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Prof. Dr. rer. nat. Peter Müller-Buschbaum

Photo von Prof. Dr. rer. nat. Peter Müller-Buschbaum.
Phone
+49 89 289-12451
+49 89 289-12458
+49 89 289-12459
+49 89 289-12460
+49 89 289-14704
Room
3278
E-Mail
muellerb@ph.tum.de
Links
Homepage
Page in TUMonline
Group
Functional Materials
Job Titles
  • Head of Heinz Maier-Leibnitz Zentrum
  • Full Professorship on Functional Materials
  • Head of Research Neutron Source FRM II

Courses and Dates

Title and Module Assignment
ArtSWSLecturer(s)Dates
Measurement and Sensor Technology (MS&E)
eLearning course
Assigned to modules:
VO 2 Große, C. Müller-Buschbaum, P. Wed, 10:00–12:00, PH II 227
Polymer Physics 2
eLearning course
Assigned to modules:
VO 2 Müller-Buschbaum, P.
Assisstants: Körstgens, V.
Tue, 10:00–12:00, PH II 227
Functional Soft Materials
Assigned to modules:
PS 2 Müller-Buschbaum, P. Papadakis, C. Tue, 08:30–10:00, PH 3734
Seminar on neutrons in research and industry
current information
Assigned to modules:
PS 2 Märkisch, B. Morkel, C. Müller-Buschbaum, P.
Assisstants: Hayward, D.Park, J.
Mon, 14:30–16:00, PH HS3
Exercise to Polymer Physics 2
eLearning course
Assigned to modules:
UE 2 Körstgens, V.
Responsible/Coordination: Müller-Buschbaum, P.
dates in groups
Exercise to Measurement and Sensor Technology (MS&E)
eLearning course
Assigned to modules:
UE 1 Kollofrath, J. Wang, P.
Responsible/Coordination: Müller-Buschbaum, P.
dates in groups
Current problems of organic photovoltaics
Assigned to modules:
SE 2 Müller-Buschbaum, P. Mon, 10:00–11:30, PH 3734
Lecturer's Consulting Hour to Polymer Physics 2
Assigned to modules:
RE 2 Körstgens, V.
Responsible/Coordination: Müller-Buschbaum, P.
Tue, 18:30–20:00
Consultation Hour to Measurement and Sensor Technology (MS&E)
Assigned to modules:
RE 2 Müller-Buschbaum, P. Wed, 18:30–20:00, PH 3278
Edgar-Lüscher Lectures "Physics in Archaeology and Art History"
This course is not assigned to a module.
WS 2 Müller-Buschbaum, P. Petry, W. Fri, 09:00–18:00
FOPRA Experiment 42: Atomic Force Microscopy (AEP, KM)
current information
Assigned to modules:
PR 1 Apfelbeck, F.
Responsible/Coordination: Müller-Buschbaum, P.
FOPRA Experiment 61: Neutron Scattering at FRM II
current information
Assigned to modules:
PR 1 Georgii, R.
Responsible/Coordination: Müller-Buschbaum, P.
Visit of the Research Neutron Source Heinz Maier-Leibnitz (FRM II) for Students of Physics
current information
Assigned to modules:
EX 0.1
Responsible/Coordination: Müller-Buschbaum, P.
Mentoring in the Bachelor’s Program Physics
Assigned to modules:
KO 0.2 Müller-Buschbaum, P.
Seminar on polymers
Assigned to modules:
SE 2 Müller-Buschbaum, P. Papadakis, C. Wed, 13:00–15:00, PH 3734
Seminar on structure and dynamics of condensed matter
Assigned to modules:
SE 2 Müller-Buschbaum, P. Papadakis, C. Tue, 13:00–15:00, PH 3734

