High‐Performance GA ₂ PbI ₄ /PVDF Composite for Energy Harvesting and Real‐Time Wireless Photodetection

ABSTRACT The increasing need for small, portable, and Internet of Things (IoT) devices requires exploring alternatives to conventional power sources. We present a flexible and self‐sustainable piezoelectric nanogenerator composed of 2D organic‐inorganic halide perovskite, namely guanidium lead iodide (GA ₂ PbI ₄ ) and polyvinylidene fluoride (PVDF) composite. By systematically incorporating optimized concentration of GA ₂ PbI ₄ into the PVDF matrix, the electroactive phase content of the composite could be substantially enhanced to a maximum value of 90% for a 4 wt.% loading of the perovskite. The piezoelectric coefficient consequently increases from ∼7.46 pC/N for pure PVDF to ∼39.5 pC/N for the 4% filler loading in the PVDF matrix. The optimized device generates an open circuit voltage of ∼60 V and a short circuit current of 6.4 µA. The device delivers a power density of ∼8.58 µW/cm ² across a 12 MΩ load, sufficient to power small capacitors and an array of LEDs. In addition to the remarkable energy harvesting capability, the composite demonstrates appreciable photosensitivity under light irradiation, acting as a potential self‐powered photodetector. The fabricated self‐powered photodetector exhibits an increase in the short circuit current under light illumination, highlighting the potential of GA ₂ PbI ₄ /PVDF composites as wearable energy harvesting devices and real‐time, wireless, IoT‐enabled self‐powered photodetectors.