Correlation between dark spot growth and pinhole size in organic light-emitting diodes
- 9 April 2001
- journal article
- conference paper
- Published by AIP Publishing in Applied Physics Letters
- Vol. 78 (15) , 2116-2118
- https://doi.org/10.1063/1.1364658
Abstract
Our in situ experimental observations of dark spot growth in organic light-emitting diodes using optical microscopy show a linear rate of growth for the area of all the dark spots. We used uniformly sized silica micro particles to intentionally create size-controllable pinholes on the cathode protective layer. Subsequently, we observed initial formation of dark spots as a result of these pinholes and then monitored their growth. Due to usage of particles of various diameters, we were able to linearly correlate the growth rate with pinhole size. This allows us to estimate the original pinhole sizes that gave rise to the dark spots, which we believe were initiated by “dust” particles. Our studies verify that dark spot formation is due to pinholes on the protective layer that creates pathways for water or oxygen permeation, and that dark spot growth is dependent on the pinhole sizes.Keywords
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