Japanese scientists have developed a technique to transform a copper-based substance into imitation of the properties of precious and expensive metals, such as gold and silver. The new medium, made from copper nanoparticles (very small copper-based structures) has promising applications when producing electronic devices that would otherwise depend on expensive gold and silver counterparts. It is also suitable for the manufacture of electronic components using printing technologies that are recognized as environmentally friendly production methods.
The study was published on 29 January Scientific Reports, an online open access magazine managed by Nature.
The development of the Internet of Things (IoT) has increased rapidly the demand for thin and visible electronic devices. For example, IoT relies on communication between devices, which requires antennas that have so far needed expensive metal compounds and expensive silver.
To date, the current techniques for the preparation of copper nanoparticles have not been ideal as they have led to impurities associated with the material. As these impurities could only be moved through extremely high temperatures, copper nanoparticles created at room temperature were inappropriate and therefore could not solidify to usable parts. So far, this has been one of the barriers to creating a more cost effective option than gold and silver parts in electronic devices.
The joint study between researchers at the University of Tohoku and Mitsui Mining & Smelting Co., Ltd. in Tokyo reports that copper nanoparticles synthesized successfully with the ability to heat at much lower temperatures while staying pure. The team has changed the structure of the copper nanoparticles and made them more stable so that they do not degrade at low temperatures.
“Copper has been an attractive alternative in the preparation of electrical circuits. The most important part of using copper is to change it so that it solidifies at low temperatures. So far, that's been difficult because copper easily interacts with the moisture in the air and degrades, which turns our unstable nanoparticles. With the methods used in this study changing the structure of the carbon and thus making it more stable, we have managed to overcome this instability issue, ”adds Kiyoshi Kanie, Ph. D., associate professor at the Multidisciplinary Research Institute for Advanced Materials from Tohoku University.
The researchers are hoping to expand the use of their copper-based nanoparticles beyond electronics alone. They believe that this material will also be useful in other sectors. “Our method has effectively created copper nanoparticle materials which can be used in different types of flexible and wearable on-demand devices that can be easily made through very low cost printing processes,” Kanie added.