Dichroic photo- and electroluminescence of oligo p-(phenylene vinylene) derivatives

The synthesis and characterization of all trans-configured, monodisperse 2-ethylhexyloxy-substituted PV-oligomers (OPVs) are presented. The synthetic route is based on a step-wise synthesis using the Horner-Wadsworth-Emmons reaction. Bright fluorescence of the OPVs makes them suitable for the use in organic light emitting diodes (OLEDs). Due to the anisotropy of shape, the oligomers can be aligned which leads to linear polarized photoluminescence and electroluminescence. Different alignment layers were tested. The best results were achieved by using poly(tetrafluoroethylene) (PTFE) as alignment layer. The pentamer shows dichroic ratios of 17.1 for fluorescence and 8.5 for electroluminescence, respectively.