Despite perovskite solar cells (PSCs) have demonstrated a promising power conversion efficiency, their long-term operational stability is still widely recognized as the key bottleneck to next-step development and commercialization [1]. Specifically, mixed-cation perovskites, which push the record efficiency up to more than 26%, suffer from intrinsic instability, especially under thermal stress [2]. However, for outdoor operation, solar cells must face with extreme and harsh conditions during their service lifetime, which has important implications for real-world energy yields. Up to now, most reported lifetimes are within thousands of hours, significantly lagging behind silicon photovoltaics with a 25 years' lifetime [3].

Regarding this stability concern, in this work we employ a novel deposition method to achieve state-of-the-art efficiency and excellent long-term stability under thermal and illumination stress, fundamentally overcoming the intrinsic instability challenge for mixed-cation perovskite materials. We found that the as-fabricated PSCs can maintain its power output for over 2,000 hours without any sign of degradation under continuous max power point tracking (MPPT) at room temperature. To further explore the full potential of the stability of our devices, we elevated to an unprecedently high temperature of 110°C and found that it can maintain 80% of initial efficiency (T₈₀) for more than 520 hours under MPPT. This performance drives us to conduct accelerated aging test to investigate the degradation mode and predict the lifetime of our devices under real-world operations. Here, we set temperature as the key stress factor and monitor indoor operational output of PSCs at different high temperatures ranging from 65 to 110°C. The data from accelerated tests is then fitted with Arrhenius model, returning an estimation of the field lifetime. As a result, the projected operational lifetimes of different temperatures converge at 45,000 hours, which aligns with the extrapolated T₈₀ lifetime derived from room-temperature measurement. Furthermore, considering different local global horizontal irradiation worldwide, the converted lifetime of PSCs can sufficiently ensure 25 years of outdoor exposure in Singapore, Japan and most areas in US. This result is the best-to-date stability performance of mixed-cation PSCs reported so far in literature. More importantly, it's the first time that PSCs is proved to realize such a long lifespan comparable to silicon solar cells, paving the way to future development and commercialization of perovskite-based photovoltaics.