Improving the accuracy of suns-VOC measurements using spectral mismatch correction

ISC-VOC curves measured by the Suns-VOC method are widely used for solar cell characterization due to its unique feature of not being affected by series resistance effects. Although the accuracy of the Suns-Voc is good for standard silicon solar cells, care has to be taken when measuring solar cells whose spectral response differs significantly from that of the high-efficiency back contact silicon solar cell used as a reference cell due to a spectral mismatch. Two options are possible in order to reduce this systematic measurement error. Firstly the spectral mismatch can be calculated and the measurement corrected for. Secondly, an appropriate filter can be introduced into the flash beam in order to adjust the spectrum of the flash. With both methods a significant improvement in measurement accuracy can be achieved, as will be shown in this contribution.