Development and Characterization of Inkjet-Printed-Silver and Conducting Polymer Transparent Mesh-Type Electrodes

• Main Authors: Yu, Po-Chin, 游博進
• Other Authors: Liou, Tong-Miin
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/32164937553865444636

碩士 === 國立清華大學 === 動力機械工程學系 === 102 === Transparent conductive films has been widely used in solar cells, LED and consumer electronics as a medium of electric current and light. Its conductivity and transmittance affect the efficiency of these devices. The mainstream material for transparent conductor is ITO (indium tin oxide) in recent years. However, the price of ITO has increased dramatically due to the huge demand and the strained supply of indium. Seeking the replacement materials for ITO becomes an important issue, and the way how to fabricate a transparent conductor with comparable conductivity and transmittance under the same cost is the only solution. This study presents a transparent mesh-type electrode by integrating inkjet-printed-silver and modified conductive polymer (PEDOT). A mathematical model has been proposed for calculating the optimized grid pattern, and the optimized line width/line spacing ratio is 0.05 by this model. Furthermore, the theoretical relationship between line width/line spacing ratio and figure of merit has been verified by experimental results. For improving the conductivity of electrodes, the aspect ratio of lines has been raised by overprinting. The conductivity of four-layers printed electrodes is 50 times as high as the conductivity of monolayer printed electrode, and their transmittance are still higher than 90%. Moreover, planarization of transparent mesh-type electrodes by hot-pressing has been proposed and demonstrated. The thickness of grid lines decreases from 150 nm to 10 nm by this planarization. Integrating all of these processes, the sheet resistance of fabricated electrode is 7.2 Ω/□, the transmittance is 84.03 % and the figure of merit is 24.39×10-3 Ω-1 which is 2 times as high as the mean value of the literature before. After 23000 times of bendings to a 11 mm radius curvature, the resistance incensement of electrode developed by this study is still less than 10%.