Light-emitting diodes based on phenylenevinylene oligomers with defined chain lengths

We present characteristic electroluminescence data on single-layer devices based on three different oligo phenylenevinylene compounds with defined chain lengths. Light-emitting diodes (LEDs) were prepared by subsequent vacuum evaporation of the oligomer film and the A1 top electrode onto an indium—tin oxide (ITO) substrate. The LEDs show light emission in the spectral range of yellow to orange depending on the conjugation length of the compound used. We report photoluminescence and optical absorption data of the thin sublimed films, together with the wavelength dependence of the electroluminescence and with the current—voltage characteristics of the LED devices. The redox behavior and, thus, the pertinent electronic energy levels of the phenylenevinylene oligomers were characterized using cyclic voltammetry. The experimental data can be interpreted within a consistent model description.