Engineering Interfaces for Fiber Solar Cells

Abstract Fiber solar cells have received considerable attention as a promising energy solution for wearables, and have achieved great progress in performance by strategies of material innovation, structural design, and light management. Fiber solar cells are constructed with multiple functional layers, and their interfaces determine the separation, transport, collection, and recombination of the photogenerated carriers. Engineering interfaces are critical to improve both power conversion efficiency (PCE) and stability of fiber solar cells. Still, it faces great challenges in constructing high‐quality functional layers and establishing tight and stable interfaces on high‐curvature fiber surfaces. Here, the main issues on interfaces in fiber solar cells are discussed, emphasizing interface defects, energy level mismatching, low charge collection efficiency, and interface instability. The possible solutions to the above problems are then carefully investigated. Finally, future directions are highlighted to present strategies of engineering interfaces to optimize fiber solar cells for higher performances.