Production has started on a second-generation solar cell at Suniva that is claimed to achieve efficiencies above 19%, a record for monocrystalline-based cells in volume production using conventional screen-printing processes, according to the company. As highlighted by PV-Tech previously, the company is the first to adopt ion implantation techniques for emitter performance improvements.
“Combined with Suniva’s innovative R&D and proprietary processes, ion implantation provides us with a very cost-effective way to manufacture solar cells of 19% efficiency without adding complex processes for a selective emitter,” noted Dr. Ajeet Rohatgi, Suniva founder and CTO. “We do have the capability to use a selective emitter, but we have not yet chosen to do so.”
Indeed, Suniva also touted its third-generation cell technologies that are built around multiple proprietary cell structures certified by NREL as achieving 20% efficiency.
“Our unique development process is what will ultimately enable Suniva to achieve efficiencies in the 20% range in our third-generation cells on n-type wafer and maintain an equally attractive manufacturing cost,” added Dr. Rohatgi.
The use of ion implantation in Suniva’s manufacturing process is based on years of development collaboration with equipment supplier, Varian Semiconductor Equipment Associates. Varian has claimed a potential 2% efficiency gain is achievable when using ion implantation techniques when migrating to selective emitters and back-contact designs. In Suniva’s case the doping technique produced a 1% efficiency gain, without these more advanced cell configurations.
Bruce McPherson, vice president of research and development for Suniva, said, “Leveraging ion implantation in solar cell processing has traditionally proven too costly and slow. Combined with Suniva’s deep research and our own proprietary design, recipes and processes, we have unlocked the value of the ion implanter as an enabling technology for solar cell processing. The result is an immediate, one percent efficiency gain in ARTisun Select, and an ongoing reduction in our cell conversion costs.”
Cost reductions also come from the elimination of certain process steps that normally required with conventional cell processing.