Austempered ductile iron (ADI) is an attractive material with excellent mechanical properties, like high strength, good ductility, wear resistance and fatigue strength. Its mechanical properties are largely determined by the ausferritic microstructure which contains retained high carbon enriched austenite. The retained austenite will become unstable under plastic deformation and will transform...
Mesoporous Fe2O3 thin films with large area homogeneity demonstrate tremendous application potential in photovoltaic industry, lithium ion batteries, gas or magnetic sensors. In the present work, the synthesis of morphology‐controlled Fe2O3 thin films is realized with the polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymer assisted sol-gel chemistry. The effect of the solvent...
Molybdenum Nitride (MoNx) films are investigated as hole-selective layer of crystal Si solar cells due to having a proper work function (5.62 eV) and high conductivity (2000 S/cm). The hole-selectivity so far is limited by the poor surface passivation, which is highly correlated to the interface structure between Si and MoNx. The open circuit voltage and fill factor of devices with thicker...
Metal halide perovskite light-emitting diodes (PeLEDs) are regarded as alternative candidates for next-generation display technologies due to their high efficiency, superior color purity and tunable bandgap. However, PeLEDs based on isotropic perovskite emitting layers with randomly oriented emissive transition dipole moments (TDMs) remain to be inefficient to get upper limit efficiencies of...
Non-fullerene organic solar cells have undergone significant improvements via both, synthesis of novel organic synthesis materials and application of easy fabrication methods. However, device degradtion is still a major problem. For example, the peeling-off of the top electrode fabricated by thermal evaporation leads to an intrinsic device degradation, which is one ofamong the main reasons for...
In the present work authors studied magnetic and structural properties of Fe/Pd/Gd superlattices. The particular system [Fe(35 Å)/Pd(t)/Gd(50 Å)/Pd(t)]x12 was chosen with different layer thicknesses of Pd spacer.
By means of x-ray low-angle diffraction (reflectometry, XRR) and scanning transmission electron microscopy (STEM) with the energy dispersive x-ray (EDX) microanalysis the structural...
Multilayers composed of heavy metals and ferromagnets with strong perpendicular anisotropy are potential candidates for magnetic memory applications [1,2]. Magnetic skyrmions in particular may enable ultra-dense storage devices due to their extremely low spin currents [2]. Pt/Co-based multilayers generally exhibit worm domains, which can nucleate into domains of skyrmions through...
Layered Fe/MgO/Cr/MgO/Fe nanostructures are an artificial ferromagnetic material in which the exchange interaction of magnetic moments of Fe layers through intermediate dielectric and metal layers can lead to magnetic configurations that are not realized in the well-studied Fe/MgO/Fe and Fe/Cr/Fe systems. The correlation between the structural and magnetic properties of layered Fe(10...
The creation of extreme conditions on the sample by means of high external pressure together with changes in the magnetic field and temperature allows to obtain the comprehensive amount of experimental data for a detailed description of the internal properties of materials.
We investigated the Mn$_{1-x}$Fe$_{x}$Ge compounds, which crystallize into a noncentrosymmetric cubic structure of the...
The solid electrolyte interphase (SEI) is a solid protective barrier that forms at the surface of lithium-ion batteries (LIB) operating outside the stability range of the electrolyte. In particular, that happens at the anode where Li metal reduces the liquid electrolyte forming a solid mixture of inorganic and organic components during the lithiation reaction [1]. A good barrier layer...
The myelin basic protein (MBP) is a key player when it comes to the formation of tight membrane wrapping around vertebrate’s nerve cells. In physiological conditions, MBP is acting as a glue that stacks multiple myelin layers to build up an insulating sheath which covers axons. To accomplish this task, MBP undergoes a so-called Liquid-Liquid Phase Separation (LLPS) - a property which has...
With an aim of obtaining high-efficient titania photoanodes, we introduce germanium nanocrystals (GeNCs) into a diblock-copolymer polystyrene-block-polyethylene oxide (PS-b-PEO) template-assisted sol-gel synthesis. The surface and inner morphologies of the TiO2/GeNC films with different GeNC content after thermal annealing are investigated via scanning electron microscopy and grazing incidence...
The saponin aescin can be extracted from the horse chestnut tree and is known for its anti-inflammatory and anti-oedematous properties. Using small, unilamellar lipid vesicle (SUV) as model membrane, we study the mixing properties of aescin with the phospholipid 1,2-dioleoyl-sn-glycero-3-phospho-(1’-rac-glycerol) (DOPG) by using small-angle neutron scattering (SANS), small- and wide-angle...
Layer formation and annealing of nanoparticles especially colloidal inks applied to porous materials is very relevant for functional coatings and printing. The goal is to distinguish and quantify the differences in structure formation during annealing of deposited colloidal inks on a porous and a solid material. Therefore, we compare two different substrates: As porous template we use a layer...
Lithium-Ion Batteries turned out as an indispensable energy supplier in modern society which however suffers from safety concerns due to the flammability of the liquid electrolyte. Solid polymer electrolytes (SPEs) can bypass this obstacle and therefore represent a serious alternative to conventional electrolytes. Especially single-ion conducting polymers (SICPs), which have the anion...
The Coincidence Doppler-Broadening (CDB) spectrometer at NEPOMUC has recently been upgraded with six additional HPGe Detectors, bringing the total number of detectors to ten. To take full advantage of the even more capable instrument a novel data evaluation software package (STACS) was created.
