Regensburg 2010 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Poster: Electronic and Optical Properties of Organic Systems
CPP 12.8: Poster
Montag, 22. März 2010, 16:30–18:00, Poster C
Excited states in hole-transporting polymers for phosphorescent OLEDs — •Bianca Höfer1, Manuel Thesen2, Silvia Janietz2, Hartmut Krüger2, and Anna Köhler1 — 1University of Bayreuth, Experimental Physics II, Bayreuth, Germany — 2Fraunhofer Institute of Applied Polymer Research, Potsdam, Germany
Organic light-emitting diodes (OLEDs) have by now demonstrated efficiencies that enable applications not only for display functions but also for lighting purposes. Current efficient OLEDs are typically fabricated using host-guest-systems. The investigation of excited state formation can help to find ways to suppress efficiency lowering effects like intermolecular excited states. Understanding of the underlying inter- and intra-molecular processes that lead to the formation of excited states can help to optimise host materials. Here we present a comparative spectroscopic study of six hole-transporting materials. These materials consist of a polystyrene backbone with triphenylamine derivatives as pendent side chains. Absorption and photoluminescence measurements as well as time resolved spectroscopy were used to assign emission from singlet, triplet and intermolecular states and determine the transition rates between these states. Furthermore, we discuss the relation between chemical structure and formation of intermolecular states.