HZB Newsroom

Sear results - Keyword: HZB own research

  • <p>Schematic illustration: the solvants (ink) are used to produce a thin film of polycrystalline perovskite.&nbsp;</p>
    Science Highlight
    Perovskite Solar Cells: paving the way for rational ink design for industrial-scale manufacturing
    For the production of high-quality metal-halide perovskite thin-films for large area photovoltaic modules often optimized inks are used which contain a mixture of solvents. An HZB team at BESSY II has now analysed the crystallisation processes within such mixtures. A model has also been developed to assess the kinetics of the crystallisation processes for different solvent mixtures. The results are of high importance for the further development of perovskite inks for industrial-scale deposition processes of these semiconductors.


  • <p>Nine samples with mixtures from CsPbBr<sub>2</sub>I (ink 1, left) to pure CsPbI<sub>3</sub> (ink 2 right).</p>
    Science Highlight
    Solar cells: Mapping the landscape of Caesium based inorganic halide perovskites
    Scientists at HZB have printed and explored different compositions of caesium based halide perovskites (CsPb(BrxI1−x)3 (0 ≤ x ≤ 1)). In a temperature range between room temperature and 300 Celsius, they observe structural phase transitions influencing the electronic properties. 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.


  • <p>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)</p>
    Science Highlight
    Order in the disorder: density fluctuations in amorphous silicon discovered
    For the first time, a team at HZB has identified the atomic substructure of amorphous silicon with a resolution of 0.8 nanometres using X-ray and neutron scattering at BESSY II and BER II. 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 dramatically influences the quality and lifetime of the semiconductor layer. The study was selected for the cover of the actual issue of Physical Review Letters.


  • <p>Ultracold atoms in an optical lattice have been considered for quantum simulation.</p>
    Science Highlight
    Modelling shows which quantum systems are suitable for quantum simulations
    A joint research group led by Prof. Jens Eisert of Freie Universität Berlin and Helmholtz-Zentrum Berlin (HZB) has shown a way to simulate the quantum physical properties of complex solid state systems. This is done with the help of complex solid state systems that can be studied experimentally. The study was published in the renowned journal Proceedings of the National Academy of Sciences of the United States of America (PNAS). [...]
  • <p>Scalable large area BiVO<sub>4</sub> photoanode on FTO with Ni current collectors.</p>
    Science Highlight
    Solar hydrogen: Let’s consider the stability of photoelectrodes

    As part of an international collaboration, a team at the HZB has examined the corrosion processes of high-quality BiVO4 photoelectrodes using different state-of-the-art characterisation methods. The result is the first operando stability study of high-purity BiVO4 photoanodes during the photoelectrochemical oxygen evolution reaction (OER). This work shows how the stability of photoelectrodes and catalysts can be compared and enhanced in the future. [...]

  • <p>(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.</p>
    Science Highlight
    Nanopatterns of proteins detected by cryo-electron microscopy
    A team from Helmholtz-Zentrum Berlin (HZB) used cryo electron microscopy to detect regular, two-dimensional structures in the form of Pascal triangles in a shock frozen protein material.  The samples have been synthesized by a Chinese research group. The method of cryo electron microscopy has the potential for new insights into energy materials as well. [...]
  • <p>Dr. Michael Tovar working at FALCON at the neutron Source BER II.</p>
    Science Highlight
    Perovskite materials: Neutrons show twinning in halide perovskites
    Solar cells based on hybrid halide perovskites achieve high efficiencies. These mixed organic-inorganic semiconductors are usually produced as thin films of microcrystals. An investigation with the Laue camera at the neutron source BER II could now clarify that twinning occurs during crystallisation even at room temperature. This insight is helpful for optimising production processes of halide perovskites. 


  • <p>Periodic metasurfaces (grey) can enhance photon upconversion of nanoparticles (yellow) by more than three orders of magnitude.</p>
    Science Highlight
    Upconversion of photons at low light intensities – the key to new applications in energy and bioengineering
    The region of the spectrum that can be utilised for producing electrical energy can be considerably extended by converting low-energy (longer wavelength) photons into high-energy (shorter wavelength) photons. But so far, this has only been possible at high intensities of light. Now for the first time, scientists from the Helmholtz-Zentrum Berlin (HZB) and the Federal Institute for Materials Research and Testing (BAM) have been able to produce a usable effect from relatively weak light by combining certain nanoparticles with what is known as a meta-surface. This paves the way for future applications in photovoltaics, for the detection of biological substances, and for electrical-field sensors. [...]
  • <p>Structure of TUB75: the entire MOF architecture (top) and its conductive inorganic unit (bottom)</p>
    Science Highlight
    Molecular architecture: New class of materials for tomorrow's energy storage
    Researchers at the Technische Universität Berlin (TUB) have created a new family of semiconductors, the properties of which were investigated by the Helmholtz-Zentrum Berlin (HZB). The researchers christened the first member “TUB75”. The material belongs to the class called metal-organic frameworks, or MOFs for short, and could open up new opportunities for energy storage. The work was published in Advanced Materials. [...]
  • <p>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 J&uuml;lich (shown here is JUWELS).</p>
    Science Highlight
    Mathematical tool helps calculate properties of quantum materials more quickly
    Many quantum materials have been nearly impossible to simulate mathematically because the computing time required is too long. Now a joint research group at Freie Universität Berlin and the Helmholtz-Zentrum Berlin (HZB) has demonstrated a way to considerably reduce the computing time. This could accelerate the development of materials for energy-efficient IT technologies of the future.


  • <p>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.</p>
    Science Highlight
    Hope for better batteries – researchers follow the charging and discharging of silicon electrodes live

    Using silicon as a material for electrodes in lithium-ion batteries promises a significant increase in battery amp-hour capacity.The shortcoming of this material is that it is easily damaged by the stress caused by charging and discharging.Scientists at the Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) have now succeeded for the first time in observing this process directly on crystalline silicon electrodes in detail.Operando experiments using the BESSY II synchrotronprovided new insights into how fractures occur in silicon – and also how the material can nevertheless be utilised advantageously. [...]

  • <p>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.</p>
    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. It consists of 1103 organic molecules that could be used as building blocks for new drugs. The MX team has now validated this library in collaboration with the FragMAX group at MAX IV. The substance library of the HZB is available for research worldwide and also plays a role in the search for substances active against SARS-CoV-2.


