Injection-level dependent series resistance: Comparison of CELLO and photoluminescence-based measurements

摘要

We have investigated the spatially resolved series resistance R_(ser) of multicrystalline silicon solar cells in dependence on the injection level. For the global series resistance, a variation with the injection level is known from literature. Using CELLO and photoluminescence-based R_(ser) measurements we find a qualitative change in the series resistance distribution: For low injection levels, highly recombination-active areas lead to locally increased ohmic losses; with increasing injection level, these areas become less pronounced in the R_(ser) images. This can be understood in terms of lateral currents whose strength varies with the injection level due to varying current fractions passing through the grid or being shorted by the p n junction. A linear response-based series resistance description, comprising the variation of the series resistance with the injection level, is used to explain these findings.