Optical properties and photoexcitations of an organic blue emitter embedded in a polymeric active matrix

The doping of a widely used active polymeric matrix, the polyvinyl
carbazole (PVK) with a novel organic blue emitter has been studied by both
continuous wave and time resolved photoluminescence spectroscopy. It is
found that the overall emission efficiency of the blend is controlled by
two processes, the resonant transfer from the donor to the acceptor and
the hopping between the donor sites. Because of the observed spectral
variations of the emission spectrum of PVK (donor) with the temperature,
both processes exhibit a strong, albeit opposite temperature dependence.
The existence of the hopping process accounts for the sharp increase of
the transfer efficiency with the concentration, not predicted by the
Foerster theory.