  • <p>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.</p>
    Science Highlight
    Robust high-performance data storage through magnetic anisotropy
    The latest generation of magnetic hard drives is made of magnetic thin films, which are invar materials. They allow extremely robust and high data storage density by local heating of ultrasmall nano-domains with a laser, so called heat assisted magnetic recording or HAMR. The volume in such invar materials hardly expands despite heating. A technologically relevant material for such HAMR data memories are thin films of iron-platinum nanograins. An international team led by the joint research group of Prof. Dr. Matias Bargheer at HZB and the University of Potsdam 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. The study has been published in Science Advances.


  • <p>Graphic representation of the printing process for the perovskite LED.</p>
    Science Highlight
    Printed perovskite LEDs – an innovative technique towards a new standard process of electronics manufacturing

    A team of researchers from the Helmholtz-Zentrum Berlin (HZB) and Humboldt-Universität zu Berlin has succeeded for the first time in producing light-emitting diodes (LEDs) from a hybrid perovskite semiconductor material using inkjet printing.This opens the door to broad application of these materials in manufacturing many different kinds of electronic components.The scientists achieved the breakthrough with the help of a trick: "inoculating" (or seeding) the surface with specific crystals. [...]

  • <p>The publication made it onto the cover of the current issue of SCIENCE.</p>
    Science Highlight
    BESSY II: Experiment shows for the first time in detail how electrolytes become metallic
    An international team has developed a sophisticated experimental technique at BESSY II to observe the formation of a metallic conduction band in electrolytes. To accomplish this, the team first prepared cryogenic solutions of liquid ammonia containing different concentrations of alkali metals. The colour of the solutions changes with concentration from blue to golden as the individual atoms of metal in solution transition to a metallic compound. The team then examined these liquid jets using soft X-rays at BESSY II and subsequently has been able to analyse this process in detail from the data they acquired combined with theoretical predictions. The work has been published in Science and appears even on the cover. [...]
  • <p>Perovskite oxides are characterized by the molecular formula ABO<sub>3</sub>, where the elements A (green) and B (blue) are located on specific lattice sites and are surrounded by oxygen (red).</p>
    Science Highlight
    Catalysts: Efficient hydrogen production via structure

    Regeneratively produced hydrogen is considered the ecological raw material of the future. In order to produce it efficiently by electrolysis of water, researchers today also investigate perovskite oxides. The Journal of Physics: Energy invited Dr. Marcel Risch from the Helmholtz-Zentrum Berlin (HZB) to outline the current state of research. [...]

  • <p>The illustration shows the changes in the structure of FASnI<sub>3</sub>:PEACl films during treatment at different temperatures.</p>
    Science Highlight
    On the road to non-toxic and stable perovskite solar cells
    The promising halide perovskite materials for solar energy conversion show high efficiencies, but this comes at a cost: The best perovskite materials incorporate toxic lead which poses a hazard to the environment. 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. [...]
  • <p>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 PbCuTe<sub>2</sub>O<sub>6</sub>.</p>
    Science Highlight
    Future information technologies: 3D Quantum Spin Liquid revealed
    Quantum Spin Liquids are candidates for potential use in future information technologies. So far, Quantum Spin Liquids have usually only been found in one or two dimensional magnetic systems only. Now 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 experimental data fit extremely well to theoretical simulations also done at HZB. [...]
  • <p>The CIGS-Pero tandem cell was realised in a typical lab size of 1 square centimeter.</p>
    Science Highlight
    Tandem solar cell world record: New branch in the NREL chart
    A special branch in the famous NREL-chart for solar cell world records refers to a newly developed tandem solar cell by HZB teams. The world-record cell combines the semiconductors perovskite and CIGS to a monolithic "two-terminal" tandem cell. Due to the thin-film technologies used, such tandem cells survive much longer in space and can even be produced on flexible films. The new tandem cell achieves a certified efficiency of 24.16 percent. [...]
  • <p>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).</p>
    Science Highlight
    Condensed Matter Physics: Long-standing prediction of quantum physics experimentally proven
    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. They used neutron scattering experiments at various neutron facilities including the unique high-field magnet of BER II* at HZB. The experimental data are in excellent agreement with the theoretical prediction of Bethe and prove once again the power of quantum physics. [...]
  • <p>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.</p> <p>&nbsp;</p> <p></p>
    Science Highlight
    BESSY II: Ultra-fast switching of helicity of circularly polarized light pulses
    At the BESSY II storage ring, a joint team of accelerator physicists, undulator experts and experimenters has shown how the helicity of circularly polarized synchrotron radiation can be switched faster - up to a million times faster than before. They used an elliptical double-undulator developed at HZB and operated the storage ring in the so-called two-orbit mode. This is a special mode of operation that was only recently developed at BESSY II and provides the basis for fast switching. 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. [...]
  • <p>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).</p>
    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. Like a battery,MXenes can store large amounts of electrical energy through electrochemical reactions- but unlike batteries,can be charged and discharged in a matter of seconds. In collaboration with Drexel University, a team at HZB showed that the intercalation of urea molecules between the MXene layers can increase the capacity of such "pseudo-capacitors" by more than 50 percent. At BESSY II they have analysed how changes of the MXene surface chemistry after urea intercalation are responsible for this. [...]
  • <p>60s on the new detector were sufficient to obtain the electron density of the PETase enzyme.</p>
    New detector accelerates protein crystallography

    Last week a new detector was installed at one of the three MX beamlines at HZB. 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. [...]

