Flexible Piezoelectric Generators by Using the Bending Motion Method of Direct-Grown-PZT Nanoparticles on Carbon Nanotubes.

Jongsun Lim

doi:10.3390/nano7100308

Abstract

Recently, composite-type nanogenerators (NGs) formed from piezoelectric nanostructures and multi-walled carbon nanotubes (CNTs), have become one of the excellent candidates for future energy harvesting because of their ability to apply the excellent electrical and mechanical properties of CNTs. However, the synthesis of NG devices with a high proportion of piezoelectric materials and a low polymer content, such as of polydimethylsiloxane (PDMS), continues to be problematic. In this work, high-piezoelectric-material-content flexible films produced from Pb(Zr,Ti)O3 (PZT)-atomically-interconnected CNTs and polytetrafluoroethylene (PTFE) are presented. Various physical and chemical characterization techniques are employed to examine the morphology and structure of the materials. The direct growth of the piezoelectric material on the CNTs, by stirring the PZT and CNT mixed solution, results in various positive effects, such as a high-quality dispersion in the polymer matrix and addition of flexoelectricity to piezoelectricity, resulting in the enhancement of the output voltage by an external mechanical force. The NGs repeatedly generate an output voltage of 0.15 V. These results present a significant step toward the application of NGs using piezoelectric nanocomposite materials.

Highlights

Renewable energy harvesting through piezoelectric nanogenerators (PNGs) has become one of the most important requirements to resolve the energy crisis arising from the highly increased energy consumption, a result of burning fossil fuels [1,2,3,4]
There have been various reports of PNGs composed of one-dimensional perovskite-type nanostructures such as Pb(Zr,Ti)O3 (PZT) nanowires [5], Pb(Mg,Nb)O3-PbTiO3 nanowires [6], (K,Na)NbO3 nanorods [7], PbTiO3 (PTO) [8], and BaTiO3 (BTO) nanotubes [9]; these materials are used owing to their outstanding piezoelectric properties
The PZTNPs nucleated at the carboxylic groups in the defects of carbon nanotubes (CNTs) that were introduced by a functionalizing process involving a reaction with HNO3 acid solution [15,16]

Summary

Introduction

Renewable energy harvesting through piezoelectric nanogenerators (PNGs) has become one of the most important requirements to resolve the energy crisis arising from the highly increased energy consumption, a result of burning fossil fuels [1,2,3,4]. To avoid splitting and cleavage during the fabrication process and to enhance the endurance and flexibility of the PNGs, composite-type PNGs composed of piezoelectric materials and flexible one-dimensional structures, such as carbon nanotubes (CNTs) [10,11,12,13] and viruses [14], have been utilized. Such composites employ a polymer matrix, such as polydimethylsiloxane (PDMS) that improves the flexibility, but lowers the power generation properties by limiting the amount of the piezoelectric material in the sample. Our results represent a momentous step towards the application of energy harvesting in flexible electronics, portable devices, and mechanical sensors

Results and Discussion

Experimental Section

Conclusions