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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
Materialphysik auf atomarer Skala 2
eLearning-Kurs
Zuordnung zu Modulen:
VO 2 Leitner, M. Mi, 10:00–12:00
Mess- und Sensortechnologie (MS&E)
eLearning-Kurs
Zuordnung zu Modulen:
VO 2 Große, C. Müller-Buschbaum, P. Mi, 10:00–12:00, virtuell
Physics with neutrons 2
eLearning-Kurs
Zuordnung zu Modulen:
VO 2 Petry, W.
Mitwirkende: Senyshyn, A.
Mi, 12:00–14:00, PH-Cont. C.3202
Polymer Physics 2
eLearning-Kurs
Zuordnung zu Modulen:
VO 2 Müller-Buschbaum, P.
Mitwirkende: Körstgens, V.
Di, 10:00–12:00, PH II 227
Funktionelle weiche Materialien
Zuordnung zu Modulen:
PS 2 Müller-Buschbaum, P. Papadakis, C. Di, 08:30–10:00, PH 3734
Seminar über Neutronen in Forschung und Industrie
aktuelle Informationen
Zuordnung zu Modulen:
PS 2 Märkisch, B. Morkel, C. Müller-Buschbaum, P. Pfleiderer, C.
Mitwirkende: Franz, C.Park, J.
Mo, 14:30–16:00, virtuell
Exercise Physics with Neutrons 2
eLearning-Kurs
Zuordnung zu Modulen:
UE 2 Senyshyn, A.
Leitung/Koordination: Petry, W.
Termine in Gruppen
Exercise to Polymer Physics 2
eLearning-Kurs
Zuordnung zu Modulen:
UE 2 Körstgens, V.
Leitung/Koordination: Müller-Buschbaum, P.
Termine in Gruppen
Übung zu Mess- und Sensortechnologie (MS&E)
eLearning-Kurs
Zuordnung zu Modulen:
UE 1 Kollofrath, J. Reitenbach, J.
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.
FOPRA-Versuch 42: Rasterkraftmikroskopie
aktuelle Informationen
Zuordnung zu Modulen:
PR 1 Müller-Buschbaum, P.
Mitwirkende: Weindl, C.
FOPRA-Versuch 61: Neutronenstreuung am FRM II
aktuelle Informationen
Zuordnung zu Modulen:
PR 1 Müller-Buschbaum, P.
Mitwirkende: Georgii, R.
Führung durch die Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II) für Studierende der Physik
aktuelle Informationen
Zuordnung zu Modulen:
EX 0.1
Leitung/Koordination: Müller-Buschbaum, P.
Seminar: Polymere
Zuordnung zu Modulen:
SE 2 Müller-Buschbaum, P. Papadakis, C. Mi, 13:00–15:00, PH 3734
Seminar über Struktur und Dynamik kondensierter Materie
Zuordnung zu Modulen:
SE 2 Müller-Buschbaum, P. Papadakis, C. Di, 13:00–15:00, PH 3734

Offers for Theses in the Group

Bioinspired electrodes for brain wave detection
With increasing demands in brain computer interfaces measuring biosignals non-invasively becomes more important. Applications like measuring brain waves via electroencephalography (EEG) with dry electrodes remains challenging as for a steady biosignal acquisition adhesion to the skin has to be maintained all the time. The thesis will include the preparation of mussel-inspired hydrogels and the investigation of its conductive and adhesive properties. Furthermore, the EEG-performance of these electrodes will be evaluated with a dedicated setup.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Conductive paper
Transparent flexible substrates with electrical conductivity are an essential component for display technologies of devices like smartphones. In organic photovoltaics the use of flexible substrates allows for applications with a new versatility. We follow an environmentally friendly approach with the use of nanocellulose derived from wood in combination with conductive polymers. This project comprises the preparation of composite films with printing technology and the characterization of conductivity and optical properties.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Doping of thermoelectric polymer films
Thermoelectric device transform waste heat into electricity and thereby are essential in energy saving in the future. Doping of the polymer blend PEDOT:PSS is known to improve its thermoelectric (TE) performance. In this work, PEDOT:PSS is doped with different zwitterions, and their effect on the relationship of structure-properties of the films is characterized. It can be expected that the zwitterions can effectively induce a charge screening between PEDOT and PSS and consequently lead to significant conductivity enhancement, while the enhancement in the Seebeck coefficient is ascribed to the dipole moment of zwitterion and the interfacial dipole moment formed at the surface of the PEDOT:PSS films. Our findings will provide an understanding of the zwitterion-treated modification for PEDOT:PSS films which will be important for TE device applications.
suitable as
  • Bachelor’s Thesis 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 18%. 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 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
Lightweight Organic Solar Cells as Alternative to Nuclear Batteries for Deep Space Power Generation
The exploration of the outer solar system so far relied heavily on the use of scarce, highly radioactive plutonium stockpiles for power generation, as traditional solar cells have a too low power-to-mass ratio in low light environments to be suitable for those missions. Latest advances in organic solar cells now open up the possibility of utilising them on lightweight foils as photovoltaic solar sails for efficient power generation in low solar irradiation conditions. We have just recently successfully demonstrated the first power generation of organic solar cells on a suborbital space-mission, featuring our in-house developed "Organic and Hybrid Solar Cells In Space" (OHSCIS) experiment. While this demonstration still employed a more traditional, non weight-optimised solar cell design for more typical earth-bound applications, your task will now be to further optimise the design and material selection to reduce the mass of our organic solar cells for our next upcoming space-mission. The solar cells you build will then take part in this mission and be launched into space.
suitable as
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Low-temperature fabrication of titania films for hybrid solar cells on flexible substrates
Low-temperature (<150°C) route towards titania films offer promise for simple manufacturing, compatibility with flexible substrates, and titania-based solar cells. Herein, we use a specific titania precursor, ethylene glycol-modified titanate, to fabricate titania films as an electron-transporting layer. This experimental bachelor thesis aims at understanding the working principle of hybrid solar cells and the corresponding fabrication process. Different film characterization will be used such as SEM, GISAXS, XRD, UV-Vis, XPS, etc. The project will involve a literature review, sample preparation process, data analysis and result evaluation.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Near-infrared Quantum Dot Solar Cells for Space Application

