Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia in Charlottesville, USA have found a way to write and delete magnets in an alloy using a laser beam – a surprising effect. The reversibility of the process opens up new possibilities in the fields of material processing, optical technology, and data storage. [...].
Bacteria exist in many shapes and with very different talents. Magnetotactic bacteria can even sense the earth’s magnetic field by making use of magnetic nanoparticles in their interior that act as an internal compass. Spanish teams and experts at Helmholtz-Zentrum Berlin have now examined the magnetic compass of Magnetospirillum gryphiswaldense at BESSY II. Their results may be helpful in designing actuation devices for nanorobots and nanosensors for biomedical applications. [...].
The first “Twin Orbit User Test week” at BESSY II in February 2018 was a big success and can be considered as an important step towards real user operation. Physicists at Helmholtz-Zentrum Berlin have been able to store two separate electron beams in one storage ring. The twin orbit operation mode can serve users with different needs of the time structure of the photon pulses simultaneously and offers elegant options regarding the future project BESSY VSR. [...].
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. [...].
Simple organic molecules form complex materials through self-organization
An international team of researchers lead by the Technical University of Munich (TUM) has discovered a reaction path that produces exotic layers with semiregular structures. These kinds of materials are interesting because they frequently possess extraordinary properties. In the process, simple organic molecules are converted to larger units which form the complex, semiregular patterns. With experiments at BESSY II at Helmholtz-Zentrum Berlin this could be observed in detail. [...].
The nominal cell operating life of perovskite solar cells is strongly influenced by their inner architecture.This was shown by two scientists at the Helmholtz-Zentrum Berlin and the Technical University of Munich. They combined experiments with numerical simulations in order to explain this observation. [...].
Experiments at BESSY II reveal why even inhomogeneous perovskite films are highly functional
Metal-organic perovskite layers for solar cells are frequently fabricated using the spin coating technique. If you follow the simplest synthesis pathway and use industry-relevant compact substrates, the perovskite layers laid down by spin coating generally exhibit numerous holes, yet attain astonishingly high levels of efficiency. The reason that these holes do not lead to significant short circuits between the front and back contact and thus high-rate charge carrier recombination has now been discovered by a HZB team headed by Dr.-Ing. Marcus Bär in cooperation with the group headed by Prof. Henry Snaith (Oxford Univ.) at BESSY II. [...].
It happens quite often that Nikolay Kardjilov has interesting guests. The HZB expert on neutron tomography is in demand worldwide, even when it comes to investigating valuable cultural treasures. Just recently, four knight helmets were waiting for its analysis. [...].
Scientists analysed how a special treatment improves cheap metal oxide photoelectrodes. [...].
Lupins not only produce colourful blossoms but also nutritious beans rich in proteins. Just how these plants draw water approaching their roots in soil has now for the first time been observed in three dimensions by a University of Potsdam team at the HZB-BER II neutron source in Berlin. To accomplish this, they worked with the HZB imaging group to improve the temporal resolution of neutron tomography more than onehundred-fold so that a detailed 3D image was generated every ten seconds. This ultrafast neutron tomography is generally suitable as well for analyses of dynamic processes in porous materials. [...].
An international research team has for the first time investigated the optical properties of three-dimensional nanoporous graphene at the IRIS infrared beamline of the BESSY II electron storage ring. The experiments show that the plasmonic excitations (oscillations of the charge density) in this new material can be precisely controlled by the pore size and by introducing atomic impurities. This could facilitate the manufacture of highly sensitive chemical sensors. [...].
Nanoparticles at the back help harvesting light.
Ultrathin CIGSe solar cells need much less rare earth elements and energy for production. Unfortunately, they are much less efficient too. Now a team at HZB together with a group in the Netherlands has shown how to prevent the absorption loss of ultrathin CIGSe cells. They designed nanostructured back contacts for light trapping and could achieve a new record value of the the short circuit current density reaching nearly the best values for thicker CIGSe-cells. [...].
HZB is equipped with the latest scanning electron and ion microscopes made by ZEISS and has been a member of the labs@location partner program since 2015. ZEISS uses this program to cooperate with proven expert researchers to share experience and give interested people access to its microscopes. Now the first test customer demonstration has been given at the HZB.
The capacity of lithium-ion batteries might be increased by six times by using anodes made of silicon instead of graphite. A team from 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 achieve the maximal load of lithium.
Two Freigeist Fellows are conducting research at the HZB Institute for Methods of Material Development through support received fom 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 another. [...].
A novel and rare state of matter known as a quantum spin liquid has been empirically demonstrated in a single crystal of the compound calcium-chromium oxide. 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. These results have been published in Nature Physics. [...].
An international team has discovered an elegant way to decouple organic nanosheets grown on metal surfaces. After iodine intercalation, measurements at the synchrotron source BESSY II of Helmholtz-Zentrum Berlin (HZB) showed that a network of organic molecules behave almost as it was free-standing. The strong influence of the metal on the network was reduced. This opens up new ways to transfer organic nanostructures from metal surfaces onto more suitable substrates for molecular electronics. The results have been published in "Angewandte Chemie". [...].