New 12 T magnet on BESSY II’s experimental floor strengthens energy and magnetism research
Exhausted but happy: f.l.t.r. - K. Holldack (HZB), A. Schnegg (MPI CEC Mülheim, HZB), T. Lohmiller (HZB, HUB), D. Ponwitz (HZB) after the successful commissioning of the new 12T magnet (green).
Electron paramagnetic resonance (THz-EPR) at BESSY II provides important information on the electronic structure of novel magnetic materials and catalysts. In mid-January 2022, the researchers brought a new, superconducting 12-T magnet into operation at this end station, which promises new scientific insights.
At the THz-EPR end station, unique experimental conditions are provided through a combination of coherent THz-light from BESSY II and high magnetic fields. These capabilities have now been extended by a new superconducting 12 T magnet, acquired through funding from the BMBF network project “ERP-on-a-Chip” and HZB.
“The extended capabilities of the new setup will allow exciting new science with user groups and within our joint lab EPR4Energy operated together with Max Planck Institute for Chemical Energy Conversion, Mühlheim. We are very pleased about the successful commissioning of the superconducting magnet, which currently delivers the highest magnetic field at BESSY II”, says Karsten Holldack, the responsible beamline scientist.
- CIGS-perovskite tandem cell achieves record efficiency of 25.5 %A Berlin-based team from HZB and Center for the Science of Materials Berlin (CSMB) at the Humboldt-Universität zu Berlin has set a new record for a tandem solar cell. Using a combination of a CIGS semiconductor layer and perovskite, along with several optimised intermediate layers, they were able to convert 25.5% of sunlight into electrical energy. The previous record for this combination of materials and this size of cell stood at 24.6%. The new record has been certified and is visible in the prestigious Solar Cell Efficiency Tables (the "Green Tables"), which serve as the definitive ledger for the global photovoltaic community.
- Disorder creates new properties in compound semiconductorsAn international research team has demonstrated that the intrinsic disorder of the compound semiconductor CuInSnS₄ can be exploited to influence its optical properties. While the atomic vibrations also sense the local disorder, their response is averaged over many different local environments and therefore appear isotropic, as expected for a cubic crystal. In contrast, the optical excitations, known as excitons, are much more sensitive to the local arrangement of atoms. Surprisingly, they show a direction-dependent optical response even though the average crystal structure is cubic. These findings shed new light on the relationship between disorder and material properties, opening up new options for targeted 'disorder engineering' in optoelectronic and photocatalytic devices.
- Superconducting TES array X-ray spectrometer goes into operation at BESSY IIEurope's first and only TES-spectrometer at a synchrotron source is now in operation at BESSY II, developed within a collaboration between the HZB, the MPI-CEC (Mühlheim-an-der-Ruhr, Germany) and the NIST (Boulder CO, USA). The photon detection efficiency of the new instrument exceeds that of wavelength-dispersive X-ray emission spectrometers by a factor of 100 to 1000. It will be used to investigate the electronic properties of atomically thin layers, nanostructures and highly diluted atomic and molecular samples. The team is looking forward to receiving exciting research proposals from the user community.