ABSTRACT

Comprehensive studies performed by the author on the materials best suited for solar cells intended for use in space indicate that enhanced conversion efficiency, low material cost, and high space radiation resistance are the most essential material requirements. In addition, materials must be capable of absorbing maximum incident solar photon energy in the shortest time. In other words, the optical absorption constant as a function of photon energy must be high enough to allow a larger fraction of the carriers generated by the absorption of the solar photons to be produced within a shorter distance from the surface of the incident on the solar cell. The intensity of the solar light at a distance x below the surface of which a flux I0 is incident cane be given as

I(x) = [I0 e-αx] (6.1)

where α is the optical absorption constant for the material as a function of photon energy hυ (eV).