Angle of incidence corrections for GaAs/Ge solar cells with low absorptance coverglass

A total of four different types of coverglass/filter combinations were tested over a 0 to 85 degree angle of incidence range. One group of cells was irradiated to provide additional data. A predicted cell response was calculated using the cosine and Fresnel corrections. A comparison of measured versus predicted values showed a good fit for blue reflection or anti-reflection (AR) filters. Both blue-red and infrared reflection filtered cells showed decreased output in the 40 to 80 degree range due to movement of filter IR band-edge into cell response range. Performance at very high incidence angles is still not fully understood. A special infrared filter was used which did not have an angle of incidence effect. Irradiation of cells improved angle of incidence performance for cells with infrared reflection filters.