Researchers developed a method to overcome the vulnerability of silver nanowires, making them suitable for commercial applications.
Today’s nanoscale technologies have enabled a variety of electronic applications such as sensors which are applicable in smartphones as well as medical diagnostics. These devices are able to precisely measure chemical levels in our blood, muscle movement, breathing and pulse rate. These devices are usually made by applying thin coatings of conductive materials onto glass or ceramic substrates. The electrodes are, however, fragile and non-flexible, and they are costly to fabricate.
Silver nanowires is a promising candidate as an alternative to existing nanoscale technologies. Silver nanowires have very small diameters (as small as one-thousandth of a millimeter) and can be fabricated into various cross-sectional shapes and configurations. They have high electrical conductivity, have superior mechanical strength and flexibility and can easily be synthesized with readily available materials.
Silver nanowires have been employed as electrodes in various electronic devices earlier, but their commercial usage is limited due to their vulnerability to the corrosive effects of heat, light, and moisture. Corrosion negatively affects their electrical, mechanical, and optical properties.
To overcome this challenge, researchers from the Terasaki Institute for Biomedical Innovation (TIBI) have developed a method for fabricating ultrathin shells around silver nanowires, resulting in superior stability and effectiveness. Their work is described in the journal Nano Research.
The researchers considered gold as protective shells, but gold reacts with silver and forms holes and pores. The researchers solved this problem by choosing a chemical to complex with the charged gold atoms which effectively suppressed pore formation.
They then developed a room temperature, solutions-based fabrication method which offered easy setup and straightforward, scalable steps. Moreover, their technique can adjust the reaction times, and thickness of the gold layer deposited.
“We considered every possible challenge in designing an effective method to increase longevity of silver nanowire-based devices,” said Yangzhi Zhu, Ph.D., first author of the project. “Our data clearly shows that we were able to create effective solutions to these challenges.”
The researchers exposed nanowires to high heat and humidity; the non-coated nanowires failed after 12 days, but the gold-coated silver nanowires’ performance was comparable to top-performing commercial nanowires.
“There are many advantages to using silver nanowires in countless devices, so the ability to improve their performance and durability creates a big impact,” said Ali Khademhosseini, Ph.D., Director and CEO of TIBI. “The methods we’ve devised to achieve that exemplify the quality of our institute’s work.”