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

Anna Pajor-Świerzy,Radosław Pawłowski,Krzysztof Szczepanowicz,Franciszek Szendera

doi:10.3390/colloids5010015

Abstract

Nanocomposite inks composed of nickel–silver core–shell and silver nanoparticles (NPs) can combine the advantages of lower cost, high conductivity, and low-temperature sintering processes, which have attracted much attention in the development of materials for printed flexible electronics. In this context, in the present paper, we report the process of preparation of nanocomposite ink containing nickel–silver core–shell nanoparticles, as the main filler, and silver nanoparticles, as doping material, and their application for the fabrication of conductive coatings. It was found that the addition of a low concentration of Ag NPs to ink formulation based mainly on low-cost Ni-Ag NPs improves the conductive properties of coatings fabricated by ink deposition on a glass substrate. Two types of prepared nanocomposite ink coatings showed promising properties for future application: (1) doped with 0.5% of Ag NPs sintered at 200 °C as low cost for larger industrial application and, (2) containing 1% of Ag NPs sintered at 150 °C for the fabrication of conductive printed patterns on flexible substrates. The conductivity of such nanocomposite films was similar, about of 6 × 106 S/m, which corresponds to 35% of that for a bulk nickel.

Highlights

During the last years, printing methods have attracted much attention as low cost, low pollution, and convenient ways for the fabrication of electronic circuits or devices
The electrical conductivity of up to 16% of that for bulk Cu was observed when sintering was carried out at 130 ◦C and more than 25% of bulk Cu was observed above 150 ◦C
We found out that Ni-Ag coatings doped with 1% of Ag NPs can be sintered at a much lower temperature (150 ◦C) in comparison with coatings based on only Ni-Ag NPs

Summary

Introduction

During the last years, printing methods have attracted much attention as low cost, low pollution, and convenient ways for the fabrication of electronic circuits or devices. The protection of nickel NPs from the oxidation process is of crucial importance for the fabrication of printed tracks with high conductivity. 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]. A similar value was achieved for the nanocomposite film at only a slightly higher sintering temperature of 200 ◦C, but lower Ag NPs’ concentration (0.5%), which is important from an economic point of view and can help decrease the cost of fabrication of conductive materials

Materials

Synthesis of Metallic Nanoparticles

Nanocomposite Ink Formation and Conductive Coatings’ Fabrication

Findings

44.. Conclusions