Composite Encapsulation Films with Ultrahigh Barrier Performance for Improving the Reliability of Blue Organic Light‐Emitting Diodes
Yun Li, Kun Cao, Ying Xiong, Huizhi Yang, Yinghao Zhang, Yanyan Fang, Binze Zhou, Jing Huang, Rong Chen
Abstract
Abstract This work presents a facile method to fabricate composite encapsulation bilayer films with ultrahigh barrier performance for the blue organic light‐emitting diodes (OLEDs). The encapsulation film is composed of the SiN x and Al 2 O 3 layers prepared via incorporation of plasma enhanced chemical vapor deposition (PECVD) and spatial atomic layer deposition (S‐ALD) methods. It is found that the hybrid bilayer films possess excellent barrier performance with water vapor transmission rate (WVTR) of ≈10 −6 g m −2 day −1 and a long lag time. No black spots are found when applied to the blue OLEDs for more than 1000 h under the accelerated aging condition. The improved stability of the composite barrier originates from introduction of the nanoscale Al 2 O 3 to SiN x layer, leading to the decrease of the stored strain energy. Besides, the Al 2 O 3 layer could help decouple the pinholes on the SiN x surfaces, which blocks permeation of the moisture to degrade the OLEDs. The interface toughness between the OLED and barrier remains stable, which hinders the delamination of the SiN x layer in the severe environment completely.