Space Environment Durable and Flexible Coating for Multi-Junction Solar Cells

ABSTRACT: The development of multi-junction solar cells enables more efficient capture of sunlight that enables them to achieve efficiencies of over 40% as compared to 20% for single junction solar cells. The inverted metamorphic (IMM) solar cell allows them to achieve the same conversion efficiency but at much greater flexibility, affordability and mobility. Lightweight, flexible multi-junction solar cells with high efficiency have great promise for spacebased applications where payload sizes are limited but energy demands are high. However, protective cover layers must be used to protect them from atomic oxygen (AO) and ionizing radiation attack, pre-launch humidity, and high-voltage discharge. It must also have high transparency in the wavelength that the solar cell is active. A number of currently used polymeric materials such as Kapton, silicone adhesives, POSS, and polymer matrix carbon fiber composites that are used as carriers in solar cell construction have shown signs of deterioration due to these space environmental effects. In this SBIR Phase I project we propose to develop a space durable, flexible, highly transparent coating system for the protection of multi-junction solar cells. The coating will be applied to the multi-junction solar cells via a low cost technique. Preliminary space environment simulation tests proved that it has great performance. BENEFIT: The proposed space durable, flexible, highly transparent coating system will have numerous potential applications for coating of multi-junction solar cells for space and ground structures including communication spacecraft, NASA spacecraft, large-scale space-based transparent thin films, based material for deployable space mirrors, X-ray telescope, earth-observation radiometry, remote sensing, space-orbiting very-long-baseline interferometry, ground based laser relay mirror, space-based radar, and microspacecraft components.