Impact of localized regions with very high series resistances on cell performance

The JV curves recorded under illumination for solar cells having a high series resistance can appear shunted when a fraction of the cell area is affected by very high series resistance values. This apparent shunting behaviour was observed in n-type rear-junction, laser-doped cells with light-induced plated front contacts. Localized series resistance measurements of the affected cells by photoluminescence imaging revealed that over 20% of the cell area had a series resistance above 10 Omega cm2 and extending up to a maximum value of 168 Omega cm2. It was found that cells with localized series resistances have a detrimental impact on the FF and J(sc) of the device. Furthermore, an unusual FF recovery was also observed with decreasing level of illumination. A solar cell model with localized high series resistances was developed to further study this apparent shunting behaviour with respect to its impact on cell performance. Copyright (c) 2011 John Wiley & Sons, Ltd.