Infrared Reflecting Solar Cells

The equilibrium temperature of a solar cell panel in space is a function of the ratio of solar absorptance to infrared emittance of the surface. This paper describes a method for reducing solar absorptance by constructing the solar cell so that it will be a reflector in the infrared part of the solar spectrum. Spectral transmittance, spectral reflectance, and spectral absorptance of silicon wafers and N/P and P/N solar cells are presented. A N/P cell equipped with a silver coating on the back surface and a 0.400 micron cutoff cover glass on the front was found to have solar absorptance of 0.66 which is 11 percent less than that of a standard N/P cell equipped with a similar cover glass.