摘要： We report an all-polymer flexible piezoelectric fiber that uses both judiciously chosen geometry and advanced materials in order to enhance the piezoelectric response. The fiber features a soft hollow microstructured/nanostructured polycarbonate core surrounded with a spiral multilayer cladding consisting of alternating layers of piezoelectric nanocomposites and conductive polymer. Kilometer-long piezoelectric fibers of submillimeter diameters are thermally drawn from macroscopic preforms. The fibers exhibit high output voltage of up to 6V under moderate bending, and they show excellent durability in a cyclic test. The micron/nano-size multilayer structure enhances in-fiber poling efficiency thanks to the small distance between the conducting electrodes sandwiching the piezoelectric composite layers. Additionally, spiral structure greatly increases the active area of piezoelectric composites, thus promoting higher voltage generation and resulting in 10-100 higher power generation efficiency over the existing piezoelectric cables. Finally, we weave the piezoelectric fibers into technical textiles and demonstrate their potential applications in power generation.