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.

Electron paramagnetic resonance (EPR) provides detailed information about the material's inner structure, down to the atomic level, via the excitation of electron spin in the material. EPR spectroscopy is an important instrument in biophysics, chemistry and medical diagnostics, but is also used in research on energy materials such as catalysts, battery electrodes and solar cell components.

However, EPR spectrometers are usually large and expensive devices that can only be found in particularly well-equipped research laboratories. In addition, it is very difficult to perform investigations under real process conditions (operando measurement) with conventional EPR instruments.

But there is another way: The first demo version of a miniaturized EPR spectrometer was presented in 2017. As part of the BMBF project "EPRoC", a chip-based electron paramagnetic resonance spectroscopy (EPRoC) is to be developed under the direction of Prof. Dr. Klaus Lips and in close cooperation with the University of Stuttgart, the Max Planck Institute for Chemical Energy Conversion, the Karlsruhe Institute of Technology and the Bruker company.

The EPR spectrometer is miniaturized to chip size so that it can even be inserted inside the sample. The aim is to use EPRoC to directly analyze growth processes of thin films for photovoltaics and to investigate and improve catalytic processes during the production of solar hydrogen. This would allow to elucidate how structure formation on the nanoscale is related to the functionality of processes and materials.

During the three-year term of the project, the partners will explore the potential of the technology by further improving the efficiency of the processes and components and reducing costs. In addition, they aim to use EPRoC technology to dramatically improve the sensitivity of nuclear magnetic resonance (NMR) spectrometers. This could also have a long-term impact on magnetic resonance imaging used in medicine.

The findings should ensure that EPRoC technology can be developed to market maturity within the next ten years. The miniaturisation of EPR will open up new fields of application and can lead to faster progress in energy materials research, sensor technology, medicine, environmental technology, as well as food and analytical chemistry.

Partners:
- Helmholtz-Zentrum Berlin, Institute for Nanospectroscopy (HZB), Coordination Prof. Dr. Klaus Lips
- University of Stuttgart
- Karlsruhe Institute of Technology, Institute for Microstructure Technology (KIT)
- Max Planck Institute for Chemical Energy Conversion (MPICEC)
- Bruker Biospin GmbH