Fundamental understanding of stability for halide perovskite photovoltaics: The importance of interfaces

Perovskite solar cells (PSCs) have shown great progress over the past decade, with efficiencies of single -junction devices approaching those of silicon photovoltaics. However, their long-term stability still lags behind that of their silicon competitors, which has decelerated their commercialization progress. Faced with this challenge, major efforts have been made to unravel instability mechanisms, develop long-term performance -tracking protocols, and explore approaches for enhancing the PSC stabilities. Among these strategies, interface manipulation is most critical as it can simultaneously passivate perovskite surface defects and acts as a barrier to protect the bulk of perovskites from the external environment. Recently, the development of interface molecules and regulation strategies has greatly contributed to the improvement of PSC stability. This perspective aims to elucidate the factors influencing the stability of PSCs and provide insights into device degradation with advanced techniques. Additionally, we discuss pressing topics on interface manipulation, including low -dimensional (LD) capping layers, interface modification and reaction, and charge transport layer design. Lastly, we shed light on the core aspects related to the future development of PSC stability.