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Funktionelle Materialien

Peter Müller-Buschbaum

Forschungsgebiet

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.

Adresse/Kontakt

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

Mitarbeiterinnen und Mitarbeiter der Arbeitsgruppe

Professorinnen und Professoren

Mitarbeiterinnen und Mitarbeiter

Lehrangebot der Arbeitsgruppe

Lehrveranstaltungen mit Beteiligung der Arbeitsgruppe

Ausgeschriebene Angebote für Abschlussarbeiten an der Arbeitsgruppe

Analysis of metal nanostructure evolution on polymer surfaces

Via sputter deposition thin metal films have been deposited on top of conductive polymer surfaces. Such metal layers are typically used for contacts in organic electronics. During the sputter deposition the growth of the metal film was followed with in-situ scattering. In this project the student will analyze the in-situ scattering data with existing model software. Data will be fitted and from these fit characteristic structure parameters will be determined. From the temporal evolution of such structure parameters the scaling laws of metal growth on polymer can be deduced. The project will involve a literature review, fitting of the existing data with model software and discussion of structure parameters.

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Peter Müller-Buschbaum
Development of a flexible sample environment for neutron scattering on multi-stimuli responsive hydrogel thin films

Since several decades, multi-stimuli responsive hydrogels are attracting the scientific focus, based on their versatile applicability in the fields of sensoric, drug delivery or nano-switches. When changing an external stimulus such as pH, temperature, pressure or light illumination specific dynamic processes are taking place inside the hydrogel network. Thus, these polymers are an interesting foundation for new research fields such as green architecture or soft robotics. In order to apply responsive hydrogels in the aforementioned technical fields, the mechanisms behind these dynamic processes are an object of current research.

Neutron scattering is a powerful and suitable measurement technique for studying dynamic activities inside a hydrogel. Information about thickness, material composition and roughness can be obtained, even during dynamic processes.

The task is to develope a setup for grazing incidence small angle neutron scattering (GISANS) and as such development is required onthe final design and layout of the measurement setup,a quick and reliable sample change system,the electronical circuit and connections to the measurement chamber,a remote-control of all elements andthe read-out system.

First measurements with the constructed sample environment will be performed at neutron scattering instruments at the MLZ.

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Peter Müller-Buschbaum
High efficiency next generation solar cells

Next generation solar cells are solar cells beyond the silicon type photovoltaic devices. Organic solar cells have reached efficiencies in the champion solar cells well above 10%. Key element of such solar cells is the highly designed active layer, which transfers light into separated charge carriers. Aim of this experimental project is the preparation and full characterization of an active layer for high performance organic photovoltaic devices to further understand the fundamental correlation between morphology and solar cell performance. In this work a novel efficiency record-setting system will be investigated regarding the influence of an additional third component, in our case, either solvent additive or polymer. The project will involve a literature review, sample preparation, photovoltaic device fabrication and photoluminescent measurements. The focus is the usage of advanced scattering techniques for the determination of structural length scales of the active layer in the solar cell.

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Peter Müller-Buschbaum
Interfaces between polymer electrolyte, electrodes and metal current collectors of thin film lithium-ion batteries

Our world without lithium ion batteries (LIBs) is hardly imaginable. They are used in nearly every electronic mobile device like laptops, cellphones, cars and medical power implants. But their potential for developing safer and more powerful batteries is not exploited yet since the major LIB production uses technologies commercialized in 1991. Aiming for novel thin film LIBs from solution based processing using polymer electrolytes and sophisticated hybrid electrodes can be the key to new, fast chargeable, high energy and power density LIBs.

Using diblock copolymers like polystyrene-block-polyethylene oxide (PS-b-PEO) with a mechanically and thermally stable PS block and a soft, lithium-ion conducting PEO block enables the fabrication of solid state polymer thin film lithium-ion batteries and even the application of metallic lithium as anode. To increase charge and discharge rates of Li-ion batteries – one of the main drawback of batteries compared to e.g. fossil fuels – these thin film batteries are a promising approach.

The task will be the fabrication of lab scale thin film Li-ion batteries via spin-coating, the morphological investigation of the functional polymer based layers of the battery and their interfaces as well as the revelation of their conductivity and influence on the batteries’ performance. Therefor advanced scattering techniques like grazing incidence small angle X-ray scattering (GISAXS) and X-ray reflectometry (XRR), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and battery cycling.

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Peter Müller-Buschbaum
Looking into the soft behavior of hybrid crystalline perovskite thin film

Solar cells based on organometallic lead halide perovskites have established themselves as a promising alternatives to commercial thin film solar cells. Photovoltaic conversion efficiencies have seen an increase from first reports of 3.8% to certified efficiencies of over 22% in less than a decade since the inception of the field. The crystallographic versatility of the material allows the possibility of extensive chemical tuning, which manifests in the material as a spectra of properties that may be obtained. This entices research on hybrid perovskite structures combining different organic and inorganic groups into a crystalline framework. Recent evidence indicates that the class of perovskite materials display characteristics which are suggestive of ‘soft matter’ like behavior. Ideal candidates would be helping demonstrate this claim through experimental work. The opportunity to be carrying out work in sophisticated environments, such as working in glovebox or carrying out state-of-the-art experiments at synchrotron sources are feasible. Other characterization techniques would be utilized for relevant archetypal measurements.