Offered Bachelor’s or Master’s Theses Topics

Air degradation process of green-solvent based organic solar cells

Organic solar cells are exciting since they can be flexible, light-weight and potentially cheap. Non-fullerene organic solar cells have gained great attention in recent years due to their increasing performance and stability, while the inevitable moisture and oxygen during production and operation would still cause degradation of the devices. Here, we select one high-efficiency green-solvent based organic solar cell and observe their degradation process in air under illumination. The device performance change as well as the degradation origin will be observed and analysed. Furthermore, the degradation mechanism under illumination in air is explored to help to find some improvement approaches. The device performance and stability are tested in air, the morphology of degraded layer is studied with imaging in real space and the crystallinity and molecular stacking is probed with X-ray scattering.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Data analysis of X-ray/neutron scattering images using Jupyter Notebook

When grazing incidence X-ray/neutron scattering experiments on thin films are performed, we obtain 2d scattering patterns. The data analysis typically involves reduction from 2d to 1d lines and then model-fitting using certain assumptions for the morphology and the interference between the nanosized domains in the films. However, the 2d images can also be simulated by existing softwares (e.g. BornAgain) if precise assumptions for the morphology are made. The 2d model-fitting can be a very successful understanding of the real morphology. Given the popularity of Python as data analysis language in natural sciences, a robust analysis requires adaptation of existing modelling algorithms to Jupyter notebooks. In this project you will export existing modelling scripts from BornAgain software to Jupyter notebook.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Effect of microwave irradiation on the morphology and performance of PEDOT:PSS electrodes
It is generally acknowledged that treating PEDOT:PSS with certain additives, such as ethylene glycol (EG), dimethyl sulfoxide (DMSO) and sorbitol, has been shown to increase the conductivity by several orders of magnitude. Moreover, drying method seems to play a big role in the morphology and performance of this material. Using a slow drying method via the commonly used hot plate, additive can induce an obvious separation between free PSS and reorganized PEDOT:PSS complexes in the highly conductive PEDOT:PSS films. Upon complete drying, PSS formed a transparent rim film around the conducting PEDOT film, resulting in the inhomogeneous film. Here, microwave irradiation is expected to rapidly and evenly heat the PEDOT:PSS film. The solidifying time can be easily controlled by adjusting microwave power and irradiation time. We anticipate that the controllable separation between PSS and PEDOT will pave the path to designing strategies to process high-performance PEDOT:PSS electrodes.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Effect of moisture on the morphology and electrical performance of mesoporous ZnO film

Moisture can strongly influence the conductivity of ZnO semiconductors via the physisorption and chemisorption of water molecules on the ZnO surface. Mesoporous ZnO structures can facilitate the absorption process by providing a large surface area and active sites, and thus can be used as a sensor to monitor humidity changes. However, little effort has been devoted yet to gain an in-depth understanding of the effect of water on morphology and electrical property. In this work, different mesoporous ZnO thin films will be explored by exploiting different diblock copolymers as structure-directing agents. The film morphologies will be checked by a combination of real-space scanning electron microscopy and reciprocal-space grazing-incidence small-angle X-ray scattering techniques. Consequently, information about both the surface and inner nanostructures will be provided. To evaluate the sensing performance, in situ electrochemical impedance spectroscopy will be used to monitor the conductivity changes.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Environmentally friendly perovskite solar cells

