Mixed-Dimensional All-Organic Polymer Heterostructures with Enhanced Piezoelectricity

Enhancing the piezoelectricity of polymers while maintaining all components organic is still challenging but significantly important for developing flexible wearable energy harvesters and self-powered devices. Here, a novel and versatile strategy is introduced to construct mixed-dimensional all-organic polymer heterostructures (MPHs) for enhanced piezoelectricity. By combining all-polymer 1D nanofibers (NFs) with 2D crystals through epitaxial crystallization-driven assembly (ECA), MPHs are engineered to capitalize on the synergistic effects of both dimensional nanostructures. The intrinsic piezoelectric activity of 1D NFs is amplified by the growth of 2D crystals, enhancing force-sensitivity and overall piezoelectricity. The mixed-dimensional assembly not only enables controlled in-situ growth of MPHs, but also simultaneously induces preferential formation of electroactive phases through solvent-induced phase transition. By modulating the epitaxial growth of 2D crystals on 1D NFs, effective tuning of MPH growth amount and morphology is achieved, resulting in significant improvements in deformability, dipole polarization, and durability. MPHs exhibit remarkable piezoelectric improvements, achieving higher output under lower-level forces with a record-high sensitivity of ≈670 mV kPa⁻¹. Their superior responsivity enables the development of self-powered wireless wearable motion-monitoring systems for real-time physiological movement detection and analysis. This work inspires the development of all-organic piezoelectric devices for innovative flexible energy-harvesting and sensing applications.