Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 50: Organic semiconductors: Transistors and OLEDs (with CPP/DS)
HL 50.6: Vortrag
Dienstag, 1. April 2014, 15:15–15:30, POT 081
IR spectroscopic investigation of charge transfer in organic semiconductors I: Doped layers — •Tobias Glaser1,2, Sebastian Beck1,2, David Gerbert1,2, Johannes Zimmermann1,2, and Annemarie Pucci1,2,3 — 1Kirchhoff-Institut für Physik, Universität Heidelberg — 2InnovationLab GmbH, Heidelberg — 3Centre for Advanced Materials, Universität Heidelberg
Electrochemical doping of amorphous organic semiconductors is a frequently used technique in order to increase the amount of free charge carriers and thereby the conductivity of the doped layers. But for organic semiconductors, in general very low doping efficiencies in the range of only a few percent have been reported.
We performed infrared (IR) spectroscopy under ultrahigh vacuum conditions in order to investigate the process of charge transfer in various p-doped material systems. The charge transfer in doped layers can be determined with IR spectroscopy, as the new electronic structure of the charged molecules leads to a change in bond length and bond strength within the charged molecules that therefore exhibit a different vibrational spectrum compared to the neutral molecules. The appearance of broad electronic excitations in these systems shows the formation of new electronic states due to hybridization. We investigated the behavior of these electronic states after annealing as well as after degradation of the doped layers.
Financial support from the BMBF via the MESOMERIE Project (FKZ 13N10724) is gratefully acknowledged.