Measuring and Mitigating Edge Recombination in Modules Employing Cut Cells

Power losses in solar cells and modules due to recombination at cut cell edges is a problem of increasing concern since many new and future module concepts use cut cells, and particularly as the PV industry moves to larger wafer formats. Herein, we first demonstrate the use of high resolution photoluminescence imaging combined with quasi steady state photoconductance measurements to calculate carrier lifetime directly from photoluminescence images, and discuss the factors and limitations involved in this method. We then compare the edge recombination dynamics in interdigitated back contact solar cells and heterojunction solar cells as a function of the method used to cut them, and show several important differences. Finally, we explore some edge passivation strategies that could be used to mitigate the negative effects of cutting.