Synthesis And Properties Research Of Silver Nanoparticles With High Dispersion Stability

Recengly, along with the rapid development of electronic technology in printing,tremendous interests have been paid to the inkjet printed electronics technology for itsenvirmental-friendly, low-cost and high-efficient features. Inkjet metal nanoparticleinks are one of key studies to develop inkjet printed electronics technology. Inkjetconductive inks with high conductivity, good stability and low heat-treatmenttemperature are the foundation to develop the inkjet printed electronics. This thesisaims to develop solvent silver nanoparticle conductive ink and water silvernanoparticle conducteive ink and explore the influence factors of concentration,stability of suspensions and coating resistivity.Firstly, dodecanethiol (DDT), dodecylamine (DDA) and mercaptoethanol (MEA)were employed as the protective agents (PAs) to prepare the silver nanoparticles, andthe effects of PAs on silver nanoparticle suspension concentration, stability ofsuspension and the conductivity of the silver nanoparticle films were studied. Theconclusions are as the following:(1) The Ag-NS nanoparticles were prepared with DDA and DDT as mixedprotective agent and the particle size is about5nm. A small amount of DDT inprotective agent helps to improve the dispersion stability and suspensionconcentration. The Ag-NS2suspension concentration of20%can be stored stablely atroom temperature for two months, which is longer than that of Ag-DDAand Ag-DDTdispersion. At the same time, the conductivity of silver nanoparticle films reduces dueto the presence of capped DDT on the surface of silver nanoparticles. DDT can notdecompose at a heating temperature below150oC and remain in the coating, which isagainst the sintering process and leading to an improved resistivity.(2) Silver nanoparticles with MEA as protective agent were prepared using thedisplacement method and chemical reduction synthesis method. It’s found thatparticles with uniform size were obtained by chemical reduction method. Incomparison with the displacement method, silver nanoparticles obtained via thechemical reduction method show higher concentrations of suspensions and betterconductivity of silver nanopartilce films.Secondly, the silver nanoparticle inkjet conductive inks were prepared withAg-NS2nanoparticles and inkjet printed by Epson Me1+printer. Stable polymer-free conductive inks with the silver nanoparticle concentration of20%were produced tofabricate patterns by ink-jet printing and the resistivity of the patterns on PI is7.17μΩ·cm and5.50μΩ·cm heating at130oC for10min and60min respectively, whichwas close to the resistivity of bulk silver.