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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 28: Poster III

CPP 28.9: Poster

Wednesday, March 20, 2024, 11:30–13:30, Poster C

Film Growth and Work Function of 3-Phenyl-1-(quinoline-2-yl)imidazo[1,5-a]quinoline on Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate and Injection Barriers in a Layered System with Bathocuproine — •Gustav Nolte¹, Pascal Schweitzer¹, Carina Rössiger², Richard Göttlich², and Derck Schlettwein¹ — ¹Institut für Angewandte Physik, Justus-Liebig-Universität Gießen — ²Institut für Organische Chemie, Justus-Liebig-Universität Gießen

3-Phenyl-1-(quinoline-2-yl)-imidazo-[1,5-a]-quinoline (PhCIC) is an organic semiconductor which could be applicable in organic light emitting diodes (OLEDs) as a blue emitter. To assess the potential of its application we prepared thin films of PhCIC on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) by physical vapor deposition and investigated film growth and work function in situ by means of Kelvin probe force microscopy (KPFM). Similarly, the film growth of bathocuproine (BCP) on PhCIC was studied. On PEDOT:PSS, PhCIC showed a Stranski-Krastanov type film growth, with the formation of an interface dipole in the base layer and a notable difference in work function between base layer and islands. In contrast, BCP showed a rather homogeneous film growth on PhCIC, forming a space charge region. The alignment of energy levels in the layered system was inferred, showing a significant hole injection barrier from PEDOT:PSS to PhCIC and a smaller barrier for the injection of electrons from BCP to PhCIC.

Keywords: organic semiconductor; organic light-emitting diode (OLED); Kelvin probe force microscopy (KPFM); contact formation