Dresden 2006 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 23: POSTER Functional Organic Thin Films
CPP 23.31: Poster
Thursday, March 30, 2006, 17:00–19:00, P2
Efficient polymer electrophosphorescent devices with interfacial layers — •Xiaohui Yang1, Frank Jaiser1, Burkhard Stiller 1, Dieter Neher1, Frank Galbrecht2, and Ulli Scherf2 — 1Universität Potsdam,Am Neuen Palais 10, 14469 Potsdam — 2Bergische Universität Wuppertal, Fachbereich Chemie, Makromolekulare Chemie,Gaußstr. 20, 42097 Wuppertal
We show that several large band-gap hole-transporting polymers can form insoluble interfacial layers on PEDOT:PSS. The thickness of the interlayer is dependent of the characteristics of underlying PEDOT:PSS and the molecular weight of the polymers. It is further shown that the electronic structures of the interlayer polymers have a significant effect on the properties of red-emitting polymer-based electrophosphorescent devices. Upon increasing the HOMO and LUMO level positions, a significant increase in current density and in device efficiency was observed. This is attributed to the efficient blocking of electrons in combination with the direct injection of holes from the interlayer to the triplet dye. Upon proper choice of the interlayer polymer, efficient polymer deep-red electrophosphorescent devices with a peak luminance efficiency of 5.5 cd/A (external quantum efficiency = 6 %) and a maximum power conversion efficiency of 5 lm/W could be realized.