Talk given by Dr. Michal Valášek Institute of Nanotechnology, KIT Abstract: Further miniaturization of electronic devices remains an enormous technological challenge but conventional silicon based technology will soon reach a limit. Molecular electronic can help to overcome the technical hurdles and physical limits of silicon devices. Since Aviram and Ratner theoretically proposed the original idea about molecular rectifier in 1974 to predict the feasibility of constructing a functional molecular device using single molecules as active components, the field of molecular electronics has attracted significant interest. The aim of molecular electronics is appealing for at least two reasons. The first is the ultimately small size of molecules and possible lower costs of a molecular circuit element. The second advantage of using molecular components is that molecules can be designed and tailor-made to provide a range of interesting functions of devices with tunable properties. The ultimate goal of molecular electronics is to use assembly of molecules or even single molecule as functional building blocks and to integrate them into electric circuit between electrodes. Realization of a practical single-molecule device requires reliable contact between the bridging molecule and the electrodes, where sufficiently strong binding between two terminal anchoring groups of the bridging molecule and the metal electrode is achieved. In this talk, I will firstly focus on the multipodal platforms based on 9,9′-spirobifluorene and tetraphenylmethane scaffolds that form rigid and well-defined contact to the gold surfaces. Several molecular platforms have been synthetized and further studied. The self-assembly features of the target compound were analyzed in UHV-STM experiments to corroborate the promising potential of the concept of the tripodal structure to stabilize the molecule on metal surfaces in order to control the spatial arrangement of the protruding molecular subunits (e.g. molecular wires, switches) with respect to the substrate´s surface. The charge transport measurements through the conjugated tripodal platforms using MCBJ and STM-BJ techniques will be also discussed. In the second part of my talk I will present our results dealing with molecular switches based on azobenzenes in order to study self-assembly and surface behavior of these molecules upon photoisomerization on gold and graphene surfaces. Furthermore, several azobenzenes bearing ethoxy(dimethylsilane) termini for the immobilization on a Si/SiO2 substrate have been prepared in order to optically switch the doping level of the conjugated materials, in particular for n-type semiconductors. At the end, I will briefly talk about our attempts to investigate a behavior of the covalently immobilized functional molecules in a graphene and/or CNTs based junctions as well as about recent results in the sorting of SWCNTs via polymer wrapping and particularly focus on varying of solubilizing alkyl chains, aromatic backbone structures and a weak bonding between each subunits of copolymers to selectively disperse semiconducting and metallic SWCNTs.

This event is part of the eventgroup INT Talks

Homepage
https://www.int.kit.edu/events.php

Speaker
Dr. Michal Valášek

Institut of Nanotechnology, KIT
http://www.int.kit.edu/staff_684.php

Organizer
Prof. Dr. Marcel Mayor
Institut für Nanotechnologie
KIT
Hermann-von-Helmholtz-Platz 1
76344 Eggenstein-Leopoldshafen
Mail: marcel mayor ∂does-not-exist.kit edu
https://www.int.kit.edu/staff_marcel.mayor.php

Targetgroup
Interested / Everyone