  • <p>3D architecture of the cell with different organelles:&nbsp; mitochondria (green), lysosomes (purple), multivesicular bodies (red), endoplasmic reticulum (cream).</p>
    Science Highlight
    X-ray microscopy at BESSY II: Nanoparticles can change cells
    Nanoparticles easily enter into cells. New insights about how they are distributed and what they do there are shown for the first time by high-resolution 3D microscopy images from the lightsources BESSY II and ALBA. For example, certain nanoparticles accumulate preferentially in certain organelles of the cell. This can increase the energy costs in the cell. "The cell looks like it has just run a marathon, apparently, the cell requires energy to absorb such nanoparticles" says lead author James McNally. [...]
  • <p>Bei 25,8 Tesla findet in dem Urankristall ein Phasen&uuml;bergang statt und ein komplexes magnetisches Muster etabliert sich.</p>
    Science Highlight
    Not everything is ferromagnetic in high magnetic fields
    High magnetic fields have a potential to modify the microscopic arrangement of magnetic moments because they overcome interactions existing in zero field. 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 experiments took place at the high-field magnet at HZB's neutron source BER II, which generates a constant magnetic field of up to 26 Tesla. This is about 500,000 times stronger than the Earth's magnetic field. Further experiments with pulsed magnetic fields up to 45 Tesla were performed at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR).  [...]
  • <p>The x-ray tomography shows ruptures (black) in the regions of electrical contacts (white).</p>
    Science Highlight
    Battery research: Using neutrons and X-rays to analyse the ageing of lithium batteries
    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 new mathematical method, it was possible to virtually unwind electrodes that had been wound into the form of a compact cylinder, and thus actually observe the processes on the surfaces of the electrodes. The study was published in Nature Communications. [...]
  • 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 was published in Nature Energy and is considered a milestone for the further development of this new type of solar cell on its way to industrial application. [...]
  • <p>The tandem solar cell was realized on a typical laboratory scale of one square centimeter. However, scaling up is possible.</p>
    Science Highlight
    World Record: Efficiency of perovskite silicon tandem solar cell jumps to 29.15 per cent
    In the race for ever higher efficiency levels, an HZB development team has once again pulled ahead. The groups of Steve Albrecht and Bernd Stannowski have developed a tandem solar cell made of the semiconductors perovskite and silicon, that converts 29.15 per cent of the incident light into electrical energy. This value has been officially certified by the CalLab of the Fraunhofer Institute for Solar Energy Systems (ISE) and means that surpassing the 30 per cent efficiency mark is now within reach. [...]
  • <p>Mint plants have been analysed after having grown on contaminated soil samples.</p>
    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. This is shown in a study by HZB researcher Antonio Abate with partners in China and Italy, published in Nature communications. [...]
  • Science Highlight
    Topological materials for information technology offer lossless transmission of signals
    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. In the future, it might be possible to develop materials that display this phenomenon at room temperature and can be used as processing units in a quantum computer, for example. The study has been published in the renowned journal Nature. [...]
  • <p>The drawing illustrates the interaction of the organic methylammonium cation (CH<sub>3</sub>NH<sub>3</sub><sup>+</sup>) 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.</p>
    Science Highlight
    Perovskite solar cells: Possible aspects of high efficiency uncovered
    Using crystallographic analyses at the Diamond Light Source (DLS) synchrotron in the United Kingdom, an HZB team has demonstrated that hybrid halide perovskites crystallise without inversion centre. Interactions between the organic molecules and adjacent iodine atoms can lead to the formation of ferroelectric domains, which, indirectly, can result in higher solar-cell efficiencies. The formation of these ferroelectric domains cannot occur in purely inorganic perovskites. [...]
  • <p>The illustration demonstrates skyrmions in one of their Eigen modes (clockwise).</p>
    Science Highlight
    Dynamic pattern of Skyrmions observed
    Tiny magnetic vortices known as skyrmions form in certain magnetic materials, such as Cu2OSeO3. These skyrmions can be controlled by low-level electrical currents – which could facilitate more energy-efficient data processing. 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). [...]
  • <p>The Pero-CIGS tandem cell achieves a record efficiency of 23.26 percent.</p>
    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 cell at EU PVSEC, the world's largest international photovoltaic and solar energy conference and exhibition, in Marseille, France on September 11, 2019. This tandem solar cell combines the semiconducting materials perovskite and CIGS and achieves a certified efficiency of 23.26 per cent. One reason for this success lies in the cell’s intermediate layer of organic molecules: they self-organise to cover even rough semiconductor surfaces. Two patents have been filed for these layers. [...]
  • <p>The operando cell was developed at HZB and allows to analyse processes inside the battery during charging cycles with neutrons.</p>
    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 results can help increase the service life of lithium-sulphur batteries. [...]
  • <p>The nano-antennae werde produced in an electron microscope by direct electron-beam writing.</p>
    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 information technology. [...]
  • <p>The rotary sample table turns around its axis at several hundred revolutions per second with extreme precision.</p>
    Science Highlight
    World record in tomography: Watching how metal foam forms
    An international research team at the Swiss Light Source (SLS) has set a new tomography world record using a rotary sample table developed at the HZB. With 208 three-dimensional tomographic X-ray images per second, they were able to document the dynamic processes involved in the foaming of liquid aluminium. The method is presented in the journal Nature Communications. [...]
  • <p>Prof. Dr. Christiane Becker in the clean room at HZB campus side Berlin-Adlershof.</p>
    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. “On top of everything else, there’s this spirit at HZB that we are working on the renewable energies of the future, and that is incredibly inspiring,” she relates in portrait. [...]
  • <p>At the MX-Beamlines at BESSY II, Gottfried Palm, Gert Weber and Manfred Weiss could solve the 3D structure of MHETase.</p>
    FOCUS TOPIC: Using BESSY II to combat plastic waste
    Plastics are excellent materials: extremely versatile and almost eternally durable. But this is also exactly the problem, because after only about 100 years of producing plastics, plastic particles are now found everywhere – in groundwater, in the oceans, in the air, and in the food chain.


