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Institute of Solid State Physics
Tunneling Probability Increases with Distance in Junctions Comprising Self-assembled Monolayers of Oligothiophenes
Molecular tunneling junctions should enable the tailoring of charge-transport at the quantum level through synthetic chemistry but are hindered by the dominance of the electrodes. We show that the frontier orbitals of molecules can be decoupled from the electrodes, preserving their relative energies in self-assembled monolayers even when a top-contact is applied. This decoupling leads to the remarkable observation of tunneling probabilities that increase with distance in a series of oligothiophenes, which we explain using a two-barrier tunneling model. This model is generalizable to any conjugated oligomers for which the frontier orbital gap can be determined and predicts that the molecular orbitals that dominate tunneling charge-transport can be positioned via molecular design rather than by domination of Fermi-level pinning arising from strong hybridization. The ability to preserve the electronic structure of molecules in tunneling junctions facilitates the application of well-established synthetic design rules to tailor the properties of molecular-electronic devices.
This work is a collaboration between the Stratingh Institute for Chemistry and the Zernike Institute for Advanced Materials, University of Groningen (Netherlands) with the Institute of Solid State Physics, TU Graz.
Embedded-dipole self-assembled monolayers tune contact resistances in p‐type and n‐type organic transistors
Highly conductive interfacial layers are designed, which allow tuning the contact resistance of organic thin‐film transistors over three orders of magnitude with minimum values well below 1 kΩ cm. This not only permits the realization of highly competitive p‐type (pentacene‐based) devices on rigid as well as flexible substrates, but also enables the realization of n‐type (C60‐based) transistors with comparable characteristics utilizing the same electrode material (Au). The contact resistances are reduced by i) eliminating the injection barrier through a suitable dipole orientation, and by ii) boosting the transmission of charge carriers through a deliberate reduction of the SAM thickness. Notably, the embedding of the dipolar group into the backbones of the SAM‐forming molecules allows exploiting their beneficial effects without modifying the growth of the active layer.
This work is a collaboration between the Institute of Solid State Physics, TU Graz, the Stadlober group at the Materials Institute, Joanneum Research, Weiz (Austria), the Zharnikov group at the University of Heidelberg (Germany), and the Terfort group at the Goethe University Frankfurt/Main (Germany).
Pit stop for paper bags
The Research Journal of the TU Graz published an article on the Christian Doppler Laboratory on Mass Transport in Paper
Opening of the Christian Doppler Laboratory for mass transport through paper
The Christian Doppler Laboratory on Mass transport through paper was inaugurated on April 24th.
Karin Zojer was awarded an Elise Richter fellowship from the FWF. This program is designed for highly qualified female scientists who strive for an university career. Dr. Zojer's proposal,
"Transient characteristics of organic thin-film transistors", focuses on the operation frequencies of organic thin film transistors (OTFTs). Such transistors represent an increasingly important technology, since they can be cheaply fabricated on large and flexible substrates. To date, however, their operating speed cannot compete with the switching speed of silicon-based transistors. Theoretical simulations will employed to demonstrate that the apparent lack of switching speed is due to an inefficient injection of charge carriers from the electrodes.
The Master thesis of Bernhard Burtscher on “Inkjet-printed organic photodiode on an ultrathin, commercial, conformal and transferrable polymer substrate” has been awarded by the WKO-Steiermark for its applicability to industry.
Oliver Hofmann won this year's START-prize, Austria's most prestigious award for young scientists. In his project, MAP-DESIGN, Oliver and his group aim at predicting novel materials with outstanding properties using quantum-mechanical calculations, as well as providing recipes describing how these materials can be actually obtained in a lab. More information can be found in the press release and the interview by Die Presse and Der Standard, or Die Kronenzeitung
Best Student Paper Award
Jennifer Prohinig won the Best Student Paper Award at the 41st International Semiconductor Conference, CAS 2018, October 10-12, Sinaia, Romania, for her contribution, "Influence of Platinum-Hydrogen Complexes on Silicon p+/n-Diode Characteristics."
Electrodes for long-term monitoring of electrical impulses of heart or muscles were fabricated in the form of temporary tattoos produced using an ink-jet printer. An international research team involving Institute of Solid State Physics TU Graz together with IIT, Universitá degli Studi di Milano and Scuola Superiore Sant'Anna in Italy, presents this novel method in Advanced Science.
Last week the workshop Interfacing Machine Learning and Experimental Methods
Together with a consortium of five international collaborators from the United States, Germany and Finland, Oliver Hofmann won a 2017 Innovative and Novel Computational Impact on Theory and Experiment (INCITE) award. This gives his group access to MIRA, a national labs based supercomputer. Mira was the fifth-fastest supercomputer in 2013. The award comprises 160 million CPUh, worth approximately 1.6 million USD.
Start-up idea award to Anna Maria Coclite
The Science Park Graz awarded Anna Maria Coclite with a 1000 € in the Startup Idea Competition. Anna's idea was to create artificial skin that has similar temperature, pressure, and humidity perception as real skin. Together with the cash prize, she also got the opportunity to attend the Science Park Academy: a series of workshops to coach scientists in being entrepreneurs.
