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The picture shows the glowing filament which keeps the sample at constant temperatures during the measurements.
SCIENCE HIGHLIGHT
Ultrafast magnetism: heating magnets, freezing time A team at HZB has developed a new method at BESSY II to quantify one of these mechanisms and applied it to the rare-earth element Gadolinium, whose magnetic properties are caused by electrons on both the 4f and the 5d shells.
Map obtained for a thin barium titanate film after clustering the data measured by contact Kelvin probe force microscopy (cKPFM) by a machine learning method. From this map, scientists can obtain detailed information on how the ferroelectric domains are distributed and what their respective polarization amplitude is.
SCIENCE HIGHLIGHT
A sharp look into tiny ferroelectric crystals What happens to ferroelectric materials when their dimensions are greatly reduced? A team of researchers at HZB has now been able to show how this question can be answered in a detailed way.
Annette Pietzsch infront of her instrument at the PTB hall at BESSY II.
PORTRAIT
Portrait Annette Pietzsch: Researching fundamental phenomena of our world Annette Pietzsch has many jobs: the physicist develops instruments for BESSY II that researchers can use to observe how molecules interact with each other.
Five different types of defects in MAPI-perovskites were examined and characterised. The result: a large proportion of defects is not trapping the charge carriers for long.
SCIENCE HIGHLIGHT
Perovskite solar cells: Defects trap charge carriers - and release them again An international team at HZB and Charles University Prague has investigated how charge carriers in so called MAPI-perovskite semiconductors interact with different defects. Their results help to improve perovskite solar cells.
Information on beam quality can be extracted via the interference patterns at different focal lengths and photon intensities.
SCIENCE HIGHLIGHT
Beam diagnostics for future laser wakefield accelerators Such compact particle accelerators are interesting for future accelerator-driven light sources. A team from HZB and PTB has now developed a method to advance the technology.
Such metal foams based on aluminium alloys are being investigated as lightweight materials, for example for the construction of electric cars. The morphology, size and cross-linking of the bubbles are important to achieve the desired mechanical properties such as strength and stiffness in large components.
SCIENCE HIGHLIGHT
New world record in materials research - X-ray microscopy with 1000 tomograms... With 1000 tomograms per second, it is now possible to non-destructively document very fast processes and developments in materials on the micrometre scale, such as the burning of a sparkler or the foaming of a metal alloy ....
The illustration shows how the APECS measurement works on a nickel single crystal with an oxidised surface. An X-ray beam ionises atoms, either in the nickel crystal or on the surface. The excited photoelectrons from the surface and from the crystal have slightly different binding energies. The Auger electrons make it possible to determine the origin of the photoelectrons.
SCIENCE HIGHLIGHT
Surface analysis at BESSY II: sharper insights into thin-film systems An HZB team at BESSY II has combined two different spectroscopic methods and used a model system to demonstrate how well adjacent thin films can be distinguished.
The Dirac cone is typical for topological insulators and is practically unchanged on all 6 images (ARPES measurements at BESSY II). The blue arrow additionally shows the valence electrons in the volume. The synchrotron light probes both and can thus distinguish the Dirac cone at the surface (electrically conducting) from the three-dimensional volume (insulating).
SCIENCE HIGHLIGHT
Disorder brings out quantum physical talents The material proves to be a topological insulator and is ferromagnetic up to comparatively high temperatures of 50 Kelvin, measurements at BESSY II show. This makes this class of material suitable for quantum bits...
During the operation of conventional battery storage, the tree-like lithium dendrites grow continuously and can pierce the electrically insulating separator layer between anode and cathode. The result: a short circuit and the end of life for the battery.
SCIENCE HIGHLIGHT
On the trail of lithium dendrites: How destructive formations develop in... A group of researchers has taken a look inside lithium batteries and examined in more detail the structures that severely limit the service life of batteries. Their results provide starting points for longer-lasting and safer lithium batteries.
Resonant X-ray excitation (purple) core excites the oxygen atom within a H2O molecule. This causes ultrafast proton dynamics. The electronic ground state potential surface (bottom) and the bond dynamics is captured by distinct spectral features in resonant inelastic X-ray scattering (right).
NEWS
Review: X-ray scattering methods with synchrotron radiation In the Reviews of Modern Physics, an international team now gives an overview of elastic and inelastic X-ray scattering processes, explains the theoretical background and sheds light on what insights these methods provide.
SCIENCE HIGHLIGHT
Green hydrogen: Why do certain catalysts improve in operation? Now a HZB-team headed by Marcel Risch has observed at BESSY II how two simultaneous mechanisms are responsible for this. The catalytic activity of the individual catalysis centres decreases, but the morphology of the catalyst layer also changes.
The development of this speckle pattern over time reveals microsocopic fluctuations in the material.
SCIENCE HIGHLIGHT
When vibrations increase on cooling: Anti-freezing observed An international team has observed an amazing phenomenon in a nickel oxide material during cooling: Instead of freezing, certain fluctuations actually increase as the temperature drops. This is interesting also for high Tc-Superconductor research.
After about 5 seconds, a thin film of metallic water has formed around the NaK drop, recognisable by the golden shimmer.
SCIENCE HIGHLIGHT
Water as a metal - detected at BESSY II Water only develops metallic properties under extreme pressure, such as exists deep inside of large planets. Now, an international collaboration has used a different approach to produce metallic water and documented the phase transition at BESSY II.
Fluoride additives increase the quality of the perovskite layer. At BESSY II a team has now explored the chemistry in detail.
SCIENCE HIGHLIGHT
Lead-free perovskite solar cells - How fluoride additives improve quality Using a clever combination of measurement methods at BESSY II and with NMR at the Humboldt-University Berlin, they were able to show that fluoride prevents the oxidation of tin and leads to a more homogeneous film formation with fewer defects.
Snapshots of the electronic structure of Sb acquired with femtosecond time-resolution. Note the changing spectral weight above the Fermi energy (EF).
SCIENCE HIGHLIGHT
Future information technologies: Topological materials for ultrafast spintronics Using time- and spin-resolved methods at BESSY II, the physicists explored how, after optical excitation, the complex interplay in the behavior of excited electrons in the bulk and on the surface results in unusual spin dynamics.
In polar regions and at high altitudes the conversion of solar radiation into hydrogen could certainly be worthwhile.
SCIENCE HIGHLIGHT
Solar hydrogen for Antarctica - study shows advantages of thermally coupled... A team from the Helmholtz-Zentrum Berlin, Ulm University, and Heidelberg University has now investigated how hydrogen can be produced at the South Pole using sunlight, and which method is the most promising.
DESY researcher Wiebke Ewert shows on a so-called electron density map where a drug candidate (green) binds to the main protease of the corona virus (blue).
NEWS
Synchrotrons accelerate corona research Information by the German Committee Research with Synchrotron Radiation (KFS). Synchrotron light sources were originally built to study particles. Today, they are even used in the fight against COVID-19.
Using Small-Angle Scattering the early stages of structure formation in precursor solutions of perovskite solar cells have been explored.
SCIENCE HIGHLIGHT
Perovskite Solar Cells: Insights into early stages of structure formation Using small-angle scattering at the PTB X-ray beamline of BESSY II, an HZB team was able to experimentally investigate the colloidal chemistry of perovskite precursor solutions used for solar cell production.
The illustration shows two quantum dots "communicating" with each other by exchanging light.
SCIENCE HIGHLIGHT
How quantum dots can "talk" to each other A group at HZB has worked out theoretically how the communication between two quantum dots can be influenced with light. The team led by Annika Bande also shows ways to control the transfer of energy from one quantum dot to another.
Renske van der Veen has a lot of experience with ultrafast x-ray measurements.
NEWS
Renske van der Veen heads new department "Atomic Dynamics in Light-Energy... The chemist is an expert in time-resolved X-ray spectroscopy and electron microscopy and studies catalytic processes that enable the conversion of solar energy into chemical energy.
Orbital hybridization between organic and inorganic components of MAPI perovskite in ground-state geometry.
SCIENCE HIGHLIGHT
Perovskite solar cells: Hydrogen bonds measured The evaluation of X-ray measurements on methylammonium perovskite semiconductors now shows what role hydrogen bonds play in these materials.
From the measurement data, the team was able to determine that the xenon atoms first accumulate on the inner walls of the pores (state 1), before they fill them up (state 2). The X-ray beam penetrates the sample from below.
