced a patent-pending antireflective passivation coating technology that it says will greatly reduce the light-induced degradation problem for crystalline-silicon solar cells. The company claims to have demonstrated an 88% reduction in LID on cells treated with its silane-free Silexium coating.

The optimized process flow and reference architecture was developed by Sixtron at its lab in Montreal, with resulting cells benchmarked by the University Center for Excellence in Photovoltaics (UCEP) at the Georgia Institute of Technology.

The company says that with appropriate process optimization, solar cells coated with Silexium films can deliver net efficiency gains to existing production lines. The precursor for the AR films is delivered to standard plasma-enhanced chemical vapor deposition equipment by the firm's SunBox silane-free gas generation system.

“With the release of our Silexium process technology, Sixtron is addressing a major concern of cell and module manufacturers,” notes Bates Marshall, VP of sales and marketing. “Sixtron’s Silexium process provides solar cell manufacturers with the only simple, low-cost solution to improve the efficiency of their products while simultaneously reducing manufacturing costs by eliminating the pyrophoric hazards of silane.”

To minimize the effects of LID--a phenomenon that can decrease the efficiency of modules in the field by up to 5% in the first hours of solar exposure--manufacturers of high-efficiency monocrystalline cells have had to opt for expensive high-grade boron-doped p-type Czochralski wafers or use alternatives to the traditional wafer manufacturing process to try to maintain end-of-line efficiency once cells are deployed to the field.

Solar cells made with Silexium coatings also deliver increased shunt or leakage resistance and
reduced reverse current by an order of magnitude, representing additional significant protections against cell degradation, according to Sixtron.

The company says that its AR passivation coating process technology offers manufacturers a drop-in solution to the LID problem that enables maximum flexibility within their silicon wafer supply chain and can result in further economic advantages to higher-priced LID reducing technologies.

“We have known for some time that Sixtron's silane-free antireflective coatings were a novel, low-cost way to match the performance of silicon nitride coatings while also eliminating the dangers of silane gas," comments Ajeet Rohatgi, UCEP's founder and director. "Our latest studies confirm that Sixtron's Silexium coatings can offer performance advantages over silane-based coatings by significantly reducing LID, a major obstacle for the majority of today's high-efficiency solar cell makers."