The proposal "Materials and Interfaces for Organic and Hybrid Photovoltaics" has been selected for a 2018 Innovative and Novel Computational Impact on Theory and Experiment (INCITE) award by Argonne Leadership Computing Facility (ALCF). A total of 330 Mio CPUh have been awarded to a consortium of top-notch researchers from around the world, including the Hofmann group. The activities in Graz will focus on determining the structure and the properties of inorganic/organic interfaces using the recently developed SAMPLE algorithm – always with the purpose of finding the ideal material combination for photovoltaic cells, which are a cruicial factor in the quest for renewable, clean energy sources.
Electronic objects of daily life are becoming increasingly smaller – but at the same time more powerful and efficient. The research area of molecular electronics, a sub-area of microelectronics, aims at miniaturisation, and research in this field is being carried out at the Institute of Solid State Physics at TU Graz. At the centre of interest is how electricity can flow in individual molecules, molecular layers (i.e. in a layer of arranged molecules) and in molecular clusters. “Molecular electronics is the ultimate miniaturisation of electronics – single molecules suddenly become active elements and circuits become considerably smaller than they are, for instance, in microelectronics,” explains Egbert Zojer from TU Graz’s Institute of Solid State Physics.
June has been a very successful month for Oliver Hofmann and his group, with three papers accepted in peer-reviewed journals.
Anna Maria Coclite gave a presentation on artificial skin in the TEDxGraz series. Watch the video here.
Paul will spend 6 months at MIT in the group of Karen Gleason to perform research on Oxidative and initiated Chemical Vapor Deposition for the Synthesis of Sulfonated Polymer Electrolyte Membranes. His research stay will be funded by the Marshall Plan.
The Master thesis of Paul on “Designing actuator arrays based on thermo-responsive polymers by initiated Chemical Vapor Deposition” has been awarded by the WKO-Steirermark for its applicability to industry.
The aim of Anna Maria Coclite’s ERC-sponsored project “Smart Core” is to develop a hybrid material which can perceive temperature, humidity and pressure simultaneously and react accordingly. State-of-the-art materials currently include three different sensors for the perception and transmission of individual stimuli. The three-in-one hybrid material which Coclite and her team will work on simplifies the sensors of artificial skin and can increase sensory resolution 20-fold in comparison to human skin. This hugely increased sensory resolution of the novel hybrid material is achieved using a variety of nanorods on a surface. The “smart core” of these nanorods, hence the name of the project, consists of a polymer which responds to temperature and humidity by expanding. The change in thickness of the polymer exerts pressure on its shell, i.e. the nanorods, and these react sensitively to the pressure and in turn trigger stimuli. The hybrid material will achieve some 2,000 sensors per square millimetre, and thus spatial resolutions far below one millimetre, which corresponds to that of the human fingertip.
Anna Maria Coclite won the IAAM Scientist Medal 2016, awarded by the International Association of Advanced Materials for her “notable and outstanding research in the Advanced Materials Science and Technology” (as written in the certificate). The award ceremony took place during the European Advanced Material Congress.
David Egger won a 2016 Sofja Kovalevskaja Award from the Humboldt Foundation. This award is granted to excellent young researchers who have completed their doctorate in the last six years and have published work in prestigious international journals. The Sofja Kovalevskaja Award will fund him for five years to build up a working group at the University of Regensburg. David investigates organic-inorganic perovskites which offer especially favourable properties for applications in solar cells. His goal is to optimise the material at the atomic level using supercomputers and with that increase its efficiency for using it in novel renewable energy technologies.
Oliver T. Hofmann was granted a three-year stand-alone project by the Austrian Science Fund FWF to study “Defects at Inorganic/Organic Interfaces”. Within the project, we will use density functional theory to study the impact of structural defects, such as dislocations, voids, etc., as well as the impact of chemical defects (i.e., contamination), on the electronic structure of molecule/metal interfaces. Such defects can be of high relevance, e.g., for organic electronics, where they potentially lead to the formation of “hot spots” that later lead to accelerated device degradation. A major challenge in the context of this project, however, is that the nature and the quantity of these defects is completely unknown. In order to elucidate these, we will develop a tailored first-principles structure search algorithm.
In collaboration with colleagues at the Université Libre de Bruxelles in Brussels, Belgium, Andrew Jones and Roland Resel have published a feature article in Advanced Functional Materials.
Robert Schennach is the new representative of TU Graz in the Austrian Vacuum Society (ÖGV). This society promotes advances in vacuum related science and technology in Austria.
Oliver T. Hofmann was granted a three-year stand-alone project by the Austrian Science Fund FWF. Within the project, entitled “Interaction Strength Tuning at Inorganic/Organic Interfaces”, a post-doc and a PhD student will be employed to study charge transfer at interfaces between organic molecules and coinage metals semiconductors. Such interfaces are of high technological relevance for organic electronics as well as for catalysis. Interestingly, semiconductor and metal substrates seem to induce very different charge-ordering phenomena. Using doping to make semiconductors gradually “more metallic”, and alloying to make coinage metals “less metallic”, the transition between the differently ordered phases will be studied using various computational methods, including density functional theory and post Hartree-Fock methods.
