Cesium Lead Halide Perovskite Decorated Polyvinylidene Fluoride Nanofibers for Wearable Piezoelectric Nanogenerator Yarns

Abstract

Piezoelectric nanogenerators (PENGs) provide a viable solution to convert the mechanical energy generated by body movement to electricity. One-dimensional yarns offer a platform for flexible wearable textile PENGs, which can conform to body for comfort and efficient energy harvesting. In this context, we report a flexible piezoelectric yarn, assembled by one-step cocentric deposition of cesium lead halide perovskite decorated polyvinylidene fluoride (PVDF) nanofibers, on a stainless-steel yarn. Perovskite crystals were formed in situ during electrospinning. Our work demonstrates a nanofiber morphology in which perovskite crystals spread over the nanofiber, leading to a rough surface, and complementing piezoelectric nanocomposite formation with PVDF for superior stress excitation. We investigated how the halide anions of perovskite affect the piezoelectric performance of PENG yarns by comparing CsPbBr 3 and CsPbI 2 Br. Effects of the perovskite concentration, annealing temperature, and deposition time on the piezoelectric properties of PENG yarns were investigated. Devices assembled with a single yarn of CsPbI 2 Br decorated PVDF nanofibers yield the optimal performance with an output voltage of 8.3 V and current of 1.91 μA in response to pressing from an actuator and used to charge capacitors for powering electronics. After aging in the ambient environment for 3 months, the device maintained its performance during 19,200 cycles of mechanical stresses. The excellent and stable electrical performance can be ascribed to the optimized crystallization of CsPbI 2 Br crystals, their complementing performance with PVDF, and formation of nanofibers with uniformity and strength. The flexibility of piezoelectric yarns enables them to be bent, twisted, braided, and woven for different textile integrations while harvesting energy from body movements, demonstrating the potential for wearable mechanical energy harvesting.

Enhanced nanogenerator by embedding lead-free double perovskite Cs2AgBiBr6 in polymer matrix for hybrid energy harvesting

“…Regrettably, XRD analysis cannot quantify β-phase content, but the Fourier transform infrared (FTIR) spectra in Fig. 2(b) can calculate it 27 in detail. The vibrational bands at 765, 795, and 976 cm −1 are ascribed to the PVDF α-phase, while those at 840 and 1275 cm −1 indicate the electroactive β-phase, and that at 1234 cm −1 suggests the semi-electroactive γ-phase.…”

“…These properties originate from the semiconducting and ionic properties of perovskites, which serve as effective nucleating agents and could facilitate the conversion of amorphous-or nonpolar-phase PVDF into the polar b-crystalline phase. In some recent studies, CsPbI 2 Br-decorated PVDF nanofibers 27 possessed the most desirable morphology and functionality with a V oc of 8.3 V and I SC of 1.91 mA. Considering the PE effect of PVDF, using the above functional materials to establish HENGs 28,29 could be regarded as a progressive scheme to achieve an efficient energy conversion mode.…”

Ultrasonic Electroporation for Cells Grown on Piezoelectric Film Composed of Hydroxyapatite Nanowire and PVDF

“…When loading is above 9 wt %, excess nanowire limits the optimum interaction with PVDF, resulting decrease in polar phase content. 18 Differential scanning calorimetry is used to analyze the thermal properties and crystallinity of PVDF and its derivative polymers. 21 The thermal parameters, which include melting temperature (T m ), heat of fusion (ΔH f ), and crystallinity (X c ) of the piezoelectric films are summarized in Table S1 (see Figure S4 and Table S1 of the Supporting Information).…”

Simulation Guided Coaxial Electrospinning of Polyvinylidene Fluoride Hollow Fibers with Tailored Piezoelectric Performance

“…[18][19][20] Current strategies for improving the piezoelectric output of the PVDF fibers mainly focus on increasing the 𝛽 active phase, such as adding salts, [21] compositing with nanofillers, [22,23] and thermal annealing. [24] Alternatively, fiber morphological regulation is another promising route for enhancing the electromechanical conversion efficiency. [25,26] Jin et al [27] constructed cactus-shaped PVDF nanofibers through electrospinning at a high relative humidity of 62%.…”