Polypyrrole-modified tips for functional group recognition in scanning tunneling microscopy

Takashi Ito, Philippe Bühlmann, Yoshio Umezawa

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

Tailored chemical modification of scanning tunneling microscopy (STM) tips is a promising method for the recognition of specific chemical species and functional groups in STM images. The present study shows for the first time that tips modified with polypyrrole can be used to measure STM images with molecular resolution. A high conductivity of the polypyrrole film was found to be important for the observation of STM images, while the thickness of the polymer film did not affect the images significantly. Furthermore, it was shown that recognition of functional groups in STM images is possible with tips coated with conductive polypyrroles. 1-Octadecanol and 1- octadecanoic acid monolayers with polypyrrole-modified tips gave high- resolution STM images in which aligned OH and COOH residues were represented by easily recognizable elevated bands. These selective contrast enhancements resemble those observed by us previously with gold tips modified with self- assembled monolayers (SAMs) and seem to be due to hydrogen bond interactions between functional groups of the tip-modifying molecules and the sample. The reproducibility of contrast enhancements in this study was significantly higher than for SAM-modified tips, suggesting that polymer modification of STM tips is particularly promising for specific functional group recognition with chemically modified STM tips.

Original languageEnglish (US)
Pages (from-to)1699-1705
Number of pages7
JournalAnalytical chemistry
Volume71
Issue number9
DOIs
StatePublished - May 1 1999
Externally publishedYes

Fingerprint Dive into the research topics of 'Polypyrrole-modified tips for functional group recognition in scanning tunneling microscopy'. Together they form a unique fingerprint.

  • Cite this