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Local surface potential of pi-conjugated nanostructures by Kelvin Probe Force Microscopy: effect of the sampling depth

Andrea Liscio, Vincenzo Palermo, Oliver Fenwick, Slawomir Braun, Klaus Müllen, Mats Fahlman, Franco Cacialli and Paolo Samorì, Weinheim (2011)

Kelvin Probe Force Microscopy (KPFM) is usually applied to map the local surface potential of nanostructured materials at surfaces and interfaces. In this frame, a quantification of the surface sensitivity of KPFM in the study of the electrical properties at the nanoscale is needed. Here we present a versatile 3D-model to provide a quantitative explanation of KPFM results, which takes into account the vertical structure of the sample. The model is tested on nanostructured films obtained from two relevant semiconducting systems for field-effect transistor and solar cell applications, i.e. poly(3-hexylthiophene) (P3HT) and perylene-bisdicarboximide (PDI) These materials have been chosen in view of their different interfacial properties when adsorbed on Au and SiOx substrates. While in the first case, the organicsubstrate interface is usually described as a flat-band condition, in the second one the energetics of PDI film shows band-bending. Our findings are especially important since they enable quantitative determination of the local surface potential of conjugated nanostructures, and thereby pave the way towards optimization of the electronic properties of nanoscale architectures for organic electronic applications.

Partners : UdS, UCL, LiU, MPG

Place of Publication : Weinheim

Date of Publication : 2011/01/31

Additional Data : Volume 7, Issue 5, pages 634–639

Link to the online version of the article.

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