Superposition and Reciprocity in the Electroluminescence and Photoluminescence of Solar Cells

The reciprocity relation between electroluminescent emission and photovoltaic quantum efficiency of solar cells and light-emitting diodes is extended to the case of photoluminescence emission. Here, a superposition principle between voltage-driven electroluminescence and photoluminescence under short-circuit conditions is derived from the principle of detailed balance. Further generalizations of the reciprocity relation are discussed, as well as the limitations of the approach.