LAUSR

With the rapid rise in device performance of perovskite solar cells (PSCs), overcoming instabilities under outdoor operating conditions has become the most crucial obstacle towards their commercialization. Among stressors such as light, heat, voltage bias, and moisture, the latter is arguably the most critical, as it can decompose metal-halide perovskite (MHP) photo-active absorbers instantly through its hygroscopic components (organic cations and metal halides). In addition, most charge transport layers (CTLs) commonly employed in PSCs also degrade in the presence of water. Furthermore, photovoltaic module fabrication encompasses several steps, such as laser processing, sub-cell interconnection, and encapsulation, during which the device layers are exposed to the ambient atmosphere. Therefore, as a first step towards long-term stable perovskite photovoltaics, it is vital to engineer device materials towards maximizing moisture resilience, which can be accomplished by passivating the bulk of the MHP film, introducing passivation interlayers at the top contact, exploiting hydrophobic CTLs, and encapsulating finished devices with hydrophobic barrier layers, without jeopardizing device performance. In this article, we review existing strategies for enhancing the performance stability of PSCs and formulate pathways toward moisture-resilient commercial perovskite devices. This article is protected by copyright. All rights reserved.