Suns‐PLI as a powerful tool for spatially resolved fill factor analysis of solar cells

We show the benefits of spatially resolved pseudo fill factor analysis on multicrystalline silicon solar cells. Hereby, we present a method based on quasi‐steady‐state photoluminescence‐calibrated photoluminescence images at varying generation rate. We verify the method by a comparison with global and local Suns‐Voc measurements and apply Suns‐PLI to multicrystalline heterojunction samples with and without conductive top layer, the latter being not accessible by Suns‐Voc. Thereby, we obtain detailed insight into the influence of injection‐dependent local recombination on fill factor and of losses only due to recombination‐driven lateral balancing currents. The conclusions are supported by Spice network simulations.