Photoluminescence based open circuit voltage and effective lifetime images re-interpretation for solar cells: The influence of horizontal balancing currents

We present a method to display photoluminescence imaging results in a different way for open circuit voltage for metallised solar cells. This method virtually eliminates the influence of horizontal balancing currents, which have limited the validity of previously reported methods. It is achieved by creating a “virtual static” situation. At this virtual situation, there is no horizontal current flowing and the calculation of local open circuit voltage can be more reliable. Then effective lifetime image can be calculated more accurately. Compared to other spatially resolved lifetime measurement methods, this method does not require calibration. It is made more convenient by only using one laser wavelength and existing photoluminescence systems. The total measurement time of 2-3 min increases its practicability. Moreover, it is free of horizontal balancing current and the accuracy is experimentally verified.