SCIENCE HIGHLIGHT
Direct observation of the ad- and desorption of guest atoms into a mesoporous... Batteries or catalysts are often porous structures with guest atoms. A team from HZB has observed at the PTB X-ray beamline for the first time directly how atoms migrate into a mesoporous model system.
The HZB team was able to determine the photoconductivity in the thin layers of rust using time-resolved microwave measurements; here is a picture of the measurement setup.
SCIENCE HIGHLIGHT
Green hydrogen: "Rust" as a photoanode and its limits Metal oxides such as rust are intriguing photoelectrode materials for the production of green hydrogen with sunlight. They are cheap and abundant, but in spite of decades of research, progress has been limited. Why? This study finds out.
Electron density map of the most antiviral active ingredient calpeptin (yellow) binding at the main protease.
SCIENCE HIGHLIGHT
X-ray lightsource at DESY identifies promising candidates for COVID drugs The MX team from HZB examined part of the measurement data with special analysis algorithms in order to identify suitable active substances.
Movie showing the 3D crystal structure as a function of the cell modulation phase. (grey: Pb, brown: Br, black: C, blue: N; white: H)
SCIENCE HIGHLIGHT
New insights into the structure of organic-inorganic hybrid perovskites A team at HZB has used four-dimensional modelling to interpret structural data of methylammonium lead bromide, identifying incommensurable superstructures and modulations of the predominant structure.
A conductive AFM tip is used to scan the sample surface of an a-Si:H/c-Si interface under ultra-high vacuum on the nm scale, revealing the transport channels of the charge carriers via defects in the a-Si:H (red states in the magnified section).
SCIENCE HIGHLIGHT
Solar cells: Losses made visible on the nanoscale Now, for the first time, a team at Helmholtz-Zentrum Berlin (HZB) and the University of Utah, USA, has experimentally shown how such contact layers generate loss currents on the nanometre scale and what their physical origin is.
A new instrument at BESSY II can be used to study molybdenum-sulfide thin films that are of interest as catalysts for solar hydrogen production. A light pulse triggers a phase transition from the semiconducting to the metallic phase and thus enhances the catalytic activity.
SCIENCE HIGHLIGHT
Instrument at BESSY II shows how light activates MoS2 layers to become catalysts A new instrument at the Helmholtz-Berlin Zentrum’s BESSY II now shows how a light pulse alters the surface properties of the thin film and activates the material as a catalyst.
SCIENCE HIGHLIGHT
Accelerator physics: Experiment reveals new options for synchrotron light... Using this method, specialised synchrotron radiation sources would potentially be able to fill a gap in the arsenal of available light sources and offer a prototype for industrial applications. The work was published in Nature.
The liquid solution of perovskite precursor, solvent, and additive flows from a slit-shaped nozzle onto the glass substrate being conveyed below.
SCIENCE HIGHLIGHT
The perfect recipe for efficient perovskite solar cells hey have improved a process for vertically depositing a solution made from an inexpensive perovskite solute onto a moving substrate below.
The electronic structure of complex molecules can be assessed by the method of resonant inelastic X-ray scattering (RIXS) at BESSY II.
SCIENCE HIGHLIGHT
An efficient tool to link X-ray experiments and ab initio theory The evaluation of RIXS data has so far required very long computing times. A team at BESSY II has now developed a new simulation method that greatly accelerates this evaluation.
TEM-Image of a α-SnWO4 film (pink) coated with 20 nm NiOx (green). At the interface of α-SnWO4 and NiOx an additional interfacial layer can be observed.
SCIENCE HIGHLIGHT
Solar hydrogen: Photoanodes made of α-SnWO4 promise high efficiencies Combined with theoretical methods, the measurement data reveal the presence of an oxide layer that impairs the efficiency of the photoanode.
For the measurement campaign, two couplers were mounted in a horizontal test position under a local clean room tent.
NEWS
Accelerator Physics: HF-Couplers for bERLinPro prove resilient A first measurement campaign with optimised couplers at bERLinPro shows that the goal can be achieved.
The illustration visualizes the composition of the tandem solar cell.
SCIENCE HIGHLIGHT
Perovskite/silicon tandem solar cells on the threshold of 30% efficiency The tandem cell provided stable performance for 300 hours – even without encapsulation. To accomplish this, the group headed by Prof. Steve Albrecht investigated physical processes at the interfaces to improve the transport of the charge carriers.
Schematic illustration: the solvants (ink) are used to produce a thin film of polycrystalline perovskite.
SCIENCE HIGHLIGHT
Perovskite Solar Cells: paving the way for rational ink design for... For the production of perovskite thin-films for large photovoltaic modules often inks are used which contain a mixture of solvents. An HZB team at BESSY II has now analysed how the crystallisation processes within such mixtures.
Nine samples with mixtures from CsPbBr2I (ink 1, left) to pure CsPbI3 (ink 2 right).
SCIENCE HIGHLIGHT
Solar cells: Mapping the landscape of Caesium based inorganic halide perovskites The study provides a quick and easy method to assess new compositions of perovskite materials in order to identify candidates for applications in thin film solar cells and optoelectronic devices.
Structural model of highly porous a-Si:H, which was deposited very quickly, calculated based on measurement data. Densely ordered domains (DOD) are drawn in blue and cavities in red. The grey layer represents the disordered a-Si:H matrix. The round sections show the nanostructures enlarged to atomic resolution (below, Si atoms: grey, Si atoms on the surfaces of the voids: red; H: white)
SCIENCE HIGHLIGHT
Order in the disorder: density fluctuations in amorphous silicon discovered Such a-Si:H thin films have been used for decades in solar cells, TFT displays, and detectors. The results show that three different phases form within the amorphous matrix, which influences the quality and lifetime of the semiconductor layer.
Ultracold atoms in an optical lattice have been considered for quantum simulation.
SCIENCE HIGHLIGHT
Modelling shows which quantum systems are suitable for quantum simulations Theoretical physicists have demonstrated a way to simulate the quantum properties of complex solid state systems.
Scalable large area BiVO4 photoanode on FTO with Ni current collectors.
SCIENCE HIGHLIGHT
Solar hydrogen: Let’s consider the stability of photoelectrodes This is the first operando stability study of high-purity BiVO4 photoanodes during the photoelectrochemical oxygen evolution reaction (OER). It shows how the stability of photoelectrodes and catalysts can be compared and enhanced.
(a,b) Cryo-electron microscopy of the 2D-grating and the diffraction pattern of a section. (c-e) Magnification shows the 2D Pascal triangular pattern, with the inserted protein molecules.
SCIENCE HIGHLIGHT
Nanopatterns of proteins detected by cryo-electron microscopy A Team at HZB used cryo electron microscopy to detect regular, two-dimensional structures in the form of Pascal triangles, which a Chinese research group assembled from proteins in the laboratory for the first time.
Dr. Michael Tovar working at FALCON at the neutron Source BER II.
SCIENCE HIGHLIGHT
Perovskite materials: Neutrons show twinning in halide perovskites An investigation with the Laue camera at the neutron source BER II could now clarify that twinning occurs during crystallisation even at room temperature.
Periodic metasurfaces (grey) can enhance photon upconversion of nanoparticles (yellow) by more than three orders of magnitude.
SCIENCE HIGHLIGHT
Upconversion of photons at low light intensities – the key to new applications... Through upconversion the usable range of the light spectrum can be significantly expanded and is the key for future applications in photovoltaics or for the detection of biological substances.
Structure of TUB75: the entire MOF architecture (top) and its conductive inorganic unit (bottom)
SCIENCE HIGHLIGHT
Molecular architecture: New class of materials for tomorrow's energy storage TUB75 is the name of a newly created material from the class of metal-organic frameworks, or MOFs. It could open up new opportunities for energy storage.
Intelligent mathematical tools for the simulation of spin systems reduce the computing time required on supercomputers. Some of the fastest supercomputers in the world are currently located at Forschungszentrum Jülich (shown here is JUWELS).
SCIENCE HIGHLIGHT
Mathematical tool helps calculate properties of quantum materials more quickly A joint research group at Freie Universität Berlin and HZB has demonstrated a way to considerably reduce the computing time. This could accelerate the development of materials for energy-efficient IT technologies.
The structure of crystalline silicon electrodes changes into a chessboard-like fracture pattern as a result of loading and unloading. At the HZB it has now been observed that these defects do not become larger during charging and discharging but remain in their pattern.
