Er³⁺/Fe³⁺ Stimulated Electroactive, Visible Light Emitting, and High Dielectric Flexible PVDF Film Based Piezoelectric Nanogenerators: A Simple and Superior Self-Powered Energy Harvester with Remarkable Power Density

Abstract

The design of an energy-harvesting unit with superior output characteristics, i.e., high power density, is a great technological challenge in the present time. Here, simple, lightweight, flexible, and cost-effective piezoelectric nanogenerators (PENGs) have been fabricated by integrating the aluminum electrodes onto Er/Fe stimulated electroactive, visible-light-emitting, and large dielectric PVDF films in which ErCl·6HO and Fe(NO)·9HO act as the catalytic agents for electroactive β polymorph nucleation and the enhancement of dielectric properties. The developed PENGs exhibit excellent energy-harvesting performance with very high power density and very fast charging ability compared with the previously reported PVDF-assisted prototype nanogenerators. The PENGs lead to very large power density (∼160 and ∼55.34 mW cm) under periodic finger imparting for Er- and Fe-stimulated PVDF-film-based energy-harvester units, respectively. The fabricated self-powered PENG is also able to light up 54 commercially available light-emitting diodes.

Role of Cationic Oxidation States to Enhance the Electroactive β‐Phase of Poly(vinylidene Fluoride) and its Energy Harvesting Performance

“…The absorption spectrum of alpha phase commercial PVDF powder observed in the wavenumbers 763, 796, 975, 1149, 1214, 1384, and 1425 cm −1 . The minor peak in the region of 840 cm −1 represented the content of β‐phase, and the peak at 1701 cm −1 indicated the linear behavior related to the composite film thickness . During the sonication process, molecular dipoles of ferroelectric PVDF polymer (−CH 2 −/−CF 2 −) involves vibrational stretching that gives rise to the transformation of α‐phase into β and γ‐phases.…”

“…Mainly, the β and γ phases were more attractive due to their high spontaneous polarization property . Up to date, many efforts have been adopted to enhance the electroactive β phase thus promoting self‐polarization through methods like in‐situ mechanism, Langmuir‐Blodgett, spin coating, phase inversion method, mechanical stretching, electrospinning and substitution of fillers atoms Mendez et al. stated that β phase was improved through the substitution of CNT as fillers through sonication methodology compared to the mechanical mixture route .…”

“…Similarly, the addition of inorganic salt like Yb 3+ gave the enhanced β phase and created highly sensitive self‐polarized PVDF based ferroelectric nanogenerator was reported to convert the waste mechanical energy into electrical energy . The incorporation of Er 3+ /Fe 3+ catalytic agents for the enhancement of β nucleation as well as the dielectric properties and further developed the superior energy harvesting performance with high power density . Recently a spongy type mesoporous thin film based on PVDF polymer was reported with better piezoelectric performances .…”

“Self‐Matched” Tribo/Piezoelectric Nanogenerators Using Vapor‐Induced Phase‐Separated Poly(vinylidene fluoride) and Recombinant Spider Silk

“…Then, the spin‐coated PET/PVDF was relocated to a humid environment for vapor‐induced phase‐separation processing (Figure S1, Supporting Information), during which PVDF chains would be polarized in the direction from the substrate to humid air as shown in the gray dashed line box of Figure b . Compared with electric‐field polarization, metal ion doping, and other reported methods, the vapor‐induced phase‐separation process is safer, more energy‐saving, and generates less pollution . In addition, the in situ polarization of PVDF on PET substrates provided robust adhesion, directly obtaining the triboelectric layer.…”

Improving the dielectric performance of poly(vinylidene fluoride)/polyaniline nanorod composites by stretch‐induced crystal transition

“…However, the intrinsic low dielectric constant of polymers limits their practical application markedly but a requirement for compatible properties of flexibility and high dielectric constant still impels researchers to test all sorts of strategies to overcome this fatal drawback of polymers . The common way is by blending high dielectric ceramic powder into polymer, while high ceramic loadings and poor compatibility between rigid filler and soft matrix dramatically degrade the mechanical properties of the composites, thus negating the original flexibility of the polymers and restricting their applications.…”