Spectral and temperature sensitivity of area de-coupled tandem modules

Area de-coupling is a recently suggested method for current- or voltage-matching two-terminal tandem modules. It has previously been shown that under standard conditions, area de-coupled modules have the same theoretical efficiency as four-terminal tandem cells for any combinations of band gaps. In this work, the spectral and temperature sensitivity of ideal area de-coupled modules is investigated by detailed balance modeling. Voltage-matched area de-coupled modules are found to be considerably less sensitive to changes in the spectrum than current-matched modules. Current-matched modules are, on the other hand, found to be less sensitive to changes in the temperature. Under normal conditions, the difference in temperature sensitivity has a negligible impact on the efficiency compared to the difference in spectral sensitivity, making voltage-matched modules the preferred choice. The difference in efficiency between an area de-coupled voltage-matched module and a four-terminal device is found to be too small to be of any practical consequence even under changing conditions. This finding is in agreement with earlier work by Lentine et al. on microsystem-enabled photovoltaic modules.