SCIENCE HIGHLIGHT
Hope for better batteries – researchers follow the charging and discharging of... The use of silicon in batteries promises to increase their capacity. At the HZB, charging and discharging was observed live for the first time and insights were gained into how the material can be used even more advantageously.
For the study, the enzyme endothiapepsin (grey) was combined with molecules from the fragment library. The analysis shows that numerous substances are able to dock to the enzyme (blue and orange molecules). Every substance found is a potential starting point for the development of larger molecules.
SCIENCE HIGHLIGHT
New substance library to accelerate the search for active compounds In order to accelerate the systematic development of drugs, the MX team at the Helmholtz-Zentrum Berlin (HZB) and the Drug Design Group at the University of Marburg have established a new substance library.
This is how the experiment went: Two laser pulses hit the thin film of iron-platinum nanoparticles at short intervals: The first laser pulse destroys the spin order, while the second laser pulse excites the now unmagnetised sample. An X-ray pulse then determines how the lattice expands or contracts.
SCIENCE HIGHLIGHT
Robust high-performance data storage through magnetic anisotropy An international team led by Prof. Dr. Matias Bargheer has now observed experimentally for the first time how a special spin-lattice interaction in these iron-platinum thin films cancels out the thermal expansion of the crystal lattice.
Graphic representation of the printing process for the perovskite LED.
SCIENCE HIGHLIGHT
Printed perovskite LEDs – an innovative technique towards a new standard... LEDs from the inkjet printer - For the first time, it has been possible to produce light emitting diodes from hybrid perovskite semiconductor material using inkjet printing.
The publication made it onto the cover of the current issue of SCIENCE.
SCIENCE HIGHLIGHT
BESSY II: Experiment shows for the first time in detail how electrolytes become... For the first time an experiment was developed at BESSY II that shows how electrolytes become metallic. The transition to the state is shown by a change of colour from blue to gold. The publication even appears on the front page of SCIENCE Magazine.
Perovskite oxides are characterized by the molecular formula ABO3, where the elements A (green) and B (blue) are located on specific lattice sites and are surrounded by oxygen (red).
SCIENCE HIGHLIGHT
Catalysts: Efficient hydrogen production via structure In order to produce regenerative hydrogen efficiently by electrolysis of water, researchers also investigate perovskite oxides. Dr. Marcel Risch has been invited to publish an overview article.
The illustration shows the changes in the structure of FASnI3:PEACl films during treatment at different temperatures.
SCIENCE HIGHLIGHT
On the road to non-toxic and stable perovskite solar cells To replace lead by less toxic elements is not easy since lead-free perovskites show lower stability and poor efficiencies. Now, an international collaboration has engineered a new hybrid perovskite material with promising efficiency and stability.
Two of the four magnetic interactions form a new three-dimensional network of corner-sharing triangles, known as the hyper-hyperkagome lattice, leading to the quantum spin liquid behavior in PbCuTe2O6.
SCIENCE HIGHLIGHT
Future information technologies: 3D Quantum Spin Liquid revealed An international team led by HZB scientists has investigated crystals of PbCuTe2O6 with neutron experiments at ISIS, NIST and ILL. They found spin liquid behaviour in 3D, due to a so called hyper hyperkagome lattice.
The CIGS-Pero tandem cell was realised in a typical lab size of 1 square centimeter.
SCIENCE HIGHLIGHT
Tandem solar cell world record: New branch in the NREL chart The world-record cell combines the semiconductors perovskite and CIGS to a monolithic "two-terminal" tandem cell. It achieves a certified efficiency of 24,16 percent.
In the ground state the magnetic moments are either upward or downward, the spins antiparallel to the external magnetic field (red) are never together (right). By excitation, further spins can align antiparallel and Bethe chains are formed (white spins, left).
SCIENCE HIGHLIGHT
Condensed Matter Physics: Long-standing prediction of quantum physics... 90 years ago, the physicist Hans Bethe postulated that unusual patterns, so-called Bethe strings, appear in certain magnetic solids. Now an international team has succeeded in experimentally detecting such Bethe strings for the first time.
This picture shows an X-ray image of the electron beam in TRIB-mode where two orbits co-exist: the regular orbit and the second one winding around it closing only after three revolutions.
SCIENCE HIGHLIGHT
BESSY II: Ultra-fast switching of helicity of circularly polarized light pulses The ultra-fast change of light helicity is particularly interesting to observe processes in magnetic materials and has long been expected by a large user community.
MXenes are 2D materials forming multi-layered particles (left) from which pseudocapacitors are made. Shining X-ray light on MXenes revealed changes of their chemical structure upon intercalation of urea molecules (right) compared to pristine MXenes (center).
SCIENCE HIGHLIGHT
Fast and furious: New class of 2D materials stores electrical energy Two dimensional titanium carbides, so-called MXenes, are being discussed as candidates for the rapid storage of electrical energy. The intercalation of urea between the MXene layers can increase the capacity.
60s on the new detector were sufficient to obtain the electron density of the PETase enzyme.
NEWS
New detector accelerates protein crystallography Compared to the old detector the new one is better, faster and more sensitive. It allows to acquire complete data sets of complex proteins within a very short time.
3D architecture of the cell with different organelles: mitochondria (green), lysosomes (purple), multivesicular bodies (red), endoplasmic reticulum (cream).
SCIENCE HIGHLIGHT
X-ray microscopy at BESSY II: Nanoparticles can change cells Nanoparticles easily enter into cells. How they are distributed and what they do there is now shown for the first time by high-resolution 3D microscopy images from BESSY II: Nanoparticles accumulate in certain organelles of the cell.
Bei 25,8 Tesla findet in dem Urankristall ein Phasenübergang statt und ein komplexes magnetisches Muster etabliert sich.
SCIENCE HIGHLIGHT
Not everything is ferromagnetic in high magnetic fields Usually, high fields exceeding a certain critical value force the moments to align in the same direction as the field leading to ferromagnetic arrangement. However, a recent study showed that this is not always the case.
The x-ray tomography shows ruptures (black) in the regions of electrical contacts (white).
SCIENCE HIGHLIGHT
Battery research: Using neutrons and X-rays to analyse the ageing of lithium... An international team has used neutron and X-ray tomography to investigate the dynamic processes that lead to capacity degradation at the electrodes in lithium batteries. Using a mathematical method, it was possible to virtually unwind electrodes.
SCIENCE HIGHLIGHT
Perovskite solar cells: International consensus on ageing measurement protocols Experts from 51 research institutions have now agreed on the procedures for measuring the stability of perovskite solar cells and assessing their quality. The consensus statement is considered a milestone.
The tandem solar cell was realized on a typical laboratory scale of one square centimeter. However, scaling up is possible.
SCIENCE HIGHLIGHT
World Record: Efficiency of perovskite silicon tandem solar cell jumps to 29.15... In the race for ever higher efficiency levels, an HZB development team is once again ahead. The scientists have developed a tandem solar cell made of perovskite and silicon, which converts 29.15 per cent of the incident light into electrical energy.
Mint plants have been analysed after having grown on contaminated soil samples.
SCIENCE HIGHLIGHT
Plants absorb lead from perovskite solar cells more than expected Lead from metal-organic perovskite compounds can be absorbed particularly easily by plants. The bioavailability is significantly higher than that of lead from inorganic compounds as found in batteries.
SCIENCE HIGHLIGHT
Topological materials for information technology offer lossless transmission of... New experiments with magnetically doped topological insulators at BESSY II have revealed possible ways of lossless signal transmission that involve a surprising self-organisation phenomenon.
The drawing illustrates the interaction of the organic methylammonium cation (CH3NH3+) with the surrounding iodide ions. The shift of the iodide atoms out of the common plane with lead causes the breaking of the inversion symmetry.
SCIENCE HIGHLIGHT
Perovskite solar cells: Possible aspects of high efficiency uncovered An HZB team has shown that hybrid halide perovskites crystallise without inversion centre. This can lead to the formation of ferroelectric domains, which, indirectly, can result in higher solar-cell efficiencies.
The illustration demonstrates skyrmions in one of their Eigen modes (clockwise).
SCIENCE HIGHLIGHT
Dynamic pattern of Skyrmions observed Now a team has succeeded in developing a new technique at the VEKMAG station of BESSY II for precisely measuring these vortices and observing their three different predicted characteristic oscillation modes (Eigen modes).
