SnO2 Surface Modification and Perovskite Buried Interface Passivation by 2,5‐Furandicarboxylic Acid for Flexible Perovskite Solar Cells

Abstract Flexible perovskite solar cells (PSCs) have received great attention due to their low weight, high power ratio, and potential applications in wearable electronic products. The efficiency and stability of flexible PSCs are directly affected by the carrier extraction and transport capabilities of electron transport layer. Herein, efficient flexible PSCs are prepared through incorporating 2,5‐Furandicarboxylic acid (FDCA) multifunctional intermediate layer between tin oxide (SnO 2 ) and perovskite, which can effectively eliminate defects at the interfacial to increase the electron mobility of the SnO 2 layer, modify the surface of SnO 2 to shift the conduction band upward to improve interface charge extraction, passivate the buried interface of perovskite to induce larger perovskite crystal growth, and establish a bridge between SnO 2 and perovskite to improve charge collection efficiency. As a result, the rigid PSCs with FDCA display a champion power conversion efficiency (PCE) of 24.53% with a high open circuit voltage ( V OC ) of 1.204 V. Furthermore, the flexible device with FDCA achieves a high PCE of 22.10%, and preserve 90% of its initial PCE after aging for 500 h at ambient condition without encapsulation, and maintain 81% of its original PCE after 10,000 bending cycles.