Mapping exactly how energy flows in organic solar cells

• Efficient as well as environmentally friendly solar cells are required for a transition to a fossil-free energy supply. Researchers at Linköping University have mapped exactly how energy flows in organic solar cells, something that formerly had been unknown. The outcomes, which can contribute to a lot more efficient solar cells, are published in Nature Communications.

"To enable the full possibility of organic solar cells to be made use of, there is a requirement for a clear picture of how they work. We have actually currently gotten that photo. This gives a much better understanding of how to develop new efficient as well as sustainable solar cell products," says Mats Fahlman, a professor at the Laboratory of Organic Electronics at Linköping University.

Today, solar energy meets around 2% of the globe's energy requirements. However its potential is far in excess of that. The energy included in the sun's rays is ample to meet our requirements today and also in the future. Solar cells that are cheap and also environmentally friendly to produce are needed to be successful. In addition, they need to be efficient at taking in a large proportion of the sun's rays as well as transforming to electrical energy.

Organic solar cells based upon organic semiconductors are progressively becoming a sustainable alternative. But up until just a few years ago they could not stand comparison with typical silicon-based solar cells for effectiveness. This was due to energy loss in charge separation, which was believed to be inevitable.

Yet in 2016, a research group at Linköping University together with colleagues in Hong Kong had the ability to show that it was possible to prevent the energy loss using different donor-acceptor products that aid the electron to escape from its hole much more conveniently. Energy loss after that decreased as well as performance boosted. The problem was that nobody knew precisely how it happened. It was possible to see that it worked, but not why.

Some of the exact same study team at Linköping University have actually currently fixed the mystery that had resulted in difference in this field of study. In a new research study released in Nature Communications, the researchers have identified what energy levels are required to minimize energy losses.

"To find out just how the energy flows, we laid nanometre-thick organic semiconduction movies in several layers one in addition to the other, instead like a strawberry as well as lotion cake. After that we gauged the energy required to separate the electrons from their holes in each private layer," says Xian'e Li, a Ph.D. trainee at Linköping University and also major writer of the clinical short article.

The scientists were then able to map the mechanism behind the energy-efficient charge separation. This systematic mapping aims a new way ahead for the development of organic solar cells.

The organic solar cells in the research are of a type with an electron acceptor made from a material apart from fullerene (a form of carbon), which formerly was the most common material used. Non-fullerene-based organic cells come to be a lot more stable as well as are capable of taking in a greater proportion of the sun's rays for conversion to energy.