Bottom-emission organic light-emitting diodes using semitransparent anode electrode by O2 plasma

To improve the performance of bottom-emission organic light-emitting diodes (BEOLEDs), the effect of oxygen plasma treatment duration on the electrical properties of multi-metal Ni/Ag/Ni thin film anode was investigated. The results revealed that a Ni/Ag/Ni thin-film layer formed upon oxygen plasma treatment for 60 s. Our indium-free bottom-emission OLEDs effectively increased the electrical and optical properties by improving their electron–hole recombination and doing a strong micro-cavity effect with the semitransparent multi-metal anode. The green bottom-emission OLEDs show a luminance of 14,280 cd/m2, a luminous efficiency of 8.5 cd/A, external quantum efficiency 2.6% EQE, a Commission Internationale de L’Eclairage coordinates of (0.32, 0.58) on flexible substrate.

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► A multi-metal stack of Ni/Ag/Ni are fabricated on a plastic substrate.
► The electrical and optical characteristics were efficiently enhanced by O2 plasma.
► Our OLED exhibits a 14,280 cd/m2, 8.5 cd/A, 2.6%, and (0.32, 0.58) on PET substrate.
► We introduce an ITO-free structure produced on PET substrate by a simple process.