Georg Urstöger has won a stipend from the Styrian Chamber of Commerce for master thesis that have a strong bond to industrial research. The granted thesis, "Proton Conductive Polymers deposited by Plasma Enhanced Chemical Vapor Deposition”, focuses on the production of proton conductive membranes to be used in the fuel cell industry. Proton conductive membranes are the heart of the fuel cell that allows the protons to permeate but block the electrons which are guided through an external circuit to generate electricity. The technique we use is plasma enhanced chemical vapor deposition (PECVD) which due to its nature has many advantages such as the tendency to produce crosslinked, stable polymers. The outcome of this thesis is to create a product that is feasible in cost but incorporates the good qualities of the currently best choices such as Nafion®.
Sebastian Nau won the 2014 Nano Prize of the Erwin Schrödinger Society. This prize is awarded to young scientists for excellent work in the field of nanoscience or nanotechnology. He reported a breakthrough in the understanding of organic memory devices in the journal Advanced Materials.
Anna Maria Coclite was awarded a Marie Curie International Incoming Fellowship within the 7th European Community Framework Programme. The fellowship funds top-class researchers from non-European Countries to work on projects in Europe. The granted project, "Smart multi Stimuli-responsive Supports for controlled cell growth (Three S) " , aims to the development of a material that respond to several external stimuli such as humidity, light and temperature. Multi-stimuli responsive materials have not been widely investigated because they require fine control over the material composition and response. The material will be obtained by initiated Chemical Vapor Deposition (iCVD), a method, invented at MIT, that allows obtaining thin films with high versatility. The envisioned outcome will be that the water uptake of the material changes with the afore-mentioned stimuli, resulting in stiffness change.
Emil J.W. List-Kratochvil has been appointed to the International Advisory Board of the Wiley journal Advanced Electronic Materials.
Researchers at the NanoTecCenter Weiz have developed a Electrolyte-Gated Organic Field-Effect Transistor (EGOFET) that can measure the concentration of specific ions in solution. These sensors could be used for biomedical diagnostics,
An article on paper strength was featured on the cover of the Journal of Physics: Condensed Matter. The strength of fiber-fiber bonds was measured for different water content in the paper. This research was performed at the Christian Doppler Laboratory of Surface Chemical and Physical Fundamentals of Paper Strength along with collaborators at the Peter Grünberg Institute in Jülich, the International Centre for Theoretical Physics in Trieste, Montanuniversität in Leoben, and Joanneum Research.
David Egger, Dissertant am Institut für Festkörperphysik der TU Graz, erhielt für seine Arbeit zu Wechselwirkungen und physikalischen Eigenschaften von Molekülen am 26. November den Nano-Preis der Erwin Schrödinger Gesellschaft für Nanowissenschaften (ESG-Nano).
Den „Award of Excellence“ für eine besonders herausragende Dissertation verlieh das Bundesministerium für Wissenschaft und Forschung (BMWF)am 12. Dezember Ferdinand Rissner für seine Dissertation zu Monolagen organischer Moleküle, also zu Materialschichten mit geringstmöglicher Dicke.
Den „Award of Excellence“ für eine besonders herausragende Dissertation verlieh das Bundesministerium für Wissenschaft und Forschung (BMWF) Eduard Gilli für seine Dissertation zu Entwicklung von Analysemethoden für Faser Bindungen in Papier
Die elektronischen Bauelemente der Zukunft sollen schneller, leistungsfähiger und vor allem immer kleiner sein. Die langfristige Vision der ultimativen Miniaturisierung sind einzelne Moleküle, die elektrisch leiten und schalten. Um dieser Vision näher zu kommen, müssen die Wechselwirkungen und physikalischen Eigenschaften von Molekülen im Detail erforscht werden. David Egger, Dissertant am Institut für Festkörperphysik der TU Graz, hat genau das getan und ist dabei auf ein interessantes Phänomen gestoßen: Im Kollektiv verhalten sich die chemischen Bauteile nicht als „Einzelkämpfer“, sondern arbeiten zusammen. Die Forschungsarbeit, die der junge Wissenschafter in Kooperation mit Kollegen der Humboldt-Universität zu Berlin verfasste, wurde kürzlich im renommierten Fachjournal „Advanced Materials“ publiziert.
On October 5, 2012 the institute made an excursion to the electronic components manufacturer EPCOS. We toured the facilities where they produce multilayer ceramic components, including piezo actuators.
Physical Review B maintains a collection of visually attractive images that convey important scientific information. This collection is called the Kaleidoscope Images. In August 2012, one of the images from Film of para-hexaphenyl on a sputtered mica surface, L. Tumbek, C. Gleichweit, K. Zojer, and A. Winkler, Phys. Rev. B 86, 085402 (2012) was selected for this collection.
