Zwitterion-Stabilizing Scalable Bladed α-Phase Cs_0.1FA_0.9PbI₃ Films for Efficient Inverted Planar Perovskite Solar Cells

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.