Determination and Modeling of Injection Dependent Series Resistance in CIGS Solar Cells

The total series resistance of industrially produced Cu(In,Ga)Se
₂
solar cells is investigated using photo-and electro-luminescence imaging at various applied voltages. A strong dependence of the series resistance on the cell operating point was observed. It decreases with increasing illumination intensity and increasing applied voltage. This injection dependent behavior was reproduced using numerical simulations, and was found to be due to the transport properties of the Cu(In,Ga)Se
₂
bulk. To take the injection dependency of the series resistance into consideration is important when dealing with quantitative luminescence or electrical measurements of CIGS solar cells.