PHYSICS OF SOLAR-CELLS

The photovoltaic mechanism is analyzed with special attention to the boundary conditions between emitter and junction. In frontwall cells, these boundary conditions are rather simple and permit a transparent analysis. They connect the current, determined by the emitter/junction boundary, with the potential drop in the junction, determined by the same condition, and yield the current-voltage characteristic without invoking the superposition principle. The chemistry of the interlayer between the emitter and the junction may modify this characteristic when causing major interface recombination, resulting in a potential deformation. Such behavior is analyzed in more detail for the example of CdS/Cu2S and CdzZn1-zS/Cu2S solar cells. Substantially improved agreement between the results of this theory and experiment is reached.