The project falls within a rapidly progressing field with great potential for industrialization. Inspired, promising candidates with good academic background and research experience may apply in order to acquire experience on relevant materials, electronic devices made thereof and characterization techniques for holistic knowledge within the booming field.


geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Peter Müller-Buschbaum
McStas neutron ray tracing calculations of an upgrade of the small-angle scattering instrument SANS-1 with a second detector

The properties of many materials are governed by their structure on the nanoscale (20–2000 Å). This structure can be studied with many methods, with small-angle neutron scattering (SANS) probably being the premier choice if magnetic materials or polymers are involved – or if a process is to be studied in-situ, i.e. one wants to watch the nanoscopic regime while working with the sample (heating, deforming, mixing, external magnetic or electric field, …).

There are several neutron small-angle scattering instruments at the Heinz Maier-Leibnitz Zentrum (MLZ), one of which is the SANS-1, jointly operated by TUM and Helmholtz Zentrum Geestacht (HZG). It is currently equipped with a 1m by 1m neutron detector with a pixel size of 8mm x 8 mm. A second, additional, detector is to be installed at this instrument. It has a smaller pixel size, but is also smaller in overall size. In this thesis project, two scenarios are to be compared:

  1. Placing the new detector further away from the sample than the current one. In this setup, even smaller scattering angles can be resolved than at the moment due to the smaller pixel size. Even larger structures than accessible at the moment can be resolved with this arrangement – but how much will be gained exactly?
  2. Placing the new detector closer to the sample than the current one. In this case, a wide range of scattering angles can be covered simultaneously, so that many different length scales can be watched at the same time during in-situ measurements. Would it be possible to find instrument settings that yield a usable signal on both detectors at the same time?

The well established Monte Carlo computer simulation program McStas-model of the instrument has to be completed with the two detectors, and then the scattering of some typical samples have to be calculated and compared. The neutron counts have to be histogrammed in bins of the neutron momentum transfer. The work will be performed together with the German Engineering Materials Science team @ MLZ and offers the unique possibility to work at the MLZ, an internationally leading large scale neutron facility.


Contact: Dr. Sebastian Busch, Sebastian.Busch@hzg.de, 089 289 10764

Prof. Dr. Winfried Petry, winfried.petry@frm2.tum.de, 089 289 14704


geeignet als
  • Bachelorarbeit Physik
Themensteller(in): Winfried Petry
McStas neutron ray tracing calculations of the reflectometer REFSANS

McStas neutron ray tracing calculations of the reflectometer REFSANS

A neutron reflectometer can be used to study thin films at interfaces by illuminating the film under a shallow angle with neutrons and counting how many neutrons are reflected specularly. The reflectometer REFSANS at the Heinz Maier-Leibnitz Zentrum (MLZ) is in particular designed to look at the water-air interface. Since this interface cannot be tilted, a complex neutron optic bends the neutron beam onto this horizontal surface in order to realize different shallow angles.

There are currently two separate Monte Carlo McStas simulations of parts of the instrument: The neutron guide from the source to the start of the neutron optics, and the neutron optics itself. The task in this project is to use the output of the neutron guide simulation as input for the neutron optics simulation and to optimize the configuration of the neutron optics in the simulation for bent beams.


The work will be performed together with the German Engineering Materials Science team @ MLZ and offers the unique possibility to work at the MLZ, an internationally leading large scale neutron facility.

Contact: Dr. Sebastian Busch, Sebastian.Busch@hzg.de, 089 289 10764

Prof. Dr. Winfried Petry, winfried.petry@frm2.tum.de, 089 289 14704

geeignet als
  • Bachelorarbeit Physik
Themensteller(in): Winfried Petry
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.

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Peter Müller-Buschbaum
Radio frequency neutron spin flipper @ SANS-1: simulation, implementation and characterization

Small-angle neutron scattering (SANS) is a powerful technique to study correlations of condensed matter samples in the range of 20–2000 Å. The new small angle scattering instrument SANS-1 is a joint project of TUM and Helmholtz Zentrum Geestacht (HZG). SANS-1 is located at the end of neutron guide NL4a in the Neutron Guide Hall West of Heinz Maier-Leibnitz Zentrum (MLZ).  SANS-1 is a standard pinhole SANS instrument with both 20 m collimation distance and 20 m sample detector distance, respectively.

For magnetic SANS with polarized neutrons a radio-frequency (RF)-Spin-flipper is required. Recently such a RF flipper has been newly built has to be installed within an air chamber.  This new flipper will undergo different optimization procedures to ensure its performance for the wide wavelength range of SANS-1.  Therefore calculations and measurements will be performed to get optimal results for the final setup.  This task requires both mechanical work, knowledge of electronics and simulations of RF magnetic fields.


