Designing Reflective Hybrid Counter Electrode for Fiber Dye‐Sensitized Solar Cell with Record Efficiency

Abstract Fiber solar cells can be woven into textiles to effectively supply electricity for wearables and have attracted increasing interests in the past decade. However, achieving high power conversion efficiencies in real‐world applications remains a significant challenge for power supply textiles. Here a unique hybrid counter electrode made from metal current collector fiber with high electrical conductivity, aligned carbon nanotube sheet with high electrocatalytic property, and porous titanium dioxide/poly(vinylidene fluoride‐ co ‐hexafluoropropylene) film with high light reflectance is designed. For the resulting fiber dye‐sensitized solar cell, a rapid charge collection and transport are achieved, and the unique advantage of absorbing light from all directions is effectively realized, producing a record power conversion efficiency of 12.52%. The power conversion efficiency varies below 10% after bending, twisting, or pressing for 1000 cycles. These fiber dye‐sensitized solar cells are further integrated with fiber batteries as power systems for a smart bracelet, demonstrating the effective power solution for wearables.