High photoluminescence (PL) efficiencies are desired to increase the brightness and operating lifetimes of organic light-emitting diodes. We present data on the transient PL-decay of PPV-type oligomers composed of 3 to 5 phenylene rings in blends and as pure films. The variation of the PL-decay with temperature, emission energy, and excitation energy is studied, and the changes in lifetime are correlated with the changes in relative efficiency. The results are compared with those of thin films of PPV. In blends the PL-decay is essentially independent of the number of phenylene rings of the oligomer. The temperature dependence of the oligomer blends is smaller than in the case of polymer films. In the oligomer blends, the PL spectrum changes with excitation energy and emission energy, indicating an inhomogeneous distribution of molecular sites.
|Original language||English (US)|
|Journal||International SAMPE Technical Conference|
|State||Published - Dec 1 1995|