Stability of Perovskite-Silicon Tandem Cells Under Thermal Cycling

We report accelerated thermal-cycling results for monolithic perovskite-silicon tandem photovoltaics across 1,200 cycles between -40 and 85 C. We identify halide segregation at the perovskite/transport-layer interface as the dominant degradation pathway and show that a 2D passivation layer recovers 94% of initial efficiency after cycling. We discuss implications for outdoor module lifetimes.