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Functional Materials

Prof. Peter Müller-Buschbaum

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 judge 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

Professor

Office

Scientists

Students

Other Staff

Teaching

Course with Participations of Group Members

Titel und Modulzuordnung
ArtSWSDozent(en)Termine
Höhere Physik 2
Zuordnung zu Modulen:
VO 4 Papadakis, C. Fr, 08:00–12:00, PH 2271
Materialphysik auf atomarer Skala 2
Zuordnung zu Modulen:
VO 2 Leitner, M. Mi, 10:00–12:00, PH-Cont. C.3201
Mess- und Sensortechnologie (MS&E)
Zuordnung zu Modulen:
VO 2 Große, C. Müller-Buschbaum, P. Mi, 10:00–12:00, PH II 227
Polymer Physics 2
Zuordnung zu Modulen:
VO 2 Müller-Buschbaum, P.
Mitwirkende: Körstgens, V.
Di, 10:00–12:00, PH II 227
Seminar über Neutronen in Forschung und Industrie
Zuordnung zu Modulen:
PS 2 Böni, P. Morkel, C. Müller-Buschbaum, P.
Mitwirkende: Koutsioumpas, A.Skoulatos, M.
Mo, 14:30–16:00, PH HS3
Exercise to Polymer Physics 2
Zuordnung zu Modulen:
UE 2 Körstgens, V.
Leitung/Koordination: Müller-Buschbaum, P.
Termine in Gruppen
Übung zu Höhere Physik 2
Zuordnung zu Modulen:
UE 2 Geiger, C.
Leitung/Koordination: Papadakis, C.
Termine in Gruppen
Übung zu Mess- und Sensortechnologie (MS&E)
Zuordnung zu Modulen:
UE 1
Leitung/Koordination: Müller-Buschbaum, P.
Termine in Gruppen
Aktuelle Probleme der organischen Photovoltaik
Zuordnung zu Modulen:
SE 2 Müller-Buschbaum, P. Mo, 10:00–11:30, PH 3734
Dozentensprechstunde Polymerphysik 2
Zuordnung zu Modulen:
RE 2 Müller-Buschbaum, P.
Dozentensprechstunde zu Mess- und Sensortechnologie (MS&E)
Zuordnung zu Modulen:
RE 2 Müller-Buschbaum, P. Mi, 18:30–20:00, PH 3278
Edgar-Lüscher-Lehrerfortbildungs-Seminar "Physik in Archäologie und Kunstgeschichte"
Diese Lehrveranstaltung ist keinem Modul zugeordnet.
WS 2 Müller-Buschbaum, P.
Seminar: Polymere
Zuordnung zu Modulen:
SE 2 Müller-Buschbaum, P. Papadakis, C. Di, 13:00–15:00, PH 3734
Seminar über Struktur und Dynamik kondensierter Materie
Zuordnung zu Modulen:
SE 2 Müller-Buschbaum, P. Papadakis, C. Mi, 13:00–15:00, PH 3734

Offers for Theses in the Group

Biopolymer templated hierarchical structures for hybrid solar cells

Hybrid solar cells have promising potential for playing a major role in renewable energy transition. They provide the possibility of flexible and light weighted photovoltaic in a large scale roll-to-roll fabrication, by combining the advantages of organic and inorganic semiconductors. For improved device performance, the morphological structure of the system has a crucial influence. This experimental bachelor thesis aims for a novel approach in templating desired hierarchical structure of the inorganic part, using environmentally friendly, non-toxic biopolymers such as proteins. Thin films of protein/semiconductor composites will be fabricated by spray coating for further structural investigations with the help of scanning electron and atomic force microscopy. Besides the laboratory work, the project also involves a literature review.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Block copolymer membranes for lithium ion microbatteries

Lithium ion microbattery is the type of battery where all components (electrodes, membrane, and packaging) are in the thin film format. The need for such types of batteries is to provide light-weight and shape flexible solid-state energy sources for some miniature medical devices, such as implantable pumps, biosensors, and wireless capsule endoscopes. Membrane based on mixing both lithium slat and polyelectrolyte block copolymers will be prepared and investigated using small-angle X-ray scattering and impedance spectroscopy. The effect of a third component such as inorganic SiO2 nanoparticles on the morphology and conductivity of the prepared thin film membranes will be studied. The best performing membrane will be assembled between two electrodes to probe the performance of a complete assembly of a solid-state lithium battery. The project will involve a literature review, sample preparation, x-ray scattering and impedance spectroscopy.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: 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.