  • <p class="MsoCommentText">The photomontage shows a sample of solid, pure niobium before coating (left), and coated with a thin layer of Nb<sub>3</sub>Sn (right).</p>
    Science Highlight
    Accelerator physics: alternative material investigated for superconducting radio-frequency cavity resonators
    In modern synchrotron sources and free-electron lasers, superconducting radio-frequency cavity resonators are able to supply electron bunches with extremely high energy. These resonators are currently constructed of pure niobium. Now an international collaboration has investigated the potential advantages a niobium-tin coating might offer in comparison to pure niobium. [...]
  • <p>An X-ray pulse probes the delocalization of iron 3d electrons onto adjacent ligands.</p>
    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 this description of the process is too simple. For the first time, a team there has investigated the fundamental photochemical processes around the metal atom and its ligands. The study has now been published in “Angewandte Chemie, international Edition” and is displayed on the cover. [...]
  • <p>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&deg;C (right).</p>
    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 experimentally assess the principal microscopic process of ultra-fast magnetism. The methodology developed for this purpose can also be used to investigate interactions between spins and lattice oscillations in graphene, superconductors or other (quantum) materials. [...]
  • <p>The illustration is alluding to the laser experiment in the background and shows the structure of TGCN.</p>
    Science Highlight
    Organic electronics: a new semiconductor in the carbon-nitride family
    Teams from Humboldt-Universität and the Helmholtz-Zentrum Berlin have explored a new material in the carbon-nitride family. Triazine-based graphitic carbon nitride (TGCN) is a semiconductor that should be highly suitable for applications in optoelectronics. Its structure is two-dimensional and reminiscent of graphene. Unlike graphene, however, the conductivity in the direction perpendicular to its 2D planes is 65 times higher than along the planes themselves. [...]
  • 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. The Federal Ministry of Education and Research (BMBF) is funding the "EPR-on-a-Chip" or EPRoC project with 6.7 million euros. On June 3, 2019, the kick-off meeting took place at the Helmholtz-Zentrum Berlin. [...]
  • <p>A green laser pulse initially excites the electrons in the Cu<sub>2</sub>O; just fractions of a second later, a second laser pulse (UV light) probes the energy of the excited electron.</p>
    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 determine where these losses take place: not so much at the interfaces, but instead far more in the interior of the crystalline material. These results provide indications on how to improve copper oxide and other metal oxides for applications as energy materials. [...]
  • <p>Tomography of a lithium electrode in its initial condition.</p>
    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 of Munster, and partners in China have documented the degradation process of lithium electrodes in detail for the first time. They achieved this with the aid of a 3D tomography process using synchrotron radiation at BESSY II (HZB) as well at the Helmholtz-Zentrum Geesthacht (HZG). Their results have been published open access in the scientific journal "Materials Today". [...]
  • <p></p> <p>By co-evaporation of cesium iodide and lead iodide thin layers of CsPbI<sub>3</sub> can be produced even at moderate temperatures. An excess of cesium leads to stable perovskite phases.</p>
    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 solar cells from this material. In comparison to metal-organic hybrid perovskites, inorganic perovskites are more thermally stable. The work has been published in Advanced Energy Materials. [...]
  • <p>SnSe is a highly layered orthorhombic structure. SnSe undergoes a phase transition of second order at 500&deg;C with an increase of the crystal symmetry from space group Pnma (left) to Cmcm (right).</p>
    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 BESSY II and PETRA III synchrotron sources show that tin selenide can also be utilised as a thermoelectric material at room temperature – so long as high pressure is applied. [...]
  • <p>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.</p>
    Science Highlight
    "Molecular scissors" for plastic waste
    A research team from the University of Greifswald and Helmholtz-Zentrum-Berlin (HZB) has solved the molecular structure of the important enzyme MHETase at BESSY II. 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. This 3D structure already allowed the researchers to produce a MHETase variant with optimized activity in order to use it, together with PETase, for a sustainable recycling of PET. The results have been published in the research journal Nature Communications. [...]
  • <p>The SEM shows Molybdenum sulfide deposited at room temperature.</p>
    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 amorphous molybdenum sulphide works best. The results have been published in the journal ACS Catalysis. [...]
  • <p>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.</p>
    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 contribute. [...]
  • <p>Schematic view of carbon structures with pores.</p>
    Science Highlight
    X-ray analysis of carbon nanostructures helps material design
    Nanostructures made of carbon are extremely versatile: they can absorb ions in batteries and supercapacitors, store gases, and desalinate water. How well they cope with the task at hand depends largely on the structural features of the nanopores. 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. The results have now been published in the journal Carbon. [...]
  • <p>Water molecules are excited with X-ray light (blue). From the emitted light (purple) information on H-bonds can be obtained.</p>
    Science Highlight
    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 case. At room temperature and normal pressure, the water molecules form a fluctuating network with an average of 1.74 ± 2.1% donor and acceptor hydrogen bridge bonds per molecule each, allowing tetrahedral coordination between close neighbours. [...]
  • <p>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</p>
    Science Highlight
    Spintronics by “straintronics”: Superferromagnetism with electric-field induced strain
    Data storage in today’s magnetic media is very energy consuming. Combination of novel materials and the coupling between their properties could reduce the energy needed to control magnetic memories thus contributing to a smaller carbon footprint of the IT sector. Now an international team led by HZB has observed at the HZB lightsource BESSY II a new phenomenon in iron nanograins: whereas normally the magnetic moments of the iron grains are disordered with respect each other at room temperature, this can be changed by applying an electric field: This field induces locally a strain on the system leading to the formation of a so-called superferromagnetic ordered state. [...]
  • <p>An extremely thin layer between CIGSe and Perovskite improves the efficiency of the tandemcell.</p>
    Science Highlight
    Ultra-thin and extremely efficient: Thin-film tandem cells made of perovskite and CIGSe semiconductors
    An HZB team has fabricated and characterised a thin-film tandem solar cell made of perovskite and CIGSe. They relied on a simple, robust fabrication process that is also suitable for scaling up to large surface areas. The tandem solar cell is a fully thin film device with an impressive efficiency of 21.6 %. With further improvements it might reach efficiencies above 30 %. [...]
  • <p>Neutrons (red arrows) detect the presence of Lithium ions which have migrated into the silicon anode.</p>
    Science Highlight
    Batteries with silicon anodes: Neutron experiments show how formation of surface structures reduces amp-hour capacity
    In theory, silicon anodes could store ten times more lithium ions than graphite anodes, which have been used in commercial lithium batteries for many years. However, the amp-hour capacity of silicon anodes so far has been declining sharply with each additional charge-discharge cycle. Now an HZB team at BER II of the HZB in Berlin and the Institut Laue-Langevin in Grenoble has utilised neutron experiments to establish what happens at the surface of the silicon anode during charging and what processes reduce this capacity. [...]
  • <p>The model refers to a cubic crystal structure (pyrochlore lattice). Not only were magnetic interactions between the nearest neighbours included, but also with the next nearest neighbours (see drawing).</p>
    Science Highlight
    New insights into magnetic quantum effects in solids
    Using a new computational method, an international collaboration has succeeded for the first time in systematically investigating magnetic quantum effects in the well-known 3D pyrochlore Heisenberg model. The surprising finding: physical quantum phases are formed only for small spin values. [...]
  • <p class="MsoPlainText">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.</p>
    Science Highlight
    Climate change: How could artificial photosynthesis contribute to limiting global warming?

    If CO2 emissions do not fall fast enough, then CO2 will have to be removed from the atmosphere in the future to limit global warming. Not only could planting new forests and biomass contribute to this, but new technologies for artificial photosynthesis as well. An HZB physicist and a researcher at the University of Heidelberg have estimated how much surface area such solutions would require. Although artificial photosynthesis could bind CO2 more efficiently than the natural model, there are still no large modules that are stable over the long term. The team published their calculations in "Earth System Dynamics".


