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DS: Fachverband Dünne Schichten
DS 9: Organic Thin Films II
DS 9.3: Talk
Monday, March 7, 2016, 15:30–15:45, H11
Investigation of Solution-Processable Electron Injection Layers in Organic Light-Emitting Diodes — •Florian Ullrich1,2,3, Sebastian Stolz1,3, Michael Scherer1, Malte Jesper4, Manuel Hamburger1,4, Gerardo Hernandez-Sosa1,3, and Eric Mankel1,5 — 1InnovationLab GmbH, Heidelberg — 2University of Heidelberg, Kirchhoff-Institute for Physics — 3Karlsruhe Institute of Technology, Light Technology Institute — 4University of Heidelberg, Organisch-Chemisches Institut — 5TU Darmstadt, Material-Wissenschaft, Surface Science
One crucial obstacle for the realization of efficient organic light-emitting diodes (OLEDs) produced by high-throughput printing technologies is the poor injection of electrons since typical low work-function cathode layers like calcium or barium are highly reactive and cannot be solution-processed.
In this work, we investigate alkali metal stearates as solution processable electron injection layers in OLEDs. We fabricated yellow emitting OLEDs with different concentrations of Cs, Rb and K stearate and studied the influence on device performance, e.g. efficiency and efficacy. Values of about 9 cd/A and 10 lm/W were reached equalling the respective values of reference devices. The results were correlated to topography studies using atomic force microscope. The electronic interaction of the alkali metal stearates with the emitting layer and the aluminum top contact was examined by various photoelectron spectroscopy measurements.