Michael Schär

 

PhD Student

Location:

HCI G-322

Phone:

+41-1-632 4515

e-mail:

Michael Schär

Education

2000-2004:

Study of chemistry at ETH Zurich

2004:

2004 Diploma Thesis with Prof. F. Diederich at ETH Zurich

2005:

Assistantships in Organic Chemistry and Material Sciences at ETH Zurich

since 2006:

PhD with Prof. F. Diederich at ETH Zurich

Bottom-up Nanodevices by Hierarchical Self-assembly on Surfaces

Since the invention of STM (1981) and AFM (1986), by which particles and surfaces in the nanoscale world could be visualized and even manipulated, nanotechnology and nanoscience emerged and experienced a strong boom – it became one of the most important research areas.

In the contest of miniaturization of devices, in particular electronic integrated circuits and sensoric units, the microelectronic industry will reach soon certain limits applying the contemporary techniques. In comparison with the “top-down” strategy of the microelectronic industry, the “bottom-up” approach using hierarchical self-assembly shows several advantages in the construction of functional materials and nanoscale devices. Even though an ever increasing pool of self-assembled architectures in solution and through crystal engineering is known to the scientific community, these structures suffer from the impossibility to selectively locate, address and manipulate individual molecules. Immobilization of (sub)monolayers of molecules on surfaces (Ag, Au, Cu, Si, graphite) proved to be a viable solution, which includes the opportunity of mechanical manipulation, for example by a STM-tip. In order to place functional molecules in a defined long-range order in an addressable manner to generate nanodevices, a templating network featuring pores with defined size would be of interest. In last years much effort was made by creating two-dimensional networks with a defined pore geometry and size.


Fig. 1: The laboratory of the Diederich group recently created a porphyrin-based porous network, which was successfully tested as host for C60 on a Ag(111) surface.

Using hierarchical self-assembly, the hosting properties of these networks were tested by additional deposition of simple guests, in particular the research group of Prof. Diederich recently demonstrated the possibility to selectively address and relocate fullerene guests onto a porphyrinic network.

The first self-assembled two-component two-dimensional nanoporous network from multiple hydrogen-bonding building blocks was recently presented by Beton and coworkers. Moreover they reported stable and ordered incorporation of guest-aggregates (C60, C84) into the pores of the hexagonal network, which was created from both an angular unit and a linear linker building block. Expanding this concept, in the present Ph. D. project we plan to synthesize a library of differently shaped angular units and linear linkers.


Deposition of a functional molecule as guest onto these self-assembled two-dimensional networks should lead to incorporation of the guest into the pores, which ultimately should give rise to potential nanodevices.

This Ph. D. work is an important part of the project “PRAIRIES” which is supported by a grant from the EU Marie Curie RTN and by the NCCR (University of Basel). (PRAIRIES = SuPRAmolecular hIeraRchIcal self-assembly of organic molecules onto surfaces towards bottom-up nanodevicES). The project “PRAIRIES” involves a consortium of seven countries across Europe – namely six universities (UTS, ISIS, HAS, UCHA, UBA, UCLM), two national research institutes (ETH, ISOF) and BASF as industrial partner. Imaginable future applications of these nanodevices reach from electronic conductors and insulators, organic light emitting diodes, displays (LCD-displays) to information storage cells, sensoric units (chemical and biological) and light energy conversion devices.

Publications

S. Sergeyev, M. Schär, P. Seiler, O. Lukoyanova, L. Echegoyen, F. Diederich, Chem. Eur. J. 2005, 11, 2284-2294.

F. Hof, M. Schär, D. M. Scofield, F. Fischer, F. Diederich, S. Sergeyev, Helv. Chim.Acta 2005, 88, 2333-2344.

Last update: Oct. 2006