Realization of Al 2 O 3 /MgO laminated structure at low temperature for thin film encapsulation in organic light-emitting diodes

作者：Min Li, Miao Xu, Jianhua Zou, Hong Tao, Lei Wang, Zhongwei Zhou, Junbiao Peng · 发表于：Nanotechnology · 年份：2016 · DOI：10.1088/0957-4484/27/49/494003 · 被引用次数：28 · 研究领域：Organic Light-Emitting Diodes Research、Thin-Film Transistor Technologies、Semiconductor materials and devices

A laminated structure of Al 2 O 3 and MgO deposited by atomic layer deposition (ALD) is used to realize a thin film encapsulation technology in organic light-emitting diodes (OLEDs). This film was targeted to achieve an excellent barrier performance. As the thickness of MgO layer increased from 0 nm to 20 nm, its physical properties transformed from the amorphous state into a crystalline state. The optimized cyclic ratio of ALD Al 2 O 3 and MgO exhibited much lower water vapor transmission rate (WVTR) of 4.6 × 10 −6 gm −2 /day evaluated by Calcium (Ca) corrosion at 60 °C&100% RH, owing to the formation of a terrific laminated structure. Top-emitting OLEDs encapsulated with laminated Al 2 O 3 /MgO show longer operating lifetime under rigorous environmental conditions. These improvements were attributed to the embedded MgO film that served as a modified layer to establish a laminated structure to obstruct gas permeation, as well as a scavenger to absorb water molecules, thus alleviating the hydrolysis of bulk Al 2 O 3 material.