The work will be performed together with the SANS-1 team @ MLZ and offers the unique possibility to work at an internationally leading large scale neutron facility like the MLZ.


Contact: Dr. André Heinemann, Andre.Heinemann@hzg.de, 089 289 14534

Prof. Dr. Winfried Petry, winfried.petry@frm2.tum.de, 089 289 14704

geeignet als
  • Bachelorarbeit Physik
Themensteller(in): Winfried Petry
Self organization routes for nanostructuring hybrid perovskites toward high efficiency photovoltaics

Nanostructuring of thin films has been utilized as a method for light trapping and enhancing the optical path-length of photons within the absorbing material. Structured surfaces utilize geometries to enforce such routes which are commonly attained by energy, cost-extensive techniques such as lithography, plasmon resonance. Hybrid perovskites are solution processable materials that exhibit efficiencies competitive with the state-of-the-art silicon solar cells, at significantly lower costs. The precursors exhibit colloidal nature which makes it possible to tune thin film morphologies by controlling the chemical nature of these precursors by harnessing self-assembly behaviour in drying colloidal dispersions.

Mixed hybrid perovskite thin films will be prepared from colloidal solutions. The solution will be characterized by SAXS, DLS, UV-Vis. Interaction of the solution with substrates will be studied by means of contact angle measurements. Thin films prepared from colloidal dispersions will be characterized by XRD, SEM, AFM, UV-Vis. Solar cells will be prepared and characterized for their photovoltaic response.

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Peter Müller-Buschbaum
Smart nano-sensors made of stimuli-responsive polymers in solution and in thin films

Whereas macroscopic sensors made of stimuli-responsive hydrogels are well established, in the nanoworld such sensors still face many challenges. Potential fields of application of such sensors extend from engineering to bioengineering and medicine, e.g. as nanosensors for the control of concentration of glucose for diabetes patients or as switchable surface in the frame of tissue engineering. In this experimental project smart hydrogels, made of stimuli-responsive hydrogels will be investigated. Hydrogel films with thicknesses of a few tens to some hundreds of nanometers and spontaneously deswell or swell due to external stimuli, like temperature or the concentrations of ions. The changes in thickness and in molecular interactions in swelling or collapsing hydrogels will be probed during the switching process by different lab-based techniques. A comprehensive understanding of the switching process can be achieved by complementary neutron scattering experiments at large scale facilities. The project will involve a literature review, preparation of hydrogels, as well as experimental investigations and interpretations of the repeated switching of the stimuli-responsive hydrogels.


geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): 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.

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Peter Müller-Buschbaum
TISANE: AC coil setup for kinetic neutron scattering on ferro fluids

Small-angle neutron scattering (SANS) is a powerful technique to study correlations of condensed matter samples in the range of 20–2000 Å. As an extension of a standard SANS setup, TISANE (Time Involved Small Angle Neutron Scattering) is a new neutron scattering technique for time resolved kinetic neutron scattering. TISANE is able to resolve dynamic processes up to microsecond time-scales. The setup is based on two counter-rotating chopper disks installed at a standard small angle neutron scattering beamline.

Such a TISANE setup has recently been installed at the SANS-1 beamline at MLZ, jointly operated by TUM and Helmholtz Zentrum Geesthacht.  The task of this Bachelors thesis is the development, characterization and testing of new, dedicated high frequency AC coils to provide an experimental setup to study the dynamic correlations of ferro fluids (colloidal liquid made of nanoscale ferromagnetic particles in a carrier fluid) by means of time resolved SANS in a range of Hz to kHz. The task requires both mechanical work, knowledge of electronics and simulations of RF magnetic fields.


After characterization and implementation at the instrument SANS-1, the new setup will be used for experiments on ferro fluid samples. Besides the actual experiments, the second stage of the project involves the analysis and fitting of the gathered small angle neutron scattering data and requires a solid background in condensed matter physics and magnetism.


The work will be performed together with the SANS-1 team @ MLZ and offers the unique possibility to work at an internationally leading large scale neutron facility like the MLZ.

Contact: Dr. Sebastian Mühlbauer, sebastian.muehlbauer@frm2.tum.de, 089 289 10784

Prof. Dr. Winfried Petry, winfried.petry@frm2.tum.de, 089 289 14704

geeignet als
  • Bachelorarbeit Physik
Themensteller(in): Winfried Petry

Abgeschlossene und laufende Abschlussarbeiten an der Arbeitsgruppe

Bildung von UMo/Al-Interdiffusionsschichten durch Risse im Coating
Abschlussarbeit im Masterstudiengang Physik (Physik der kondensierten Materie)
Themensteller(in): Winfried Petry
Development of a Serpent 2 full-core model of FRM 2 with coupling to ANSYS CFX.
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Winfried Petry
hoch effiziente Solarzellen der nächsten Generation
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Peter Müller-Buschbaum
Smart nano-sensors made of stimuli-responsive polymers in solution and in thin films
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Peter Müller-Buschbaum
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