Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 77: Organic Electronics and Photovoltaics - Transport and Doping

CPP 77.6: Vortrag

Freitag, 16. März 2018, 11:15–11:30, C 243

Band bending in crystalline silicon induced by molecular doped P3HT — •Matthias Zellmeier, Mathias Mews, Dorothee Menzel, Lars Korte, and Jörg Rappich — Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut für Silizium-Photovoltaik, Kekuléstr. 5, 12489 Berlin, Germany

Molecular doping of the organic semiconductor poly-(3-hexylthiophene), P3HT, with the strong molecular acceptor 2,3,5,6-tetrafluorotetracyano-quinodimethane, F4TCNQ, is one of the most common techniques to overcome the restriction of low conductivity in this organic material. The well-established method leads to a decrease of the hole mobility in the low-to-medium doping regime, while the hole density increases linearly with the doping concentration. Additionally, it presents an important prerequisite towards controlling p/n-junctions involving organic materials. Hybrid interfaces combining organic materials and inorganic semiconductors are of special importance as they are crucial for the performance of most applications, e.g. light emitting devices or solar cells. Employing photoelectron spectroscopy, we studied the interface between crystalline silicon, c-Si, and doped P3HT. The doping in the spin coated organic layer was varied from a low doping concentration of 1:1000 F4TCNQ molecules per 3HT monomer units up to 1:3. UPS was used to monitor the development of the HOMO-onset upon doping as well as the work function. A special focus is placed on the shift of the silicon 2p orbital binding energy, which is measured using XPS. The data is used to extract the band bending at the silicon/organic semiconductor junction.