Co-Assembled Piezoelectric Nanofibers as Self-Powered Sensors for Human Physiological Signals

Abstract

Soft supramolecular materials have emerged as promising alternatives to conventional inorganic systems for next-generation bioelectronic and self-powered sensing applications due to their intrinsic flexibility, biocompatibility, and mechanical compliance. Herein, we report a coassembled piezoelectric nanofibrous organogel system constructed from a functionalized peptide–appended pyrene (Py–P) donor and a core-substituted naphthalene diimide (c-NDI) acceptor. While the individual organogels exhibit relatively lower piezoelectric response, their coassembled state at an equimolar ratio displays a remarkable enhancement in piezoelectric performance. The engineered donor–acceptor coassembly produces a highly ordered supramolecular architecture with a piezoelectric coefficient of 55 pm/V, approaching the upper limit of reported supramolecular organic piezoelectric materials and convincingly demonstrating the effectiveness of donor–acceptor engineering for high-performance piezoelectric energy harvesting. Combined experimental investigations and theoretical analyses consistently demonstrate the origin of the amplified piezoelectricity in the coassembled system. Leveraging this high piezoelectric response, self-powered devices were fabricated and successfully employed for the detection of human physiological signals, including finger movements and highly sensitive arterial pulse signals. The results demonstrate that this coassembled nanofiber-based supramolecular system represents a potent soft piezoelectric material platform for self-powered physiological sensing and wearable bioelectronic applications.