Berlin 2018 – scientific programme

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DS: Fachverband Dünne Schichten

DS 17: Poster Session I

DS 17.65: Poster

Tuesday, March 13, 2018, 18:15–20:15, Poster B

Kelvin-Probe Force Microscopy and Conductive-AFM Studies of the Contact Formation with 1-(Pyridin-2-yl)-3-(quinolin-2-yl)imidazo[1,5-a]quinoline in Layered Structures — •Clemens Geis¹, Eric Yanchenko¹, Georg Albrecht¹, Jasmin Martha Herr², and Derck Schlettwein¹ — ¹Institute of Applied Physics, JLU Giessen, Germany — ²Institute of Organic Chemistry, JLU Giessen, Germany

1-(Pyridin-2-yl)-3-(quinolin-2-yl)imidazo[1,5-a]quinoline was investigated as a model compound of a new class of organic semiconductors which receives increased interest for applications in material science, mainly regarding blue organic light emitting diodes (OLED). In order to construct electronic devices, a proper alignment of the energy levels of contact materials and emitters is mandatory for an efficient charge carrier injection. In this work the contact potential differences of emitters, anode and cathode materials are investigated by Kelvin-probe force microscopy (KPFM). A layered sample design allowed to measure all potential differences in a single device. A Fermi level close to the occupied orbitals of the organic layer was determined showing the dominance of hole conduction. Current-voltage characteristics of test devices confirmed appropriate contact formation by current onsets at low voltages. These results are compared to first measurements at 1,3-disubstituted imidazo[1,5-a]pyridines and -quinolines to establish a systematic optimization.