Mitigating ion migration in perovskite solar cells

Intrinsic ion migration in the metal halide perovskite (MHP) absorber layer and its interfaces seriously limits the device stability of perovskite solar cells (PSCs). Despite considerable efforts to mitigate the ion migration issue, it remains a formidable challenge in the commercialization of PSCs. Here, we provide a short review of the device failure mechanisms induced by intrinsic ion migration and discuss the detrimental effects of ion migration on the different component layers of PSCs. We outline the corresponding strategies to mitigate ion migration in PSCs and provide an insight on materials engineering to attain long-term stabilized perovskite photovoltaics (PVs). Perovskite solar cells (PSCs) show great promise as a revolutionary photovoltaic (PV) technology. However, the instability issue caused by intrinsic ion migration is a major hurdle in the commercialization of this new PV technology.Recent progress in understanding the origins of intrinsic ion migration in metal halide perovskites and its impact on the degradation of each component layer in PSCs are briefly summarized.Strategies to mitigate ion migration are discussed, including engineering of perovskite composition, the incorporation of large organic cations, the introduction of ionic additives, the construction of robust charge-transfer layers and interfaces, and the development of corrosion-resistant electrodes.