The Pero-CIGS tandem cell achieves a record efficiency of 23.26 percent.
SCIENCE HIGHLIGHT
World record for tandem perovskite-CIGS solar cell A team headed by Prof. Steve Albrecht from the HZB will present a new world-record tandem solar at EU PVSEC in Marseille, France on September 11, 2019.
The operando cell was developed at HZB and allows to analyse processes inside the battery during charging cycles with neutrons.
SCIENCE HIGHLIGHT
Nanoparticles in lithium-sulphur batteries detected with neutron experiment An HZB team has for the first time precisely analysed how nanoparticles of lithium sulphide and sulphur precipitate onto battery electrodes during the course of the charging cycle.
The nano-antennae werde produced in an electron microscope by direct electron-beam writing.
SCIENCE HIGHLIGHT
Save time using maths: analytical tool designs corkscrew-shaped nano-antennae For the first time, an HZB team has derived analytically how corkscrew-shaped nano-antennas interact with light. The mathematical tool can be used to calculate the geometry that a nano-antenna must have for specific applications in sensor technology or ...
The rotary sample table turns around its axis at several hundred revolutions per second with extreme precision.
SCIENCE HIGHLIGHT
World record in tomography: Watching how metal foam forms Researchers from the HZB and the Paul Scherrer Institute have developed a more powerful imaging method with which more than 200 three-dimensional tomographic X-ray images can be taken every second during measurement intervals of just several minutes.
Prof. Dr. Christiane Becker in the clean room at HZB campus side Berlin-Adlershof.
PORTRAIT
FOCUS TOPIC: Catching more light in solar cells Christiane Becker uses microscopic structures to increase the amount of light captured in solar cells and is currently scaling up the technology for industrial application.
At the MX-Beamlines at BESSY II, Gottfried Palm, Gert Weber and Manfred Weiss could solve the 3D structure of MHETase.
NEWS
FOCUS TOPIC: Using BESSY II to combat plastic waste MHETase was discovered in bacteria and together with a second enzyme - PETase - is able to break down the widely used plastic PET into its basic building blocks.
The photomontage shows a sample of solid, pure niobium before coating (left), and coated with a thin layer of Nb3Sn (right).
SCIENCE HIGHLIGHT
Accelerator physics: alternative material investigated for superconducting... An international collaboration has investigated the potential advantages a niobium-tin coating might offer in comparison to pure niobium.
An X-ray pulse probes the delocalization of iron 3d electrons onto adjacent ligands.
SCIENCE HIGHLIGHT
Charge transfer within transition-metal dyes analysed Transition-metal complexes in dye-based solar cells are responsible for converting light into electrical energy. A model of spatial charge separation within the molecule has been used to describe this conversion. However, an analysis at BESSY II shows that ...
When illuminated by the synchrotron light, nickel emits x-rays itself due to the decay of valence electrons. The number of emitted photons reduces when increasing the temperature from room temperature (left) to 900°C (right).
SCIENCE HIGHLIGHT
Utrafast magnetism: electron-phonon interactions examined at BESSY II How fast can a magnet switch its orientation and what are the microscopic mechanisms at play ? These questions are of first importance for the development of data storage and computer chips. Now, an HZB team at BESSY II has for the first time been able to ...
The illustration is alluding to the laser experiment in the background and shows the structure of TGCN.
SCIENCE HIGHLIGHT
Organic electronics: a new semiconductor in the carbon-nitride family Triazine-based graphitic carbon nitride (TGCN) is a semiconductor that should be highly suitable for applications in optoelectronics.
NEWS
Development of a miniaturised EPR spectrometer Several research institutions are developing a miniaturized electron paramagnetic resonance (EPR) device with industrial partner Bruker to investigate semiconductor materials, solar cells, catalysts and electrodes for fuel cells and batteries.
A green laser pulse initially excites the electrons in the Cu2O; just fractions of a second later, a second laser pulse (UV light) probes the energy of the excited electron.
SCIENCE HIGHLIGHT
Copper oxide photocathodes: laser experiment reveals location of efficiency loss Solar cells and photocathodes made of copper oxide might in theory attain high efficiencies for solar energy conversion. In practice, however, large losses occur. Now a team at the HZB has been able to use a sophisticated femtosecond laser experiment to ...
Tomography of a lithium electrode in its initial condition.
SCIENCE HIGHLIGHT
3D tomographic imagery reveals how lithium batteries age Lithium batteries lose amp-hour capacity over time. Microstructures can form on the electrodes with each new charge cycle, which further reduces battery capacity. Now an HZB team together with battery researchers from Forschungszentrum Jülich, the University ...
By co-evaporation of cesium iodide and lead iodide thin layers of CsPbI3 can be produced even at moderate temperatures. An excess of cesium leads to stable perovskite phases.
SCIENCE HIGHLIGHT
Inorganic perovskite absorbers for use in thin-film solar cells A team at the Helmholtz-Zentrum Berlin has succeeded in producing inorganic perovskite thin films at moderate temperatures using co-evaporation – making post-tempering at high temperatures unnecessary. The process makes it much easier to produce thin-film ...
SnSe is a highly layered orthorhombic structure. SnSe undergoes a phase transition of second order at 500°C with an increase of the crystal symmetry from space group Pnma (left) to Cmcm (right).
SCIENCE HIGHLIGHT
High-efficiency thermoelectric materials: new insights into tin selenide Tin selenide might considerably exceed the efficiency of current record holding thermoelectric materials made of bismuth telluride. However, it was thought its efficiency became enormous only at temperatures above 500 degrees Celsius. Now measurements at the ...
The enzyme MHETase is a huge and complex molecule. MHET-molecules from PET plastic dock at the active site inside the MHETase and are broken down into their basic building blocks.
SCIENCE HIGHLIGHT
"Molecular scissors" for plastic waste MHETase was discovered in bacteria and together with a second enzyme - PETase - is able to break down the widely used plastic PET into its basic building blocks.
The SEM shows Molybdenum sulfide deposited at room temperature.
SCIENCE HIGHLIGHT
Catalyst research for solar fuels: Amorphous molybdenum sulphide works best Efficient and inexpensive catalysts will be required for production of hydrogen from sunlight. Molybdenum sulphides are considered good candidates. A team at HZB has now explained what processes take place in molybdenum sulphides during catalysis and why ...
At the end of his contribution, Phillippe Wernet makes a great arch from the past (Opticae Thesaurus, 1572) of research with light to the future.
SCIENCE HIGHLIGHT
HZB contributions to special edition on Ultrafast Dynamics with X-ray Methods In the new special issue of the "Philosophical Transactions of the Royal Society of London", internationally renowned experts report on new developments in X-ray sources and ultrafast time-resolved experiments. HZB physicists have also been invited to ...
Schematic view of carbon structures with pores.
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X-ray analysis of carbon nanostructures helps material design A new study from the HZB has now shown that structural changes that occur due to morphology transition with increasing temperature of the synthesis can also be measured directly – using small-angle X-ray scattering.
Water molecules are excited with X-ray light (blue). From the emitted light (purple) information on H-bonds can be obtained.
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Water is more homogeneous than expected In order to explain the known anomalies in water, some researchers assume that water consists of a mixture of two phases even under ambient conditions. However, new X-ray spectroscopic analyses at BESSY II, ESRF and Swiss Light Source show that this is not ...
The cones represents the magnetization of the nanoparticles. In the absence of electric field (strain-free state) the size and separation between particles leads to a random orientation of their magnetization, known as superparamagnetism
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Spintronics by “straintronics”: Superferromagnetism with electric-field induced... Spintronics by “straintronics”: Switching on superferromagnetism with electric-field induced strain
An extremely thin layer between CIGSe and Perovskite improves the efficiency of the tandemcell.
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Ultra-thin and extremely efficient: Thin-film tandem cells made of perovskite... Ultra-thin and extremely efficient: Thin-film tandem cells made of perovskite and CIGSe semiconductors
Neutrons (red arrows) detect the presence of Lithium ions which have migrated into the silicon anode.
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Batteries with silicon anodes: Neutron experiments show how formation of... Batteries with silicon anodes: Neutron experiments show how formation of surface structures reduces amp-hour capacity
The atmosphere can be compared to a bathtub that can only be filled to its rim if global warming is to be limited to a certain level. We could create another small outward flow with negative emissions. However, there is no way around turning off the tap.