In a collaboration between the Institute of Solid State Physics in Graz and the Humboldt-Universität zu Berlin, David Egger, Ferdinand Rissner, Egbert Zojer and Georg Heimel recently published an article in Advanced Materials.
Egbert Zojer has been appointed to the editorial board of the research journal Advanced Functional Materials. This journal reports breakthrough research in all aspects of materials science, including nanotechnology, chemistry, physics, and biology.
Oliver Hofmann was awarded an FWF Schrödinger Fellowship. These fellowships fund the stay of Austrian scientists at leading foreign research institutions. When the scientists return, they bring critical research skills to Austria. Hofmann will spend two years as a postdoc at the Fritz Haber Institute in Berlin and then return for one year as a postdoc to the TU Graz.
In collaboration with the Fritz Haber Institute in Berlin, Egbert Zojer has published an article in Physical Review Letters about organic molecules on metal surfaces.
Two publications recently appeared in Advanced Materials from the x-ray diffraction team headed by Roland Resel. They are experts on determining how molecules arrange themselves in thin films.
In einem steirischen Großprojekt wurden organische Sensoren zur Onlinekontrolle von Luft, Wasser oder Lebensmitteln entwickelt - Sie ermöglichen flexible, maßgeschneiderte und billige Technologien.
David Egger was honored by the Styrian government for his work on organic semiconductors with the "Young Researcher Award for Simulation and Modelling 2011." He received the prize for quantum mechanical simulations of the behavior of organic molecules on metal surfaces that were described in his master thesis. The research was performed in collaboration with the Humboldt-University in Berlin.
A winterschool on self-assembly within thin films, the basic properties of organic hybrid structures, and their devices will be held March 3rd - March 9th, 2012 at the Universitäts-Sportheim Planneralm, Donnersbach, Austria. The workshop organizer is Roland Resel.
On November 4, 2011, the institute made an excursion to the semiconductor manufacturer Austriamicrosystems. We had a tour of the fabrication facilities. After the tour we went to the Buschenschank Wieser in Gundersdorf.
An article written by Georg Heimel, Lorenz Romaner, Jean-Luc Brédas, and Egbert Zojer was the most cited article in the journal Surface Science in the period 2005 - 2010.
Emil J. W. List and Norbert Koch were the guess editors of an Optics Express Focus Issue on organic light-emitting diodes. They reviewed the status quo and described the current developments.
Die Erfindung „Optische Anordnung für spektroskopische Infrarot-Ellipsometrie“ von E. Gilli, M. Kornschober und R. Schennach wurde im Jahr 2009 mit dem PRIZE Award ausgezeichnet. Damit wurde der Bau eines Prototyps ermöglicht. Schon während des Baus konnte die Firma Anton Paar als Partner für eine internationale Patentanmeldung (PCT) gewonnen werden. Darauf hin wurde das Projekt im Herbst 2010 bei Houska Preis der B&C Provatstiftung eingereicht.
Von Harten Kristallen zu Weicher Materie
Am 7.12.2010 hat Hartmut Kalhert einen Vortrag gehalten in der Reihe "Nachhaltige Entwicklungen an der TU Graz und ihre Initiatoren".
A one-day symposium on computer models of advanced materials was held at the TU Graz on May 2, 2011. Solving the quantum equations that describe how atoms and molecules combine into solids is one of the most difficult computational problems known. The participants at this workshop discussed different methods to attack this problem. The approximations used have to be changed as the volume of material involved in the simulation grows. The symposium was organized by Egbert Zojer and funded by SIMNET Styria.
The TU Graz Research Journal produced a special issue on Advanced Materials Science.
Physiker der TU Graz haben auf Basis einer quantenmechanschen Simulation Antworten auf grundlegende Fragen zur Änderung von Grenzflächeneigenschaften von Elektrodenmaterianlien mit organischen Molekülen gefunden.
The Austrian Newspaper die Presse published an article about how organic semiconductors can be used to make sensors, displays, and solar cells.
David Egger receives one of the prestigious 3 year DOC fellowships by the Austrian Academy of Sciences. Within his project "Applying Green’s function techniques to interfaces between self-assembled monolayers and noble metals" David will continue his investigation of metal/organic interfaces and devices he started with Georg Heimel from HU Berlin in the course of his master's thesis. As a long term goal several ways to conquer the notorious shortcomings of common density functional approximations shall also be analyzed. Since August 2009 David is a member of Egbert Zojer's group at the Institute of Solid State Physics. He finished his master's study in April 2010.
An article in the Austrian newspaper der Standard describes the research on paper strength that is being performed at the Christian Doppler Laboratory for Paper Strength. This is a collaboration between the TU Graz and the Montan University in Leoben.
We proudly announce that 2011 Nano and Photonics will be jointly organised with
The insertion of a thin photoacid generator layer between the dielectric and the active layer in organic thin-film transistors (OTFTs) allows control of the threshold voltage through UV illumination by means of interfacial channel doping. All p-type organic inverters can be realized by combining an OTFT working in depletion mode and one operating in enhancement mode.
