One Year of Outdoor Performance of Perovskite/Perovskite/Silicon Triple‐Junction Solar Cell

Outdoor performance indicates the end use performance of solar modules and is therefore essential to monitor for emerging technologies, preferably at an early stage to elucidate optimal improvement paths. We study the performance of triple‐junction perovskite–perovskite–silicon sample during 1 year outdoor by monitoring the performance in situ by performing I – V curves. It is shown that the temperature step necessary for encapsulation degraded the performance significantly; however, this power loss could be reclaimed after a few weeks outdoors. The degradation to a performance of 80% of original takes 4 months. Further degradation until 50% of original performance was reached after 6 months. This degradation is for a significant part due to degradation of the top and middle perovskite and transport layers. Although the voltage, current, and resistances degraded significantly, all three subcells remained operational until the end of the measurement period after a full year, although the sample changed from middle cell limited to top cell limited. During that year, the energy yield was 0.75 kWh/Wp, or 10% of available solar energy, which was caused by degradation of the perovskite and transport layers, decrease of shunt resistance and the suboptimal low‐light performance during the entire runtime.