Development of Silver Fiber Flexible Transparent Electrodes

Overcoming Silver Nanowires’ Limitations and Enabling Flexible OLED Introduction

While OLEDs are emerging as a new display technology, there are many reasons why nanowires used for OLED production have limitations. Accordingly, Korean researchers have developed a technology to overcome this shortcoming.
The National Research Foundation of Korea (Chairman Cho Mu-je) announced that professor Ju Byeong-kwon (Korea University) and Professor Park Yeong-wook (Sun Moon University) of developed flexible transparent electrodes for displays with remarkably improved luminous efficiency by producing silver fibers 100 times longer than silver nanowires.
Silver nanowires feature silver wire network structures with sections whose diameters are in centimeters. While current ITOs are not flexible, silver nanowires are flexible and have excellent conductivity and transparency as ITO electrodes. Due to this fact, silver nanowire is gaining popularity as a promising material for flexible transparent electrodes for next-generation flexible displays and lighting devices.
However, the length of nanowires is limited to several dozen micrometers (µm), which limits improvements in conductivity and transparency in utilizing silver nanowires in OLED displays and surface roughness increase due to line joining, giving rise to a limitation of being electrically unstable.
Using an electrospinning process, the team developed silver fiber electrodes with a length of several centimeters (centimeters) in length and no junctions, ensuring conductivity, transparency and electrical stability.

The electrospinning process is a process by which fibers produced by injecting a polymer solution into an electric field. As the process is simple and can produce a large area of fibers, this process can thus be applied to large OLEDs for display and illumination.
The research team maximized conductivity and transparency by controlling the thickness and density of silver fibers, resulting in 19% higher energy conversion efficiency than OLEDs using ITOs.
“This research is the first case of developing a silver electrode that overcomes the limitations of silver nanowires and introducing them to OLED,” explained Professor Ju Byeong-kwon. “It is expected that the silver fiber will contribute to securing the core technologies in wearable display and lighting market.”
“Silver fiber flexible transparent electrodes can be applied to various optical electronic devices such as LEDs, solar cells, touch screens, and optical sensors in addition to OLEDs. Silver fibers with excellent conductivity and transparency have great potential in various application fields, “Silver fiber electrodes can be produced to have wide areas and have low resistance. Therefore, when a silver electrode is applied to OLED lighting, which is being researched as next-generation lighting, we can solve problems such as high driving voltage and non-luminescence.

korean-electronics.com | Blog Magazine of korean electronics, brands and Goods