Abasifreke Ebong, assistant director of Georgia Tech’s Photovoltaic Research Center, says to confirm that this is happening, the next step is to study the oxygen content of the solar wafers after they’re removed from the firing furnace. If the oxygen is lower, the theory holds. “That’s the data we’re waiting for,” he says.
According to Mike Davies, senior vice president at Sixtron, every 0.1 percentage of net efficiency spared from light-induced degradation results, on average, in a $600,000 gain in profit margin for each 60-megawatt cell production line.
Sixtron’s system eliminates the silane gas hazard, relying instead on a proprietary solid polymer material that contains silicon and carbon. Using heat and pressure, the solid is converted to a less dangerous methyl silane gas during the cell-coating process. The solid-to-gas conversion takes place inside the company’s gas-handling cabinet system, called SunBox, which has been designed to plug directly into industry-standard systems that exist on most cell-production lines.
Joshua Pearce, a professor of advanced materials at Queen’s University in Kingston, Ontario, says Sixtron may be overstating the risks of using silane in a photovoltaic cell plant. “There are standard safety procedures that make working in a photovoltaic factory very safe,” he says. Still, he adds, “anything to drop the cost of photovoltaic, even if by a small amount, is a great contribution.”
Sixtron says it is already working with the top three providers of photovoltaic cell manufacturing equipment in Germany, and has interest from several others. The company plans to rent out the system at a cost roughly the same as using a silane-based system. Importantly, it avoids the need to use other light-induced degradation reduction strategies, based on alternative manufacturing methods or the use of higher-cost wafers doped with gallium.