Generalized relationship between dark carrier distribution and photocarrier collection in solar cells

A recently identified relationship between the probability of collection of a photogenerated carrier in a solar cell and the dark minority-carrier concentration at the point of generation is generalized to three-dimensional geometries with arbitrary doping profile and variable band gap including abrupt compositional changes, grain boundaries, and floating junctions. The proof of the resulting relationship is simpler and more transparent than in earlier work with more restricted geometries.