Highly Efficient Polymeric Electrophosphorescent Diodes


  • This work was supported by the Bundesminsterium für Bildung und Forschung (BMBF, Germany) through grant 13N8213. We acknowledge experimental support by N. Riegel, A. Köhnen, Dr. R. Alle, and P. Zacharias from the University of Cologne. We also express our thanks to Prof. O. Nuyken (TU Munich, Germany) and his group for fruitful discussions.


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Polymeric electrophosphorescent LEDs with internal quantum efficiencies approaching unity have been fabricated. Such performance levels are previously unknown for OLEDs. The key to this success is redox chemically doped oxetane-crosslinkable hole-transporting layers with multilayer capability (see figure). They improve hole injection and act as electron-blocking layers, without the need to include exciton- or hole-blocking layers.