Buried and bulk synergistic engineering enables high-performance inverted 2D/3D perovskite solar cells

Abstract

Crystal growth regulation plays a key role in the fabrication of high-quality perovskite films. While surface defects have been extensively studied, the optimization of buried interfaces and bulk properties remains a significant challenge due to their complex influence on film morphology and device performance. Here, a synergistic strategy was developed to improve perovskite film quality by modifying the buried interface with FuMACl and controlling bulk crystallization using (DFP)₂PbI₄ 2D perovskite crystal seeds. The FuMACl layer improves the wettability, alleviates residual stress at the buried interface, and passivates defects. Combined with the (DFP)₂PbI₄ seeds in bulk, these modifications effectively enhance film quality and increase grain size, leading to a significantly reduced defect density. Compared to the control device with an efficiency of 23.11%, the target device demonstrated a champion efficiency of 26.03% and a notable fill factor of 86.79%, along with improved stability. Moreover, perovskite mini-modules with an aperture area of 10.80 cm² achieved 22.89% efficiency. These findings highlight the potential of the synergistic effects of buried interfaces and bulk engineering strategies to significantly enhance the performance of PSCs.