Self-assembled monolayers (SAMs) play an ever increasing role in organic and molecular electronics. Consequently, there is a high interest in an in-depth understanding of their intrinsic electronic properties as a prerequisite for future developments. The current Progress Report summarizes recent efforts in the area of computational modeling of SAMs geared at developing a clear understanding of the relationship between the chemical structure of the SAM-forming molecules and the electronic properties of the monolayer.
Charge-transfer monolayers hold a high potential for modifying carrier-injection properties of electrodes in organic electronics. A particular promising molecule in this context is HATCN. The electronic properties of HATCN on Au(111), however, display a very unexpected dependence on film thickness with a work-function increase setting in only for films thicker than 3 Angstrom. In a study joining groups from Berlin, Graz, Mainz, and Groningen, this peculiar behavior could be clarified by combining various experimental techniques with quantum-mechanical modeling. It was attributed to an unprecedented complete change in the film structure with layer thickness.
Circuits such as a seven stage ring oscillator and a four bit code generator were built using self-assembled monolayer field effect transistors (SAMFETs) grown on a polymer surface. This demonstrates the feasibility of using SAMFETs on flexible substrates.
Mit der Research 2010 wird das in Österreich einzigartige Projekt einer Präsentationsplattform für Wissenschaft, Forschung und Innovation am 11. und 12. Juni 2010 in der Halle A der Messe Graz über die Bühne gehen.
The Physics Brochure 2009 summarizes the achievements of the Physics Institutes at the TU Graz in 2009.
Organic Light Emitting Diodes (OLEDs) are a promising technology for the next generation of fullcolor-flat-panel displays and lighting applications. A new material for OLEDs has been developed by a team from the Max-Planck Institute for Polymer Research in Mainz and the NanoTecCenter in Weiz. The pyrene based material emits blue-turquoise light with a maximum in the electroluminescence at 465 nm.
An international winter school on the fundamental properties of organic devices (sensors, transistors, and solar cells) is being organized by Prof. Roland Resel for the Austrian Research Project Cluster "Interface Controlled and Functionalized Organic Films." This is a network of scientific groups from Austria, which are working together to perform joint research on basic science of organic thin films and their application in organic electronics. The winterschool will be focused on device physics, contributions on that topic will be preferably selected as short lectures.
The Austrian ministry of economics (BMWFJ) awarded a prototype PRIZE to researchers in the Christian Doppler Laboratory for Paper Strength. €113000 was awarded to build a prototype of an ellipsometry insert for an infrared spectrometer. The insert was designed by Eduard Gilli, Robert Schennach, and Martin Kornschober.
The 8th International Symposium on Functional π-Electron Systems was voted one of the five best scientific conference in Graz in 2008. This was the only conference which was held at the TU Graz which won an award. The conference took place from July 21st to 25th, 2008 and was organized by Prof. Emil List.
The Institute of Solid State Physics won a €3000 prize for being one of the three most inventive institutes at the TU Graz. The prize was awarded at Erfindertag on Nov. 6, 2009.
The mobility of self-assembled monolayer field-effect transistors (SAMFETs) traditionally decreases dramatically with increasing channel length. Recently, however, SAMFETs using liquid-crystalline molecules have been shown to have bulk-like mobilities that are virtually independent of channel length. Here, we reconcile these scaling relations by showing that the mobility in liquid crystalline SAMFETs depends exponentially on the channel length only when the monolayer is incomplete. We explain this dependence both numerically and analytically, and show that charge transport is not affected by carrier injection, grain boundaries or conducting island size. At partial coverage, that is when the monolayer is incomplete, liquid-crystalline SAMFETs thus form a unique model system to study size-dependent conductance originating from charge percolation in two dimensions.
The ultimate miniaturization of electronics would be to use single molecules as electronic components. In a recent Nanoletters article, a team from M.I.T., Humbolt University, Montan University, Georgia Tech, and the TU Graz, explain why exchanging a single carbon atom with a nitrogen atom in certain molecules increases the electrical conductivity of the molecules by more than two orders of magnitude. The results provide clear guidelines for the rational design of single-molecule metals and highly doped single-molecule semiconducting devices. This is important for the development of bio-compatible interfaces between inorganic and organic matter. The image visualizes the transport channel in one of the studied molecules, a boron doped dithiol derivative of pyrene where the thiol groups are separated from the π-conjugated core by a methylene (i.e., -CH2-) spacer.
On October 1st the Advanced Materials Science research cluster (Field of Expertise) will hold Materials Day. Recent research results in materials science will be presented by graduate students of the university. At the end of the day, Prof. Jürgen Rödel will give an invited lecture on the Development of new lead-free piezoceramics.
A one day NAWI-Graz workshop will be held Friday June 26, at the Seifenfabrik in Graz. The workshop is planned for both supervisors and PhD students of the NAWI-Graz doctoral schools. It includes two plenary sessions and nine focus sessions, covering a wide variety of research topics from nanoscience to systems biology (see list of sessions below). A number of outstanding scientists from other universities have been invited and will complement the list of speakers from both the Karl-Franzens University and the Graz University of Technology.
