Structure Optimization Strategy of PbI ₂ Vacuum Deposition Process for Efficiency Enhancement of Perovskite Solar Cells

Perovskite solar cells based on formamidinium (FA) hold great application prospects in the field of renewable energy due to their excellent power conversion efficiency (PCE) and low cost, but the controllable preparation of large‐area, high‐quality perovskite films remains the core bottleneck for their industrialization. To address this critical challenge, this study fabricates lead iodide (PbI 2 ) thin films using the evaporation method and systematically reveals the mechanism by which morphology regulation of the precursor films influences the crystallization quality and optoelectronic properties of perovskite films. By employing the evaporation distance of PbI 2 as the core regulation strategy, we optimize the deposition state of the precursor films, enabling precise control over the micro‐morphology and significantly enhancing the light absorption capability and charge transport performance of the films, which provides a clear mechanistic basis for preparing high‐quality perovskite films. On this basis, combined with a two‐step solution‐assisted vapor deposition method, this study successfully achieves efficient and controllable preparation of large‐area perovskite films. The solar cell devices fabricated using this method exhibit a PCE of 14.57% at an active area of 64 cm 2 (total area 100 cm 2 ).