Rapping up Perovskite Solar Cells With Polymers: A Flexible Point of View

Abstract The application of vast kinds of materials in functional layers of flexible perovskite solar cells (FPSCs) renders a rapid improvement power conversion efficiency (PCE), yet such characteristic is still outcompeted by their nonflexible counterpart. To date, the key challenges in FPSCs come from the suboptimal film crystallinity and built‐up stress due to mismatch of lattice constant between functional layers, making the whole device prone to mechanical vulnerability and degradation of optoelectronic performance. Among reported solutions for above issues, the polymeric materials are particularly used as additives and interfacial layers in FPSCs, which promote crystallization of perovskite, defect passivation, and self‐healing, hence improving the device's PCE and long‐term stability. In this review the application and progress of polymers in FPSCs are gone through, aiming to present a comprehensive overview of how to utilize polymers to further push the envelope of FPSCs efficiency, and its underlying mechanisms. Furthermore, this study delved into the contributions of polymers in encapsulation and large‐area manufacturing processes, which is critical to facilitate lab‐to‐fab process for FPSCs. Finally, forward‐looking insights that set requirements for future material design and selection are presented, with the hope of constructing efficient, stable, and environmentally friendly FPSCs.