Review and perspective of materials for flexible solar cells

Thin-film flexible solar cells are lightweight and mechanically robust. Along with rapidly advancing battery technology, flexible solar panels are expected to create niche products that require lightweight, mechanical flexibility, and moldability into complex shapes, such as roof-panel for electric automobiles, foldable umbrellas, camping tents, etc. In this paper, we provide a comprehensive assessment of relevant materials suitable for making flexible solar cells. Substrate materials reviewed include metals, ceramics, glasses, and plastics. For active materials, we focus primarily on emerging new semiconductors including small organic donor/acceptor molecules, conjugated donor/acceptor polymers, and organometal halide perovskites. For electrode materials, transparent conducting oxides, thin metal films/nanowires, nanocarbons, and conducting polymers are reviewed. We also discuss the merits, weaknesses, and future perspectives of these materials for developing next-generation flexible photovoltaics.