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Climate change: How could artificial photosynthesis contribute to limiting... Climate change: How could artificial photosynthesis contribute to limiting global warming?
Photocathode in superconducting photoinjector system.
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Milestone for bERLinPro: photocathodes with high quantum efficiency Milestone for bERLinPro: photocathodes with high quantum efficiency
The molecule organises itself on the electrode surface until a dense, uniform monolayer is formed.
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Molecules that self-assemble into monolayers for efficient perovskite solar... Molecules that self-assemble into monolayers for efficient perovskite solar cells
The illustration shows a molecule with an iron atom at its centre, bound to 4 CN groups and a bipyridine molecule. The highest occupied iron orbital is shown as a green-red cloud. As soon as a cyan group is present, the outer iron orbitals are observed to delocalize so that electrons are also densely present around the nitrogen atoms.
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Transition metal complexes: mixed works better A team at BESSY II has investigated how various iron-complex compounds process energy from incident light. They were able to show why certain compounds have the potential to convert light into electrical energy. The results are important for the development ...
The SEM image shows the cross-section of a silicon perovskite tandem solar cell.
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New records in perovskite-silicon tandem solar cells through improved light... Using microstructured layers, an HZB team has been able to increase the efficiency of perovskite-silicon tandem solar cells, achieving 25.5 %, which is the highest published value to date. At the same time, computational simulations were utilized to ...
The data show that In the case of the two-layer graphene, a flat part of bandstructure only 200 milli-electron volts below the Fermi energy.
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Graphene on the way to superconductivity Scientists at HZB have found evidence that double layers of graphene have a property that may let them conduct current completely without resistance. They probed the bandstructure at BESSY II with extremely high resolution ARPES and could identify a flat area ...
Andriy Zakutayev (NREL), member of the jury, has awarded Fredrike Lehmann for her poster at ICTMC-21 in Boulder, Colorado, USA.
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Poster award to HZB doctoral student Frederike Lehmann from the HZB Department Structure and Dynamics of Energy Materials received a poster award at an international conference, the ICTMC-21 in Boulder, Colorado, USA. She presented her results on the synthesis and characterization of hybrid ...
Doped Diamond Foam.
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Nanodiamonds as photocatalysts Diamond nanomaterials are considered hot candidates for low-cost photocatalysts. They can be activated by light and can then accelerate certain reactions between water and CO2 and produce carbon-neutral "solar fuels". The EU project DIACAT has now doped such ...
The STM image shows blue phosphorus on a gold substrate. The calculated atomic positions of the slightly elevated P atoms are shown in blue, the lower lying ones in white. Groups of six elevated P atoms appear as triangles.
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Blue phosphorus - mapped and measured for the first time Until recently, the existence of "blue" phosphorus was pure theory: Now an HZB team was able to examine samples of blue phosphorus at BESSY II for the first time and confirm via mapping of their electronic band structure that this is actually this exotic ...
Shown are the magnetic fluxlines inside a superconducting sample of lead in two different directions. The scale bar is 5 mm.
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Neutrons scan magnetic fields inside samples With a newly developed neutron tomography technique, an HZB team has been able to map for the first time magnetic field lines inside materials at the BER II research reactor. Tensorial neutron tomography promises new insights into superconductors, battery ...
Principle of a silicon singlet fission solar cell with incorporated organic crystalls
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HZB researchers boost the efficiency of silicon solar cells The efficiency of a solar cell is one of its most important parameters. It indicates what percentage of the solar energy radiated into the cell is converted into electrical energy. The theoretical limit for silicon solar cells is 29.3 percent due to physical ...
The computer simulation shows how the electromagnetic field is distributed in the silicon layer with hole pattern after excitation with a laser. Here, stripes with local field maxima are formed, so that quantum dots shine particularly strongly. Picture. C. Barth/HZB
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Machine learning helps improving photonic applications Photonic nanostructures can be used for many applications, not just in solar cells, but also in optical sensors for cancer markers or other biomolecules, for example. A team at HZB using computer simulations and machine learning has now shown how the design ...
The laser pulse (red) generates heat in the thin-film system. The physical mechanisms by which the heat is distributed can be analysed by temporally resolved X-ray diffraction experiments.
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Future information technologies: nanoscale heat transport under the microscope A team of researchers from the Helmholtz-Zentrum Berlin (HZB) and the University of Potsdam has investigated heat transport in a model system comprising nanometre-thin metallic and magnetic layers. Similar systems are candidates for future high-efficiency ...
Granules of aluminium (grey) become a metallic foam when heated.The tompgraphies document the evolution of pores with time.
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World record: Fastest 3D tomographic images at BESSY II An HZB team has developed an ingenious precision rotary table at the EDDI beamline at BESSY II and combined it with particularly fast optics. This enabled them to document the formation of pores in grains of metal during foaming processes at 25 tomographic ...
The analysed perovskite cell has a surface of 1 cm2. Credit. Uni Potsdam
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Insight into loss processes in perovskite solar cells enables efficiency... In perovskite solar cells, charge carriers are mainly lost through recombination occurring at interface defect sites. In contrast, recombination at defect sites within the perovskite layer does not limit the performance of the solar cells at present. Teams ...
Manganese compounds also play a role as catalysts in photosynthesis.
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Insight into catalysis through novel study of X-ray absorption spectroscopy An international team has made a breakthrough at BESSY II. For the first time, they succeeded in investigating electronic states of a transition metal in detail and drawing reliable conclusions on their catalytic effect from the data. These results are ...
Fossils like this 250 million year old skull of a lystrosaurus can be examined very carefully by neutron tomography.
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Neutron tomography: Insights into the interior of teeth, root balls, batteries,... A team of researchers at Helmholtz-Zentrum Berlin (HZB) and European Spallation Source (ESS) has now published a comprehensive overview of neutron-based imaging processes in the renowned journal Materials Today (impact factor 21.6). The authors report on the ...
The picture shows the typical arrangement of cations in a kesterite type structure. In the background the crystal structure is shown, a unit cell is highlighted.
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Kesterite solar cells: germanium promises better opto-electronic properties... Specific changes in the composition of kesterite-type semiconductors make it possible to improve their suitability as absorber layers in solar cells. As a team at the Helmholtz-Zentrum Berlin showed, this is particularly true for kesterites in which tin was ...
PCN nanolayers under sunlight can split water.
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Solar–to-hydrogen conversion: nanostructuring increases efficiency of... Polymeric carbon nitrides exhibit a catalytic effect in sunlight that can be used for the production of hydrogen from solar energy. However, the efficiency of these metal-free catalysts is extremely low. A team at the Tianjin University in China, in ...
The GaAs nanocrystal has been deposited on top of a silicon germanium needle, as shown by this SEM-image. The rhombic facets have been colored artificially.
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Luminescent nano-architectures of gallium arsenide A team at the HZB has succeeded in growing nanocrystals of gallium arsenide on tiny columns of silicon and germanium. This enables extremely efficient optoelectronic components for important frequency ranges to be realised on silicon chips.
Pencil, paper and co-polymer varnish are sufficient for a thermoelectrical device.
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Hidden talents: Converting heat into electricity with pencil and paper Thermoelectric materials can use thermal differences to generate electricity. Now there is an inexpensive and environmentally friendly way of producing them with the simplest of components: a normal pencil, photocopy paper, and conductive paint are sufficient ...
Electrons with differing energies are emitted along various crystal axes in the interior of the sample as well as from the surface. These can be measured with the angular-resolved photoemission station (ARPES) at BESSY II. Left image shows the sample temperature at 25 K, right at only 1 K. The energy distribution of the conducting and valence band electrons can be derived from these data. The surface remains conductive at very low temperature (1 K).
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40-year controversy in solid-state physics resolved An international team at BESSY II headed by Prof. Oliver Rader has shown that the puzzling properties of samarium hexaboride do not stem from the material being a topological insulator, as it had been proposed to be. Theoretical and initial experimental work ...
Simplified cross-section of a perovskite solar cell: the perovskite layer does not cover the entire surface, but instead exhibits holes. The scientists could show that a protective layer is being built up which prevents short circuits.
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Perovskite solar cells: perfection not required! Experiments at BESSY II reveal why even inhomogeneous perovskite films are highly functional
A short laser pulse pertubates magnetic order in dysprosium. This happens much faster if the sample had a antiferromagnetic order (left) compared to ferromagnetic order (right).
