Fiber-based flexible magneto-mechano-electric generators enhanced by UV and IR treatments for sustainable IoT sensors†

The Internet of Things (IoT) demands sustainable energy sources for power sensors and communication components. This study presents a magnetoelectric (ME) coupled magneto-mechano-electric (MME) energy harvester designed to capture energy from low-amplitude stray magnetic fields. The device incorporates a truncated cantilever structure with a flexible fiber composite of piezoelectric AlN-PVDF polymer matrix combined with magnetostrictive Metglas, enhancing magneto-mechanical vibrations and power generation. The piezoelectric fibers are UV-treated to enhance piezoelectric properties, while the magnetic properties of Metglas are improved through IR treatment. These optimizations significantly enhance the ME composite's performance, as confirmed by P–E hysteresis loops, dielectric measurements, and M–H hysteresis loops, supported by MFM data. The designed MME generator achieves an open-circuit voltage of 32.8 V and an RMS DC power density of 1.4 mW cm⁻³ under a tiny 6 Oe AC magnetic field at 50 Hz. Finite element simulations using COMSOL Multiphysics 6.2 show excellent agreement with experimental results. The harvested output power of an optimized MME generator is approximately 1100% higher than that of the untreated device (0.1 mW cm⁻³). Structural variations linked to these enhancements are characterized through XRD, FTIR, XPS, and HRTEM analysis. The harvested energy effectively powers flame microsensors, supporting IoT integration in smart infrastructure systems.