We’re looking for a master student to join the next flight project of NIR CQDs solar cells to space. The general idea about this research topic and your major tasks in this project are introduced as follow.

Quantum dots (QDs) are semiconductor nanocrystals with typical size of 2-10 nm. When the size of materials become very small in the range of nanometers, the optoelectronic properties or other properties are significantly different from their bulk counterparts. Notably, colloidal QDs’ unique advantages and properties have shown great promises as the light absorbers in solar cells, such as solution-processability and size tunability of bandgap, which enables the QD absorbers to harvest infrared low-energy photons of the solar spectrum beyond the absorption edge of silicon very efficiently. Therefore, as opposed to the costly and complicated fabrication process of conventional NIR solar cells, colloidal QDs based NIR solar cells have shown great promises. To date, great advances and improvements of the device performance, exceeding efficiencies of 10 % already, have been achieved by several fabrication strategies.

In a previous experiment, we launched organic and perovskite solar cells to space for the first time ever and studied how these devices operate in the space environment. For the second space flight, we want to test the operation of NIR colloidal QD solar cells in orbital altitudes for the first time. Here, your master thesis starts.

The first part of your project will be to learn how to fabricate NIR CQD solar cells and characterize them with different spectroscopic and morphologic analysis methods. You will find yourself in a team of motivated master students that are all working on the fabrication and optimization of their solar cell systems, where knowledge exchange and communication create a solid base for a productive and educational environment. Thus, you will learn a lot about solar cells and the principles behind many of their typical characterization methods. Based on your measurements of your solar cells, you will be guided to optimize the fabrication methods and solar cell layers to improve the device performance.

The second part of this project will be to study your solar cells before and after their space flight to learn how the solar cells behave after experiencing extreme conditions during the rocket flight and exotic space environment. Your novel results will be worth publishing in a scientific journal, giving you the possibility to become a co-author in this future work. We’re looking forward to meeting you and telling you more about this project!

suitable as
  • Master’s Thesis Applied and Engineering 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 Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Perovskite solar cells for space applications

