PBO and Silicone-Resin Free-Standing High-Temperature Films for Monolithically-Integrated CIGS Devices

"ITN Energy Systems, Inc. is developing a space photovoltaic (PV) product based on our commercialization partner, Global Solar Energy, Inc.'s (GSE) flexible thin-film polycrystalline copper-indium-gallium-diselenide (CIGS) technology. These devices arebeing made as discrete cells on metallic foil substrates, as well as a monolithically integrated device on a polymeric substrate. While we have demonstrated a cell efficiency approaching 10% on a polyimide (PI) substrate, the record efficiency of 18.8% asmeasured at the National Renewable Energy Laboratory (NREL) was deposited on a rigid glass substrate, and approaching 18% on a flexible stainless steel foil substrate. ITN has demonstrated that PBO films can survive higher processing temperature than ourbaseline Upilex PI substrate. Furthermore, we have teamed with Dow Corning to develop free-standing silicon-resin based foils that will be capable of achieving the higher processing temperatures in order to pursue higher efficiencies. Both the PBO andsilicones should be able to achieve processing temperatures above 500¿C while providing an electrically insulated substrate to facilitate monolithic integration. ITN shall acquire PBO films and Dow Corning shall provide prototype silicone-based films todemonstrate CIGS devices, and the best performing substrate shall be utilized in Phase 2 to demonstrate monolithically-integrated PV modules. Reduced manufactured cost due to monolithic integr