Stabilization Strategies of Buried Interface for Efficient SAM-Based Inverted Perovskite Solar Cells

In recent years, self-assembled monolayers (SAMs) anchored on metal oxides (MO) have greatly boosted the performance of inverted (p-i-n) perovskite solar cells (PVSCs) by serving as hole-selective contacts due to their distinct advantages in transparency, hole-selectivity, passivation, cost-effectiveness, and processing efficiency. While the intrinsic monolayer nature of SAMs provides unique advantages, it also makes them highly sensitive to external pressure, posing a significant challenge for long-term device stability. At present, the stability issue of SAM-based PVSCs is gradually attracting attention. In this minireview, we discuss the fundamental stability issues arising from the structural characteristics, operating mechanisms, and roles of SAMs, and highlight representative works on improving their stability. We identify the buried interface stability concerns in three key aspects: 1) SAM/MO interface, 2) SAM inner layer, and 3) SAM/perovskite interface, corresponding to the anchoring group, linker group, and terminal group in the SAMs, respectively. Finally, we have proposed potential strategies for achieving excellent stability in SAM-based buried interfaces, particularly for large-scale and flexible applications. We believe this review will deepen understanding of the relationship between SAM structure and their device performance, thereby facilitating the design of novel SAMs and advancing their eventual commercialization in high-efficiency and stable inverted PVSCs.