Perovskite solar cells have become a hot research topic in the last few years. The lightweight thin-film solar cells are of particular interest for space applications due to their exceptional power per mass, exceeding their inorganic counterparts by magnitudes. Presently, the next space study of perovskite solar cells is under preparation. Thus, the task will be to build perovskite solar cells on flexible substrates and characterize them under terrestrial condition to identify interesting candidates, which can be selected for a future space mission. Main characterization will be IV-curve measurements and EQE studies.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Perovskite Solar Cells for Space Applications
Perovskite solar cells have become a hot research topic in the last few years. The lightweight thin-film solar cells are of particular interest for space applications due to their exceptional power per mass, exceeding their inorganic counterparts by magnitudes. Recently, we performed the Organic and Hybrid Solar Cells In Space experiment (OHSCIS) and launched of perovskite solar cells to space for the first time. The mechanical and electronic design of the experiment aimed at maximizing the data collection rate and precise measurements. We showed that the perovskite solar cells operate in space conditions and produce reasonable power per area of up to 14 mW cm-2. Also during a phase being turned away from the sun, the solar cells produced power from collecting faint Sun-light scattered from Earth. Our results highlight the potential for near-Earth applications and deep space missions of these technologies. Soon a next space missing will come up and presently we are looking for an interested master student to join the exiting next flight of perovskite solar cells to space. The task will be to make new sets of perovskite solar cells and test them with the set-up. After the successful flight to space, the solar cell data need to be evaluated and analyzed in detail to learn from the space flight.
suitable as
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Printed perovskite solar cells
Organic-inorganic lead halide perovskite solar cells have recently achieved 25.5% efficiency owing to their tunable bandgap, high carrier mobility and long diffusion length. Nevertheless, most of the solar cells were fabricated based on the spin-coating method, which suffers from waste of material and missing scalability. In this regard, the printing technique, a simple and scalable method, is advantageous to realize a future commercial application of perovskite solar cells. In this project, we aim to fabricate perovskite solar cells by printing and have an overall understanding of the growth mechanism of the perovskite film during printing. We use imaging techniques (e.g. electron microscopy) and methods for structure and morphology determination, e.g. X-ray scattering.
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 Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Printed ZnO films
ZnO nanostructures with tunable optical, electrical properties can enable the realization of high-efficient nanodevices such as gas sensors, solar cells, light-emitting diodes and energy harvesters. Due to the rich phase separation behavior of block copolymers, they serve as the soft template to construct ZnO architectures with different morphologies and physical properties. Towards large-scale fabrication, an industrial-based slot-die printing technique is used as the film formation method. In this work, the morphology tuning of mesoporous ZnO thin films based on the slot-die coating and self-assembly pathway during the film formation process will be investigated and correlated with optical properties of the printed ZnO films.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Silicon-Germanium based anode coatings for Lithium-ion batteries
Lithium-ion batteries (LIBs) have taken over a major role in the field of energy storage since several years. Especially in sectors such as portable devices, renewable storage systems and electric vehicles, this technology is already dominating the market. In order to meet the ever-increasing requirements such as durability, energy density and manufacturing costs, it is essential to implement new performance-enhancing materials into the cell architecture. Group IV elements as Silicon (Si) and Germanium (Ge) are considered to be appealing alternatives to commercial graphite anodes due to their high-energy capacity. In this respect, Si is becoming the focus of research due to the highest theoretical capacity (4200 mAh g-1) and low working potential. Additional advantages such as environmental friendliness, resource abundance and low cost have prompted several research groups around the world to look closer into this topic. However, the cycling performance and the rate capacity of these novel anodes are still limited by the low intrinsic electron conductivity and poor Li+ diffusivity. In addition, Ge can provide better cyclability and a dramatically improved electron conductivity into the system. Within this thesis, we focus on diblock copolymer templating of Si/Ge thin films as novel anode materials for LIBs. Here CR2032 Litihium-ion coin cells will be manufactured. Mayor topic will be an extensive study on different anode coatings with real and reciprocal space analysis methods.
suitable as
  • Master’s Thesis Applied and Engineering 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 Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Superlattice deformation in quantum dot films and its impact on optoelectronic performance

Quantum dots (QDs) nowadays find a broad application, ranging from TV screens to next- generation solar cells. Like artificial atoms, QDs form a superlattice structure when prepared as a thin film. This project aims to investigate the impact of deformed superlattices on optoelectronic performance. You have the chance to prepare QD films on stretchable substrates and introduce superlattice deformation by stretching in a custom-built apparatus. At the same time, you will trace the introduced optoelectronic changes with photoluminescence measurements and UV-Vis spectroscopy to deepen the understanding of this fascinating quantum material.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Synthesis and self-assembly of gold nanoparticles for optoelectronic devices
Gold nanoparticles (Au NPs) show peculiar optical and electrical properties compared with the macroscopic metal owing to the characteristic of a nanoscale. Recently many advantages were made in optoelectronic devices applications with broadening band and energy transfer. In this project, your work will focus on the Au NPs structure regulation, since the size, density, and morphology of the Au NPs will influence the crystallinity of the photoactive film and charge transportation of the device. Specifically, you can work on one of the following topics: a) Synthesis and investigate optical properties of different morphology of gold nanoparticles b) Self-assembly of monolayer Au NPs array for optoelectronic devices.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum

Current and Finished Theses in the Group

Development, verification and validation of computational models within a compact molten salt reactor core
Abschlussarbeit im Masterstudiengang Physik (Kern-, Teilchen- und Astrophysik)
Themensteller(in): Peter Müller-Buschbaum
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