TY - JOUR
T1 - Degradation of nonencapsulated polymer-based light-emitting diodes
T2 - Noise and morphology
AU - Savvate'ev, Vadim N.
AU - Yakimov, Aharon V.
AU - Davidov, Dan
AU - Pogreb, Roman M.
AU - Neumann, Ronny
AU - Avny, Yair
PY - 1997/12/8
Y1 - 1997/12/8
N2 - We show that the degradation of a nonencapsulated polymer-based light-emitting diode (LED) is accompanied by the appearance of strong fluctuations, - that is noise both in the radiance and in the film resistance. We demonstrate a correlation between the morphological changes which occur during the degradation process and the noise, suggesting that the sampling of noise during LED operation can be used as a very efficient tool to predict the approaching failure of LEDs in real-life applications. The morphological changes in LED degradation are essentially a two-stage process. First, there is formation of "bubbles" at the metal-polymer interface due to delamination of the polymer film from the metal surface. Second, carbonized areas in the form of "black spots" are formed. Accumulation of carbonized areas leads to short and/or open circuits and final LED failure.
AB - We show that the degradation of a nonencapsulated polymer-based light-emitting diode (LED) is accompanied by the appearance of strong fluctuations, - that is noise both in the radiance and in the film resistance. We demonstrate a correlation between the morphological changes which occur during the degradation process and the noise, suggesting that the sampling of noise during LED operation can be used as a very efficient tool to predict the approaching failure of LEDs in real-life applications. The morphological changes in LED degradation are essentially a two-stage process. First, there is formation of "bubbles" at the metal-polymer interface due to delamination of the polymer film from the metal surface. Second, carbonized areas in the form of "black spots" are formed. Accumulation of carbonized areas leads to short and/or open circuits and final LED failure.
UR - http://www.scopus.com/inward/record.url?scp=0031560335&partnerID=8YFLogxK
U2 - 10.1063/1.120332
DO - 10.1063/1.120332
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AN - SCOPUS:0031560335
SN - 0003-6951
VL - 71
SP - 3344
EP - 3346
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 23
ER -