Al2O3/Ag/Al2O3 multilayer thin film passivation prepared by plasma damage-free linear facing target sputtering for organic light emitting diodes

• Multilayer passivation for organic light emitting didoes (OLEDs) was investigated.
• The Al2O3/Ag/Al2O3 multilayer showed a high transparency due to the antireflection effect.
• The lifetime of an OLED passivated with Al2O3/Ag/Al2O3 multilayer was improved.

Al2O3/Ag/Al2O3 multilayer passivation prepared by plasma damage-free linear facing target sputtering (LFTS) was investigated as a function of inserted Ag thickness. Using antireflection effect of the Ag layer that is sandwiched between dielectric Al2O3 layers, we can obtain a transparent Al2O3/Ag/Al2O3 multilayer passivation for organic light emitting diodes (OLEDs). It was found that insertion of the Ag layer with optimized thickness between Al2O3 layers lead to improvement of the optical transparency and water vapor transmission rate of the Al2O3/Ag/Al2O3 multilayer. In addition, current density–voltage–luminescence of an OLED passivated with Al2O3/Ag (10 nm)/Al2O3 multilayer was similar to that of an OLED with nonpassivated sample, indicating that the performance of an OLED is not affected by high-density plasma during the LFTS process. Moreover, the lifetime to half initial luminance of an OLED passivated with Al2O3/Ag (10 nm)/Al2O3 multilayer was longer than that of a nonpassivated sample.