Flexible perovskite solar cells: device design and perspective

Flexible perovskite solar cells (FPSCs) have gained more and more attention in a short period of time, attributing to their unique properties, which including being lightweight, and its flexibility, compatibility and stretchability with curved surfaces. So far, the FPSCs have obtained notable milestones and the champion-cell efficiency has achieved 19.11%. In the meanwhile, the advantage of extraordinary ease of processing for large-area flexible devices, permits their employ in niche applications, such as vehicle-integrated photovoltaics, portable electronics, wearable power sources, and large-scale industrial roofing, etc. In this review paper, we retrospect recent developments in FPSCs, focusing on the device design and materials selection of the substrate, the transparent electrodes and the interface layers. Moreover, we summarize the large-area processes for fabricating scalable flexible devices. In addition, some promising research directions are provided for the future design of FPSCs.