Low-temperature atomic layer deposition of Al2O3/alucone nanolaminates for OLED encapsulation

Abstract

Thin film encapsulation (TFE) is one of the key problems that hinders the lifetime and widespread commercialization of flexible organic light-emitting diodes (OLEDs). In this work, TFE of OLEDs with Al₂O₃/alucone laminates grown by atomic layer deposition (ALD) and molecular layer deposition (MLD) as moisture barriers were demonstrated. The barrier performances of Al₂O₃/alucone laminates with respect to the individual layer thickness and the number of dyads were investigated. It was found that alucone with suitable layer thickness could reduce the permeation to the defect zones of the inorganic layer by prolonging the permeation pathway, sequentially improving the moisture barrier performance. The water vapor transmission rate (WVTR) could be further lowered with increasing the number of dyads of the laminates, the WVTR value reached 1.44 × 10⁻⁴ g per m² per day for laminates with 5.5 dyads. These laminates were incorporated in OLEDs with pixel define layer (PDL), and were found to be able to evidently prolong the lifetime of the OLED.