Functional Materials

Prof. Winfried Petry

Research Field

We examine the physical fundamentals of material properties using scattering methods (neutrons-, x-ray and dynamic light scattering). The general goal of our research is to jugde from the knowledge of the microscopic dynamics and structure for explaining the functional characteristics of condensed matter.

Address/Contact

James-Franck-Str. 1/I
85748 Garching b. München
+49 89 289 12452
Fax: +49 89 289 12473

Members of the Research Group

Professors

Staff

Teaching

Course with Participations of Group Members

Titel und Modulzuordnung
ArtSWSDozent(en)Termine
Experimentalphysik 1 (MSE)
Zuordnung zu Modulen:
VU 4 Müller-Buschbaum, P. Mittwoch, 15:00–16:30
sowie Termine in Gruppen
Nanostructured Soft Materials 1
Zuordnung zu Modulen:
VU 4 Müller-Buschbaum, P. Dienstag, 15:00–16:30
sowie Termine in Gruppen
Physics with neutrons 1
Zuordnung zu Modulen:
VU 4 Leitner, M. Mittwoch, 10:00–12:00
Materialphysik auf atomarer Skala 1
Zuordnung zu Modulen:
VO 2 Leitner, M. Mittwoch, 16:00–18:00
Seminar über Neutronen in Forschung und Industrie
Zuordnung zu Modulen:
PS 2 Böni, P. Petry, W. Schröder, T. Montag, 14:30–15:45
Studentenseminar: Grundlegende Phänomene der Physik der weichen Materie
Zuordnung zu Modulen:
HS 2 Müller-Buschbaum, P. Papadakis, C. Montag, 13:00–14:30
Aktuelle Probleme der organischen Photovoltaik
Zuordnung zu Modulen:
SE 2 Müller-Buschbaum, P. Montag, 10:00–11:30
Edgar-Lüscher-Lehrerfortbildungs-Seminar "Bionik"
Diese Lehrveranstaltung ist keinem Modul zugeordnet.
WS 2 Müller-Buschbaum, P. Mittwoch, 08:00–20:00
FOPRA-Versuch 42: Rasterkraftmikroskopie
Zuordnung zu Modulen:
PR 1 Müller-Buschbaum, P.
Mitwirkende: Xia, S.
FOPRA-Versuch 61: Neutronenstreuung am FRM II
Zuordnung zu Modulen:
PR 1 Petry, W.
Mitwirkende: Georgii, R.
Führung durch die Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II) für Studierende der Physik
Zuordnung zu Modulen:
EX 0.1 Petry, W.
Mitwirkende: Niiranen, C.
Seminar: Polymere
Zuordnung zu Modulen:
SE 2 Müller-Buschbaum, P. Papadakis, C. Mittwoch, 13:00–15:00
Seminar über Struktur und Dynamik kondensierter Materie
Zuordnung zu Modulen:
SE 2 Müller-Buschbaum, P. Papadakis, C. Dienstag, 13:15–15:00
Sprechstunde zu Nanostrukturierte, weiche Materialien
Diese Lehrveranstaltung ist keinem Modul zugeordnet.
KO 2 Müller-Buschbaum, P. Dienstag, 18:30–20:00
Sprechstunde zur Experimentalphysik für MSE
Zuordnung zu Modulen:
KO 2 Müller-Buschbaum, P. Dienstag, 17:00–18:30

Offers for Theses in the Group

Fabrication and investigation of enhanced organic light emitting diode devices (OLEDs)

Organic light emitting diodes (OLEDs) have received high attention in research and industry due to their broad range of potential applications. With their small film thickness, easy processibility and high image quality, they are already used in flat panel displays and lighting elements.  However, their efficiency and lifetime could still be increased. For this purpose, the properties of the materials used in OLED devices need to be better understood.

