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A Low Frequency Vibration Energy Harvester Using ZnO Nanowires on Elastic Interdigitated Electrodes
摘要： This paper presents a low frequency piezoelectric vibration energy harvester using ZnO nanowires on elastic interdigitated electrodes. The interdigitated electrodes are formed using electroplated Ni and have suspended parts at the edges that are elastic and deformable by applying external force. A spherical Ni ball is used as a proof mass, which transforms a low frequency mechanical vibration into the force applied to deform the elastic electrodes. The ZnO nanowires are grown selectively on the electrodes and can generate a piezoelectric potential when the elastic electrodes are deformed by the proof mass activated by the external mechanical vibration. The proposed operation concept is demonstrated using two different types of energy harvesters, which have simple suspended part and cantilever array structures added to the electrodes, respectively. The output voltage of the fabricated harvesters is measured using a vibration exciter at 6 Hz sinusoidal vibration with an acceleration of 0.5 g. Maximum output power of 12.8 pW and 18.8 pW was generated with a load resistance of 1 MΩ for the harvesters using the simple suspended structure and cantilever array, respectively.
关键词： Spherical Proof Mass,Elastic Interdigitated Electrodes,ZnO Nanowires,Low Frequency Piezoelectric Vibration Energy Harvester
更新于2025-09-23 15:23:52
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Effect of post-annealing on microstructure and piezoelectric properties of ZnO thin film for triangular shaped vibration energy harvester
摘要： In this paper, a triangular shaped piezoelectric vibration energy harvester (TS-PVEH) with zinc oxide (ZnO) thin films as the piezoelectric layer is reported. The effect of post-annealing temperature on the microstructure and piezoelectric performance of ZnO thin film deposited by magnetron sputtering method is investigated firstly. The results show that the optimum post-annealing temperature of 150 °C was the most beneficial to improve the piezoelectric properties of ZnO thin films. Four prototypes of TS-PVEH with different structure parameters are fabricated and optimized. The simulation and experiment results indicate that the height and width of the triangular structure have a significant influence on the vibration mode and the output performance of TS-PVEHs. The optimization results indicate that the third prototype has the best output performance. Its open-circuit voltage and short-circuit current are 290mV and 1.25 μA, respectively, when the vibration acceleration is 5m/s2 and the frequency is 56Hz. Moreover, it has the highest load power density of 0.035μW/cm2 when the load is 0.1MΩ.
关键词： Triangular substrate,ZnO thin film,Structure optimization,Post-annealing temperature,Vibration energy harvester
更新于2025-09-23 15:23:52
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Effect of elastic modulus of cantilever beam on the performance of unimorph type piezoelectric energy harvester
摘要： Piezoelectric energy harvesting is a technique that can utilize ambient vibration energy to generate useful electrical energy, which is promising for powering small-scale autonomous devices such as sensors for wearable, biomedical, and industrial applications. Typically, cantilever-type piezoelectric energy harvesters (PEHs) are operated under resonance condition to achieve the maximum output power at low frequency stimuli. Along with resonance matching, it is also necessary to optimize the PEH configuration with high electromechanical properties for the efficient energy conversion. The purpose of this study is to investigate the effect of the elastic modulus of the passive layer in the cantilever structured PEH on the electromechanical properties and thus harvesting performance. In this regard, two unimorph type PEHs having the identical geometry, piezoelectric properties, and proof mass but with different elastic modulus (55 GPa and 97 GPa) of Ti alloy-based passive layers were fabricated and their output performance was compared under the same acceleration amplitude excitation stimuli. The PEH with the smaller elastic modulus passive layer exhibited almost 53% improvement in the maximum power than that with the higher elastic modulus passive layer, which is attributed to a smaller mechanical damping ratio, higher quality factor, and larger vibration amplitude.
关键词： vibration energy,piezoelectric energy harvesting,cantilever beam,elastic modulus,unimorph type
更新于2025-09-04 15:30:14
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[Solid Mechanics and Its Applications] Piezoelectric Shells Volume 247 (Sensing, Energy Harvesting, and Distributed Control—Second Edition) || Linear/Nonlinear Piezoelectric Shell Energy Harvesters
摘要： Development of energy harvesting technologies, e.g., converting vibration energy to electric energy, has attracted much attention in recent years. Among the proposed technologies, piezoelectric energy harvesters can easily convert the vibration induced energy to useful electric energy with the electromechanical coupling of piezoelectricity. Most piezoelectric energy harvesters have been designed based on various non-shell structures, such as cantilever beams and plates. Electromechanical coupling mechanism and distributed sensing of shell structures, which are commonly used in aerospace, civil and mechanical systems, also have captured researchers’ attention for decades. However, most of them only considered the signal generations in the open-circuit condition and the sensing theory becomes impractical when it is used to power electric devices whose impendence can no longer be ignored. Therefore, the output energy across a resistive load in a closed-circuit condition for the shell energy harvesters should be exploited. Accordingly, this study focuses on a development of a generic piezoelectric shell energy harvesting mechanism that can be simplified and applied to many linear/nonlinear shell and non-shell distributed energy harvesters.
关键词： shell structures,energy harvesting,electromechanical coupling,vibration energy,piezoelectric
更新于2025-09-04 15:30:14
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Effect of an underdamped vibration with both diagonal and off‐diagonal exciton–phonon interactions on excitation energy transfer
摘要： A numerically exact approach, named as the hierarchical stochastic Schr?dinger equation, is employed to investigate the resonant vibration-assisted excitation energy transfer in a dimer system, where an underdamped vibration with both diagonal and off-diagonal exciton–phonon interactions is incorporated. From a large parameter space over the site-energy difference, excitonic coupling, and reorganization energy, it is found that the promotion effect of the underdamped vibration is significant only when the excitonic coupling is smaller than the site-energy difference. Under the circumstance, there is an optimal strength ratio between diagonal and off-diagonal exciton–phonon interactions for the resonant vibration-assisted excitation energy transfer as the site-energy difference is greater than the reorganization energy, whereas in the opposite situation the most efficient energy transfer occurs as the exciton–phonon interaction is totally off-diagonal.
关键词： underdamped vibration,energy transfer,exciton–phonon interaction,non-Condon effect
更新于2025-09-04 15:30:14