The recent development of polymer light emitting diodes (PLEDs) has trigger
ed a lot of interest for their use in displays, backlights, and for lightin
g applications. Their high efficiency and ease of manufacturing make PLEDs
especially attractive. Various conjugated polymers have been employed, but
especially soluble phenyl-poly-p-phenylene vinylene(s) show excellent prope
rties.
The chemical as well as the structural purity of the polymers has proven to
be essential for high performance, long lifetime PLEDs. Mechanistic invest
igations allowed the identification of one major polymerization defect in P
PVs, the so called tolane-bisbenzyl moiety. This in turn has enabled us to
eliminate the most significant failure mechanism of these PPVs during devic
e operation.
The newly developed polymers are manufactured on an industrial scale. A com
bination of a glass lined 370/560 L vessel cascade allows manufacturing in
kilogram scale quantities while still maintaining high purity levels. A sig
nificant extension of this facility is now in use and ensures availability
of large quantities ready-to-use solution of various light emitting polymer
s with photo-resist type purity. (C) 2001 Published by Elsevier Science B.V
.