The Realization of Thin Film Encapsulation by
Atomic Layer Deposition of Al2O3 at Low
Temperature
†
Yong-Qiang Yang，Yu Duan ，Ping Chen，Feng-Bo Sun，Ya-Hui Duan，Xiao Wang ，
Dan Yang
State Key Laboratory on Integrated Optoelectronics, College of electronic science and
engineering, Jilin University, Jilin, 130012, China
†
Corresponding Author:
Yu Duan
Address: Tang Aoqing Building #217
Jilin University, 2699 Qianjin Street, Changchun 130012, China
Corresponding authors:
E-mail: [email protected]
Telephone number: +86-13756531922
Fax number: +86-43185168270
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Supporting Information
(1) The measurement of water vapor transmission rate:
Ca is a conductive metal, which has a resistance against an applied voltage. The
resistance of the Ca film is inversely proportional to the amount of average decreasing
Ca height if a constant voltage is applied because Ca-oxide serves as an insulator. The
reaction equations are as follows:
2Ca + O2→2CaO;
Ca + H2O →CaO+H2;
CaO +H2O→Ca(OH)2.
Using this properties, we can derive the water vapor transmission rate (WVTR)
though Calcium testing method, which though measuring the I-V curve of
encapsulation Ca film exposure in the air at equal interval time, getting the film
resistance change rate, input these measuring data into the following formula to
calculate the WVTR:
WVTR[ g / m 2 / day ] = −n × δ Ca × ρCa ×
d 1 M ( H 2O )
Ca _ Area
( )×
×
dt R
M (Ca ) Window _ Area
Here, n as the mole ratio of chemical reaction, the value is 2; The Ca resistivity δ Ca
is 3.91×10-8Ω.·m; The density ρ Ca of Ca is 1.55g/cm3; 1 / R is the resistivity from
the I-V curve measurement; The M (H2O) and M(Ca) are 18 g/mol and 40 g/mol,
which are the molar mass of the Ca and water, respectively. The structure of Ca test
system was shown in Figure S1.
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Figure S1. The schematic diagram of water permeation measurements system
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(2) The atomic force microscopy images
Figure S2. The AFM images of ALD- Al2O3 films deposited on the Si substrate: (a)
80℃-H2O based Al2O3; (b) 140℃-H2O based Al2O3; (c) 200℃-H2O based Al2O3; (d)
80℃-O3 based Al2O3.
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(3) Side leakage effect for encapsulation
Figure S3. Ca corrosion test device with glass-cap encapsulation. Common side
leakage phenomenon with traditional cap encapsulation, which using polymer as
adhesive to glue glass cap and substrate together, was observed.
Figure S4. Ca corrosion test device with ALD- Al2O3 thin-film encapsulation.
Compare with glass-cap encapsulation, TFE shows a direct surface corrosion. The
electronic resistance and optical transmittance of the Ca layer are inversely
proportional to the amount of average decreasing Ca height. This demonstrate that the
side leakage was ignorable during TFE measurements process.
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(4) Optical microscope images of OLEDs with TFE protection after harsh
environment storing
Figure S5. The optical microscope images of various TFE on the OLEDs, took photos
after storing 200 hous in the climate chamber under 60 ℃, 90% RH conditions: (a)
Bare OLEDs; (b) 20nm-thick 80℃-H2O based Al2O3; (c) 60 nm-thick 80℃-H2O
based Al2O3; (d) 60nm-thick 80℃-O3 based Al2O3.
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