Researchers from Linköping University have developed a new design principle that makes the large-scale production of highly efficient, environmentally friendly organic solar cells possible. The study, published in the journal Nature Energy, examined the shape and interactions of molecules in organic solar cells.
Solar cells based on several non-toxic solvents are now possible. Image Credit: Thor Balkhed
With electrification and the development of AI, we will probably see a significant increase in the world’s energy needs. That electricity needs to come from environmentally sustainable sources if we are to slow down climate change at the same time.
Feng Gao, Professor, Department of Optoelectronics, Linköping University
Solar cells are one green energy source that researchers worldwide are concentrating on. Numerous alternative varieties are being developed to supplement conventional silicon solar cells. Organic electronics, based on electrically conductive plastics, is one of the most promising technologies.
Organic solar cells are relatively inexpensive and simple to produce. Furthermore, because they are flexible and lightweight, they can power personal electronics on clothing, windows, or indoor surfaces. Currently available on the market, organic solar cells are predicted to grow in market share.
Sustainable Mass Production
About 20% of the sun's rays can be converted into electricity by organic solar cells, whose efficiency is catching up to that of conventional solar cells. Years of intensive materials research and studies of the material's molecular interactions, or “morphology,” have produced high efficiency.
A physical mixture is used to create organic solar cells, and when the mixture is placed on a substrate, its solvent evaporates. Nevertheless, the chemical solution contains substances that are harmful to the environment.
To realize mass production of organic solar cells, with printed technologies for example, on a large scale, we need to find methods that do not use toxins. Otherwise, it is not good for the environment or those working in the factories.
Feng Gao, Professor, Department of Optoelectronics, Linköping University
Together with colleagues in China and the US, his research team has now deciphered the secret to creating effective organic solar cells using a variety of eco-friendly solvents.
To choose the right solvent, it is important to understand the entire solar cell manufacturing process. This includes knowing the initial structures of the solution, observing the dynamic processes during evaporation, and checking the final structure of the solar cell film.
Rui Zhang, Study Lead Author and Researcher, Linköping University
Morphology and Performance
The Linköping researchers used sophisticated synchrotron X-ray and neutron techniques to map the molecular interactions between the solvent and the materials carrying the electrons. This allowed the researchers to create a design principle that works with a wide range of safe solvents. They anticipate that water will eventually be able to function as a solvent.
Since they must investigate the extremely quick transfer of electrons (charge transport) from the material that releases electrons to the receiving material, the researchers say comprehending the relationship between morphology and performance in organic solar cells is a significant challenge.
These processes take place at molecular interfaces and within nanoscale structures. Feng Gao claims that the path to ecologically friendly organic solar cells is now open.
Feng Gao concluded “Thanks to a toxin-free manufacturing method, we now have a much greater chance of commercializing the technology on a larger scale.”
The Knut and Alice Wallenberg Foundation, the Swedish Foundation for Strategic Research, the Wallenberg Initiative Materials Science for Sustainability (WISE), and the Swedish Government’s strategic research area in advanced functional materials, AFM, at Linköping University, were among the organizations that provided funding for the study.
Journal Reference:
Zhang, R., et al. (2024) Equally high efficiencies of organic solar cells processed from different solvents reveal key factors for morphology control. Nature Energy. doi.org/10.1038/s41560-024-01678-5.