Enhanced understanding of recombination mechanisms in high-performance tin-lead perovskite solar cells

Tin-lead perovskite solar cells are promising for single-junction and tandem photovoltaics due to their high efficiency and lower environmental impact. However, optimization efforts are hindered by significant discrepancies in reported carrier lifetimes, ranging from nanoseconds to hundreds of microseconds. Here, we address these inconsistencies using transient photovoltage (TPV) and time-resolved photoluminescence (TRPL) measurements under various operational conditions and rigorous data analysis. We identify a trap-assisted lifetime of 3 μs under low light and a radiative recombination coefficient of 2 × 10⁻¹⁰ cm³/s under high illumination, resulting in an effective carrier lifetime of approximately 1 μs under 1 sun illumination. These insights are critical for understanding device performance in real-world conditions. Our consistent TPV and TRPL results address a significant gap in the literature. Additionally, we reproduce the measured open-circuit voltage using parameters extracted from these measurements and attribute the discrepancies in the literature to insufficient data analysis and device degradation during testing.