Collection probability equals dark minority carrier concentration and other surprising solar cell relations

Over the last year or so, an important result originally derived 10 years earlier has been rediscovered by the photovoltaic community. This shows that, for general solar cell geometries with uniformly doped bulk regions, the probability of collection of a carrier generated at any point in the cell equals the minority carrier concentration at the same point in the dark when normalized to its value at the junction. This relationship is generalized, using a particularly simple yet elegant algorithm, both to single and multiple junction cells with arbitrary doping profiles and internal features such as voids, precipitates, dislocations, grain boundaries, and internal interfaces including those associated with polarity and bandgap changes. The relationship also has implications for simplified solar cell analysis, gaining insights into device operation and for the theory of limiting cell efficiencies and into the operation of devices with multiple independent junctions