Flexible perovskite solar cells: Material selection and structure design

With the rapid development of the Internet of Things, convenient and portable self-powered devices are in great need. Among all substitutes that could provide clean and sustainable power, the flexible perovskite solar cells (FPSCs) are the most attractive with the characteristics of flexibility, lightweight, high power conversion efficiency, and low cost. In this review, the recent advances of FPSCs are summarized, focusing on the materials' assessment of flexible and durable substrate, transparent electrode, low-temperature processed charge transporting layer, and mechanically robust perovskite film, with device design interspersed in each part. Finally, the challenges of FPSCs in terms of higher efficiency, higher flexibility, higher stability, and scalable fabrication are summarized.