Assessment of protective coatings on flexible CIGS modules for satellites

Flexible CIGS solar cells are a promising alternative for space applications where payloads are restricted by weight. They suffer from high reflection in the infrared spectrum and if un-encapsulated, are prone to mechanical damage and performance losses. We present in this paper a flexible thin single layer protection coating which enhances the emissivity of CIGS from 0.3 to 0.7 but is transparent enough to have no detrimental effect on electrical performance as was measured under AM0 illumination. The coated CIGS samples passed the thermal vacuum outgassing test and the coating process can be easily scaled up for larger modules. Large coated CIGS modules showed no performance degradation and mechanical cracks after they underwent vibration test. By replacing cover glasses on solar modules, the coating can significantly reduce specific weight of solar modules and the associated payload costs.