Inorganic/organic Multilayer Passivation Incorporating Alternating Stacks of pZA and SiO for Long-Term Air-Stable Organic Light-Emitting Diodes

Abstract

Inorganic/organic multilayer passivation films were fabricated in an effort to enhance the long-term air stability of an organic light-emitting diode (OLED). AlOx was used as an inorganic layer and 6.5 pairs of alternating silicon monoxide (SiO) and poly zinc acrylate (pZA) layers were used as the organic layers. The organic layers (Alternate stack of SiO and pZA layers) made it possible to decouple the defects present in the inorganic layer (AlOx) and to increase the penetration length of water and oxygen into the devices. The resulting film was characterized using transmission electron microscopy. The film displayed a high transmittance (> 95%) and a low water vapor transmission rate (WVTR, 7.98x10–5 g/m2day) under accelerated environmental aging conditions (a temperature of 60°C and a relative humidity (R.H.) of 90%). In addition, The OLEDs did not incur significant damage caused by temperature (100 °C) and plasma (100 W) during fabrication process by depositing of SiO onto the OLED device prior to applying the passivation layers. The passivated OLED displayed a prolonged shelf-lifetimes over a period of 3,000 h at 60°C and 90% R.H.