Researchers at the University of Sheffield in the UK have introduced a new method to analyse PCBM, a material used in polymer photovoltaic cells, to approve cell efficiency.
Spin echo resolved grazing incidence scattering (SERGIS), is believed to be the first cutting-edge neutron scattering technique being used to obtain the details of the structure of PCBM.
The new technique has only been tested on samples with known and regular structures, such as diffraction gratings.
Researchers at the Science and Technology Facilities Council Rutherford Appleton Laboratory, verified the findings of crystallites, which are on the surface of PCBM, using atomic force microscopy technique.
In future, the new method is expected to help in analysing the material’s structure deep inside the active layers of a solar cell, and enable the understanding of how various fabrication methods influence the cell’s structure and efficiency.
Dr Alan Dunbar from Sheffield’s Faculty of Engineering said the new technique enabled researchers to map the size and spread of PCBM crystallites, which are key properties to improve efficiency.
"The SERGIS technique uses polarised neutrons which are bounced off the sample being tested. Where the resulting neutrons end up and how their polarisation has changed tells us information about the structure within our samples," Dunbar said.
"The advantage of this type of technique is that because neutrons only interact weakly with the sample we can probe much deeper where many microscopy techniques cannot see."
University of Sheffield conducts research on various areas of energy including photovoltaics, wind power, nuclear power, biofuels, district heating and carbon capture.
Image: A monocrystalline solar cell. Photo: Courtesy of Ersol.