Methylammonium (MA)-free perovskites such as Cs_xFA_1−xPbX₃ (CsFA) show excellent thermal stability, favoring their use in perovskite solar cells (PSCs). However, the power conversion efficiency (PCE) of CsFA lags behind that of MA-containing formulations due to the difficulty in controlling the film morphology. Herein, we report innovative morphology engineering using solution deposition of a mixture of CsBr, PbI₂, and PbCl₂ followed by vacuum evaporation of formamidinium iodide (FAI) to fabricate CsFA films. The introduction of a chloride precursor leads to larger grain sizes, forming a high-quality CsFA film under annealing. This enables the realization of robust CsFA-based PSCs with the highest reported PCE up to 24.1% (certified 23.9%) for 0.1 cm² and 22.8% for 1 cm² devices. Moreover, the unencapsulated evaporation device shows excellent stability with negligible efficiency decline after 20,000 h of storage in dry air or 1,000 h of exposure to 50% humidity, which is much better than the device prepared using the solution procedure.

不含甲基铵(MA) 的钙钛矿，例如 Cs _x FA _1−x PbX ₃ (CsFA) 表现出优异的热稳定性，有利于它们在钙钛矿太阳能电池 (PSC) 中的应用。然而，由于难以控制薄膜形态，CsFA 的功率转换效率（PCE）落后于含 MA 的配方。_{在此，我们报告了使用 CsBr、PbI 2}和 PbCl ₂混合物溶液沉积的创新形态工程然后真空蒸发甲脒碘化物（FAI）以制造CsFA薄膜。氯化物前体的引入导致更大的晶粒尺寸，在退火下形成高质量的 CsFA 薄膜。^{这使得能够实现基于 CsFA 的稳健 PSC，对于 0.1 cm 2设备和 1 cm 2}设备的最高报告 PCE 高达 24.1%（认证为 23.9%）和 22.8% 。此外，未封装的蒸发装置在干燥空气中储存 20,000 小时或暴露于 50% 湿度下 1,000 小时后显示出优异的稳定性，效率下降可忽略不计，这比使用溶液程序制备的装置要好得多。