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-V oc measurements and apply Suns-PLI to multicrystalline heterojunction samples with and without conductive top layer, the latter being not accessible by Suns-V oc. 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.