An aqueous dispersion of semiconducting polymer nanospheres was used to fabricate polymer light-emitting devices by inkjet printing in an easy-to-apply process with a minimum feature size of 20 μm. To form the devices, the electroluminescent material was printed on a nonemitting polystyrene matrix layer and embedded by thermal annealing. The process allows the printing of light-emitting thin-film devices without extensive optimization of film homogeneity and thickness of the active layer.Evelin Fisslthaler, Stefan Sax, Ullrich Scherf, Gernot Mauthner, Erik Moderegger, Katharina Landfester, and Emil J. W. List, Inkjet printed polymer light-emitting devices fabricated by thermal embedding of semiconducting polymer nanospheres in an inert matrix, Appl. Phys. Lett. 92, 183305 (2008)
An article on a new method for nanostructure formation from conjugated polymers appeared on the December 2008 inside cover of Soft Matter. An aqueous dispersion of semiconducting polymer nanospheres (SPNs) was deposited by inkjet printing onto a polymer surface patterned by soft embossing. By interaction between the spheres and the undulated surface a self assembly process is triggered, resulting in the formation of SPN nanostructures determined by the template. Both template layer and assembled SPNs can be incorporated into a device structure. We demonstrate a light emitting structure for use in polymer light emitting devices including analyses by atomic force microscopy and Kelvin probe force microscopy.
Printing functional nanostructures: a novel route towards nanostructuring of organic electronic devices via soft embossing, inkjet printing and colloidal self assembly of semiconducting polymer nanospheres, Evelin Fisslthaler, Alexander Blümel, Katharina Landfester, Ullrich Scherf and Emil J. W. List, Soft Matter, 2008, 4, 2448, DOI: 10.1039/b812235k
On July 16 2008, the institute made an excursion to the scientific instrument maker Anton Paar.
A research team from The Netherlands, Austria, Russia, and Germany announced a breakthrough in the development of organic electronic integrated circuits in the October 16, 2008 issue of the journal Nature. Self-Assembled Monolayer Field Effect Transistors (SAMFETs) were used to build circuits including a 15-bit code generator consisting of over 300 transistors. A critical layer of the SAMFETs consisted of a single molecular layer of quinquethiophene molecules which self-assembled into an ordered two-dimensional crystal. Although they are not as small or as fast as state-of-the-art silicon transistors, the self-assembly of molecules into useful devices is considered the ultimate technology for mass production and this is an important demonstration of how self-assembly can be used in the fabrication of a complex circuit. Organic transistors such as this are most useful in applications where transistors are distributed over a large area such as they are in a display.
Prof. Emil List won the award for the best project development at the 4th Global Plastic Electronics Conference on October 28, 2008 in Berlin. The award cited his work on organic optoelectronics and sensors.
Evelin Fisslthaler won the 2008 Nano Youth Award of the Austrian Federal Ministry of Transport, Innovation and Technology. The award is given for excellent research in the field of nanoscience and nanotechnology.
Peter Pacher and Daniel Koller shared the 2008 ESG-Nano-Prize awarded by the Erwin Schrödinger Society for Nanoscience. Peter Pacher recently finished his PhD on organic electronic devices at the Institute of Solid State Physics. Daniel Koller is a graduate student at the Karl Franzens University working on plasmonic devices.
In the July 3, 2008 issue of Science magazine, a team from the Montan University in Leoben and the TU Graz explained the growth of ordered thin films of parahexaphenyl. When molecules of parahexaphenyl are evaporated on clean a clean mica surface, the molecules form crystalline needles. Within the needles the molecules are ordered in straight rows with the molecules lying flat on the mica surface.
When the surface of the mica is bombarded with ions before the parahexaphenyl is deposited, the molecules stand up on the surface. Islands of the molecules have a stepped structure where the steps are one molecule high.
The form of the island is partially determined by the difficulty that the molecules have in diffusing over the edges of the steps. The energy barrier that the molecules must overcome to go over a step is known as the Ehrlich-Schwoebel barrier. Numerical simulations show that the molecules bend when they go over a step edge. The energy it takes to bend the molecules is an important contribution to the Ehrlich-Schwoebel barrier.
Gregor Hlawacek, Peter Puschnig, Paul Frank, Adolf Winkler, Claudia Ambrosch-Draxl, Christian Teichert: 'Characterization of Step-Edge Barriers in Organic Thin-Film Growth', Science 321 p. 108 (2008).
