Organic functionalization of silicon surfaces – from mechanisms to multilayers

Title

Organic functionalization of silicon surfaces – from mechanisms to multilayers

Speaker

Prof. Michael Dürr (Institute of Applied Physics, Justus Liebig University Giessen, Germany)

Host

Prof. Kai Huang (GTIIT, Chemistry)

Time and Location

Jul. 05 2022, Tuesday, 4:00pm-5:00pm(China Time),  E211 (Education Building, 2nd floor)

Language

English

Zoom Link

https://gtiit.zoom.us/j/94609938903

Abstract

The adsorption of organic molecules on silicon has been the subject of intense research due to the potential applications of organic functionalization of silicon surfaces. The high reactivity of the silicon dangling bonds towards almost all organic functional groups, however, presents a major hindrance for the first basic reaction step of such a functionalization, i.e., chemoselective attachment of bifunctional organic molecules on the pristine silicon surface. Due to this high reactivity, the final adsorption products typically consist of a mixture of molecules adsorbed via different functional groups. For the preparation of well-ordered organic layers on silicon, it is thus important to learn how to control the reactions of the single functional groups.

Using various spectroscopic techniques, such as XPS, UPS, and nonlinear optics, in combination with scanning tunneling microscopy and molecular beam techniques, we investigated in detail the reaction mechanisms, kinetics, and dynamics of different functional groups on Si(001). We make use of these results in order to control the respective reactions by changing the molecules’ very properties. In particular, our main strategy for the functionalization of Si(001) is then based on substituted cyclooctynes, as cyclooctyne’s strained triple bond is associated with a direct adsorption channel on Si(001), in contrast to almost all other organic molecules, which adsorb via weakly bound intermediates [1]. As a consequence, cyclooctyne derivatives with different functional side groups, such as an ether, ester or terminal alkyne group, react on Si(001) selectively via the strained cyclooctyne triple bond while leaving the side groups intact [1,2]. The latter can thus be used for further reactions, e.g., using click-chemistry, when building-up molecular multilayers on the silicon substrate [3,4]. Electronic excitation [5] and hyperthermal energy distributions of the incoming molecules [6] are investigated as further means of control.

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• Glaser, et al., Chem. Eur. J. 27, 8082 (2021).
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• Mette, et al., Angew. Chemie Int. Ed. 58, 3417 (2019).
• Bohamud, et al., J. Chem. Phys. 154, 124708 (2021).

Biography

Professional Experience

2013-         Professor for Cluster Surface Dynamics and Scanning Tunneling Microscopy, Institute of Applied Physics, Justus Liebig University Giessen, Germany

2006-13    Professor for Surface and Nano Chemistry, Hochschule Esslingen, Germany

2006          Visiting Scientist at Sony Materials Laboratories, Atsugi, Japan

2002-06    Scientist/Senior Scientist at Materials Science Laboratories, Sony Dtl., Stuttgart, Germany

2000-02    Postdoc, Philipps-Universität Marburg, Germany

1999            Visiting Scientist, Physics Department, Columbia University New York, NY, USA

1997-98      Research Assistant, MPI for Quantum Optics, Garching, Germany

University Education

2000           Doctoral degree in Physics, TU München, Dissertation on “Reaction dynamics of hydrogen on silicon surfaces investigated by means of optical second harmonic generation, molecular beam techniques, and scanning tunneling microscopy”

1997             Diploma degree in Physics, TU München

1992-97       Studies in Physics, Universität Stuttgart and Technische Universität (TU) München