Currently, the European Spallation Source (ESS) is being built in Lund, Sweden. It is envisioned to be the worlds most powerful neutron spallation source and will provide new possibilities in the field of neutron research. In a cooperation between Bielefeld, Darmstadt and Munich a modular sample environment for the SKADI beamline, a small angle scattering beamline at the ESS is under development.

We are currently developing the setup for grazing incidence small angle neutron scattering (GISANS) and as such development is required on the 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, the read-out system.

First measurements with the constructed sample environment will be performed at neutron scattering instruments at the MLZ. Furthermore, the project offers the possibility of collaboration on national and international neutron radiation centers (ILL – Grenoble, ESS - Lund).

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
High efficiency next generation organic solar cells

Next generation organic solar cells are solar cells beyond the silicon type photovoltaic devices. Organic solar cells have reached efficiencies in the champion solar cells well above 15%. 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.

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
High efficiency organic solar cells

Organic solar cells have gained significant improvements via novel organic synthesis methods and optimized fabrication routes, especially with respect to their potential roll-to-roll processing for large-area device manufacturing. Printing technique, such as slot-die printing, allows for up-scaling to industrial-oriented scale which is not the case for laboratory deposition techniques like spin coating. This experimental bachelor thesis aims at understanding organic solar cell working principle and the corresponding fabrication process of solar cell via advanced slot-die printing technique. Besides, the relationship between its efficiency and morphology will be investigated by different measuring technique, such as AFM and small angle x-ray scattering. The project will involve a literature review, sample preparation process, data analysis and result exhibition.

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 GeO) such as high charge carrier mobility and very high stability with those of organic materials (e.g. conducting polymers: PTB7) 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
Novel thermoelectric materials for energy savings

Thermoelectric (TE) materials can be used in TE generators to convert a temperature gradient directly into electrical energy. Therefore they are of great interest in terms of waste heat recovery or the use of solar thermal energy. To be qualified as good TE materials, polymers should have a high Seebeck coefficient S and electrical conductivity σ. In this bachelor thesis polymer films will be post-treated with different methods in order to increase S and σ, leading to a novel efficient TE generator. This project will involve a literature review, polymer film preparation/treatment and TE measurements of the fabricated films.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Photochromic paper

The major component of conventional paper are cellulose fibers. With cellulose nanocrystals or microfibrils the manufacturing of thin transparent layers is possible. These layers serve as sustainable substrates in flexible applications. We aim for functional films which reversibly change the color with irradiation of UV-light. Composite films of cellulose and inorganic nanoparticles will be prepared by advanced deposition methods including spray deposition and slot die coating. The project will involve a literature review, sample preparation, x-ray diffraction studies and UVvis spectroscopy.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Printed organic solar cells

Organic photovoltaics are a promising alternative to conventional silicon solar cells as they offer several potential advantages e.g. low weight, high mechanical flexibility and low-cost production. The chemical structure of the polymer donor and the non-fullerene acceptor molecule as well as their ratio have an impact on the structure and performance of an organic solar cell. Printing of active layers with a slot-die-coating technique enables up-scaling of organic solar cells devices. This experimental bachelor thesis aims at the basic understanding of the printing process and the properties of the active material as well as the construction of an organic solar cell. Active layers are printed with different donor:acceptor ratios and post-characterized by methods such as UV/Vis spectroscopy, optical microscopy and scanning electron microscopy. The project will involve a literature review, sample preparation and post-characterization of the films.

suitable as
  • Bachelor’s Thesis 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
Printing of perovskite thin-films for next generation solar cells

Perovskite solar cells have dramatically progressed within the last 2 years. Meanwhile championship perovskite solar cells have demonstrated efficiencies above 25%. The general intent of this work is to optimize printed perovskite thin-films for high-quality photovoltaic devices. This will include material and solution preparation, optimizing the printing process and analysis of printed films and/or devices. Analytical methods will focus on film morphology, spectroscopic material properties, crystal structure analysis and current-voltage measurements of self-built solar cells. The thesis also includes a brief literature review.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
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.

