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Scannning Tunneling Microscopy Based on Chemically Modified Tips

Research Project

Project/Area Number 10554044
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section展開研究
Research Field 分離・精製・検出法
Research InstitutionThe University of Tokyo

Principal Investigator

UMEZAWA Yoshio  The University of Tokyo, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (80011724)

Co-Investigator(Kenkyū-buntansha) BUHLMANN Philippe  The University of Tokyo, Graduate School of Science, Assistant, 大学院・理学系研究科, 助手 (20262149)
SUGAWARA Masao  Nihon University, Collage of Humanities and Sciences, Professor, 文理学部, 教授 (50002176)
Project Period (FY) 1998 – 1999
Project Status Completed (Fiscal Year 1999)
Budget Amount *help
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1999: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywordschemical force microscopy / scanning tunneling microscopy / chemically modified tips / chemical nanosensor / self-assembled monolayer(SAM) / polypyrrole / porphyrin / surface analysis / 化学力顕微鏡(CFM) / ポルフィリン
Research Abstract

Monolayers of-mono-and diethers were studied with scanning tunneling microscopy (STM) as a new example for the chemical modification of STM tips for functional groups recognition. Bright lines revealing the positions of the ether oxygens of the monolayers were observed in STM images with tips modified with 4-mercaptobenzoic acid (4MBA) which can form hydrogen bond with ether oxygens. Such bright lines, however, were absent with unmodified tips or tips modified with thiophenol, which has no functional groups available for hydrogen bond formation. In the STM images of diethers, the brightness of the ether oxygens observed with 4MBA-modified tips was modulated depending upon the orientation of the ether oxygens. These results support that selective contrast enhancements are associated with hydrogen bond formation between sample and tip. It is demonstrated that chemical modification of STM tips allows not only selective recognition but also orientation-sensitive observation of functional groups.
Chemical modification of scanning tunneling microscopy (STM) gold tips with 4-mercaptopyridine (4MP) was used for STM measurements of 5,15-bis(4-octadecyloxyphenyl) porphyrin (Por-H2) and its zinc(II) (Por-Zn) and nickel(II) complexes (Por-Ni). Monolayers of these compounds spontaneously form at the solution-HOPG (highly oriented pyrolytic graphite) interface. STM images of porphyrin centers measured with 4MP-modified tips exhibited bright spots while those measured with unmodified tips exhibited the porphyrin centers as dark depressions. The brightness of porphyrin centers seems to result from facilitated electron tunneling due to hydrogen bond interactions for Por-H2 and due to coordination interaction for Por-Zn and Por-Ni. Interestingly, the centers of Por-Zn were brighter than those of Por-H2 and Por-Ni. In addition, STM measurements with 4MP-modified tips allowed to distinguish Por-Zn from Por-H2 or Por-Ni in mixed monolayers.

Report

(3 results)
  • 1999 Annual Research Report   Final Research Report Summary
  • 1998 Annual Research Report
  • Research Products

    (7 results)

All Other

All Publications (7 results)

  • [Publications] Takashi Ito: "Polypyrrole-Modified Tips for Functional Group Recognition in Scanning Tunneling Microscopy"Anal. Chem.. 77・9. 1699-1705 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Ito, T.; Buhlmann, P.; Umezawa, Y.: "Polypyrrole-Modified Tips for Functional Group Recognition in Scanning Tunneling Microscopy"Anal.Chem.. 71. 1699-1705 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] Takashi Ito: "Polypyrrole-Modified Tips for Functional Group Recognition in Scanning Tunneling Microscopy"Anal.Chem.. 71・9. 1699-1705 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] Takashi Ito: "Observation of Silver and Hydrogen Ion Binding to Self-Assembled Monolayers with Chemically Modified AFM Tips"Langmuir. 15・8. 2788-2793 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] Takashi Ito: "Polypyrrole-Modified Tips for Functional Group Recognition in Scanning Tunneling Microscopy." Anal.Chem. (in press).

    • Related Report
      1998 Annual Research Report
  • [Publications] Takashi Ito: "Observation of Silver and Hydrogen lon Binding to Self-Assembled Monolayers with Chemically Modified AFM Tips." Langmoir. (in press).

    • Related Report
      1998 Annual Research Report
  • [Publications] Takashi Ito: "Scanning Tunneling Microscopy Using Chemically Modified Tips." Analytical Chemistry. 10・2. 255-259 (1998)

    • Related Report
      1998 Annual Research Report

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Published: 1999-04-01   Modified: 2021-04-07  

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