Quantifying the performance gain of 100 cm 2 bifacial four terminal perovskite-Si tandem modules

Improving the performance of solar modules requires the implementation of both spectral and directional irradiance optimization. The performance of bifacial four-terminal tandem minimodules with a 100 cm 2 area is reported, both indoor and outdoor measurements. We demonstrate a 24.5 mW/cm 2 (bifacial irradiance 200 W/m 2 ) bifacial tandem power density, measured according to a tandem adapted IEC60904-1-2 protocol, which constitutes a 3 mW/cm 2 gain with respect to monofacial use. In addition, we show that in outdoor measurements bifacial four terminal tandems outperform identical monofacial four terminal tandems by 26% on average, depending on incident angle, injection level and temperature, in a 10% albedo environment. The average gain is higher for outdoor performance than for indoor performance, due to variations in relative rear irradiance.