RASIRC, the Steam Purification Company, announces the availability of the white paper, Using Water Vapor to Improve Photovoltaic Performance and Reduce Cost, by Jeffrey Spiegelman. The paper can be accessed at: http://www.rasirc.com/resources/whitepapers/whitepaper_solar.pdf. The paper describes uses for water vapor during the fabrication of photovoltaic (PV) cells. Focused on improvements from water vapor, the paper surveys internal reports and third party published data related to lowered cost through thinner substrates and improved efficiency by reduction in recombination losses.
Leading edge PV cell manufacturers are improving cell efficiencies by adding water vapor to grow backside thick oxide films, adding SiO2 interface layers, and annealing interface layers to reduce grain boundary defects. The paper cites data which concludes that High Temperature Steam Annealing (HSA) generates the best carrier lifetimes with a very short annealing cycle time. The authors state that HSA can both improve performance and eliminate hydrogen and the plasma damage required with older technologies.
“The photovoltaic industry is increasing efficiency and reducing cost through reduced silicon content and improved cell design,” said Jeffrey Spiegelman, president and founder of RASIRC. “To make this happen, new materials and process steps need to be introduced to the manufacturing process. These processes require the use of water vapor during PV cell fabrication. Ultra pure water vapor, produced by RASIRC steamers, is the only purified steam available today. They deliver safety, low cost of purchase and ownership, ease-of-use, and high flow capability. Using these products, process engineers have achieved increased growth rate, process uniformity, and contamination/particle-free films.”