Low-temperature gas-barrier films by atomic layer deposition for encapsulating organic light-emitting diodes.
Dependences of gas-barrier performance on the deposition temperature of atomic-layer-deposited (ALD) Al2O3, HfO2, and ZnO films were studied to establish low-temperature ALD processes for encapsulating organic light-emitting diodes (OLEDs). By identifying and controlling the key factors, i.e. using H2O2as an oxidant, laminating Al2O3with HfO2or ZnO layers into AHO or AZO nanolaminates, and extending purge steps, OLED-acceptable gas-barrier performance (water vapor transmission rates ∼ 10-6g m-2d-1) was achieved for the first time at a low deposition temperature of 50 °C in a thermal ALD mode. The compatibility of the low-temperature ALD process with OLEDs was confirmed by applying the process to encapsulate different types of OLED devices, which were degradation-free upon encapsulation and showed adequate lifetime during accelerated aging tests (pixel shrinkage <5% after 240 h at 60 °C/90% RH).
Department of Materials Science and Engineering, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei, Taiwan, People's Republic of China.
Ming-Hung
MH
Tseng
Hui-Huan
HH
Yu
Kun-Yi
KY
Chou
Jwo-Huei
JH
Jou
Kung-Liang
KL
Lin
Chin-Chiun
CC
Wang
Feng-Yu
FY
Tsai