This experimental work comprises the fabrication and analysis of additional layers applied for enhancing the performance of OLEDs. Special attention is set to the application of a rough, mesoporous and transparent metal oxide film, which serves as a scattering layer to increase the photon extraction and thereby the efficiency. In an OLED device, it shares an interface with the semitransparent, conducting polymer electrode needed to introduce charge carriers into the photoactive material.  The structure of the scattering layer as well as this interface are of particular interest, as they have a pronounced influence on the performance of the OLED. Characterization techniques include electron and atomic force microscopy, electronic measurements and spectroscopic methods of OLED devices and their components. The light scattering ability of the applied metal oxide interlayer is particularly investigated using angle dependent transmission spectroscopy.


suitable as
  • Bachelor’s Thesis Physics
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Membrane Technologies for Vanadium Redox Flow Batteries

In recent years of energy research Vanadium Redox Flow Battery (VRFB) Technology has emerged as providing itself as a low priced and sustainable solution to meet the increasing storage demands of electrical energy. Ion exchange and nanofiltration membranes as separator of the (V2+/3+) anolyte and the (V4+/5+) catholyte both are still addressed in ongoing research. For the performance of a VRFB a high (H+, OH--) ion conductivity as well as low (Vx+) cross-over is decisive. In a joint cooperation with the Paul Scherrer Insitute PSI (Villingen, Switzerland) it is planned to investigate a new, at the PSI developed membrane technology which promises a lower cross-over depressed by more than an order of magnitude. The new polymer is to be compared with already established separator materials regarding its cost and performance in a full RFB cell, in order to bring the different membrane types into correlation. Furthermore, currently employed graphite electrodes will be validated and enhanced in terms of their performance for the electrochemical conversion of the Vanadium redox species. This includes the development of new electrode geometries and the implementation of different electrode surface modification methods enhancing the catalytic activity towards the Vanadium redox reactions. Consequently, a combination of the material improvements will result in a boost of the power density and energy efficiency of a demonstrator flow cell unit.

The experimental work will use technqiues such as cyclic voltammetry on rotating disk electrodes, potentiostatic electrochemical impedance spectroscopy, X-ray photoemission spectroscopy and battery cycling by chrono-potentiometry.

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Metal-polymer nanocomposites for sensor applications
The dispersion of metal ions by selective deposition to one block of ordered block copolymer nanostructures can provide a control over metal ion location and orientation in the polymer matrix. Upon metal ion reduction, arrays of metal nano-patterns can be produced that are important for applications such as sensors and high-density memory devices. Via spin coating method, a mixture of metal salt and block copolymer solution will be applied to solid substrates to obtain nanostructured hybrid films. A second type of metal nanoparticles will be applied to the as-prepared hybrid film via a solution casting method. With the help of the chemical selectivity metallic interconnects will be prepared. The hybrid films will be characterized by a variety of methods including electron microscopy, atomic force microscopy, small angle x-ray scattering and impedance spectroscopy. The project will involve a literature review, sample preparation and measurements of the morphology-conductivity relationship.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Novel nanostructured thermoelectric hybrid materials
In this project, we aim to fabricate and investigate novel organic-inorganic hybrid materials for thermoelectric applications. The goal is to realize efficient low temperature (T < 100°C) thermoelectric thin films and coatings which can contribute for example to energy efficient buildings. By combining nanostructured inorganic materials with conducting polymers a novel approach for this class of materials shall be realized. Possible inorganic nanomaterial components include Silicon nanocrystals (either undoped, n-type or p-type doped) as well as other nanoparticles. Different polymer materials such as the polymer blends of conjugated polymers, which can be tuned in conductivity and in its nanostructure, shall be used as the organic partner in our hybrid approach.
suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Novel pathways to hybrid solar cells

