Highly reliable hybrid nano-stratified moisture barrier for encapsulating flexible OLEDs

Abstract

Herein, a novel thin-film encapsulation for flexible organic light-emitting diodes (FOLEDs) is proposed, and its long-term reliability in tensile stress conditions was tested. The hybrid nano-stratified moisture barrier consists of 2.5 dyads of an Al2O3/ZnO nano-stratified structure and a S-H nanocomposite organic layer. The nano-stratified structure is prepared by low-temperature atomic layer deposition and the S-H nanocomposite by spin-coating at a thickness of 30 and 120 nm, respectively. An optical transmittance of 89.05% was measured with the 2.5-dyad hybrid nano-stratified moisture barrier with a total thickness of 330 nm. A low water vapor transmission rate (WVTR) of 1.91 x 10(-5) g/m(2) day was recorded based on an electrical Ca test at 30 degrees C and 90% R.H. without losing its properties after a bending test. With this highly reliable hybrid nano-stratified moisture barrier, FOLEDs were successfully encapsulated. After 30 days under conditions of 30 degrees C and 90% R.H. with tensile stress, the J-V-L performances of the FOLEDs were comparable to those of the initial state without dark spots. These results suggest that this hybrid nanostratified moisture barrier is an excellent method for encapsulating FOLEDs. (C) 2016 Elsevier B.V. All rights reserved