Regensburg 2010 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 27: Poster: Organic Electronics and Photovoltaics

CPP 27.22: Poster

Wednesday, March 24, 2010, 17:30–19:00, Poster C

Band bending at interfaces between polymers and electrodes — •Ilja Lange — Universität Potsdam, Institut für Physik und Astronomie, Karl-Liebknecht-Strasse 24/25, 14476 Potsdam-Golm

There is an ongoing discussion on whether bend bending is present in organic semiconductors near metallic contacts and how it affects device properties. Here, we present Kelvin Probe studies on various polymers coated with different thickness on the well known polymeric anode poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). Band bending was detected for poly(3-hexylthiophene) (P3HT), poly{3-hexylthiophene-co-[1,4-(2,2-dithienyl)-5,5-2,3,5,6-tetrafluorbenzene]} (P3HTTFT), poly[2,5-dimethoxy-1,4-phenylene-1,2-ethenylene-2-methoxy-5-(2-ethylhexyloxy)-(1,4-phenylene-1,2-ethenylene)] (M3EH-PPV) and poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV). The experimental results can be well fitted with a model that explicitly takes into account a Gaussian density of transport sites [1]. This analysis is based on iterative numerical solution of the carrier density according to Fermi statistics and the one-dimensional Poisson equation. By comparing these results with measurements on films of the same materials on different metals, a consistent picture of bend bending in conjugated polymers is developed.

[1] J.C. Blakesley and N.C. Greenham, J. Appl. Phys. 106, 034507 (2009)