Dresden 2009 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 40: POSTERS Electronic and Optical Properties

CPP 40.12: Poster

Donnerstag, 26. März 2009, 17:00–19:30, P3

Charge Trapping and Color Stability in a White-Emitting Copolymer — •Sebastian Bange and Dieter Neher — Universität Potsdam, Institut für Physik und Astronomie, Karl-Liebknecht-Str. 24–25, 14476 Potsdam-Golm, Germany

Organic white light-emitting devices are of considerable interest as a technology capable of providing low-cost, potentially highly efficient lighting. Precise control over the emission color is especially difficult for polymeric devices, where several chromophores compete for excitations within a single active layer.

We investigate the role of charge trapping for the emission color of polymeric light-emitting devices comprising a copolymer based on polyspirofluorene with additional hole transporting units and blue, green and red singlet emitting moieties. Strong influence of drive parameters on the emission spectrum are observed and explained by an analytic model accounting for charge trapping on the red dye. Contrary to purely kinetic arguments[1], this model allows to understand the effects of electrode modifications and provides insight into interface conditioning effects[2] during operation.

[1] Gather et al., Advanced Materials 19, 4460 (2007)

[2] Bange et al., Journal of Applied Physics 104, 104506 (2008)