Side leakage into the organic interlayer of unstructured hybrid thin-film encapsulation stacks and lifetime implications for roll-to-roll produced organic light-emitting diodes
article
Side leakage experiments have been performed on the organic interlayer, so-called organic coating for planarization (OCP), in a hybrid thin-film encapsulation (TFE) stack based on two silicon nitride (SiN) barrier layers that was developed for organic light-emitting diodes (OLED). To measure the side leakage into OCP, a metallic Ca thin-film monitor can be used. However, the water uptake capacity of the Ca monitor affects the measurements. Here, we eliminated the contribution of the Ca layer from the measurement by variation of the Ca thickness and by measuring the side leakage until it reaches the Ca layer. For OCP with a water getter inside (5% CaO) the side leakage can be monitored by the loss of scattering of the CaO when it reacts with water to Ca(OH)2. This work describes measurements of the rate of side leakage into the OCP layer of the TFE stack, both for plain OCP and for OCP with CaO getter inside. The side leakage curves are used to derive diffusion coefficients. Performing measurements at various climates provides acceleration factors that are relevant for the performance quantification of the TFE stack. The limiting factors on the performance of an unstructured TFE stack as produced in a roll-to-roll (R2R) process are presented. For small OLED devices side leakage would drastically reduce the shelf lifetime but for larger devices the permeation properties of the TFE stack determine the shelf lifetime.
TNO Identifier
788156
ISSN
15661199
Source
Organic Electronics, 53, pp. 256-264.
Publisher
Elsevier
Place of publication
Amsterdam
Pages
256-264
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