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Future IT: Antiferromagnetic dysprosium reveals magnetic switching with less... HZB scientists have identified a mechanism with which it may be possible to develop a form of magnetic storage that is faster and more energy-efficient. They compared how different forms of magnetic ordering in the rare-earth metal named dysprosium react to a ...
The Bismut doping is enhanced from 0% (left) to 2.2% (right). Measurements at BESSY II show that this leads to increased bandgaps.
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Missing link between new topological phases of matter discovered HZB-Physicists at BESSY II have investigated a class of materials that exhibit characteristics of topological insulators. During these studies they discovered a transition between two different topological phases, one of which is ferroelectric, meaning a ...
Scanning Tunneling Microscopy shows the regular corrugation pattern of graphene over clusters of gold.
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The miracle material graphene: convex as a chesterfield Graphene possesses extreme properties and can be utilised in many ways. Even the spins of graphene can be controlled through use of a trick. This had already been demonstrated by a HZB team some time ago: the physicists applied a layer of graphene onto a ...
Scanning electron micrographs show a 10-micron planar deposition. The constituting silver crystals are about 100 nanometres in size.
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Writing with the electron beam: now in silver For the first time an international team realized direct writing of silver nanostructures using an electron beam applied to a substrate. Silver nanostructures have the potential to concentrate visible light at the nanoscale. Potential applications include ...
This optical zone melting furnace is producing large single crystals.
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New at Campus Wannsee: CoreLab Quantum Materials Helmholtz-Zentrum Berlin has expanded its series of CoreLabs for energy materials research. In addition to the five established CoreLabs, it has now set up a CoreLab for Quantum Materials. A research team from the HZB Institute for Quantum Phenomena in New ...
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New lab for electrochemical interfaces at BESSY II The Helmholtz-Zentrum Berlin (HZB) is establishing a joint lab together with the Max Planck Society (MPS) to study electrochemical phenomenon at solid/liquid interfaces. The Berlin Joint Lab for Electrochemical Interfaces, or BElChem for short, will employ ...
The porous structure of the nanoparticles is visible under the electron microscope. adfm.201701176
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Better cathode materials for Lithium-Sulphur-Batteries A team at the Helmholtz-Zentrum Berlin (HZB) has for the first time fabricated a nanomaterial made from nanoparticles of a titanium oxide compound (Ti4O7) that is characterised by an extremely large surface area, and tested it as a cathode material in ...
The experimental data show, how a light pulse dissociates a hydrogen nucleus from the nitrogen atom without destroying important bonds within the molecule.
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Proton transfer: Researcher find mecanism to protect biomolecules against light... A team at the Helmholtz-Zentrum Berlin (HZB) together with researchers in Sweden and the USA has analysed a mecanism which protects biomolecules such as the DNA against damage by light. They observed how the energy of incoming photons can be absorbed by the ...
Nanostructures trap the light, shows this illustration on the cover in Advanced Optical Materials.
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How to increase efficiencies of ultrathin CIGSe solar cells Nanoparticles at the back help harvesting the light.
PFIA-molecules self-orient with their hydrophobic backbones outside (black lines) and their hydrophilic side-chains inside, in order to form nanometer sized water channels. Each side-chain possesses two docking points (red and yellow circles) for hydrogen ions (H+). These are acidic groups, shown in the magnifying glass.
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Fuel cells with PFIA-membranes:
The new Energy Materials In-Situ Laboratory (EMIL) offers direct access to hard and soft synchrotron x-ray radiation to investigate the chemical and electronic properties of catalysts and other energy materials.
NEWS
Research for Germany’s energy transition: EMIL@BESSY II approved for the... The storage of excess solar and wind power is one of the greatest challenges in Germany’s energy transition. To address this, the German Federal Ministry for Education and Research (BMBF) has created the "Power-to-X” (P2X) project under its ...
The x-ray reflectitivityof the Mo/Si multilayer mirror is changed via a time delayed laserpulse.
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Methods at BESSY II: Versatile cross-correlator for ultrafast X-ray experiments Particularly in the soft X-ray range experimentalists are lacking a broadband method to correlate ultrashort X-ray and laser pulses in space and time. Only recently, a team from Helmholtz-Zentrum Berlin and the University of Potsdam was able to achieve this ...
A pump pulse promotes the molecule's electrons to an excited state and with probe pulses the binding energy of the excited electrons can be measured. However, pump-probe laser experiments are only feasible under ultra-high vacuum.
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Methodology advance at HZB: ionic liquids simplify laser experiments on liquid... An HZB team has developed a new approach to conduct photoemission spectroscopy of molecules in solution. This has been difficult up to now because the sample needed to be situated in vacuum – but liquids evaporate. The work has now demonstrated it is ...
X-PEEM images show the orientation of magnetic domains in the permalloy film overlaid on the superconducting dot (dashed square) before (left image) and after the write process (right image). In this sample the domains (arrows, right image) are reorientied in a monopole pattern.
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Future Information Technologies: New combinations of materials for producing... An international collaboration at BESSY II has discovered a new method to inscribe exotic magnetic patterns such as magnetic monopoles into thin ferromagnetic films. Such unconventional orientation of magnetic domains might open a new path for the design of ...
SEM – model of a metallic nano-network with periodic arrangement ( left) and visual representation of a fractal pattern (right).
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Nanotechnology for energy materials: Electrodes like leaf veins Nano-sized metallic wires are attracting increasing attention as conductive elements for manufacturing transparent electrodes, which are employed in solar cells and touch screen panels. In addition to high electric conductivity, excellent optical ...
More than 100 experts did gather at the international conference "Dynamic Pathways in Multidimensional Landscapes", which was held in September in Berlin.
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VI-Conference "Dynamic Pathways in Multidimensional Landscapes 2016" Near the museum island, in the heart of Berlin, the International Conference "Dynamic Pathways in Multidimensional Landscapes 2016" has taken place last week. More than 100 international experts met at the Magnus-Haus of the German Physical Society from 12 ...
Lithium ions migrate through the electrolyte (yellow) into the layer of crystalline silicon (c-Si). During the charging cycle, a 20-nm layer (red) develops on the silicon electrode adsorbing extreme quantities of lithium atoms.
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Silicon thin fims in Lithium-Ion-Batteries: Charging observed with neutron... The capacity of lithium-ion batteries might be increased theoretically by six times by using anodes made of silicon instead of graphite. A team from the Helmholtz-Zentrum Berlin (HZB) Institute of Soft Matter and Functional Materials has observed for the ...
Fabian Weber (right) is investigating the dynamics of electron processes within graphene-oxide quantum dots as a member of the team headed by Dr. Annika Bande (left). Quantum dots like these as catalysts could help make solar water splitting more efficient. Using Weber’s theoretical model, a much greater amount of information can be obtained from the empirical data gathered by the group headed by Dr. Tristan Petit.
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Two Freigeist Fellows interweave their research at HZB Two Freigeist Fellows are conducting research at the HZB Institute for Methods of Material Development through support received from the Volkswagen Foundation. Theoretical chemist Dr. Annika Bande is modelling fast electron processes, while Dr. Tristan Petit ...
A section from the crystal lattice of Calcium-chromium oxide showing how the spins are subject to conflicting demands. In this ball-and-stick model, the green and red sticks connecting the atoms (grey and black balls) represent ferromagnetic interactions while the blue sticks represent anti-ferromagnetic interactions.
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Novel state of matter: Observation of a quantum spin liquid A novel and rare state of matter known as a quantum spin liquid has been empirically demonstrated in a monocrystal of the compound calcium-chromium oxide by team at HZB. What is remarkable about this discovery is that according to conventional understanding, ...
Scanning electron microscopy in combination with EELS electron spectroscopy permits to visualise atomic positions of the individual atoms in the heterostructure: Superconducting regions of YBaCuO are identified by yttrium (blue) and copper (pink), the ferromagnetic layers by manganese (green) and lanthanum (red). Courtesy MPI Stuttgart.
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Coexistence of superconductivity and charge density waves observed
The model illustrates how the gold atoms sit under the graphene.
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Progress in the application of spin effects in graphene: from the metal to the... Graphene on silicon carbide could be an interesting candidate for future spintronik components. Squeezing gold atoms between the semiconducting substrate and graphene does enhance spin-orbit interaction at hot spots and shows ways to controll the spins. First ...
