Grain boundaries (GBs) have been shown to initiate metal halide perovskite degradation under light, moisture, and/or heat stresses due to the existence of various defects, making them extremely vulnerable in perovskite solar cells (PSCs). Although various post-treatments have been proven to be effective in repairing GBs, preventing the degradation from perovskite GBs remains an extremely difficult challenge. We report here a generic pre-annealing treatment for reconstructing sequentially deposited perovskite crystallites and GBs. With this strategy, robust GBs are created upon defect suppression with preferred oriented large perovskite grains. As a result, the resultant n-i-p-structured PSCs deliver an impressive power conversion efficiency of nearly 25% and an extremely high fill factor of 85.5%. The unencapsulated cells maintain 81% of their initial efficiencies after 1,000 h of continuous operation at maximum power point at about 55°C in an inert atmosphere, showing greatly improved light stability.

由于存在各种缺陷，晶界 (GB) 已被证明会在光、湿气和/或热应力下引发金属卤化物钙钛矿降解，这使得它们在钙钛矿太阳能电池 (PSC) 中极其脆弱。尽管各种后处理已被证明可有效修复晶界，但防止钙钛矿晶界的降解仍然是一个极其困难的挑战。我们在这里报告了一种通用的预退火处理，用于重建顺序沉积的钙钛矿微晶和 GB。通过这种策略，在用优选取向的大钙钛矿晶粒抑制缺陷后，可以创建稳健的 GB。结果，由此产生的 nip 结构 PSC 提供了令人印象深刻的近 25% 的功率转换效率和 85.5% 的极高填充因子。