Highly durable and flexible transparent electrode on PET based on copper and cupronickel multilayer

Abstract

Multilayer grid electrodes consisting of Cu0.7Ni0.3/Cu/Cu0.7Ni0.3 utilize the high conductivity of Cu to realize low electrical resistance and the high corrosion resistance of CuNi to improve reliability. The effect of thickness of outer CuNi layer on corrosion resistance and visibility was investigated. Samples prepared with 2㎛ line width on PET having grid mesh side length of 300㎛, and 60° internal angle with 280nm thickness showed a transmittance of 90.1% at 550nm and sheet resistance of 2.4Ω/□ after grid pattern formation. The low process temperature enabled electrode formation on thin substrate, 23㎛-thick PET and accomplish highly durable and flexible electrode on PET. The superior bending properties showed no change in sheet resistance after 200,000 cycles of outer/inner fatigue bending tests at 3mm-radius of curvature. Additionally, the potential for foldable usage was further supported by demonstrating the ability to form electrodes on both sides of the film.