Zinc oxide piezoelectric nano-generators for low frequency applications

Abstract

Piezoelectric Zinc Oxide (ZnO) nanogenerators (NGs) have been fabricated for low frequency (<100 Hz) energy harvesting applications. Different types of NGs based on ZnO nanostructures have been carefully developed, and studied for testing under different kinds of low frequency mechanical deformations. Well aligned ZnO nanowires (NWs) possessing high piezoelectric coefficient were synthesized on flexible substrates using the low temperature hydrothermal route. These ZnO NWs were then used in different configurations to demonstrate different low frequency energy harvesting devices. Using piezoelectric ZnO NWs, we started with the fabrication of a sandwiched NG for a handwriting enabled energy harvesting device based on a thin silver layer coated paper substrate. Such device configurations can be used for the development of electronic programmable smart paper. Further, we developed this NG to work as a triggered sensor for a wireless system using footstep pressure. These studies demonstrate the feasibility of using a ZnO NWs piezoelectric NG as a low-frequency self-powered sensor, with potential applications in wireless sensor networks. After that, we investigated and fabricated a sensor on a PEDOT: PSS plastic substrate using a one-sided growth and double-sided growth technique. For the first growth technique, the fabricated NG has been used as a sensor for an acceleration system; while the fabricated NG by the second technique works as an anisotropic direction sensor. This fabricated configuration showed stability for sensing and can be used in surveillance, security, and auto-Mobil applications. In addition to that, we investigated the fabrication of a sandwiched NG on plastic substrates. Finally, we demonstrated that doping ZnO NWs with extrinsic elements (such as Ag) will lead to the reduction of the piezoelectric effect due to the loss of crystal symmetry. A brief summary into future opportunities and challenges is also presented.

Effect of GO Additive in ZnO/rGO Nanocomposites with Enhanced Photosensitivity and Photocatalytic Activity

“…Zinc oxide (ZnO) is a promising n-type semiconductor material that is used in a wide range of applications, such as gas detection [1,2,3,4], dye-sensitized solar cells [5,6,7], antibacterial surface coatings [8], light-emitting diodes (LEDs) [9,10], nanopower generators [11], ultraviolet (UV) detection [12,13,14,15], and photocatalytic applications [16,17,18]. ZnO nanostructures have a direct wide band gap (3.37 eV) [19], chemical stability [20], optical [21], piezoelectric [22,23,24], and electrical [25] properties. Additionally, ZnO possesses piezoelectric properties and self-carrier generation when tensile strain force is applied or substrates are bent [26].…”

Gentamicin-Releasing Mesoporous ZnO Structures

“…The photocatalytic activity of ZnO was successfully demonstrated in numerous cases and for different morphologies [ 5 , 6 , 14 , 15 , 16 , 17 ], finding application for water splitting [ 18 , 19 ] and degradation of dye pollutants for waste-water treatments [ 20 , 21 ]. ZnO nanostructures with promising piezoelectric and semiconducting properties were successfully obtained as well, resulting in novel smart materials applicable for new generation energy harvesting systems [ 22 , 23 , 24 , 25 , 26 ] and sensing applications [ 8 , 23 , 27 , 28 , 29 , 30 , 31 ]. Concerning the biomedical field, ZnO was extensively investigated as active material for biosensing applications [ 32 , 33 , 34 ].…”

A Review on Piezoelectric, Magnetostrictive, and Magnetoelectric Materials and Device Technologies for Energy Harvesting Applications

“…ZnO NGs were fabricated for low frequency (< 100 Hz) energy harvesting applications, and various NGs were developed and studied for testing under low frequency mechanical deformation. [73] A maximum output voltage of 3.6 V was obtained. [74] A wind energy harvester was developed by Du et al [75] using a circular silicon plate with several symmetrically distributed rectangular cavities that were covered with ZnO thin films, and the maximum output power density was 23.39 nW cm À2 with a maximum open-circuit output voltage of 2.81 V.…”