uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Identification of vibrational signatures from short chains of interlinked molecule-nanoparticle junctions obtained by inelastic electron tunnelling spectroscopy
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. (Electron Microscopy and Nanoengineering)
Show others and affiliations
2013 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 5, no 11, 4673-4677 p.Article in journal (Refereed) Published
Abstract [en]

Short chains containing a series of metal- molecule-nanoparticle nanojunctions are a nano-materials system with the potential to give electrical signatures close to those from single molecule experiments while enabling to build portable devices on a chip. Inelastic electron tunnelling spectroscopy (IETS) measurements provide one of the most characteristic electrical signals of single and few molecules. In interlinked molecule-nanoparticle (NP) chains containing of typically 5-7 molecules in a chain, the spectrum is expected to be a superposition of the vibrational signature of individual molecules. We have established a stable and reproducible molecule-AuNP multi-junction by placing few 1,8-octanedithiol (ODT) molecules into a versatile and portable nanoparticle-nanoelectrode platform and measured for the first time vibrational molecular signatures complex and coupled few-molecule-NP junctions. From quantum transport calculations, we model the IETS spectra and identify vibrational modes as well as the number of molecules contributing to the electron transport in the measured spectra.

Place, publisher, year, edition, pages
2013. Vol. 5, no 11, 4673-4677 p.
National Category
Condensed Matter Physics Engineering and Technology
Research subject
Engineering Science with specialization in Materials Science
URN: urn:nbn:se:uu:diva-198704DOI: 10.1039/C3NR00505DISI: 000319008700011OAI: oai:DiVA.org:uu-198704DiVA: diva2:617493
Available from: 2013-04-23 Created: 2013-04-23 Last updated: 2016-03-07Bibliographically approved
In thesis
1. Computational Studies of Electron Transport in Nanoscale Devices
Open this publication in new window or tab >>Computational Studies of Electron Transport in Nanoscale Devices
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In this thesis, a combination of density functional theory (DFT) based calculations and nonequilibrium Green’s functions are employed to investigate electron transport in molecular switches, molecular cords and nanoscale devices.

  Molecular electronic devices have been proposed as an approach to complement today’s silicon based electronic devices. However, engineering of such miniature devices and design of functional molecular components still present significant challenges.

  First, the way to connect a molecule to conductive electrodes has to be controlled. We study, in a nanoelectrode-nanoparticle platform, how structural changes affect the measured conductance and how current fluctuations due to these structural changes can be decreased. We find that, for reproducible measurements, it is important to have the molecules chemically bonded to the surfaces of adjacent nanoparticles. Furthermore, we show by a combination of DFT and theoretical modeling that we can identify signals from single-molecules in inelastic electron spectroscopy measurements on these devices.

  Second, active elements based on molecules, some examples being switches, rectifiers or memory devices, have to be designed. We study molecular conductance switches that can be operated by light and/or temperature. By tuning the substituents on the molecules, we can optimize the shift of the most conducting molecular orbital and increase the effective coupling between the molecule and the electrodes when going from the OFF to the ON-state of the switches, giving high switching ratio (up to three orders of magnitude). We also study so called mechanoswitches that are activated by a mechanical force elongating the molecules, which means that these switches could operate as sensors.

  Furthermore, we have studied two different classes of compounds that may function either as rigid molecular spacers with a well-defined conductance or as molecular cords. In both cases, we find that it is of great importance to match the conjugation of the anchoring groups with the molecular backbone for high conductance.

  The last part of the thesis is devoted to another interesting semiconductor material, diamond. We have accurately calculated the band structure and effective masses for this material. Furthermore, these results have been used to calculate the Hall coefficient, the resistivity and the Seebeck coefficient.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. i-x, 89 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1090
Density functional theory, Molecular electronics, Organosilicon chemistry, Diamond, Molecular switches, Nanoelectrode bridge platform, Molecular cords
National Category
Condensed Matter Physics Physical Chemistry
Research subject
Physics with spec. in Atomic, Molecular and Condensed Matter Physics
urn:nbn:se:uu:diva-209261 (URN)978-91-554-8781-2 (ISBN)
Public defence
2013-11-29, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Available from: 2013-11-08 Created: 2013-10-16 Last updated: 2014-01-23

Open Access in DiVA

No full text

Other links

Publisher's full texthttp://dx.doi.org/10.1039/C3NR00505D

Search in DiVA

By author/editor
Jafri, Hassan M.Löfås, HenrikJonas, FranssonBlom, TobiasGrigoriev, AntonAhuja, RajeevOttosson, HenrikLeifer, Klaus
By organisation
Applied Materials SciencesMaterials TheoryPhysical Organic ChemistryPhysical Organic Chemistry
In the same journal
Condensed Matter PhysicsEngineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 720 hits
ReferencesLink to record
Permanent link

Direct link