The Research of Piezoelectric Energy Harvesters by Screen Printing Method and the Improvement of the Transferring Technique

• Main Authors: Bo-Song Yao, 姚博松
• Other Authors: Wen-Jong Wu
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/338mjp

碩士 === 國立臺灣大學 === 工程科學及海洋工程學研究所 === 107 === With the emergence of smart wearable devices connected to the Internet as IoT applications, the commercial electronics market is booming in a great diversity. The most popular applied scenarios are including health monitoring, exercise training, personal identification, etc. Besides, with the coming of aging societies, the need for health monitoring has become an urgent issue in developing and developed countries. Therefore, wearable health monitoring devices or portable medical usage take the lead in the market. However, all the wearable devices are encountering the challenge of long-term monitoring and low accuracy of measurement. To solve these two problems, screen printing method is used to fabricate the piezoelectric energy harvester (PEH) in this thesis. By doing so, PZT can be deposited thicker in batch process then transferred to any flexible substrates which means the output power and sensitivity could be supposedly improved. In this research, the PZT (Lead Zirconium Titanate) is being used as piezoelectric material. The screen-printing fabrication process has improved with proper modification including paste producing, viscosity controlling and temperature control in the sintering process. Furthermore, the dielectric layer deposition is applied to improve the stability of the poling process. The devices have been improved comparing the results previously. In transferring process, the thin gold layer on silicon with thermal oxide on top is being the sacrificial layer of the process. PZT thick layer can be easily and successfully transferred after proper sintering process and then the piezoelectric layer can be bonded to any flexible substrates. In this thesis, an improved cantilever beam piezoelectric energy harvester(PEH) and transferred PEH are successfully fabricated. In improving PEH, the thickness of the PZT layer is about 22 μm. The resonance frequency and the maximum output power are 73.8 Hz and 4.51 μW in a vibration environment of 0.5 g. In transferred PEH. The thickness of the PZT layer is 12 μm. The resonant frequency and maximum output power are 85.7 Hz and 0.57 μW in the same environment.