Piezoelectric Flexible Energy Harvester Based on BaTiO₃ Thin Film Enabled by Exfoliating the Mica Substrate

Abstract

Flexible piezoelectric energy harvesters (f‐PEHs) have exhibited significant potential as long‐lasting self‐powered sources or sensor devices, as they can generate reliable and repeatable electricity under harsh and tiny mechanical bending cycles without restraints anywhere and anytime. Herein, a new approach for transferring piezoelectric ceramic thin films onto a single flexible substrate via piecemeal elimination of the sacrificial mica substrates is proposed. The crystallized piezoelectric BaTiO3 thin film on a rigid mica substrate with electrodes and passivation layers is peeled off by means of a physical delamination process using sticky tape as the remover. The film is then transferred onto a flexible polyimide substrate using a polymer elastomer as a support. The fabricated BaTiO3 thin‐film f‐PEH successfully converts an open‐circuit voltage of ≈0.5 V and a short‐circuit current of ≈30 nA from repeated mechanical bending deformations. The energy generation mechanism and performance of the perovskite BaTiO3 thin‐film f‐PEH is supported using finite‐element analysis (FEA) with multiphysics simulations. The novel transfer techniques adopting the removal of sacrificial mica layers opens the door to various high‐performance flexible and wearable applications based on all‐inorganic materials.

Energy Harvesters for Wearable Electronics and Biomedical Devices

“…Reproduced with permission. [ 297 ] Copyright 2019, Wiley‐VCH. g) Flexible‐PEG device (above) based on vertically aligned BaTiO 3 nanotube arrays (below).…”

“…For example, a Pb‐free perovskite‐structured BaTiO 3 thin film‐based flexible PEG was reported which generated V oc and I sc of ≈0.5 V and ≈30 nA, respectively (Figure 17f). [ 297 ] Additionally, a BaTiO 3 nanotube array‐based PEG was demonstrated by Jeong et al., where the device produced V oc of ≈150 mV and I sc of ≈3 nA for a single BaTiO 3 nanotube array (Figure 17g). [ 298 ] Moreover, a nanocomposite micropillar array of BaTiO 3 nanoparticles were embedded into a highly crystalline poly[(vinylidenefluoride‐ co ‐trifluoroethylene] [P(VDF‐TrFE)] polymer to improve the flexibility and performance of PENG, as shown in Figure 17h.…”

Recent progress on flexible nanogenerators toward self‐powered systems

“…However, the brittle and rigid nature of inorganic ceramics limits their applications in flexible electronics. To solve this problem and improve the flexibility and stretchability, these rigid materials have been developed into thin film, nanowires, nanoparticles, and nanofibers, as shown in Figure …”

“…Scanning electron microscope (SEM) images of inorganic materials with various structures. Image of (A) PZT thin film, Copyright 2019, Elsevier, (B) PZT nanowires, Copy 2019, IOP Publishing, (C) PZT nanoparticles, Copyright 2016, IOP Publishing, (D) PZT nanofibers, Copyright 2019, American Chemical Society, (E) BaTiO 3 thin film, Copyright 2019, Wiley‐VCH, and (F) BZT nanoparticles, Copyright 2019, Elsevier…”

n‐ZnO/p‐NiO Core/Shell‐Structured Nanorods for Piezoelectric Nanogenerators

“…Various non‐centrosymmetric piezoelectric materials such as lead zirconate titanate (PZT), [ 8–12 ] quartz, [ 13 ] zinc oxide (ZnO), [ 3,14–16 ] barium titanate (BaTiO 3 , BTO), [ 17–22 ] zinc sulfide (ZnS), [ 23–24 ] polyvinylidene fluoride (PVDF), [ 25,26 ] etc. are widely used for PENGs.…”