Ferdinand Rissner won the 2008 Poster Prize at the 58th meeting of the Austrian Physical Society in Leoben for his contribution with the title,
Surface plasmons are hybrid modes of longitudinal electron oscillations and light fields at the interface of a metal and a dielectric. Driven by advances in nanofabrication, imaging and numerical methods, a wide range of plasmonic elements such as waveguides, Bragg mirrors, beamsplitters, optical modulators and surface plasmon detectors have recently been reported. For introducing dynamic functionality to plasmonics, the rapidly growing field of organic optoelectronics holds strong promise due to its ease of fabrication and integration opportunities. Here, we introduce an electrically switchable surface plasmon source based on an organic light-emitting diode. The source provides a freely propagating surface plasmon beam and is potentially useful for organic integrated photonic circuits and sensing applications. Furthermore, the demonstration of controlled coupling of surface plasmons and excitons in organic materials could prove useful for the fabrication of improved organic light-emitting diodes and organic photovoltaic devices.
A new Christian Doppler Laboratory for Surface Science Investigations on Paper Strength will investigate the strength of fiber – fiber bonds in paper. The surface morphology as well as the surface chemistry will be investigated using a collaborative approach. The laboratory head is Prof. Robert Schennach from the Institute of Solid State Physics, Graz University of Technology. Close collaboration with Prof. Wolfgang Bauer from the Institute of Paper Pulp and Fiber Technology, Graz University of Technology and with Prof. Christian Teichert from the Institute of Physics, University of Leoben will enable a simultaneous investigation of the fiber morphology and the surface and interface chemistry. The industrial partner is Mondi Packaging in Frantschach.
Mit der PI-LED-Technik will Lumitech die künstliche Beleuchtung revolutionieren. Treibende Kraft der Firma ist der Gründer und Grazer Physiker Günther Leising.
Joint Meeting of: 9th Multinational Congress on Microscopy 2009 & Dreiländertagung 2009
30 August - 4 September 2009
Convention Center Graz, Austria
The Microscopy Conference 2009 in Graz is joining together the "Multinational Congress on Microscopy" and the "Dreiländertagung" both having established a strong reputation as key events in the European and international microscopy communities. MC 2009 will continue this successful tradition in Graz, a city in the centre of Europe that has a long history in science, engineering and culture.
The scientific programme of MC 2009 will comprise plenary lectures, symposia, poster presentations, and tutorials. A high quality Trade Exhibition will be a main part of MC 2009 with a mixture of exhibits and technical workshops to enable delegates to interact with vendors and witness the latest developments in microscopy in the physical and life sciences, and nanotechnology.
It is our aim to encourage the participation of young scientists; therefore several fellowships will be offered and the conference fee for students will be below € 100,–.
There will be poster prize awards in different scientific fields.
Austrian Society for Electron Microscopy
Einen deutlichen Fokus auf das steirische Stärkefeld Nanotechnologie wollen die TU Graz und das Joanneum Research (JR) setzen. Dazu gründeten die beiden Grazer Forschungseinrichtungen nun die "Nano Tec Center Weiz Forschungsgesellschaft mbH" (NTC Weiz GmbH). Baubeginn für die Einrichtung der Gesellschaft im oststeirischen Weiz ist Ende April. Erste Forschungsprojekte sollen Ende 2007 an den Start gehen.
Nano and Photonics Mauterndorf 2009
The purpose of this event is to organise an informal meeting for those, who are interested in photonic applications of modern nanotechnology.
Scope of the International Symposium Fπ8
Strongly electron poor molecules can be used to continuously tune the charge carrier injection barriers in organic semiconductor devices. Combining experimental (UPS and XSW) and computational (band-structure) investigations enables an in-depth fundamental understanding of charge transfer processes and geometric distortions at the metal/organic interface. These aspects are discussed by Lorenz Romaner et al. in a recent publication in Physical Review Letters.
Ein zukünftiger Bildschirm auf SAM-Basis wird einem Blatt Papier ähneln, falt- und rollbar sein, bei geringem Energieverbrauch hervorragende bildqualität bieten und leichtgewichtig sein.
Die von Bundespräsident Dr.Heinz Fischer verliehene hohe Bundesauszeichnung wurde Prof. Kahlert am 10.12.2007 im Rahmen eines Festaktes im Weißen Saal der Grazer Burg von Landeshauptmann Mag. Franz Voves überreicht. In seiner Laudation ging der Landeshauptmann auf das vielfältige Engagement von Prof. Kahlert ein: Er war zwei Mal Rektor der Technischen Universität Graz, treibt aktiv die Gründung einer Technischen
Universität in der pakistanischen Stadt Lahore voran und engagiert
sich intensiv in der Christian Doppler Forschungsgesellschaft.
Surface plasmons are waves that appear at the surface of a metal. Light and electrons are coupled in these waves such that the light intensity and electron density go up and down together. Surface plasmon devices that process optical signals can be smaller than ordinary optical devices since the wavelength of the plasmons is shorter than the wavelength of light.
Inkjet-printed photodetectors operating at wavelengths up to 3 μm
were made using HgTe nanocrystals. Detectors operate in a spectral region of particular importance for biological applications, remote sensing and
night-vision imaging. A room temperature detectivity of D* = 3.2 × 1010 cm Hz1/2W–1 close to the important telecommunication wavelength region was observed.
A winter school on the role of interfaces in organic electronics will be held January 26th – January 31st, 2008 in Planneralm, Donnersbach, Austria.
