Title : The optimization of methods of synthesis of nickel nanoparticles with silver nanoshell as component of conductive materials
Abstract:
Conductive inks based on nickel nanoparticles (NPs) have attracted much attention as a low-cost replacement for the currently used silver and gold NPs for fabrication of printed electronic circuits and devices. The nickel NPs as a component of conductive inks should be stable against oxidation process at all stages of preparation of conductive patterns: ink formulation and storage, printing, and post-printing treatment. In the present study, spontaneous oxidation of nickel was prevented by the formation of a silver shell on their surface, which results in the formation of nickel-silver core-shell (Ni@Ag) NPs. Those NPs were formed in the two-step process: (1) the formation of a dispersion of Ni nanoparticles; and (2) the transmetalation (galvanic displacement) reaction, where the surface of the Ni NPs acted as the reducing agent of silver ions. In the optimal condition of synthesis, Ni@Ag nanoparticles with about 50 and 210 nm-diameter Ni core coated with a thin (~10-20 nm) silver shell, were obtained. Finally, the stability of the synthesized spherical shaped Ni@Ag NPs was tested and the results indicate long-term stability against aggregation and nickel oxidation. Thick films composed of Ni@Ag NPs were deposited on a glass substrate and then sintered at temperatures ranging from 250°C to 370°C. The conductivity of Ni@Ag based coatings after sintering at 350°C was high, 11% of that for a bulk nickel. The obtained results clearly indicate that prepared metallic ink based on Ni@Ag NPs possess promising properties for its application in the printing technology of circuit board.
Audience take away:
• The simple and fast methods of synthesis of air-stable Ni@Ag NPs.
• The implementation of obtained results will allow fabricating convenient and low-cost material for application in conductive features.
• This approach is very important from an economic point of view and will make possible preparation of metallic conductive materials for large scale commercial application.