The nanostructured membrane has a honeycomb pattern with nanoholes of 68 nm in diameter. The nanoholes pin down the magnetic domains.
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Spintronics: Resetting the future of Heat Assisted Magnetic Recording A HZB team has examined thin films of Dysprosium-Cobalt sputtered onto a nanostructured membrane at BESSY II. They showed that new patterns of magnetization could be written in a quick and easy manner after warming the sample to only 80 °Celsius, which is a ...
Combining the results from radiative and non-radiative relaxation processes enabled a complete picture of the filled and unfilled energy levels to be obtained.
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Ferrous chemistry in aqueous solution unravelled An HZB team has combined two different analytical methods at the BESSY II synchrotron source in order to extract more information about the chemistry of transition-metal compounds in solution. These kinds of compounds can act as catalysts to promote desirable ...
NEWS
Helmholtz Innovation Labs: HySPRINT at HZB HZB will be setting up the new Helmholtz HySPRINT Innovation Lab for jointly developing new combinations of materials and processes in energy applications with commercial partners. Silicon and metal-organic perovskite crystals will be the centre point of the ...
The illustration depicts the characteristic spin orientation (arrows) of electrons in a topological insulator (below). Using an initial circular polarised laser pulse, the spins are excited and point up or down. This can be proven by a second linearly polarised laser pulse (above).
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Spintronics for future information technologies: spin currents in topological... An international team headed by HZB researcher Jaime Sánchez-Barriga has shown how spin-polarised currents can be initiated in a controlled manner within samples of topological insulator material. In addition, they were able to manipulate the ...
NEWS
Priority programme for topological insulators begins second funding period Applicants for support funds to conduct research on topological insulators met at HZB Adlershof on February 15th and 16th. This meeting dealt with the second period of funding for the SPP 1666 Priority programme of the German Research Foundation (DFG) that ...
The illustration shows the structure of the sample: n-doped silicon layer (black), a thin silicon oxide layer (gray), an intermediate layer (yellow) and finally the protective layer (brown) to which the catalysing particles are applied. The acidic water is shown in green.
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Solar fuels:a refined protective layer for the “artificial leaf” A team at the HZB Institute for Solar Fuels has developed a process for providing sensitive semiconductors for solar water splitting ("artificial leaves”) with an organic, transparent protective layer. The extremely thin protective layer made of carbon ...
The team could observe for the first time with RIXS how the formation of hydrogen bonds does change C=O bonds in aceton molecules.
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Measuring chemistry: local fingerprint of hydrogen bonding captured in... A team from Helmholtz-Zentrum Berlin has been able for the first time to measure how new bonds influence molecules: they have reconstructed the "energy landscape” of acetone molecules using measurement data from the Swiss Light Source (SLS) of the Paul ...
The work of Galina Gurieva, Franziska Huschmann and Alex Redinger is introduced here.
NEWS
Hint: HZB Postdoc Association introduces a Postdoc of the Month on their webpage What have Galina Gurieva, Franziska Huschmann, Alex Redinger in common? They are postdocs working at HZB. For connecting each other and providing an channel for networking the HZB Postdoc Association introduces each month the work of one of the researchers at ...
Sketch of the structure of both metal oxide layers. Interesting new properties can arise at the interface.
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Metal Oxide Sandwiches: New option to manipulate properties of interfaces A Franco-German cooperation has investigated a sandwich system of transition metal oxides at BESSY II. The scientists discovered a new option to control properties of the interface between the two layers, for instance the amount of charge transferred from one ...
Preisträger des Helmholtz-Doktorandenpreises 2015 mit Otmar D. Wiestler (Mitte), Präsident der Helmholtz-Gemeinschaft, und Stephanie Dittmer (rechts), Bereichsleiterin Strategie/ Impuls- und Vernetzungsfonds der Helmholtz-Gemeinschaft, auf dem Neujahrsempfang 2016. Foto: Simone M. Neumann/helmholtz
NACHRICHT
Matthias May mit dem Doktorandenpreis der Helmholtz-Gemeinschaft ausgezeichnet Dr. Matthias May erforschte in seiner Promotion am Helmholtz-Zentrum Berlin (HZB), wie man mit Sonnenlicht noch effizienter Wasser spalten und in Form von Wasserstoff speichern kann. Für seine Arbeit erhielt er am 27. Januar 2016 den mit 5.000 Euro dotierten ...
Composite Raman intensity-distribution map on a polycrystalline CuInSe2 thin film.
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Alternative method for the representation of microstructures in polycrystalline... Also Raman microspectroscopy in an optical microscope provides the means to determine local crystal orientations of polycrystalline materials over large sample areas. This method can be used alternatively to electron backscatter diffraction in a scanning ...
Nanostructures of silicon shown in scanning electron microscope image. The diameter of the nanocolumns is 570 nm. By comparison, the nanocones taper from their upper diameter of 940 nm down to 360 nm at their base.
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Whispering gallery modes in Silicon nanocones intensify luminescence Silicon, a semiconducting material, reveals new talents when reduced to nanoscopic dimensions. A joint team at the HZB Institute of Nanoarchitectures for Energy Conversion and the Max Planck Institute for the Science of Light (MPL) has demonstrated this. ...
Sketch of the new set-up at EDDI. The high-speed camera (blue box) is on top of the sample holder.
NEWS
Filming microscopic and macroscopic changes within materials The EDDI beamline at BESSY II is now offering even more options. It has recently become possible to also obtain high-resolution three-dimensional images of microscopic structure with it, up to four such tomographies per second are possible. X-ray diffraction ...
The picture illustrates a hypothetical highway with the second path winding around the first one. Experimenters at the beamlines could then either use the dense sequence of light pulses from the primary electron path or select individual light pulses from the secondary orbital track.
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BESSY II electron highway gets second lane The particle accelerator team at Helmholtz-Zentrum Berlin (HZB) has demonstrated that BESSY II, the 3rd generation synchrotron radiation source in Berlin, can be operated with not just one, but two simultaneous electron paths. By precisely tuning the magnetic ...
Markus Kubin in front of his poster.
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Poster award to Markus Kubin At the International Conference on X-Ray Absorption Fine Structure Markus Kubin has been selected to receive one out of five poster awards. More than 300 posters have been presented at the poster session.
The SiO2 nanoparticles (black) have been imprinted directly on the Molybdenum substrate (purple) which corresponds to the back contact of the solar cell. On top of this structured substrate the ultrathin CIGSe layer (red) was grown at HZB, and subsequently all the other layers and contacts needed for the solar cell. Since all layers are extremely thin, even the top layer is showing deformations according to the pattern of the nanoparticles.
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Scientists demonstrate how to improve ultrathin CIGSe solar cells by... CIGSe solar cells are made of a thin chalcopyrite layer consisting of Copper, Indium, Gallium and Selenium and can reach high efficiencies. Since Indium is becoming scarce and expensive, it is interesting to reduce the active CIGSe layer, which however ...
The perovskite film (black, 200-300 nm) is covered by Spiro.OMeTAD, Graphene with gold contact at one edge, a glass substrate and an amorphous/crystalline silicon solar cell.
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Graphene as a front contact for silicon-perovskite tandem solar cells HZB team develops elegant process for coating fragile perovskite layers with graphene for the first time. Subsequent measurements show that the graphene layer is an ideal front contact in several respects.
HZB scientists develop new methods to investigate the electronic structure of catalytic molecules.
NEWS
Catalysis research strengthened: Helmholtz-Zentrum Berlin participates in newly... The Einstein Foundation will fund the new Einstein Center for Catalysis (EC2) beginning in 2016 in which Technical University Berlin (TU Berlin) and selected non-university institutions in Berlin will be participating. Prof. Emad Aziz, head of the HZB ...
Sara Jäckle has demonstrated the formation of a pn-heterojunction at the interface between an organic contact and n-doped silicon. Photo
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Charge transport in hybrid silicon solar cells An HZB team headed by Prof. Silke Christiansen has made a surprising discovery about hybrid organic/inorganic solar cells. Contrary to expectations, a diode composed of the conductive organic PEDOT:PSS and an n-type silicon absorber material behaves more like ...
Manuela Göbelt is evaluating SEM-images to calculate the local degree of networking. Photo: Björn Hoffmann.
