Quantum Dot Hybridization of Piezoelectric Polymer Films for Non-Transfer Integration of Flexible Biomechanical Energy Harvesters

Abstract

This work presents a low-temperature engineering strategy, from quantum dot (QD) synthesis to fabrication of a hybrid from a homogeneous dispersion to thermal annealing with elaborate use of a small organic molecule dopamine, for achieving a kind of ZnO QD-hybridized piezoelectric polymer film directly integrated into a flexible electrode and a plastic substrate. This strategy is the key for non-transfer assembly of flexible piezoelectric nanogenerators (FPENGs) with both mechanical robustness and high electrical performance via direct lamination. The rational addition of dopamine plays multiple roles of (1) significantly decreasing the size of ZnO particles to a QD level (3.77 nm), (2) formation of a stable and homogeneous dispersion of a ZnO QDs/piezoelectric polyvinylidene fluoride-co-hexafluoropropylene copolymer for uniform hybridization of a piezoelectric film, and (3) increment of the piezoelectric phase via induced crystallization at a low annealing temperature. This dopamine-assisted low-temperature annealing strategy for a hybrid piezoelectric film with a high d33 value (∼31.56 pC/N, 30.56% larger than that of a pure piezoelectric polymer film) required no additional high-voltage polarization treatment and effectively avoided the delamination, distortion, or melt phenomenon between the piezoelectric layer, flexible electrode, and plastic protective layer caused by the high temperature and thermal stress. The obtained FPENGs showed significantly enhanced output performance and mechanical robustness under repeated impact and large amounts of strain conditions. Their specific output voltage and charge density were stably maintained at 7.16 V and 2.40 nC/cm2, which were 30.7 and 50.0% higher than those of FPENGs based on a pure piezoelectric polymer film, respectively. They were further used as biomechanical energy harvesters for generating electricity to charge capacitor energy storage devices for power electronics and self-powered sensors for visual motion-detecting systems, indicating their promising applications in both wearable technology and smart homes.

Understanding contact electrification via direct covalent bond cleavage of polymer chains for ultrahigh electrostatic charge density

“…In recent years, we have been devoting ourselves to constructing a sustainable and self-sufficient biomechanical energy-driven wearable ecosystem with controllable energy transfer, conversion, storage and dissipation for various kinds of body protection and function enhancement of human beings. [9][10][11]13,[46][47][48] To efficiently harvest the random and lowfrequency mechanical energy generated by human body motion (i.e. biomechanical energy) generated in daily activities, we initiated and developed the use of a viscoelastic polymer adhesive (VPA) as an unconventional triboelectric material by controllable adhesion and separation for a kind of high performance adhesive surface-enabled TENG (AS-TENG) that can generate alternating voltage/current with unique frequencyinsensitive output characteristics.…”

ZnO@Carbon Dot Nanoparticles Stimulating the Antibacterial Activity of Polyvinylidene Fluoride–Hexafluoropropylene with a Higher Electroactive Phase for Multifunctional Devices

“…Surface modifications of inorganic nanoparticles are an effective strategy to enhance the interfacial compatibility between inorganic nanoparticles and polymer matrices. 21,22 Our research group has even incorporated carbon dots (CDs) into PVDF-HFP to improve the piezoelectric performance. 23 CDs can be regarded as core-shell carbon nanomaterials, with amorphous or sp 2 -sp 3 hybrid crystalline carbon cores and spherical shells rich in defects and functional groups.…”

“…The key to fabricating composite films is to resolve the incompatibility between polymers and inorganic nanoparticles. Surface modifications of inorganic nanoparticles are an effective strategy to enhance the interfacial compatibility between inorganic nanoparticles and polymer matrices. , …”

Triboelectric and Piezoelectric Nanogenerators for Self-Powered Healthcare Monitoring Devices: Operating Principles, Challenges, and Perspectives

“…The nanogenerators offer advantages such as a long lifetime, small volume, light weight, a non-expensive fabrication process, and high output power density [36][37][38][39][40]. The nanogenerators can use the triboelectric and piezoelectric effects for harvesting biomechanical energy into electricity [41][42][43][44][45][46][47][48][49]. The piezoelectric nanogenerators can convert the mechanical deformations of the piezoelectric materials used in their structures into electrical voltages.…”