Hybrid solar cells combine an inorganic and an organic component into a photovoltaic cell. They combine the advantages of inorganic materials (e.g. metal oxides: TiO2 or ZnO) such as high charge carrier mobility and very high stability with those of organic materials (e.g. conducting polymers: P3HT) such as cost-effectiveness and flexibility. In comparison with standard silicon solar cells, the hybrid solar cells can be easily manufactured and can allow for alternative processing techniques as for example spray-coating and printing. In contrast to dye sensitized solar cells (DSSCs), hybrid solar cell devices contain no dye as active components and consequently problems such as photo-bleaching are mitigated. Moreover, all materials in the hybrid solar cells are solid and thus no sealing to protect against leakage of aggressive solvents such as in DSSCs is required. Regarding application, the hybrid solar cells are more environmentally friendly. Compared to organic solar cells, which are composed purely out of organic components, hybrid solar cells are expected to have higher lifetime stability. In particular, a degradation of the morphology, which is one pathway in organic solar cell degradation, cannot happen in the hybrid solar cells. The inorganic component acts as a corset to the morphology and prevents structural changes. Despite all these advantages of hybrid solar cells, so far most research on alternative solar cells beyond the silicon solar cells, has been focused on DSSCs and organic solar cells. hybrid solar cells have gained much less attention and therefore have a high undiscovered potential, which will be investigated in the present thesis based on novel pathways.

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Ordnungs-induzierte Funktionalität in Heuslerverbindungen

Heuslerlegierungen sind eine prominente Klasse funktioneller Materialien mit einem weiten Anwendungsbereich, z.B. als magnetische Formgedächtnislegierungen, magnetokalorische Materialien oder Halbmetalle für Spintronik-Anwendungen. Aspekte ihrer Funktionalität wie z.B. die Arbeitstemperatur hängen empfindlich von der eingestellten atomaren Ordnung ab. In unserer Gruppe beschäftigen wir uns mit der Messung und Beschreibung der damit zusammenhängenden Phänomene und verwenden dabei kalorimetrische Methoden wie auch Neutronen- und Röntgenstreuung. Die theoretisch vorhergesagten Halbmetalle NiCoMnGa und NiCoMnAl sowie das magnetische Formgedächtnissystem Ni2MnAl sind die Systeme, an denen wir im Moment am meisten interessiert sind.

Der Schwerpunkt der angebotenen Bachelorarbeit liegt in der Untersuchung der Ordnungskinetik eines spezifischen Heuslersystems v.a. mittels Differential Scanning Calorimetry (DSC). Während im Fall von NiCoMn(Ga/Al) das Ziel in der möglichen Ordnungseinstellung am B2-L2_1-Übergang liegt, ist es im Fall von Ni2MnAl der Einfluss der Ordnung auf den martensitischen Übergang, wobei auch die Untersuchung verwandter Systeme denkbar ist. Dies ist eine genuin wissenschaftliche Fragestellung, von der Publikation der gewonnenen Erkenntnisse unter Mitwirkung der/des Bachelorkandidaten ist auszugehen.

Kontakt: Michael Leitner michael.leitner@frm2.tum.de, Pascal Neibecker pascal.neibecker@frm2.tum.de

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Winfried Petry
Pressure sensitive adhesives applied to fibers

In this experimental project, the student will investigate the debonding mechanisms of pressure sensitive adhesives applied to fiber surfaces. With pressure sensitive adhesives of adjusted viscoelasticity non-permanent bonds are formed. The debonding mechanism of planar surfaces attached to arrangements of fibers will be investigated with a tailor-made instrument combining mechanical and optical measurements. The project will involve a literature review, sample preparation and characterization of surface attached fibers.

suitable as
  • Bachelor’s Thesis Physics
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Printed polymer-based thin film batteries

