Air-stable copper-nickel complex inks for Printed Electronics

Cost-effective copper conductive inks are considered as the most promising alternative to expensive silver conductive inks for use in printed electronics. However, the low stability and high sintering temperature of copper inks hinder their practical application. Herein, we report air-stable and highly conductive copper-nickel complex inks. We found that the Cu-Ni inks can form uniform Cu@Ni core-shell nanostructures by a self-assembling process, resulting in the nickel coating on the surface. Thus, the addition of nickel overcomes the weakness of conventional copper inks, achieving high oxidation resistance and high electrical conductivity. The formed Cu-Ni wiring shows high conductivity of 10 μΩ cm and the high oxidation resistance can be maintained at 180°C. Furthermore, the printed Cu-Ni alloy patterns exhibit good adhesion to flexible substrates and high flexibility, making them ideal for flexible electronics such as flexible RF-ID tags and various wearable sensors.