Low-temperature remote plasma enhanced atomic layer deposition of ZrO/zircone nanolaminate film for efficient encapsulation of flexible organic light-emitting diodes.

Encapsulation is essential to protect the air-sensitive components of organic light-emitting diodes (OLEDs) such as active layers and cathode electrodes. In this study, hybrid zirconium inorganic/organic nanolaminates were fabricated using remote plasma enhanced atomic layer deposition (PEALD) and molecular layer deposition at a low temperature. The nanolaminate serves as a thin-film encapsulation layer for OLEDs. The reaction mechanism of PEALD process was investigated using an in-situ quartz crystal microbalance (QCM) and in-situ quadrupole mass spectrometer (QMS). The bonds present in the films were determined by Fourier transform infrared spectroscopy. The primary reaction byproducts in PEALD, such as CO, CO, NO, HO, as well as the related fragments during the O plasma process were characterized using the QMS, indicating a combustion-like reaction process. The self-limiting nature and growth mechanisms of the ZrO during the complex surface chemical reaction of the ligand and O plasma were monitored using the QCM. The remote PEALD ZrO/zircone nanolaminate structure prolonged the transmission path of water vapor and smooth surface morphology. Consequently, the water barrier properties were significantly improved (reaching 3.078 × 10 g/m/day). This study also shows that flexible OLEDs can be successfully encapsulated to achieve a significantly longer lifetime.