Roll It Up
The Korea Electronics Technology Institute (KETI) has developed an ultra-thin OLED electrode material for mobile devices that is capable of maintaining its electrical characteristics even after being bent tens of thousands of times.
“With this OLED electrode material, smartphones can be rolled and fully folded like paper,” the institute explained, adding, “We are currently discussing mass production with major chemical material manufacturers in Korea, expecting that a fully-foldable smartphone will be available on a commercial scale within two years to come.”
Indium tin oxide (ITO) is the main ingredient used in produce existing OLED panels. An ITO-based touch panel is excellent in brightness, but cracks when bent, and thus cannot be used in flexible display. KETI’s material developed at this time is the world’s first means to overcome the limitation.
The institute developed it by making use of a material in which an silver nanowire is combined with transparent polyimide. The silver nanowire-based electrode materials developed before are not suitable for flexible OLED displays, which requires a high level of flatness, because the silver nanowire layer forms a roughness on the polymer substrate. In order to deal with this problem, the KETI put the silver nanowire as an input to a polymer substrate, and then adjusted the surface roughness by means of plasma irradiation, which resulted in a level of efficiency acceptable for ITO-based OLED displays.