Novel Environmental Protection for Multi-Junction Solar Cells

ABSTRACT: Thin film flexible cells based on IMM architecture require a protective optical coating that maintains optical and mechanical integrity when rolled and unrolled. The new flexible multi-functional coating must be stable to temperature changes, ground-storage humidity, ionizing radiation, atomic oxygen, and also provide ESD and high thermal emissivity properties. Our team will apply the radiation resistant and/or space qualified deposition process and materials technology that we established and demonstrated on previous SBIR and other R & D projects to develop the new coating. UVR, AR, and ESD coatings developed in our previous work passed radiation and environmental testing, and samples on glass and flexible substrates were flown on MISSE-7. Sample substrates will be coated to meet the protective requirements and evaluated. Compatibility with cell integration and assembly procedures will be addressed. The new coating will be useful for all DoD, NASA, and communications spacecraft power, and terrestrial applications that employ flexible arrays. BENEFIT: The ability to package and stow solar cell arrays into small volumes by rolling them has large benefits in terms of launch resources expended. In the stowed configuration, power-per-weight and -per-volume are significantly reduced. Coupled with higher solar energy conversion efficiencies, flexible MJ IMM cells will soon replace conventional arrays. Our flexible optical and protective coating will maximize photon throughput to the solar cell and protect the assembly from the harsh space environment. The new coatings developed in the proposed effort can be applied to all DoD, NASA, and communications spacecraft power, and terrestrial applications that employ flexible arrays.