Fabrication of Silver Suspension and Transparent Conductive Thin Film Based on Silver Nanowire/Nanoparticle

• Main Authors: Pei-Wen Chen, 陳姵雯
• Other Authors: Wen-Yen Chiu
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/p37s46

碩士 === 國立臺灣大學 === 化學工程學研究所 === 105 === Silver nanowires and silver nanoparticles have received considerable attention due to their electrical, optimal and thermal properties used in various applications such as conductive thin film since bulk silver (Ag) has the highest thermal and electrical conductivity among all metals. Two methods were developed in this research to fabricate transparent conductive thin films from stable silver-nanowire or silver-nanoparticle suspensions. Chemical method was applied to synthesize silver nanowires; whereas electrospinning method was used to prepare silver nanoparticles. Three divided sections were contained in this thesis. In the first section, we demonstrated a parametric study on self-seeding polyol synthesis of optimal Ag nanowires. The effects of synthesizing temperature, molar ratio of poly(vinylpyrrolidone) (PVP) to silver nitrate, injecting rate of silver nitrate, concentrations of sodium chloride and potassium bromide, and stirring rate on the morphology of Ag nanostructures were examined. The morphologies of nanostructures and aspect ratio on synthesis parameters were shown via scanning electron microscopy (SEM) images. Ag nanowires were optimally synthesized by polyol process with a high aspect ratio of over than 300, where the average diameter and length were 40 nm and 12-15 μm, respectively. In terms of silver nanoparticle, single-jet electrospinning nethod was used to fabricate silver electrospun fibers, and the fibers were pre-annealed, and these fibers were re-disperded in water to form the stable silver nanoparticle suspension with the assistance of PVP from fibers. Traditionally, Ag nanowires were hardly suspended in polar or nonpolar solvents owing to their high density. In the second section, some innovative and facile formulas were proposed to prepare the water-based stable Ag nanowire suspensions with the addition of dispersive agent such as polyethylenimine (PEI), poly(vinylpyrrolidone) (PVP) and BYK-410 as suspending agent. When adding a little amount of polymers, polymer served as dispersion that associated with Ag nanowire, thus changing the interaction between Ag nanowires. We also examined the effect of pH values and zeta potential on the suspended behaviors of the polymer-bound Ag nanowire in aqueous solutions. The last section, a practical and general approach is described to fabricate the conductive thin films. Ag nanowires were dispersed stably in aqueous phase by the addition of dispersive agent under homogenization and Ag nanoparticles were dispersed in water phase then followed by three distinct processes including drop casting, spray coating and spin coating. Through the above-mentioned methods, good electrical and optical properties of prepared polymer-bound Ag nanowires/nanoparticles conductive thin films were performed. The proposed method provided a simple and practical approach for the fabrication of the conductive thin films with excellent transparency and showed the significant potential to apply in electronic fields generally.