Improving Efficiency and Stability of p–i–n Perovskite Solar Cells by Capsaicin‐Based Antisolvent Additive Engineering

Improving the morphology and crystallinity of polycrystalline perovskite films is essential for perovskite solar cells (PSCs) with high efficiency and stability. Herein, capsaicin‐based antisolvent additive engineering (AAE) is proposed to fabricate MAPbI 3 ‐based p– i –n PSCs by simply adding capsaicin into antisolvent to simultaneously regulate crystallization and passivate defects of perovskite films. Meanwhile, a more n‐type surface is formed by the spatially confined distribution of capsaicin at grain boundaries and top interfaces of perovskite induced by the proposed AAE process, which facilitates the transport of charge carriers. As a result, the MAPbI 3 ‐based PSCs with p– i –n architecture achieve a high power conversion efficiency (PCE) of 20.85% with negligible hysteresis (active area of 0.07 cm 2 ), as well as an improved stability by maintaining 70.7% of the initial PCE after monitoring for over 400 h under ambient environment (25%–35% relative humidity) without encapsulation. In this work, a facile and effective strategy is proposed to prepare high‐quality perovskite films, which improves the efficiency and stability of PSCs and paves the way for further commercialization of PSCs.