Ag Core–Ag₂Se Shell Based Stretchable Thermoelectric Fiber with Nanoparticle Networks for Wearable Electronics

Amidst the swift progression in wearable technology, electronic fibers have become an indispensable element in the arena of functional textiles, demonstrating a broad spectrum of capabilities including connectivity, sensory detection, and energy generation. This breakthrough is catalyzing the development of innovative fiber-based wearable electronics, ranging from electronic skins and health sensors to sophisticated human-machine interfaces. The complexity of joining single-function fibers and the critical need for their compact integration within wearable platforms necessitate the creation of advanced multi-functional electronic fibers. Herein, we have fabricated a novel Ag core–Ag₂Se Shell based stretchable thermoelectric (TE) fiber, engineered through selective chemical reduction, poised to redefine the integration within wearable electronics. Ag and Ag₂Se nanoparticles (NPs) were embedded into a polyurethane fiber matrix, yielding a composite with extraordinary elasticity to mechanical deformation coupled with consistent electrical durability. The fiber maintains electrical even after enduring 10,000 cycles of 20% tensile strain and preserves a Seebeck coefficient of -92 μV/K up to a 100% tensile strain, with the variation in output voltage remaining under 1.752%. The successful application of selective chemical reduction facilitates the formation of efficient n-p pairs, crucial for augmenting the thermoelectric efficiency of the fiber. This technique simplifies the manufacturing process while expanding the functional potential of wearable fibers. Consequently, the Ag core–Ag₂Se shell-based fiber emerges as a versatile and robust component, ideal for the demands of cutting-edge wearable devices, and marks a significant stride toward seamless integration of high-performance and multi-functional wearable systems.