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Smart hydrogel thin films and their potential use in soft robotics

Smart hydrogel thin films react with significant changes in their properties towards an altered external stimulus such as temperature, relative humidity or light. This flexible behavior can be exploited as nano-sensors, or artificial pumps and muscles in the field of soft-robotics. Due to the thinness of such materials (~50 – 150 nm), response times are strongly decreased. Mesoscopic parameters such as film thickness and water content upon a changing stimulus are probed with neutron scattering techniques, while polymer – water interactions are followed with Fourier-transform infrared spectroscopy.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: 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.

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Vapor-sensitive block copolymer thin films

Thermoresponsive block copolymer thin films can be applied in vapor sensors detecting water and organic cosolvents. As sensitive layers, they exhibit characteristic swelling kinetics steered by cosolvent mediated effective interactions between individual polymer chains. This bachelor thesis will cover the fundamentals of responsive polymers and the cononsolvency effect. The experimental part revolves around thin film preparation and swelling behavior analysis in our vapor chamber. The project will include a brief literature review.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum

Current and Finished Theses in the Group

Analysis and Reconstruction of X-ray and Neutron diffraction computed tomography data
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Winfried Petry
Effect of an Ionic Liquid Post-treatment on Thermoelectric Properties of Thin PEDOT:PSS Films
Abschlussarbeit im Bachelorstudiengang Physik
Themensteller(in): Peter Müller-Buschbaum
A Comparative Investigation on PEDOT:PSS-based Anodes in ITO-Free Organic Light-Emitting Diodes
Abschlussarbeit im Bachelorstudiengang Physik
Themensteller(in): Peter Müller-Buschbaum
Fundamental Characterization of Thin Films Based on a Novel Heavy Element Containing Small Molecule for Photovoltaic Applications
Abschlussarbeit im Bachelorstudiengang Physik
Themensteller(in): Peter Müller-Buschbaum
High efficiency next generation solar cells
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Peter Müller-Buschbaum
High efficiency perovskite solar cells
Abschlussarbeit im Bachelorstudiengang Physik
Themensteller(in): Peter Müller-Buschbaum
Conductive Paper
Abschlussarbeit im Bachelorstudiengang Physik
Themensteller(in): Peter Müller-Buschbaum
Novel dry electrodes for electroencephalography
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Peter Müller-Buschbaum
Photochromic Paper
Abschlussarbeit im Bachelorstudiengang Physik
Themensteller(in): Peter Müller-Buschbaum
Role of molecular interactions for stimuli-responsive polymers of potential use in soft robotics
Abschlussarbeit im Bachelorstudiengang Physik
Themensteller(in): Peter Müller-Buschbaum
Role of Molecular Interactions for Stimuli-Responsive Polymers of Potential Use in Soft Robotics
Abschlussarbeit im Bachelorstudiengang Physik
Themensteller(in): Peter Müller-Buschbaum
TISANE: AC Coil Setup for Time Resolved Kinetic Neutron Scattering
Abschlussarbeit im Bachelorstudiengang Physik
Themensteller(in): Winfried Petry
Investigations on Polymer Electrodes
Abschlussarbeit im Bachelorstudiengang Physik
Themensteller(in): Peter Müller-Buschbaum
Investigation Of New Materials For High-Efficiency Polymer Solar Cells
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Peter Müller-Buschbaum
Investigation of Polymer Electrodes
Abschlussarbeit im Bachelorstudiengang Physik
Themensteller(in): Peter Müller-Buschbaum
Films of water-processable polythiophene in energy applications
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Peter Müller-Buschbaum
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