Materials for high energy density, solid-state batteries have been tremendously explored in the last decade. In particular, lithium-ion technology has attracted major interest. Among the many different types of batteries, the so-called polymer-based thin film batteries are very attractive as they can be incorporated into thin film devices. An inherent important part of such thin film lithium ion batteries is the membrane and solid-state polymer electrolyte membranes have attracted high attention in this respect. Lithium ions’ incorporation into solid-state polymer electrolyte membranes had shown a significant effect on both, the structure and properties, of the membranes in either the bulk or film format. The morphological reorganization and the thermodynamic properties of the solid-state polymer electrolyte membrane upon adding lithium salts and small molecules are the subjects of the experimental investigation. The polymer membranes will be prepared with printing. The structure and crystallinity of the lithium-doped membranes at different temperatures will be investigated with small/wide-angle X-ray scattering (SAXS/WAXS). The effects of morphology on the ionic conductivity of these ion-conducting membranes will be investigated using impedance spectroscopy. Aim of the present study is to increase conductivity with the help of small molecule additives, which can further improve the membrane morphology beyond the possibilities of the standard approach. Such high conductivity will be very beneficial for further downsizing of polymer-based thin film batteries.

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Structural analysis of hybrid polymer–solid thin films
Nanostructured polymer–solid hybrid thin films have gained a lot of attention during the last decade owing to the broad spectrum of technological applications such as solar cell, Li-ion battery, OLEDs and sensors. The structure of metal nanoparticles-polymer hybrid thin film is successfully probed with advanced grazing-incidence small-angle X-ray technique (GISAXS). In-situ GISAXS study of metal deposition on nanostructured polymer templates is performed at large-scale facility DESY, in Hamburg. In a millisecond time-resolved experiment, large amount of data is generated that enables a real-time monitoring of the growth kinetics of metal nanoparticles on the polymer surfaces. To characterize the structure of these polymer-solid hybrid materials, analysis models needs to be developed for interpreting the resulting GISAXS patterns. Software packages, useful for data analysis for advanced grazing-incidence techniques, are currently available. Structural information on the hybrid films, including the metal particle size, size distribution, positional distribution factor, and particle mobility on the sample surface can be obtained, by applying these analysis models to fit the experimental GISAXS data. The work will answer open questions on how the high-ordered arrays of solid materials forms on polymer surfaces, starting from microscopic (atomistic) up to mesoscopic (aggregate) level.
suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Validation of ab-initio Molecular Dynamics Simulations with Neutron Scattering Data

The diffusion speed of water molecules depends i.a. on the presence of salt ions: while for example NaCl ions slow the H2O diffusion down, it is sped up in CsI solutions. While this effect could so far not be reproduced by classical molecular dynamics simulations, ab-initio molecular dynamics simulations have recently succeeded in doing so (PNAS 2014 111 (9) 3310-3315; doi:10.1073/pnas.1400675111). In this project, the student will analyse neutron scattering data measured at the instrument TOFTOF to obtain a reliable measurement of the intermediate scattering function which can then be compared with the ab-initio simulation. The project will involve a literature review, careful analysis of the existing neutron data, and discussion of the obtained agreement/disagreement between simulation and experiment.

Betreuer: Dr. Sebastian Busch, sebastian.busch@hzg.de, 089-289-10764

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Winfried Petry

Current and Finished Theses in the Group

Construction and Commissioning of a Pulsed-DC Sputtering System and Characterization of sputtered ZrN layers
Abschlussarbeit im Masterstudiengang Physik (Kern-, Teilchen- und Astrophysik)
Themensteller(in): Winfried Petry
Development of chemical gas sensors for CO2 and humidity
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Peter Müller-Buschbaum
In-Situ Messungen von organischen und hybriden Solarzellen
Abschlussarbeit im Masterstudiengang Physik (Physik der kondensierten Materie)
Themensteller(in): Peter Müller-Buschbaum
Novel nanostructured thermoelectric hybrid materials
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Peter Müller-Buschbaum
Novel pathways to hybrid solar cells
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Peter Müller-Buschbaum
Novel pathways to hybrid solar cells
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Peter Müller-Buschbaum

Condensed Matter

When atoms interact things can get interesting. Fundamental research on the underlying properties of materials and nanostructures and exploration of the potential they provide for applications.