Abstract
Organic light-emitting devices exhibiting high power conversion efficiency
and long operating lifetime may potentially be achieved with the polymer light-emitting
electrochemical cell (LEC) configuration. An LEC device typically uses a thin
layer of conjugated polymer sandwiched between two contact electrodes. The
polymer layer contains an ionically conductive species that are essential
in the formation of a light-emitting p-i-n junction. LEC devices are characterized
with balanced electron and hole injections, high current density at relatively
low bias voltages (2–4 V), and high electroluminescent power efficiency.
We will describe the working mechanism of the LECs and review the recent developments
in LEC materials, device fabrication and performance. Among the important
developments are planar (surface-typed) LECs, bilayer LECs that emit different
colors at forward and reverse biases, frozen p-i-n junction LECs that functions
like diodes, and phosphorescent LECs. Extensive efforts have been made to
improve the LEC performance by controlling the blend morphology, including
the use of bipolar surfactant additives and new electrolytes, the synthesis
of conjugated polymers with ion-transporting main chain segments or side groups
and polyelectrolyte. Degradation mechanisms that limit the lifetime of the
LECs will also be discussed.
© 2007 IEEE
PDF Article
More Like This
Cited By
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
Contact your librarian or system administrator
or
Login to access Optica Member Subscription