An Analytical Model for Resistance-Limited Recombination at Line Defects in Solar Cells

Lateral changes in p-n junction voltage as a result of recombination at line defects. The model takes into account the majority charge carrier transport in the emitter and in the base over a long distance (>1 mm) as induced by a line defect (for example, a metal finger, an edge, or any line-shaped region with a higher recombination rate). The model predicts the p-n junction voltage as a function of distance to the recombination center in one dimension. The model is compared with numerical device simulations using Quokka3 for two scenarios typical in current state-of-the-art solar cells. The deviation of the lateral p-n junction voltage is less than 1 mV for contact recombination and less than 4 mV for edge recombination. These results show that over the relevant distances, the carrier transport is almost purely resistive, validating the main hypothesis of this model. Such good agreement, and the corresponding compatibility with numerical device simulations, renders the model a useful tool for the interpretation of experimental results.