The power conversion efficiency of lead-based perovskite solar cells reached champion values of 25.8 %. However, the environmental unfriendliness and instability in ambient conditions of lead-based solar cells is detrimental to its commercial application. Lead-free double perovskite is regarded as one of the ideal candidates to replace the toxic lead-based perovskite in next generation solar cells and make such solar cells environmentally friendly. Today its optical properties are not yet fully understood. Herein, we will fabricate lead-free double perovskite thin films by spin-coating or printing method, and investigate its optical properties by photoluminescence spectroscopy and UV-Vis spectroscopy to pave the way for application in next generation solar cells.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Gold nanoparticles for optoelectronic devices
Gold nanoparticles (Au NPs) show peculiar optical and electrical properties compared with macroscopic metal owing to their unique capability of concentrating, routing, and manipulating light at the nanoscale. Recently many advantages were made in optoelectronic devices applications with broadening band and energy transfer. In this project, your work will focus on investigating doping Au NPs in optoelectronic film, since the size, density, and morphology of the Au NPs will influence the crystallinity of the photoactive film and charge transport of the device. We will use UV-vis, SEM, and x-ray scattering to investigate the optical properties and morphology of the hybrid nanostructures. Specific focus will be on the correlation between optical properties and the morphology of the Au NPs as well as the self-assembly of monolayer Au NPs array for optoelectronic devices.
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
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
Lithium-ion batteries with modified electrolyte for next generation batteries
Lithium-ion batteries are an indispensable energy supply in modern society. The ideal anode consists of lithium metal due to its high specific energy and low electrochemical potential. However, lithium-ion batteries with liquid electrolyte are prone to form lithium dendrites, which can lead to failure or even explosion of the battery. Therefore, polymer electrolytes are an attractive alternative to bypass these obstacles. However, polymer electrolytes suffer from high contact resistances and low ionic conductivities, which requires an elevated operating temperature. In this project, a hybrid electrolyte based on liquid electrolyte modified with polymer will be prepared. Then, CR2032 coin cell batteries will be fabricated and tested with standard cycling procedures. Besides electrochemical characterization techniques, complementary measurement like real space imaging techniques (scanning electron microscopy, SEM) and reciprocal space techniques (small angle x-ray scattering, SAXS) can be performed. Overall, this master thesis project involves literature review, sample preparation and data analysis.
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
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
Nanogenerator based wearable electronics for multi-dimensional sensing with machine learning assistance

Triboelectric nanogenerator originating from Maxwell’s displacement current is a new kind of technology, which can convert mechanical signals into electrical signals for further processes. Recently, many triboelectric nanogenerators have been fabricated as vertical pressure sensors. In this project, your work will focus on the fabrication of new triboelectric nanogenerator based wearable sensor systems. Moreover, machine learning technology will be introduced to systems for high-precision recognition. Both electrical measurements and signal collection by microcontrollers will be learned in this project.

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
Polymer electrolyte for high voltage lithium metal batteries
Lithium metal batteries has been widely applied in our daily life since recent years. It is essential to develop new materials to meet the increasing requirements such as stability, safety and manufacturing costs. In this project, we aim to fabricate polymer electrolyte materials which can realize high voltage fast charge/discharge for next generation electric vehicles (EVs). Varies types of coin cell is built for the battery performance test like charge/discharge simulation and electrochemical property evaluation.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Peter Müller-Buschbaum
Printed 2D perovskite solar cells

Printed perovskite solar cells will make a future contribution to energy conversion, but so far, device stability hinders their commercial success. Two-dimensional (2D) perovskite solar cells have superior stability compared to their 3D counterparts, however, their power conversion efficiency is still far behind 3D perovskite solar cells. Such behavior is correlated with preferred 2D perovskite growing along the in-plane direction with respect to the substrate, therefore the insulating bulky organic cation impedes the out-of-plane charge transfer and causes the insufficient charge transport. In this perspective, we aim to understand perovskite growth mechanism and control perovskite growth at large scale during printing. This project includes the literature review, state-of-the-art fabrication method, and advanced spectroscopy technique.

suitable as
  • Bachelor’s Thesis 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
  • 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 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
Specific Ion Effects on Co-nonsolvency Induced Phase Transition Behavior of Thermoresponsive Homopolymer Thin Films

The co-nonsolvency behavior of the diblock copolymer (DBC) of PSBP-b-PNIPMAM has already been investigated, as well as the homopolymer of PSBP and PNIPMAM. However, the factors regulating the co-nonsolvency behavior are not only the solvent composition but also the anion series, which are not well studied yet in thin film geometry. In this project, we will study the specific ion effects on co-nonsolvency behavior of PNIPMAM and PSBP thin films following a recurring trend known as the Hofmeister series, which mainly includes the samples preparation via spin coating, thickness study via spectral reflectance and the polymer-water interaction study via Fourier transform infrared, as well as the surface morphology study via atomic force microscope. Besides, X-ray reflectometry will be used as a complementary method to analyze the migration or aggregation of salt molecules in the films.

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
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Peter Müller-Buschbaum
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