Preparation, characterization and reaction mechanism of a novel silver-organic conductive ink

A novel silver-organic conductive ink with no particles, consisting of silver-amide complex dispersed in glycol-water mixture, was developed in a simple way. The reaction mechanism during sintering was also studied and a multi-mechanism was found for the first time. Silver ions in solution can be reduced by glycol to metallic silver following the typical polyol process. Meanwhile, silver-amide complex will decompose to silver oxide, and is then immediately reduced by glycol. The result indicates that the silver oxide reduction mechanism plays a major role in the whole reaction. The type of amine has a great influence on the properties of the ink. When adding a proper amount of gamma-(2,3-epoxypropoxy) propyltrimethoxysilane (KH-560), both the conductivity and adhesion of sintered silver film will be improved. Microstructures of the silver film were observed, and a multi-layered structure was detected. The relationships between structure and resistivity and adhesion were also researched. After being filled into a marker and drawn on polyimide (PI) film, the conductive ink was sintered at 150 degrees C for 1 hour using an oven, and the resistivity of the silver film was 18 mu Omega cm, about 11 times that of bulk silver.