The optimization of methods of synthesis of nickel–silver core–shell nanoparticles for conductive materials

Abstract

Nickel–silver core–shell (Ni@Ag) nanoparticles (NPs) were formed in a two-step process: (1) the formation of a dispersion of Ni NPs; and (2) the transmetalation (galvanic displacement) reaction, where the surface of the Ni NPs acted as the reducing agent of Ag ions. Ni NPs were synthesized by the ‘wet’ chemical method, i.e., by the reduction of metal ions by using NaBH4 as the reducing agent. The influence of the concentration of polymeric stabilizer, reducing agent and Ag precursor on the properties of synthesized NPs was evaluated. In the optimal condition of synthesis, Ni@Ag NPs with about 50 and 210 nm-diameter Ni core coated with a thin (∼10–20 nm) Ag 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 Ni oxidation. Thus, the resulting NPs are promising candidates for application in electronic devices, e.g., as components of conductive inks or pastes.

Sesbania Gum-Supported Hydrophilic Electrospun Fibers Containing Nanosilver with Superior Antibacterial Activity

“…Synthesis of Ag NPs was carried out according to our previous report [53]. In a typical procedure, polyvinylpyrrolidone (PVP, 0.2 g) and AgNO 3 (0.5 g) were added dropwise into 50 mL of N , N -dimethylformamide (DMF) under vigorous stirring.…”

Nanocomposite Inks Based on Nickel–Silver Core–Shell and Silver Nanoparticles for Fabrication Conductive Coatings at Low-Temperature Sintering

“…Nickel-silver core-shell NPs were obtained using an improved two-stage process, which was previously developed in our lab [12,[19][20][21]. At the first stage, Ni NPs were synthesized in the presence of two types of complexing agents.…”

“…Due to the deficiency of NaBH4, it is fully consumed in the process of reduction of Ni 2+ , which prevents the reduction of Ag + to Ag NPs, instead of their reduction on the surface of Ni NPs with the formation of a core-shell structure by transmetalation reaction. The basic as a low-cost active material of metallic hybrid ink, in the form of Ni-Ag core-shell NPs, was synthesized according to previously developed methods [12,[19][20][21]. These methods involved a two-step process: (1) synthesis of Ni NPs followed by (2) silver shell formation by transmetalation reaction [26].…”

“…The most efficient and long-term approach for the preparation of air-stable Ni NPs is their coating with a layer of noble metals (silver or gold) by transmetalation, which results in the formation of a core-shell structure. In this process, the preformed surface of the core particle acts as a reducing agent for the second metal with higher redox potential [11,12].…”

Polydispersity vs. Monodispersity. How the Properties of Ni-Ag Core-Shell Nanoparticles Affect the Conductivity of Ink Coatings

“…In the present research, we focused on the effect of polydispersity of Ni-Ag NPs on the final conductive properties of metallic coatings. Polydisperse dispersions of Ni-Ag NPs for ink formulation were prepared by mixing of three types of Ni-Ag NPs with different average sizes synthesized by previously developed methods [ 9 , 18 , 19 ] with some additional improvements. The conductive properties of ink coatings composed of monodisperse and polydisperse Ni-Ag NPs were analyzed and compared.…”