Fabrication of Sinter-free Conductive Paste based on Cu Nanomaterials

Abstract

Printed electronics became one of the most promising application for fabrication of electronic devices. Especially, manufacturing flexible electronics proved attractive in that it could be applied to numerous practical application. However, conventional methods require expensive equipment and high cost manufacturing process. Therefore, the printed electronics, which utilizes conductive ink is getting large attention as it is cost-efficient and fast. Conductive ink is usually composed of conductive material, liquid base, and various additives. Especially, metal nanomaterials have drawn considerable attention as conductive materials due the modern wet chemical technology which enabled the large-scale production. Typically, silver nanoparticles-based inks are widely utilized these days due to the high conductivity. However, high cost of silver makes the real life application of conductive ink difficult. This dissertation provides conductive paste based on cheap Cu nanomaterials. Cu nanoparticles and nanowires are used as solid loadings for the conductive paste. Also, the printed pattern does not require thermal or photo sintering process, which could reduce the manufacturing cost. Moreover, sinter-free conductive paste enables to use substrate which is weak to heat or light. Cu nanoparticles and nanowires are synthesized by wet-chemical method and hydrothermal method respectively. Cu nanowires are utilized to substitute conventional carbon paste and used as dual functional materials

conductive paste and glucose sensor. Cu nanoparticles were synthesized to enhance the conductivity of the sinter-free conductive paste. Moreover, Cu nanoparticles were mixed with Cu nanowires to increase the sinter-free conductive paste. The sinter-free conductive paste presented in this dissertation could be applied to various fields such as printed circuit boards, RFID tags, thin film transistors, light emitting devices, solar cells, transparent electrodes, and flexible displays. In addition, this dissertation might not only provide synthetic route for Cu nanomaterials based conductive paste but open a new path on fabricating sinter-free conductive paste