Investigation on Post Treatment of Nano-Size Silver Conductive Film

Abstract

This paper provides a novel post treatment method to achieve high conductivity of nano-size silver coatings. Based on the preparation of nano-size conductive ink and conductive circuit, the printed sample and the coated conductive film were treated by series concentrations of silver nitrate solution and hydrazine hydrate solution in this order. The samples were dipped in 1%~20% solutions of silver nitrate and hydrazine hydrate successively, to form the new conductive layer of Ag particles only. It was investigated that the relationship between the thickness of printed and coated layers on photo paper and final conductivity after dipped in two kinds of solutions in turn, which were printed from one to three times and coated by screw (6#). Atomic force microscopy (AFM) was used to characterize the morphologies of as printed and coated samples. The surface sheet resistance of sample was tested by four-probe tester. It was found that when the coated silver conductive ink samples were dipped in 2% silver nitrate solutions and 2% hydrazine hydrate solution at room temperature, the conductivity reaches 0.82Ω/□. The samples with thicker conductive film before dipping need solutions at lower concentration to get high conductivity. The roughness of samples after treatment falls down, as the concentrate of dipping solutions rising. It is therefore considered that the “dip in” method provides an efficient alternative to improve the conductivity of samples.