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Transparent, electrically conductive network of encapsulated silver nanowires –... A team headed by Prof. Silke Christiansen has developed a transparent electrode with high electrical conductivity for solar cells and other optoelectronic components – that uses minimal amounts of material. It consists of a random network of silver ...
The hedgehog-configuration of the spins and the Fermi-Level is shown. Illustration Thomas Splettstößer/HZB
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Spins in Graphene with a Hedgehog Texture HZB researchers demonstrate a fundamental property of the electron spin in graphene
X-ray spectroscopies have shown a higher chlorine concentration near the perovskite/TiO2 interface than throughout the rest of the perovskite film.
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Depletion and enrichment of chlorine in perovskites observed X-ray spectroscopy at BESSY II reveals inhomogenous distribution of chlorine in a special class of perovskite materials. The discovery could help to enhance efficiencies of perovskite thin film solar cells by controlled processing to optimize the chlorine ...
HZB Group at the ICT/ECT2015. From left to right: Dr. Klaus Habicht (Head of the Department for Methods for Characterization of Transport Phenomena in Energy Materials), Dr. Tommy Hofmann, Dr. Katharina Fritsch, Dr. Britta Willenberg, Dr. Katrin Meier-Kirchner
NEWS
HZB presents research on thermoelectrics The annual "International Conference on Thermoelectrics (ICT)” and the "European Conference on Thermoelectrics (ECT)” took place together from 29 June to 02 July 2015 in Dresden, Germany. For the first time, HZB participated in this international ...
Mapping of the captured magnetisation domains (right, red-blue patterns) in a sample 20 nanometres thick that had been wound in two layers into a tube. The tube has a diameter of 5 microns and a height of 50 microns.
NEWS
New technique enables magnetic patterns to be mapped in 3D An international collaboration has succeeded in using synchrotron light to detect and record the complex 3D magnetisation in wound magnetic layers. This technique could be important in the development of devices that are highly sensitive to magnetic fields, ...
These samples with precise proportions of nickel and copper were produced via an improved preparation procedure. Photo: M. Tovar/HZB
NEWS
Crystal structure and magnetism – new insight into the fundamentals of solid... HZB team decodes relationship between magnetic interactions and the distortions in crystal structure within a geometrically "frustrated” spinel system
Sunlight activates the catalytic behavior of diamond materials, thus helping to convert carbon dioxide into fine chemicals and fuels.
NEWS
Green solutions with diamond materials: Horizon 2020 invests 3.9 million Euro in research project to convert CO2 into fuels using sunlight and diamond materials
The illustration shows how maleimide compounds bind to the graphene surface. The graphene monolayer lies on a thin film of silicon nitride (red) that in turn is on a quartz microbalance (blue) and can be subjected to a potential via a gold contact (yellow).Illustration: Marc Gluba/HZB
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Towards graphene biosensors For the first time, a team of scientists has succeeded in precisely measuring and controlling the thickness of an organic compound that has been bound to a graphene layer. This might enable graphene to be used as a sensitive detector for biological molecules ...
To obtain the 3D structure of the battery electrode on a micormeter scale, snchrotron tomography at BESSY II was used.
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Realistic computer model of battery electrodes A research team has developed a new approach for more realistic computer models of battery electrodes. They combined images from synchrotron tomography that capture three-dimensional structure at micron resolution with those from an electron microscope that ...
At the MRS Spring Meeting in San Francisco, Kai Neldner was awarded for his poster contribution.
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Poster award for MatSEC PhD student at the MRS Spring Meeting The poster contribution of Kai Neldner (HZB-Department Crystallography) was awarded a poster price of the Symposium "Thin-Film Compound Semiconductors" at the MRS Spring Meeting in San Francisco. Kai Neldner, a PhD student in the HZB Graduate School ...
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Joint Lab BeJEL receives 1.4 million EUR grant The Berlin Joint EPR Laboratory (BeJEL) operated by HZB and Freie Universität Berlin has pulled in six of 27 subprojects within a DFG priority program to address"New Frontiers in Sensitivity for EPR Spectroscopy – from Biological Cells to Nano ...
Ah Reum Jeong has completed her PhD in physics at Ewha Womans University in Seoul, Korea. She now works as a postdoc in the Hybrid Material Systems & Nano-Analytics team of Dr. Marin Rusu.
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Poster Award for HZB-Postdoc at EMRS Spring Meeting During the spring meeting 2015 of the European Materials Research Society the Poster contribution of Dr. Ah Reum Jeong (HZB-Institute for Heterogeneous Material Systems) was selected for an award. The young scientist has presented results on electronic and ...
A thin magnetic FeRh film is grown onto a ferroelastic BTO substrate with two different crystal domains a and c. At 0 Volt ferromagnetic domains (red-blue pattern) are observed above BTO a-domains, whereas above c-domains the net magnetization is zero. At 50 Volt all BTO domains are converted into c-domains, which switches off ferromagnetic domains in FeRh.
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New options for spintronic devices: Switching between 1 and 0 with low voltage Scientists from Paris and Helmholtz-Zentrum Berlin have been able to switch ferromagnetic domains on and off with low voltage in a structure made of two different ferroic materials. The switching works slightly above room temperature. Their results, which are ...
A short filmclip demonstrates the production of the photocathode with ILGAR method.
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Artificial photosynthesis: New, stable photocathode with great potential A team at the HZB Institute for Solar Fuels has developed a new composite photocathode for generating hydrogen with high quantum efficiency using sunlight. This enables solar energy to be stored chemically.The photocathode consists of a thin film of ...
Illustration of the working principle of inkjet printing.
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Inkjet printing process for Kesterite solar cells A research team at HZB has developed an inkjet printing technology to produce kesterite thin film absorbers (CZTSSe). Based on the inkjet-printed absorbers, solar cells with total area conversion efficiency of up to 6.4 % have been achieved. Although this is ...
Ultra-high vacuum system in the Energy Materials In-Situ Lab (EMIL) that will combine industry-relevant deposition tools with a suite of complementary advanced characterization methods.
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EU funding strengthens solar cell research at HZB Marcus Bär and his team are participating in two international projects being funded under the EU Horizon 2020 research programme. Both research projects are concerned with development and optimisation of high-efficiency thin-film solar cells based on ...
The scanning electron microscopies (SEM) show how regularly the funnels etched in a silicon substrate are arranged (left: the line segment = 5 microns; right: 1 micron). The funnels measure about 800 nanometres in diameter above and run down to about a hundred nanometres at the tip.
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Learning by eye: silicon micro-funnels increase the efficiency of solar cells A biological structure in mammalian eyes has inspired a team headed by Silke Christiansen to design an inorganic counterpart for use in solar cells. With the help of conventional semiconductor processes, they etched micron-sized vertical funnels ...
Dichromium: both chromium atoms "share" the 12 valence electrons which leads to a multible bond.
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Stretch and relax! – Losing one electron switches magnetism on in dichromium An international team of scientists from Berlin, Freiburg and Fukuoka has provided the first direct experimental insight into the secret quantum life of dichromium. Whereas in its normal state the 12 valence electrons form a strong multiple bond between the ...
This illustrates a moment captured for the first time in experiments at SLAC National Accelerator Laboratory. The CO-molecule and oxygen-atoms are attached to the surface of a ruthenium catalyst. When hit with an optical laser pulse, the reactants vibrate and bump into each other and the carbon atom forms a transitional bond with the lone oxygen center. The resulting CO2 detaches and floats away.
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Details of a crucial reaction: Physicists uncover oxidation process of carbon... An international team has observed the elusive intermediates that form when carbon monoxide is oxidized on a hot ruthenium metal surface. They used ultrafast X-ray and optical laser pulses at the SLAC National Accelerator Laboratory, Menlo Park, California. ...
A general view of the VEKMAG end-station. The vector magnet chamber (grey) is supported by a hexapod frame. Below the magnet one can distinguish the detector chamber (green) and in the forward direction the deposition chamber (dark grey) is displayed. The beam quality is monitored by a diagnostic chamber (yellow) positioned in front of the magnet chamber.
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“VEKMAG” at BESSY II creates 3D magnetic fields in samples Together with HZB, teams from the Universität Regensburg, from the Freie Universität Berlin and from the Ruhr Universität Bochum have jointly set up a unique measurement station at BESSY II: a vector electromagnet consisting of three mutually perpendicular ...