Perovskite solar cells: From planar designs to fiber-based innovations

Much progress has been made in wearable electronics in recent years, with fiber-based devices offering unprecedented capabilities in vision, hearing, environmental sensing, communication, energy management, and computing. However, the operation of multi-functional wearable devices in fabrics requires a robust energy supply. Fibers are regarded as a suitable media for the new paradigm in perovskite solar cells owing to their unique properties, including high dynamic flexibility, large surface area, low weight, and good integrability. However, low device performance still impedes their practical applications. Forming uniform crystalline perovskite films on highly curved surfaces is a great challenge, yet much progress has been made. Herein, recent advances in the development of fiber-shaped perovskite solar cells, including those relating to device structure evolution and working principles, as well as categorical progress in optimizing perovskite growth on various substrates, designing deposition methods, and composition engineering are reviewed. Promising research directions (e.g., research on wearable photovoltaic devices) are then suggested to promote the development of fiber-shaped perovskite solar cells. Fiber-based perovskite solar cells are thus promising choices for wearable energy supplies.