  • <p>Photocathode in superconducting photoinjector system.</p>
    Science Highlight
    Milestone for bERLinPro: photocathodes with high quantum efficiency
    A team at the HZB has improved the manufacturing process of photocathodes and can now provide photocathodes with high quantum efficiency for bERLinPro. [...]
  • <p>The molecule organises itself on the electrode surface until a dense, uniform monolayer is formed.</p>
    Science Highlight
    Molecules that self-assemble into monolayers for efficient perovskite solar cells
    A team at the HZB has discovered a new method for producing efficient contact layers in perovskite solar cells. It is based on molecules that organise themselves into a monolayer. The study was published in Advanced Energy Materials and appeared on the front cover of the journal. [...]
  • <p>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.</p> <p></p>
    Science Highlight
    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 of organic solar cells. The study has now been published in the journal PCCP, and its illustration selected for the cover. [...]
  • <p>The SEM image shows the cross-section of a silicon perovskite tandem solar cell.</p>
    Science Highlight
    New records in perovskite-silicon tandem solar cells through improved light management
    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 investigate light conversion in various device designs with different nanostructured surfaces. This enabled optimization of light management and detailed energy yield analyses. The study has now been published in Energy & Environmental Science. [...]
  • <p>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.</p>
    Science Highlight
    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 at a surprising location. [...]
  • <p>Andriy Zakutayev (NREL), member of the jury, has awarded Fredrike Lehmann for her poster at ICTMC-21 in Boulder, Colorado, USA.</p>
    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 perovskite materials, which are considered interesting candidates for novel solar cells. [...]
  • <p>Doped Diamond Foam. </p>
    Science Highlight
    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 diamond materials with boron and shown at BESSY II how this could significantly improve the photocatalytic properties. [...]
  • <p>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. </p>
<p><strong> </strong></p>
    Science Highlight
    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 phosphorus modification. Blue phosphorus is an interesting candidate for new optoelectronic devices. The results have been published in Nano Letters. [...]
  • <p>Shown are the magnetic fluxlines inside a superconducting sample of lead in two different directions. The scale bar is 5 mm. </p>
    Science Highlight
    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 electrodes, and other energy-related materials. [...]
  • <p>Principle of a silicon singlet fission solar cell with incorporated organic crystalls<br /></p>
    Science Highlight
    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 material properties. In the journal Materials Horizons, researchers from Helmholtz-Zentrum Berlin (HZB) and international colleagues describe how this limit can be abolished. The trick: they incorporate layers of organic molecules into the solar cell. These layers utilise a quantum mechanical process known as singlet exciton fission to split certain energetic light (green and blue photons) in such a way that the electrical current of the solar cell can double in that energy range. [...]
  • <p>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</p>
    Science Highlight
    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 of such nanostructures can be selectively optimised. The results are published in Communications Physics. [...]
  • <p>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. </p>
    Science Highlight
    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 data storage devices that can be locally heated and rewritten by laser pulses (Heat-Assisted Magnetic Recording). Measurements taken with extremely short X-ray pulses have now shown that the heat is distributed a hundred times slower than expected in the model system. The results are published in Nature Communications. [...]
  • <p>Granules of aluminium (grey) become a metallic foam when heated.The tompgraphies document the evolution of pores with time. </p>
    Science Highlight
    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 images per second - a world record. [...]
  • <p>The analysed perovskite cell has a surface of 1 cm<sup>2</sup>. Credit. Uni Potsdam</p>
    Science Highlight
    Insight into loss processes in perovskite solar cells enables efficiency improvements
    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 from the University of Potsdam and the Helmholtz-Zentrum Berlin (HZB) were able to reach this interesting conclusion through extremely accurate quantitative measurements on 1 cm2 perovskite cells using photoluminescence. Their results contribute to improving  perovskite solar cells and have now been published in Nature Energy. [...]
  • <p>Manganese compounds also play a role as catalysts in photosynthesis. </p>
    Science Highlight
    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 helpful for the development of future applications of catalytic transition-metal systems. The work has now been published in Chemical Science, the Open Access journal of the Royal Society of Chemistry. [...]
  • <p>Fossils like this 250 million year old skull of a lystrosaurus can be examined very carefully by neutron tomography. </p>
    Science Highlight
    Neutron tomography: Insights into the interior of teeth, root balls, batteries, and fuel cells
    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 latest developments in neutron tomography, illustrating the possible applications using examples of this non-destructive method. Neutron tomography has facilitated breakthroughs in so diverse areas such as art history, battery research, dentistry, energy materials, industrial research, magnetism, palaeobiology and plant physiology. [...]
  • <p class="Default">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. </p>
    Science Highlight
    Kesterite solar cells: germanium promises better opto-electronic properties than tin
    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 replaced by germanium. The scientists examined the samples using neutron diffraction at BER II and other methods. The work was selected for the cover of the journal CrystEngComm. [...]
  • <p>PCN nanolayers under sunlight can split water. </p>
    Science Highlight
    Solar–to-hydrogen conversion: nanostructuring increases efficiency of metal-free photocatalysts by factor eleven
    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 collaboration with a group at the Helmholtz-Zentrum Berlin, has increased the catalytic efficiency of these polymeric carbon nitrides by a factor eleven through a simple process resulting in a larger surface area. The paper was published in the journal Energy & Environmental Science. [...]
  • <p>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. </p>
    Science Highlight
    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. [...]
  • <p>Pencil, paper and co-polymer varnish are sufficient for a thermoelectrical device. </p>
    Science Highlight
    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 to convert a temperature difference into electricity via the thermoelectric effect. This has now been demonstrated by a team at the Helmholtz-Zentrum Berlin. [...]
  • <p>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). </p>
    Science Highlight
    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 had previously indicated that this material, which becomes a Kondo insulator at very low temperatures, also possessed the properties of a topological insulator. The team has now published a compelling alternative explanation in Nature Communications, however. [...]
  • <p>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.</p>
    Science Highlight
    Perovskite solar cells: perfection not required!
    Experiments at BESSY II reveal why even inhomogeneous perovskite films are highly functional  [...]
  • <p>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). </p>
    Science Highlight
    Future IT: Antiferromagnetic dysprosium reveals magnetic switching with less energy
    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 short laser pulse. They discovered that the magnetic orientation can be altered much faster and with considerably less energy if the magnetic moments of the individual atoms do not all point in the same direction (ferromagnetism), but instead point are rotated against each other (anti-ferromagnetism). The study was published in Physical Review letters on 6. November 2017 and on the cover of the print edition. [...]
  • <p>The Bismut doping is enhanced from 0% (left) to 2.2% (right). Measurements at BESSY II show that this leads to increased bandgaps. </p>
    Science Highlight
    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 phase in the material that exhibits spontaneous electric polarisation and can be reversed by an external electric field. This could also lead to new applications such as switching between differing conductivities. [...]
  • <p>Scanning Tunneling Microscopy shows the regular corrugation pattern of graphene over clusters of gold.</p>
    Science Highlight
    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 nickel substrate and introduced atoms of gold in between (intercalation). The scientists now show why this has such a dramatic influence on the spins in a paper published in 2D Materials. As a result, graphene can also be considered as a material for future information technologies that are based on processing spins as units of information. [...]
  • <p class="msocomoff" align="left"><!-- [if !supportAnnotations]--><!--[endif]--></p>
<p>Scanning electron micrographs show a 10-micron planar deposition. The constituting silver crystals are about 100 nanometres in size. </p>
    Science Highlight
    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 sensor design to detect extremely small traces of specific molecules, as well as devices for optical information processing. [...]
