Project

Discipline

Molecular electronics; Molecular wires; Electronic devices; Organometallic materials; Organic materials

Lead
Lay summary
Functional organic and organometallic materials for molecular electronic applications A promising strategy towards technology at the nanometer scale is offered by a bottom-up approach, which starts from atoms or molecules and builds up nanostructures. The integration of transition metal atoms opens potential applications in molecular electronics, particularly due to the fact that metals can promote charge transport. Background Organometallic complexes with integrated transition metals having two different electronic states have the potential to be applied as memory elements. Upon removing an electron from the molecule, by applying high voltage, the molecule is oxidized and the conduction state is switched on (write process). Once the applied voltage is removed, the molecule retains its oxidized state (memory). Upon applying the reversed voltage, the molecule returns to its original oxidation state (erase process). Probing the conduction states of molecules by applying low voltage is a reading process. However, the abilities of organometallic complexes at the single molecular level have not yet been thoroughly explored. Aim Correlation of the molecular structure and electronic properties will be studied. The project aims at a detailed understanding and exploitation of the internal molecular mechanisms and processes, which can be used for radically new approaches in future nanoscale electronic devices. Significance The knowledge gained within this project is a prerequisite for the future use of small ensembles or even individual molecules as functional building blocks in electronic circuitry. Single-molecule devices are ideal candidates for future nano-electronics, as they possess the potential for creating high-density devices with low-power consumption in combination with high speed. Application The molecular materials in the current project are designed to allow the testing of these materials for electronic applications. The development of new smart materials that are able to switch by a voltage trigger between at least two states should lead to memory applications. Molecular devices taking advantage of self-assembly processes will also have low manufacturing costs. Moreover, because of their internal molecular structure, molecules may provide radically new and intrinsic functionalities not found in today’s conventional semiconductor-based electronics.

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Last update: 21.02.2013

Active participation

Active participation

Title	Year

This proposal aims at the design and development of novel organic and organometallic-based molecular wires for potential applications in molecular electronics utilizing a bottom-up approach. Synthesis and characterization of an elaborate array of rigid-rod wires based on manganese (Mn), rhenium (Re), Iron (Fe) and tungsten (W) with careful selection of appropriate conjugated organic bridges would be part of this work that would establish the transition metal and the bridge influence on the electronic properties of these molecular wires. These studies would help to make the right choice of the metal and the bridge in these rigid-rod wires for applications, which has been quite lacking in this field up to now. These molecules will be post-functionalized with sulfur end groups such these molecules can be attached on gold surfaces and further incorporate them into devices. In addition these new materials with interesting technological applications will not only be synthesized but also will be characterized by state of the art techniques that include structural determination, AFM/STM microscopies, magnetic measurements (dc and ac magnetic susceptibility), transport measurements (single molecule conduction) and other spectroscopic methods. IBM ZRL will characterize the electrical conductance of individual molecules and small ensembles of molecules using the mechanically controllable break-junction (MCBJ) technique. In this approach, the distance between two electrodes can be mechanically controlled with picometer resolution to adapt to the length of a single molecule, which can be captured in between. Using molecules with appropriate anchor groups (e.g. thiols), the MCBJ method allows for a reliable and durable chemical contact at both ends of the molecule to mimic the simplest two terminal device geometry. Systematic measurements and statistic analysis reveal the correlation between the molecular structure and electrical functionality of the molecule.