Realization of Al2O3/MgO laminated structure at low temperature for thin film encapsulation in organic light-emitting diodes.
A laminated structure of Al2O3and 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 Al2O3and MgO exhibited much lower water vapor transmission rate (WVTR) of 4.6 × 10-6gm-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 Al2O3/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 Al2O3material.
Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
Min
M
Li
Miao
M
Xu
Jianhua
J
Zou
Hong
H
Tao
Lei
L
Wang
Zhongwei
Z
Zhou
Junbiao
J
Peng