Kumar, PrabhatPrabhatKumarDas, SudiptaSudiptaDasMakani, Nisha HiralalNisha HiralalMakaniPradhan, PrabhanjanPrabhanjanPradhanPatra, Biplab KumarBiplab KumarPatraBanerjee, RupakRupakBanerjee2026-02-252026-02-252026-01-0110.1002/adom.2025031762-s2.0-105030153814https://repository.iitgn.ac.in/handle/IITG2025/34658The 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<inf>2</inf>PbI<inf>4</inf>) and polyvinylidene fluoride (PVDF) composite. By systematically incorporating optimized concentration of GA<inf>2</inf>PbI<inf>4</inf> 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/cm² 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<inf>2</inf>PbI<inf>4</inf>/PVDF composites as wearable energy harvesting devices and real-time, wireless, IoT-enabled self-powered photodetectors.en-USfalse2D halide perovskites | piezoelectric nanogenerator | piezoresponse force microscopy | self-powered wireless photodetectorsArticle2195107120260arArticle