Description: The innovation in the proposed SBIR Phase I project is the development of a unique triple unction inverted metamorphic technology (IMM), which will enable the manufacture of very lightweight, low-cost InP-based multijunction solar cells. The proposed IMM technology will consist of an all indium and phosphorous-based structure, which is designed to improve the radiation resistance properties of the triple junction solar cell. Because of the intrinsic radiation hardness of InP materials, this material system is of great interest for building solar cells suitable for deployment in very demanding radiation environments such as medium earth orbit and missions to the outer planets. It is expected that an efficiency greater than 30% could be realized with this new IMM structure.

Benefits: High efficiency solar cells along with lightweight are attractive for space power applications. The concept used in this proposal could be extended to improve solar cells for terrestrial applications. High efficiency solar cells would reduce the total area required for to generate a certain power demand.

NASA missions which require high radiation resistant solar cells could greatly benefit from this innovation. The current technology of solar cells showed limitations of radiation resistant properties due to the presence of GaAs in the middle cell of a triple junction solar cell. This innovation would provide a pathway to solar cells that would enable missions in high radiation environments.