Electrical mismatch within single junction amorphous silicon and micromorph tandem thin film PV modules

Due to the electrical mismatch between the individual cells, the actual efficiency of a PV module is always lower than the sum of the cells under normal measurement conditions. The effect of this electrical mismatch is simulated for single junction amorphous silicon PV modules as well as micromorph thin film PV modules. This paper reports on the design of the realistic parameter distribution for the I-V simulation. It shows that due to the current mismatch in a double junction solar cell, these devices seem to be more significantly affected by similar variation in parameters, which would indicate that tighter production control is necessary but also that it will be more involved to measure these devices with sufficient accuracy. It is shown that device mismatch actually results in a lower fill factor, which is slightly different to what is seen for single cells.