Additive engineering enabled non-radiative defect passivation with improved moisture-resistance in efficient and stable perovskite solar cells

Perovskite solar cells have emerged as promising candidates in the photovoltaic industry owing to their high efficiencies and low production costs. However, their commercial viability has been hampered by issues related to long-term environmental and operational stability, and their efficiency is lower than the Shockley–Queisser (SQ) limit. In this study, we explored a groundbreaking approach to enhance the efficiency and stability of CH3NH3PbI3 perovskite solar cells via the additive engineering of tetraphenylphosphonium chloride (TPPP(Cl)). By introduction of TPPP(Cl) into perovskite precursor, we demonstrated a notable amelioration in the photovoltaic performance of respective device. The presence of TPPP(Cl) enhances the crystallinity of the perovskite film, and the Cl from TPPP(Cl) can passivate halide ion defects, resulting in reduced defect density and improved charge carrier mobility. This in turn, leads to a substantial increase in power conversion efficiency, making perovskite solar cells a more competitive option for renewable energy applications. Furthermore, our research delves into the remarkable stability enhancement achieved through the incorporation of TPPP(Cl), as the champion device retained 89 % of its initial PCE for over 30 days after being placed in an ambient environment without any encapsulation. Thus, we propose that careful regulation of the concentration of TPPP(Cl) significantly increases the resistance of the device to moisture and heat, resulting in prolonged operational lifetimes.