The software can handle and visualize the data generated by Coincidence Doppler-Broadening...
High-performance energy storage solutions are a basic prerequisite for efficient portable devices and the electrification of the transport sector, and by this reaching the CO$_{2}$ emission targets. The market and progress demand for advances in electrochemical energy storage and a promising approach towards advanced batteries is the so-called all solid state battery concept, where the liquid...
Electrochemical cycling of lithium-ion batteries is supplemented by the active transport of lithium ions and electrons, which are exchanged between the cathode and anode material. Besides material properties, such exchange is facilitated by cell parameters like electrode dimensions and geometry, current density, temperature, pressure, reaction rate etc. Such parameters are neither uniformly...
Due to their application potential for new types of memory devices, the research on multiferroic materials has attracted strong interest during the last decades. A prominent mechanism that drives multiferroic behavior is given by the inverse Dzyaloshinskii-Moriya interaction, which yields the shift of a non-magnetic ligand ion due to a non-collinear magnetic structure. It was shown on a...
A low-temperature routine to realize inorganic amorphous electron-transport layers (ETLs) is of great importance for the commercialization of perovskite solar cells. The fabrication of ETLs at low temperature is energy saving and compatible with flexible substrates. In this work, titanium thin films are synthesized at low temperature (below 100 ℃) with a polymer template sol-gel method based...
The new project CAESAR funded by the Bundesministerium für Wirtschaft und Energie (BMWi) is a cooperation of the Technical University Munich (TUM) including the FRM II and several industrial partners under the leadership of the company Wacker. The aim of this project is the development of Li ion batteries (LIB) with increased specific energy (Wh/kg) and energy density (Wh/l) accompanied by a...
There are various methods for diffraction pattern calculation of powders, differing in Q-averaging procedures. Three of these were studied in detail: (1) The structure factor formula sums up all the hkl planes for a Q-vectors despite their respective orientations. Only peak intensities are calculated and the peak shape is arbitrary. (2) A Monte Carlo (MC) method of averaging used i.a. by the...
Nowadays, 2H graphites are the most common anode materials in LIBs. Despite its overall popularity, the performance of LIBs is still limited by the capability of graphite electrodes to store lithium ions in its structure. Graphite builds up a layered hexagonal structure. During charging and discharging lithium ions are reversibly incorporated in the hexagonal structure resulting in the...
In order to improve the microstructure and mechanical properties of newly developed Ni-base superalloy VDM® Alloy 780 it is necessary to understand the $\gamma$’ hardening phase precipitation process. Here the precipitation process was studied in-situ by time-of-flight (TOF) neutron diffraction (ND) and small-angle neutron scattering (SANS) experiments at high temperature, which allowed us to...
With an increase in renewable energy production, the problem of energy storage becomes more and more significant. One of the most promising ideas is storage in form of hydrogen gas, which involves the production of hydrogen by electrolysis and later its reconversion into electricity in fuel cells. It is of great importance for these processes to be carried out most efficiently with the most...
Yuqin Zoua, Shuai Yuanb, Ali Buyrukc, Johanna Eichhornd, Shanshan Yina, Manual A. Scheela, Tianxiao Xiaoa, Shambhavi Pratapa, Suzhe Lianga, Wei Chena, Christian L. Weindla, Cheng Mub, Ian Sharpd, Tayebeh Americ,&, Matthias Schwartzkopfe, Stephan V. Rothe, f, Peter Müller-Buschbaum*a, g
aLehrstuhl für Funktionelle Materialien, Physik-Department, Technische Universität München,...
The interest in all-solid-state lithium batteries mainly originates from its high safety and energy density compared with conventional Li-ion batteries. Solid polymer electrolytes (SPEs) as an essential component with high durability, long shelf life, high energy density, great flexibility for cell design and low weight are considered as the most promising material for next generation...
Latest research has revealed promising results for silicon (Si) and germanium (Ge) as anode materials for lithium-ion batteries (LIBs). Owing to their high energy capacity these two group 14 semiconductors are considered as auspicious alternatives to graphite anodes in LIBs. In this study, we set the goal of synthesizing a porous silicon-germanium structure over a well-known wet chemical...
Large-scale facilities have gained importance for extended characterization methods in the field of material sciences. In particular, structure analysis by highly brilliant X-ray beams is an ideal technique to investigate drying, crystallization, or degradation processes in-situ. These processes require a high time resolution to capture the reaction dynamics, while developments in detector...
We propose to measure a parity-odd asymmetry A in the forward scattering amplitude for neutrons on the p-wave resonance in 139La at 0.73 eV from the correlation k•I, where k is the neutron momentum and I is the spin of the nucleus. One motivation is to take another step towards a future time reversal (T) violation experiment in polarized neutron transmission through polarized 139La [1]. The...
Perovskite solar cells have been the subject of several studies aimed at increasing their operational stability, but few have looked at the underlying degradation mechanisms. The influence of the environment on the performance of devices during operation has been neglected in previous studies [4]. Using synchrotron radiation-based operando grazing-incidence X-ray scattering techniques, we...
The goal of this project was to include a portable Raman spectrometer into the time-of-flight spectrometer TOFTOF. This setup would allow us to measure neutron and Raman spectra of the sample at the same time, under the same conditions and we would be able to vary the temperature of the sample. As the sample evolves with the change of temperature, so does the Raman spectrum and it is important...