  • <p>This optical zone melting furnace is producing large single crystals. </p>
    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 Materials is responsible for the CoreLab and its modern equipment. The CoreLab is also open to experimenters from other research institutes.  [...]
  • News
    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 X-rays from BESSY II to analyse materials for renewable energy production. [...]
  • <p>The porous structure of the nanoparticles is visible under the electron microscope. <strong><a href="http://onlinelibrary.wiley.com/doi/10.1002/adfm.201701176/abstract;jsessionid=F0393DC7BB4AAE76B24CFD675C8CC430.f03t04   " class="Extern">adfm.201701176</a></strong></p>
    Science Highlight
    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 lithium-sulphur batteries. The highly porous nanomaterial possesses high storage capacity that remains nearly constant over many charging cycles. [...]
  • <p>The experimental data show, how a light pulse dissociates a hydrogen nucleus from the nitrogen atom without destroying important bonds within the molecule. </p>
    Science Highlight
    Proton transfer: Researcher find mecanism to protect biomolecules against light induced damage
    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 molecule without destroying important bonds. The experiments took place at the Linac Coherent Light Source (LCLS) free-electron laser in California as well as the BESSY II synchrotron source at the HZB in Berlin, where with resonant inelastic X-ray-diffraction a very sensitive method is available. [...]
  • <p>Nanostructures trap the light, shows this illustration on the cover in  Advanced Optical Materials. </p>
    Science Highlight
    How to increase efficiencies of ultrathin CIGSe solar cells
    Nanoparticles at the back help harvesting the light. [...]
  • <p>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. </p>
    Science Highlight
    Fuel cells with PFIA-membranes:
  • <p>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. <br /></p>
    Research for Germany’s energy transition: EMIL@BESSY II approved for the Kopernikus “Power-to-X” project
    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 Kopernikus programme. P2X will advance research into converting electrical energy from the sun and wind into basic chemical compounds, gaseous energy media, and fuels. A total of 17 research institutions, 26 industrial enterprises, as well as three non-governmental organisations are involved, and the BMBF is funding the first development phase of the project at a level of 30 million Euros. The Helmholtz-Zentrum Berlin will participate in the planned research, using the advanced synthesis capabilities and the BESSY II synchrotron-based X-ray characterization tools at the recently inaugurated EMIL@BESSY II laboratory complex. [...]
  • <p>The x-ray reflectitivityof the Mo/Si multilayer mirror is changed via a time delayed laserpulse. </p>
    Science Highlight
    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 by utilizing a standard molybdenum-silicon (Mo/Si) multilayer mirror at the FemtoSpeX facility at BESSY II. They use femtosecond laser pulses to modulate the multilayer period under the Bragg condition on a sub-picosecond up to nanosecond timescale which in turn strongly affects the mirror’s X-ray reflectivity. The presented Mo/Si cross-correlator works for the soft up to the hard X-ray regime as well as for a broad range of laser pump wavelengths (mid-IR to UV) and renders this technique as an easy to implement and versatile timing tool for various synchrotron- and lab-based pump-probe experiments. The results are published in the journal of "Structural Dynamics". [...]
  • <p>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.</p>
    Science Highlight
    Methodology advance at HZB: ionic liquids simplify laser experiments on liquid samples
    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 feasible to replace the solvent with an ionic liquid of low vapor pressure, which does not perturb the sample characteristics.  This allows the molecules to be excited with a laser pulse and to record the behaviour of the excited energy states. It provides insight into the physical and chemical processes of novel liquid energy materials that might be employed in organic solar cells or catalysts, for instance. [...]
  • <p>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. </p>
    Science Highlight
    Future Information Technologies: New combinations of materials for producing magnetic monopoles
    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 energy efficient data storage. The new materials system consists of regular arrays of superconducting YBaCuO-dots covered with an extremely thin permalloy film. A shortly applied external magnetic field leads to the creation of supercurrents within the superconducting dots. These currents produce a complex magnetic field pattern, which is inscribed into the permalloy film above. The results are published in Advanced Science. [...]
  • <p>SEM &ndash; model of a metallic nano-network with periodic arrangement ( left) and visual representation of a fractal pattern (right). </p>
    Science Highlight
    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 transmittance is one of the important parameters for an electrode in photovoltaic applications. An international team headed by HZB scientist Prof. Michael Giersig has recently demonstrated for these applications that networks of metallic mesh possessing fractal-like nano-features surpass other metallic networks in utility. These findings have now been published in the most recent edition of the renowned journal Nature Communications. [...]
  • <p>More than 100 experts did gather at the international conference "Dynamic Pathways in Multidimensional Landscapes", which was held in September in Berlin.</p>
    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 -16 September 2016. [...]
  • <p>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. </p>
    Silicon thin fims in Lithium-Ion-Batteries: Charging observed with neutron measurements
    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 first time in detail how lithium ions migrate into thin films of silicon. It was shown that extremely thin layers of silicon would be sufficient to maximise the load of lithium. The results are published in the journal ACSnano. [...]
  • <p>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&rsquo;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. </p>
    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 is investigating carbon nanoparticles. Annika Bande has now been awarded an ancillary grant of an additional 150,000 Euros from the Volkswagen Foundation to fund another doctoral student position for three years. The doctoral research will connect the two Freigeist research projects with one another. [...]
  • <p>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. </p>
    Science Highlight
    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, a quantum spin liquid should not be possible in this material. A theoretical explanation for these observations has now also been developed. This work deepens our knowledge of condensed matter and might also be important for future developments in quantum information. The results have just been published in Nature Physics. [...]
  • <p>The model illustrates how the gold atoms sit under the graphene. <br /><br /></p>
    Science Highlight
    Progress in the application of spin effects in graphene: from the metal to the semiconductor world
    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 results at BESSY II are now published in Applied Physics Letters. [...]
  • <p>The nanostructured membrane has a honeycomb pattern with nanoholes of 68 nm in diameter. The nanoholes pin down the magnetic domains.</p>
    Science Highlight
    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 much lower temperature as compared to conventional Heat Assisted Magnetic Recording systems. This paves the way to fast and energy efficient ultrahigh density data storage. The results are published now in the new journal Physical Review Applied. [...]
  • <p>Combining the results from radiative and non-radiative relaxation processes enabled a complete picture of the filled and unfilled energy levels to be obtained. </p>
    Science Highlight
    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 reactions in energy materials, but their behaviour has not been completely understood thus far.  The team demonstrated how a detailed picture of the electronic states can be ascertained by systematically comparing all of the interactive electronic processes in a simple system of aqueous iron(II).  The results have now been published in Scientific Reports, the open access journal from Nature Group publishing. [...]
  • 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 Lab’s work. The Helmholtz Association is supporting the project for the next five years with 1.9 million Euros from its Initiative and Networking Fund, with additional contributions from HZB itself as well as from industry. [...]
  • <p>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).</p>
    Science Highlight
    Spintronics for future information technologies: spin currents in topological insulators controlled
    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 orientation of the spins of these currents. They thereby demonstrated that this class of materials is suitable for data processing based on spin. The work has been published in the renowned periodical Physical Review B and was selected as “Editor’s Suggestion” article. [...]
  • 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 runs from mid-2016 to 2019. Researchers from across Germany contribute their specific expertise and work together in these Priority programmes (SPPs).
  • <p>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. </p>
    Science Highlight
    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 chains is stable, conductive, and covered with catalysing nanoparticles of metal oxides. These accelerate the splitting of water when irradiated by light. The team was able to produce a hybrid silicon-based photoanode structure that evolves oxygen at current densities above 15 mA/cm2. The results have now been published in Advanced Energy Materials.


