ITO/Ag/ITO Multilayer Polymer Films by Roll-to-Roll Process and Performance of Flexible OLED Devices

In this study polyethylene naphthalate(PEN) and polyethersulfone(PES) films were chosen as a flexible substrates for fabrication of organic light emitting diode(OLED) devices. Hard coating was applied on both PEN and PES films utilizing UV curable resin. The transparent conductive ITO/Ag/ITO multilayer was deposited by the roll-to-roll sputter on the polymer films with hard coating. The UV hard coating of thin film on the polymer films improved both the surface roughness (50% in case of PEN film) and the transmittance in the visible region. In the subsequent multilayer transparent conductive layer formation, the optimum condition was obtained in the ITO(50 nm)/Ag(17 nm)/ITO(50 nm) multilayer structure. The OLED's fabricated with the optimized multilayer conductive films exhibited high luminance and current efficiency under low operation voltages.