Polymer Boosts High Performance Perovskite Solar Cells: A Review

Abstract Perovskite solar cells (PSCs) with excellent photoelectric properties have attracted much attention in recent years. However, the solution manufacturing of PSCs inevitably introduces a large number of defects (both bulk and surface defects), which seriously affect the performance of PSCs. Defect passivation from additive engineering is an effective and simple strategy. Among these additives, polymers are increasingly attracting attention due to their excellent properties, such as adjustable structures, multiple functional groups, excellent stability, and low cost, which can further promote the commercialization of PSC technology. However, the application of polymers in PSCs have encountered some obstacles due to a lack of systematic studies, such as unelucidated interactions between polymers and perovskites, the frequent trial‐and‐error process used in material selection, and the lack of effective guidelines. In this review, the application of polymers in various layers of PSCs devices is first summarized. Then, three main roles of polymers in PSCs are summarized, including crystallization regulation, the mechanical stability enhancement of flexible perovskite solar cells (FPSCs), and their use as undoped hole transport materials (HTMs). More importantly, machine learning (ML) is proposed to design and select polymers as passivators and HTMs for PSCs. Finally, promising guidelines and recommendations are provided for the commercialization of PSCs.