  • <p>The team could observe for the first time with RIXS how the formation of hydrogen bonds does change C=O bonds in aceton molecules. </p>
    Science Highlight
    Measuring chemistry: local fingerprint of hydrogen bonding captured in experiments
    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 Scherrer Institut, and thereby empirically established the formation of hydrogen bonds between acetone and chloroform molecules. The results have been published in Nature Scientific Reports and assist in understanding fundamental phenomena of chemistry. [...]
  • <p>The work of Galina Gurieva, Franziska Huschmann and Alex Redinger is introduced <a href="https://www.helmholtz-berlin.de/angebote/jobskarriere/postdocs/postdoc-of-the-month_en.html" class="Extern">here. </a></p>
    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 HZB-website. The young scientists write briefly about their work, their favorite paper and name the instruments and beamlines they are working with. Moreover, to get a good impression of their work they show some pictures about their laboratories, instruments and beamlines. Here you can find the interesting page of the Postdoc Association. [...]
  • <p>Sketch of the structure of both metal oxide layers. Interesting new properties can arise at the interface. </p>
    Science Highlight
    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 layer to the other or the emergence of ferromagnetism.  Their insights might help to create new properties at the interface, not present in the primary materials, maybe even novel forms of High Tc superconductivity. [...]
  • <p>Preistr&auml;ger des Helmholtz-Doktorandenpreises 2015 mit Otmar D. Wiestler (Mitte), Pr&auml;sident der Helmholtz-Gemeinschaft, und Stephanie Dittmer (rechts), Bereichsleiterin Strategie/ Impuls- und Vernetzungsfonds der Helmholtz-Gemeinschaft, auf dem Neujahrsempfang 2016. Foto: Simone M. Neumann/helmholtz</p>
    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 Doktorandenpreis der Helmholtz-Gemeinschaft. May forscht seit Januar 2016 als Postdoktorand an der Universität Cambridge. [...]
  • <p>Composite Raman intensity-distribution map on a polycrystalline CuInSe<sub>2</sub> thin film.</p>
    Science Highlight
    Alternative method for the representation of microstructures in polycrystalline materials
    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 electron microscope. It was shown by a team from Helmholtz-Zentrum Berlin and the Federal Institute for Materials Research and Testing (BAM) that both characterization techniques result in similar orientation distribution maps on areas of several hundreds of square micrometers. [...]
  • <p>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. </p>
    Science Highlight
    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. Silicon nanocones generate 200 times as much infrared luminescence as comparably sized nanocolumns when excited by visible light. Modelling and experimental results show that due to their geometry, cones are able to sustain what is referred to as whispering gallery modes at infrared wavelengths which can intensify the silicon luminescence. New applications are conceivable, including silicon-based nanolasers. [...]
  • <p>Sketch of the new set-up at EDDI. The high-speed camera (blue box) is on top of the sample holder. </p>
    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 (energy-dispersive diffraction) can simultaneously be carried out to draw conclusions about the crystal structure of the material just as before. [...]
  • <p>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.  </p>
    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 components, physicists can create an additional orbital path. Packets of electrons can travel along it and emit intense light pulses at the experiment stations. This could provide the user community with the option to select light pulses from either path as needed in their experiments. The newly developed orbital mode has already been stably implemented and initial tests at the experiment stations (beamlines) show promising results. HZB is the first to enter this new territory and at the same time has reached another milestone in its pioneering BESSY-VSR project. [...]
  • <p>Markus Kubin in front of his poster. </p>
    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. [...]
  • <p>The SiO<sub>2</sub> 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.  </p>
    Science Highlight
    Scientists demonstrate how to improve ultrathin CIGSe solar cells by nanoparticles
    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 decreases the efficiency quite strongly.  Now, scientists at Helmholtz-Zentrum Berlin have produced high quality ultrathin CIGSe layers and increased their efficiency by an array of tiny nanoparticles between the back contact and the active layer. [...]
  • <p>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. </p>
    Science Highlight
    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. [...]
  • <p>HZB scientists develop new methods to investigate the electronic structure of catalytic molecules. </p>
    Catalysis research strengthened: Helmholtz-Zentrum Berlin participates in newly approved Einstein Center for Catalysis
    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 Institute for Methods of Materials Research at Helmholtz-Zentrum Berlin will be taking part in setting up the institution. His team will be contributing particular expertise in analytics of ultrafast processes in catalytic reactions. [...]
  • <p>Sara J&auml;ckle has demonstrated the formation of a pn-heterojunction at the interface between an organic contact and n-doped silicon. Photo</p>
    Science Highlight
    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 a pn junction between two semiconductors than like a metal-semiconductor contact (Schottky diode). Their results have now been published in the Nature journal Scientific Reports and could point the way toward improvements in hybrid solar cells. [...]
  • <p>Manuela G&ouml;belt is evaluating SEM-images to calculate the local degree of networking. Photo: Bj&ouml;rn Hoffmann.</p>
    Science Highlight
    Transparent, electrically conductive network of encapsulated silver nanowires – a novel electrode for optoelectronics
    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 nanowires that is coated with aluminium-doped zinc oxide. The novel electrode requires about 70 times less silver than conventional silver grid electrodes, but possesses comparable electrical conductivity. [...]
  • <p>The hedgehog-configuration of the spins and the Fermi-Level is shown. Illustration Thomas Splettst&ouml;&szlig;er/HZB</p>
    Science Highlight
    Spins in Graphene with a Hedgehog Texture
    HZB researchers demonstrate a fundamental property of the electron spin in graphene [...]