Surface scientists at the Institute of Solid State Physics study chemical reactions that take place on the surface of metals. The metals often act as catalysts that increase the rate of chemical reactions. In a recent article, E. Demirci, J. Stettner, M. Kratzer, R. Schennach, and A. Winkler studied the reactions of the methanol, a biofuel, on copper surfaces.
Martin Gaal and Emil J. W. List have developed a fully integrated self-aligned distributed feedback fiber laser device, which was liquid imprinted on the top of optical fibers. Photo-pumping the second order grating led to direct coupling into the waveguide and allowed detecting the emission at the fiber end. Since an accurate alignment and efficient coupling of a laser into a waveguide is tricky, the presented approach may be a competitive candidate for integrated optoelectronic devices.
The 8th International Symposium on Functional Π-Electron Systems will be held from July 21st to 25th, 2008 in Graz, Austria. The symposium brings together chemists, physicists and engineers to discuss recent developments in the field of Π-conjugated matter. The technical program will include plenary lectures, invited lectures, oral and posters of the contributed technical papers on:
Local organizer: Emil List
The Institute of Solid State Physics participates in the Key Research Area of Advanced Materials Science. A new website was recently launched to describe the activities in materials science taking place at the TU Graz.
A recent article in the Siemens Hi!Tech magazine (number 2/2007) describes the research that professor Robert Schennach is performing to understand what gives paper its strength.
The charge transport in organic thin film transistors (OTFTs) occurs in a very thin layer in the immediate vicinity of the interface between the active material and the dielectric. By modifying that interface, the concentration and transport of the charge carriers can be controlled and if chemo-responsive this allows the realization of sensors.
Scientific measurements and industrial processes that require an ultra-clean environment are often performed in vacuum chambers. These are metal vessels where all of the air has been pumped out. Stainless steel is one of the most commonly used structural materials for vacuum equipment. If extremely high vacuum (XHV) is to be achieved, a reduction of the outgassing rates of the materials used in the construction of the vacuum system is essential. A high-temperature vacuum firing has become a widely accepted practice of reducing the amount of hydrogen dissolved in stainless steel. Evidence suggests that the hydrogen outgassing rate is limited by the surface recombination. It is well established that the rate of recombination depends strongly on the atomic structure of the surface. In this experiment a scanning tunneling microscope was used to determine the restructuring of the surface during vacuum firing.
In September 2006, Peter Hadley became a professor in the Institute of Solid State Physics, TU Graz. He received a PhD in Applied Physics from Stanford University in 1989 and then became an assistant professor and later
A National Research Network (NFN) with the title „Interface Controlled
In a recent article published in Nano Letters, researchers at the Institute of Solid State Physics - TU Graz, and Georgia Tech. in Atlanta describe how a single layer of organic molecules modify the surface properties of metals.
A winter school on "Interface Controlled and Functionalised Organic Films" was held at the Planneralm January 27 - February 2, 2007. The winterschool was organized for diploma and PhD students of projects, associated projects and collaboration projects of the NFN.
Self-organized organic thin films have applications in lithography and sensor technology. This article describes research being done by Prof. Adolf Winkler of the Institute of Solid State Physics, TU Graz and by Prof. Michael Ramsey of the Karl Franzens University in Graz.
In an interview in the journal e&i elektrotechnik und informationstechnik, Prof. Günther Leising discussed his views on research.
Ao. Prof. DI Dr. Emil List from the Graz University of Technology and Prof. Dr. Franz Aussenegg from the University of Graz would like to invite scientists and studentes who are interested in photonic applications of modern nanotechnology to the Nano and Photonics Conference 2007. The conference will take place at the castle Mauterndorf in the heart of Salzburg from 14th to the 16th of March 2007.
One goal of this event is to create an Austrian wide discussion platform for state of the art work in basic reasearch done at the various universities as well as industrial based research and development.
Another goal is to give young students the possibility to present their work in the form of talks or poster presentation. With this orientation, the Nano and Photonics Seminar tries to go on with the long tradition of the Mauterndorf LASERSEMINARS.
For more information and the registration forms please have a look at the homepage: www.nanoandphotonics.at
Egbert Zojer of the Institute of Solid State Physics participated in a panel discussion organized by the Austrian Academy of Sciences on the flow of gifted scientists out of the Austria. Better opportunities abroad often result in the relocation of Austrian scientists to foreign countries. The panel discussed the causes and possible remedies for this trend.
Researchers at Joanneum Research Institute for Nanostructured Materials and Photonics and the Institute of Solid State Physics at TU Graz developed a technique to draw three dimensional structures with a laser. At the focus of the laser a photochemical process hardens a specially designed material. Material that was not exposed to intense laser light can then be etched away leaving only the pattern drawn by the laser.
Researchers at Joanneum Research Institute for Nanostructured Materials and Photonics and the Institute of Solid State Physics at TU Graz developed a method to print an electronic circuit on ordinary newspaper. Many people believe that this kind of printable electronics will lead to cheap displays and sensors.