Korea develops new flexible electrode using silver nanowire

A group of South Korean scientists has developed a new transparent, flexible electrode with silver nanowires instead of expensive and hard-to-find indium, paving the way for the development of better and cheaper display panels, the science ministry said Thursday.

Transparent electrodes are a key component of organic light-emitting diode panels, according to the Ministry of Education, Science and Technology.

Conventional electrodes or transparent conducting films use indium, a rare earth material that is not only hard to find, especially in South Korea, but is also hard to use in flexible display panels because of its rigidity. The ministry said only 0.05 grams of indium is found in every 1,000 kilograms of ore on average.

The new transparent electrode, developed jointly by Prof. Lee Hyo-young of Seoul’s Sungkyunkwan University and a research team from Samsung Electro-Mechanics, instead uses silver nanowires that are both transparent and flexible.

The possibility of using silver nanowires as conductors had been previously considered, but adhering silver nanowires to a transparent film remained a challenge as the use of conventional adhesives, such as polymers, significantly undermined the transparency and flexibility of films.

Also, silver quickly oxidizes when exposed to air.

The research team found a solution in graphene nanosheets, which safely secured silver nanowires in place while preventing the silver from oxidizing for over two months under experiment.

“For a country like ours where indium or other rare materials are hard to find, it is vital to find new materials or develop technologies to be able to maintain its leadership in the global market for transparent films,” Prof. Lee was quoted as saying.

“The research is expected to have a great impact in the market as it enabled the use of silver nanowires and graphene oxide nanosheets, both of which are easier to produce than indium and can be mass produced.”

The outcome of the research, partly funded by the science ministry, was published Wednesday by Scientific Reports, an online open journal published by Nature Publishing Group, under the title of “2D Graphene Oxide Nanosheets as an Adhesive Over-Coating Layer for Flexible Transparent Conductive Electrodes.” (Yonhap News)