Low-temperature remote plasma enhanced atomic layer deposition of ZrO2/zircone nanolaminate film for efficient encapsulation of flexible organic light-emitting diodes

Abstract

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, CO2, NO, H2O, as well as the related fragments during the O2 plasma process were characterized using the QMS, indicating a combustion-like reaction process. The self-limiting nature and growth mechanisms of the ZrO2 during the complex surface chemical reaction of the ligand and O2 plasma were monitored using the QCM. The remote PEALD ZrO2/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 × 10−5 g/m2/day). This study also shows that flexible OLEDs can be successfully encapsulated to achieve a significantly longer lifetime.

Structural, Optical and Electrical Properties of HfO2 Thin Films Deposited at Low-Temperature Using Plasma-Enhanced Atomic Layer Deposition

“…Using plasma to produce oxygen radicals with high reactivity can solve these problems, and plasma has been used in other low-temperature deposition processes [17]. Consequently, plasma-enhanced atomic layer deposition (PEALD) can be used to decompose a source at a lower temperature by making atomic oxygen radicals using O 2 gas as a reactant; this is in contrast to the conventional thermal ALD process, which uses O 3 as a reactant.…”

Effect of Process Temperature on Density and Electrical Characteristics of Hf0.5Zr0.5O2 Thin Films Prepared by Plasma-Enhanced Atomic Layer Deposition

“…Moreover, there has been insufficient investigation on the properties of HZO thin films deposited by plasma-enhanced atomic layer deposition (PEALD) [ 19 ]. PEALD is capable of the high-density deposition of thin films and has the advantage of enabling low-temperature deposition [ 20 , 21 , 22 ]. The regions wherein the o-, t-, and m-phases of HZO are formed vary depending on grain size and temperature.…”

Low-temperature atomic layer deposition of SiO 2 /Al 2 O 3 multilayer structures constructed on self-standing films of cellulose nanofibrils

“…[9] ALD thin layers of Al2O3 have been successfully exploited to enhance the moisture and gas barrier performance of various biobased films and coatings such as CNF, pectin and galactoglucomannan coated board. [10] Improved barrier properties have been obtained by different multilayer structures, such as Al2O3/ZrO2 [11], Al2O3/TiO2 [12], Al2O3+SiO2 [13], Al2O3/alucone [14] and ZrO2/zircone [15].…”

“…ALD thin layers of Al 2 O 3 have been successfully exploited to enhance the moisture and gas barrier performance of various bio-based films and coatings such as CNFs, pectin and galactoglucomannan-coated board [10]. Improved barrier properties have been obtained by different multilayer structures, such as Al 2 O 3 /ZrO 2 [11], Al 2 O 3 /TiO 2 [12], Al 2 O 3 + SiO 2 [13], Al 2 O 3 /alucone [14] and ZrO 2 /zircone [15]. Multilayer structures and nanolaminates are used in order to protect the vulnerable Al 2 O 3 layer and to increase the tortuous diffusion path of the molecules [16].…”