Effect of particle morphology on electrical conductivity in silver print ink synthesized by one-step method

A simple one-step method for synthesizing nano-silver print ink with high-solid content is introduced in this study. Lauric acid (C₁₂H₂₄O₂) is used as the protectant, when hydrazine hydrate (N₂H₄·H₂O) is used as deoxidizer. In this way, the silver conductive ink with the solid content of 14% is fabricated, where the diameter of silver particles is 20 nm. The effects of the silver nitrate amount and hydrazine hydrate content on the morphology and solid content of the products were investigated. The morphology and dimension distribution range of nano-silver print ink are characterized by scanning electron microscope and UV-Vis spectrophotometer. It is concluded that the morphology and solid content are directly affected by the molar concentration of silver nitrate and hydrazine hydrate. After sintering below 200℃, the resistance of silver film based on nano-silver print ink was as low as 17 mΩ/□, which established the foundation for the application of nano silver ink in the flexible circuit.