Search Results (3)

The demand for self-powered, flexible, and wearable electronic devices has been increasing in recent years for physiological and biomedical applications in real-time detection due to their higher flexibility and stretchability. This work fabricated a highly sensitive, self-powered wearable microdevice with Poly-Vinylidene Fluoride-Tetra Fluoroethylene (PVDF-TrFE) nano-fibers using an electrospinning technique. The dielectric response of the polymer was improved by incorporating the reduced-graphene-oxide (rGO) multi-walled carbon nano-tubes (MWCNTs) through doping. The dielectric behavior and piezoelectric effect were improved through the stretching and orientation of polymeric chains. The outermost layer was attained by chemical vapor deposition (CVD) of conductive polymer poly (3,4-ethylenedioxythiophene) to enhance the electrical conductivity and sensitivity. The hetero-structured nano-composite comprises PVDF-TrFE doped with rGO-MWCNTs over poly (3,4-ethylenedioxythiophene) (PEDOT), forming continuous self-assembly. The piezoelectric pressure sensor is capable of detecting human physiological vital signs. The pressure sensor exhibits a high-pressure sensitivity of 19.09 kPa⁻¹, over a sensing range of 1.0 Pa to 25 kPa, and excellent cycling stability of 10,000 cycles. The study reveals that the piezoelectric pressure sensor has superior sensing performance and is capable of monitoring human vital signs, including heartbeat and wrist pulse, masticatory movement, voice recognition, and eye blinking signals. The research work demonstrates that the device could potentially eliminate metallic sensors and be used for early disease diagnosis in biomedical and personal healthcare applications. Full article

This work adopted a strategy to use new functional high-performance piezoelectric materials for sustainable energy production in wearable self-powered electrical devices. An innovative modification in electrospinning was used to produce highly aligned nanofibers. In the nanogenerator, the flexible membrane constituents were tunefully combined. The novel composite nanofibers were made of Poly (vinylidene fluoride) PVDF, loaded with ZnO@ZnS core–shell nanoparticles to achieve a non-brittle performance of the hetero nanoparticles and piezoelectric polymer. A nanofiber mat was inserted between two thermoplastic sheets with conductive electrodes for application in wearable electronic devices. Complete spectroscopic analyses were performed to characterize the nanofiber’s material composition. It is shown that the addition of 10 wt % ZnO@ZnS core–shell nanoparticles significantly improved the piezoelectric properties of the nanofibers and simultaneously kept them flexible due to the exceedingly resilient nature of the composite. The superior performance of the piezoelectric parameter of the nanofibrous mats was due to the crystallinity (polar β phase) and surface topography of the mat. The conversion sensitivity of the PVDF device recorded almost 0.091 V/N·mm³, while that of the PVDF—10 wt % ZnO@ZnS composite mat recorded a sensitivity of 0.153 V/N·mm³, which is higher than many flexible nano-generators. These nanogenerators provide a simple, efficient, and cost-effective solution to microelectronic wearable devices. Full article

In₂O₃/SnO₂ composite hetero-nanofibers were synthesized by an electrospinning technique for detecting indoor volatile organic gases. The physical and chemical properties of In₂O₃/SnO₂ hetero-nanofibers were characterized and analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), Energy Dispersive X-Ray Spectroscopy (EDX), specific surface Brunauer–Emmett–Teller (BET) and X-ray photoelectron spectroscopy (XPS). Gas sensing properties of In₂O₃/SnO₂ composite hetero-nanofibers were measured with six kinds of indoor volatile organic gases in concentration range of 0.5~50 ppm at the operating temperature of 275 °C. The In₂O₃/SnO₂ composite hetero-nanofibers sensor exhibited good formaldehyde sensing properties, which would be attributed to the formation of n-n homotype heterojunction in the In₂O₃/SnO₂ composite hetero-nanofibers. Finally, the sensing mechanism of the In₂O₃/SnO₂ composite hetero-nanofibers was analyzed based on the energy-band principle. Full article