Contrast Formation in Kelvin Probe Force Microscopy of Single π-Conjugated Molecules

Schuler, Bruno; Liu, Shi-Xia; Geng, Yan; Decurtins, Silvio; Meyer, Gerhard; Gross, Leo (2014). Contrast Formation in Kelvin Probe Force Microscopy of Single π-Conjugated Molecules. Nano letters, 14(6), pp. 3342-3346. American Chemical Society 10.1021/nl500805x

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We report the contrast formation in the local contact potential difference (LCPD) measured by Kelvin probe force microscopy (KPFM) on single charge-transfer complexes (CTCs) on a NaCl bilayer on Cu(111). At different tip heights, we found quantitatively different LCPD contrasts that characterize different properties of the molecule. In the small distance regime, the tip penetrates the electron density of the molecule, and the contrast is related to the size and topography of the electron shell of the molecule. For larger distances, the LCPD contrast corresponds to the electrostatic field above the molecule. However, in the medium-distance regime, that is, for tip heights similar to the size of the molecule, the nonspherical distribution of π- and σ-electrons often conceals the effect of the partial charges within the molecule. Only for large distances does the LCPD map converge toward the simple field of a dipole for a polar molecule.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Departement of Chemistry and Biochemistry

UniBE Contributor:

Liu, Shi-Xia; Geng, Yan; Decurtins, Silvio and Meyer, Gerhard

Subjects:

500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry

ISSN:

1530-6984

Publisher:

American Chemical Society

Language:

English

Submitter:

Silvio Decurtins

Date Deposited:

25 Mar 2015 14:15

Last Modified:

26 Aug 2015 13:20

Publisher DOI:

10.1021/nl500805x

BORIS DOI:

10.7892/boris.65754

URI:

https://boris.unibe.ch/id/eprint/65754

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