Hysteresis-free and highly stable perovskite solar cells produced via a chlorine-mediated interdiffusion method

Although lead-halide perovskite-based solar cells hold the promise of a breakthrough in the production of next-generation photovoltaic devices, anomalous hysteresis in current-voltage curves and inadequate stability remain as major challenges. Here, we demonstrate the production of low-temperature solution-processed perovskite solar cells (ITO/PEDOT: PSS/perovskite/PC61BM/Ca/Ag) with hysteresis-free current-voltage characteristics, excellent photostability, and high reproducibility via the inclusion of methyl ammonium chloride (MACl) using the interdiffusion method. The best-performing devices exhibited a power conversion efficiency of over 12%. Our devices showed promising stability by maintaining more than 90% of their initial performance over long periods of time at ambient conditions with encapsulation using common techniques, as well as no obvious degradation after 2 h of continuous light exposure. We statistically compared fabrication processes using the interdiffusion method with or without MACl by creating a histogram of over 120 devices for each method. The results clearly indicated that including MACl gave better reproducibility and a higher average efficiency of 9.5%, as well as improved device stabilities.