P(VDF-TrFE)/BaTiO3 nanocomposite Langmuir-Schaefer thin film for piezoelectric nanogenerator

Abstract

In this study, a piezoelectric nanogenerator (PENG) was fabricated based on nanocomposite thin films comprising piezoelectric poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)) as a matrix and BaTiO3 (BTO) nanoparticles (NPs) as a nanofiller. The Langmuir-Schaefer (LS) technique was employed to prepare the films. A mixed solution of the polymer and ceramic NPs was spread on the surface of water subphase at a predetermined surface pressure, and thin films were then prepared by transferring the spread monolayer onto indium tin oxide-coated polyethylene terephthalate (ITO-PET) substrate multiple times at a constant surface pressure. Microstructure, crystallinity, beta-phase content, dielectric constant, and piezoelectric coefficient (d33) of the thin films were measured with SEM, XRD, FT-IR, LCR meter, and Quasi-static meter, respectively. Six different PENG devices with different BTO contents were fabricated by arranging the thin filmcoated substrates in sandwich structure, and they were subject to measurements of piezoelectric characteristics such as open-circuit output voltage (VOC) and short-circuit current (ISC). As results, it was found that the PENG with 4 wt% BTO with ten layers of monolayer deposited at the surface pressure of 15 mN/m yielded the highest VOC of 71.4 V, which was higher than pristine polymer LS film's 66.2 V at the same conditions, and power density of 35.7 mu W/cm2 at 2.5 Hz bending-releasing frequency. This optimum piezoelectric performance was explained in terms of the highest crystallinity, beta-phase content, and dielectric properties at the specific BTO content. The optimum PENG coupled with a capacitor and several light emitting demonstrated that it is possibly used to supply power with large energy storage capability of 470 mu J with a 1 mu F capacitor for 3 min. This PENG of improved performance is promising as a supply power for a self-powered microelectronics because it has additional advantages of facile fabrication and coating a large area. (c) 2023 Elsevier B.V. All rights reserved.