  • <p>X-ray spectroscopies have shown a higher chlorine concentration near the perovskite/TiO<sub>2</sub> interface than throughout the rest of the perovskite film. </p>
    Science Highlight
    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 distribution. [...]
  • <p>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</p>
    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 multidisciplinary meeting. The HZB Department "Methods for Characterization of Transport Phenomena in Energy Materials" headed by Dr. Klaus Habicht presented their research in two talks and one poster. [...]
  • <p>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. </p>
    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, such as in medical diagnostics for example. Their results are published now in Nature Communications. [...]
  • <p>These samples with precise proportions of nickel and copper were produced via an improved preparation procedure. Photo: M. Tovar/HZB</p>
    Crystal structure and magnetism – new insight into the fundamentals of solid state physics
    HZB team decodes relationship between magnetic interactions and the distortions in crystal structure within a geometrically “frustrated” spinel system [...]
  • <p>Sunlight activates the catalytic behavior of diamond materials, thus helping to convert carbon dioxide into fine chemicals and fuels. </p>
    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 [...]
  • <p>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).<br /><br />Illustration: Marc Gluba/HZB</p>
    Science Highlight
    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 in the future. [...]
  • <p>To obtain the 3D structure of the battery electrode on a micormeter scale, snchrotron tomography at BESSY II was used. </p>
    Science Highlight
    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 can even resolve nanometre-scale features over a small section. They were able to transfer these nano-features to areas beyond the section using a mathematical model. Properties and processes within battery electrodes can now be simulated highly realistically using this method. [...]
  • <p>At the MRS Spring Meeting in San Francisco, Kai Neldner was awarded for his poster contribution.</p>
    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 "Materials for Solar Energy Conversion" (MatSEC) has presented results on structural properties of Kesterites (Cu2ZnSnS4 - CZTS) in relation to its stoichiometry deviations. [...]
  • News
    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 Materials”. [...]
  • <p>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 &amp; Nano-Analytics team of Dr. Marin Rusu.</p>
    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 structural properties in relation to chemical composition of molybdenum oxide layers, which are widely applied in photovoltaic as well as optoelectronic devices. [...]
  • <p>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. </p>
    Science Highlight
    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 published online in  Scientific Reports, might inspire future applications in low-power spintronics, for instance for fast and efficient data storage. [...]
  • <p>A <a href="https://www.youtube.com/watch?v=gzrDtZkCwqc" class="Extern">short filmclip</a> demonstrates the production of the photocathode with ILGAR method.</p>
    Science Highlight
    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 chalcopyrite produced by HZB/PVcomB coated with a newly developed thin film of photoresistant titanium dioxide containing platinum nanoparticles. This layer does not only protect the chalcopyrite thin film from corrosion, it additionally acts as a catalyst to speed-up the formation of hydrogen as well as being a novel photodiode itself that even shows photoelectric current density and voltage comparable to those of a chalcopyrite-based thin film solar cell. [...]
  • <p>Illustration of the working principle of inkjet printing. </p>
    Science Highlight
    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 lower than the efficiency records for this material class, the inkjet printing minimizes waste and has huge advantages for industrial production. [...]
  • <p>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. </p>
    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 chalcopyrites (“Sharc 25") and kesterites (“SWInG”). These two projects will together bring in about 900,000 EUR of additional research funding for solar cell research. [...]
  • <p></p>
<p>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. </p>
    Science Highlight
    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 shoulder-to-shoulder in a silicon substrate. Using mathematical models and experiments, they tested how these kind of funnel arrays collect incident light and conduct it to the active layer of a silicon solar cell. Their result: this arrangement of funnels increases photo absorption by about 65% in a thin-film solar cell fitted with such an array and is reflected in considerably increased solar cell efficiency, among other improved parameters. [...]
  • <p>Dichromium: both chromium atoms "share" the  12 valence electrons which leads to a multible bond. </p>
    Science Highlight
    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 two chromium atoms, removing only one electron changes the situation dramatically: 10 electrons localize and align their spins, thus resulting in ferromagnetic behavior of the dichromium-kation. The bonding is done by one electron only, resulting in a much weaker bond. The scientists used the unique Nanocluster Trap experimental station at the BESSY II synchrotron radiation source at Helmholtz-Zentrum Berlin and published their results in the Journal Angewandte Chemie. [...]
  • <p>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 CO<sub>2</sub> detaches and floats away. </p>
    Science Highlight
    Details of a crucial reaction: Physicists uncover oxidation process of carbon monoxide on a ruthenium surface
    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. The reaction between carbon monoxide and adsorbed oxygen atoms was initiated by heating the ruthenium surface with optical laser pulses. Directly afterwards, changes in the electronic structure of oxygen atoms were probed via X-ray absorption spectroscopy as they formed bonds with the carbon atoms.The observed transition states are consistent with density functional theory and quantum oscillator models. [...]
  • <p>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. </p>
    “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 Helmholtz coils which enables  setting the local magnetic field at the sample position  to any orientation desired. The first measurements of magnetic materials, spin systems, and nanostructured magnetic samples are scheduled for early 2015. [...]