Regensburg 2004 – wissenschaftliches Programm
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SYOH: Organic and Hybrid Systems for Future Electronics
SYOH 5: Poster
SYOH 5.80: Poster
Donnerstag, 11. März 2004, 18:00–21:00, B
Polymer light-emitting diodes containing dendronized emitters — •Frank Jaiser1, Xiaohui Yang1, Dieter Neher1, Jianqiang Qu2, and Klaus Müllen2 — 1Universität Potsdam, Institut für Physik, Am Neuen Palais 10, 14469 Potsdam — 2Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz
One approach to the construction of efficient polymer light-emitting diodes is to dope well-defined emitting dyes into a suitable polymer hosts. Such dopants can improve LED efficiency by either influencing charge carrier transport in the material or being a highly-emissive species in the system. In this respect, various fluorescent and phosphorescent dyes have been studied in the past. In fact, both types of dyes have been used to tune the emission color through the visible spectrum.
The understanding of excitation transfer between host and guest molecules is crucial for the construction of efficient LEDs. Possible transfer routes are Förster and Dexter transfer or charge trapping on the guest molecules. Depending on the spatial distance between guest and host molecules, the different possible transfer mechanisms show vastly different transfer rates. Dendronization of small molecules is an elegant way to control this intermolecular distance without changing the electronic structure of the emitting core. We have studied polymers doped with different generations of perylene dendrimers. We found that dendronization does not help to suppress luminescence quenching in thin films but decreases the probability of direct charge trapping on the dye.