Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 18: Molecular Electronics and Photonics
CPP 18.8: Vortrag
Dienstag, 8. März 2016, 11:30–11:45, H42
Activation of Organometallic Dimers as n-Dopants for a Low Electron Affinity Organic Semiconductor — •Berthold Wegner1, Xin Lin2, Karttikay Moudgil3, Stephen Barlow3, Seth R. Marder3, Antoine Kahn2, and Norbert Koch1 — 1Humboldt-Universität zu Berlin, Germany — 2Princeton University, USA — 3Georgia Institute of Technology, USA
In the past years, several methods were developed to n-dope organic semiconducting materials in order to increase their conductivities. So far, however, these methods were only able to n-dope organic materials with electron affinities (EAs) as low as 4.0 eV. Recently, Guo et al. [1] introduced a new approach using organometallic dimers as air-stable precursors, with which they were able to n-dope several organic materials with EAs ranging down to 2.8 eV. In this work, we investigated the use of ultraviolet (UV) light to activate the n-doping of the low EA (2.4 eV) electron transport material phenyl-dipyrenylphosphine oxide (POPy2) with two different organometallic dimers. Changes in the work function and conductivity of doped POPy2 samples are measured for various doping concentrations using non-invasive contact potential difference and current-voltage measurements in the dark and in ultrahigh vacuum. Within only a few seconds of UV illumination, the conductivity was found to increase over several orders of magnitude and the Fermi level to be pinned at 2.6 eV. While both dimers show the same trends in their general doping behavior, they also differ in some details for which possible reasons are discussed.
[1] Guo et al. Adv. Mater. 24, 699-703 (2012).