Zwitterion-Stabilizing Scalable Bladed α-Phase Cs<sub>0.1</sub>FA<sub>0.9</sub>PbI<sub>3</sub> Films for Efficient Inverted Planar Perovskite Solar Cells
Ning Li, Jialiang Liu, Chen Li, Yujiao Li, Jinbiao Jia, Yangqing Wu, Huanqin Yu, Beilei Yuan, Bingqiang Cao
Abstract
Perovskite solar cells (PSCs) have attracted considerable attention as a prominent photovoltaic technology, yet the state-of-the-art PSCs still contain thermally unstable methylammonium (MA) cations and use laboratory-level assembly methods, making the device’s stability and scalability challenging. Herein, we demonstrate a generic zwitterion-assisted strategy to improve the efficiency and stability of formamidinium (FA)-based PSCs made by a scalable blade-coating technique. The zwitterion, 3-(1-pyridinio)-1-propanesulfonate (PPS), plays dual roles in effectively suppressing the formation of undesirable δ-phase and passivating the trap states of FA-based perovskite films. As a consequence, uniform FA-based perovskite films with an area as large as 16 cm2 were successfully obtained, and the small-area (0.1 cm2) device incorporating PPS achieved a champion efficiency up to 18.9%, as well as enabled a best efficiency of 16.2% for a large-area (1 cm2) device. More importantly, unencapsulated devices with PPS also exhibited superior thermal and moisture stability, remaining at 88% of initial efficiency after aging in air for 1000 h. This methodology provides a low-cost and facile pathway to realize the synergistic effect of crystallization modulation and defect passivation for large-scale perovskite devices with excellent optoelectronic performance and stability.