Lightweight, Self-Poled, Flexible Piezoelectric Tungsten Disulfide Quantum Dots-Reinforced PVDF-HFP-Based Nanogenerator

Herein, we reported the fabrication of a highly flexible, sensitive, lightweight, self-poled, hybrid tungsten disulfide (WS2) quantum dots-filled poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) nanocomposite-based piezoelectric nanogenerator device with high output performance. Highly uniform WS2 quantum dots with an average diameter of 7–8 nm were synthesized from the hydrothermal route and an enhanced piezoelectric β-phase of PVDF-HFP was obtained through the polar DMF solvent and in situ electrical poling. Structural and morphological investigation revealed the formation of the pure phase of the WS2 QDs-PVDF-HFP nanocomposite and β-phase of PVDF-HFP. Piezoelectric force microscope analysis revealed a very high piezoelectric charge coefficient (d33) of ∼294.55 pm/V from single WS2 QDs. The flexible transparent piezoelectric nanogenerator fabricated from the WS2 QDs-PVDF-HFP nanogenerator produced a remarkably high output voltage and output current density of about 22 V and 1.06 μA/cm2, respectively, even under low pressure and without external electrical poling. The WS2 QDs-PVDF-HFP nanocomposite exhibited a high dielectric constant of 30 at low frequency. The high performance of the nanocomposite nanogenerators was discussed in light of the high piezoelectricity, interface polarization, and large dielectric constant. The present study opens an excellent route to developing a self-powered, ultralight, flexible energy-harvesting system for wearable and body implantable nanodevices.