Materials Science

Why Do Thin-Film Silicon Solar Cells ‘Age’?

A unique project is examining why non-crystalline silicon suffers certain ‘aging effects’ and why the current efficiency of thin, amorphous silicon layers decreases steadily within the first thousand operating hours. The joint solar energy research project is seeing EPR solar scientists across five institutes collaborating research driven by ultra-high-resolution EPR spectroscopy.

The project began in 2008 with funding from the German Federal Ministry of Education and Research (BMBF) and now, with a further allocation of EUR 1.6 million, Dr Klaus Lips and Dr Alexander Schnegg at the Helmholtz Zentrum Berlin (HZB) will be able to equip their lab with a very special high field spectrometer.

The purchase will establish their laboratory as the first in the world to be equipped with the latest generation state-of-the-art EPR spectrometer.

Alexander Schnegg, coordinator of the EPR Solar Project is excited by the power of the new spectrometer, “It will give us an understanding of the internal structure of the silicon material that simply hasn’t been possible up to now”.

The highest magnetic field strength commercially available for an EPR spectrometer is held by Bruker at 12 Tesla in combination with a record-breaking 263 Gigahertz microwave source, both some 30 times higher than conventional spectrometers.

Dr. Schnegg and the team can now undertake high field / high resolution EPR measurements using the new spectrometer and, with a special measuring station at the synchrotron storage ring BESSY II, take complementary variable frequency EPR measurements.

The team at HZB are working closely with colleagues at the four other leading institutes: Forschungszentrum Jülich, Free University Berlin, Max-Planck Institute for Iron Research and the Technical University Munich.

More news from the project will appear on the resonance soon, so watch this space. Make sure you have signed up for our newsletter or our RSS feed to stay up to date.