Indoor Photovoltaic Fiber with an Efficiency of 25.53% under 1500 Lux Illumination

Abstract Photovoltaic devices represent an efficient electricity generation mode. Integrating them into textiles offers exciting opportunities for smart electronic textiles—with the ultimate goal of supplying power for wearable technology—which is poised to change how electronic devices are designed. Many human activities occur indoors, so realizing indoor photovoltaic fibers (IPVFs) that can be woven into textiles to power wearables is critical, although currently unavailable. Here, a dye‐sensitized IPVF is constructed by incorporating titanium dioxide nanoparticles into aligned nanotubes to produce close contact and stable interfaces among active layers on a curved fiber substrate, thus presenting efficient charge transport and low charge recombination in the photoanode. With the combination of highly conductive core–sheath Ti/carbon nanotube fiber as a counter electrode, the IPVF shows a certified power conversion efficiency of 25.53% under 1500 lux illuminance. Its performance variation is below 5% after bending, twisting, or pressing for 1000 cycles. These IPVFs are further integrated with fiber batteries as self‐charging power textiles, which are demonstrated to effectively supply electricity for wearables, solving the power supply problem in this important direction.