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P‐49: Dependence of Dark Spot Growth on Electrical Stressing Voltage in OLED Devices
Author(s) -
Lin Karen Ke,
Chua Soo Jin,
Lim Shuang Fang
Publication year - 2001
Publication title -
sid symposium digest of technical papers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.351
H-Index - 44
eISSN - 2168-0159
pISSN - 0097-966X
DOI - 10.1889/1.1831969
Subject(s) - materials science , dark field microscopy , optoelectronics , voltage , cathode , layer (electronics) , dark current , delamination (geology) , nanotechnology , chemistry , electrical engineering , optics , microscopy , physics , paleontology , subduction , biology , tectonics , engineering , photodetector
The formation of dark spot in OLED devices has long been identified as pinholes on the protective layer that creates pathways for water or oxygen permeation and causes the cathode delamination and chemical change. In this work, we demonstrate that using micro‐sized silica particles to create uniform sized defects on protective layer is an efficient way of controlling the location and the number of dark spots. The dark spot growth was then studied at different driving voltage in the range from turn on voltage to about 11V, dark field microscopy was used to observe dark spot growth behaviour when device is driven lower than turn on voltage. Our observations indicate that the growth was strongly affected by the electrical stressing voltage. In other words, the chemical and physical changes reflected by the growth are speeded up with the increasing driving voltage. We discuss possible mechanisms for these degradation processes also.