TU Dresden: Toward More Environmentally Friendly Solar Cells

Using computer models, scientists from the Cluster of Excellence “REC²—Responsible Electronics in the Age of Climate Change” at TUD and the Leibniz Institute for Solid State and Materials Research (IFW) in Dresden can predict which less harmful solvents are suitable for production. These include substances that have primarily been used as flavorings in the food industry up to now. The first solar cells produced using these solvents achieve performance comparable to that of conventional cells made with toxic solvents, pointing the way toward a more responsible production of electronic technologies.

Perovskite solar cells are considered a promising technology for next-generation photovoltaics because they can achieve high efficiency using solvent-based manufacturing processes. However, their production has so far mostly relied on solvents that can be harmful to human health and the environment. Finding suitable alternatives is a challenge, as the properties of the solvent have a strong influence on how the materials for solar cells are processed and how well the resulting component performs.

The search for new solvents has traditionally relied on trial-and-error experimentation. Researchers test various substances in the lab until they find a suitable combination. The team from the REC² Cluster of Excellence at TU Dresden, the IFW Dresden, and the Universidad Nacional del Sur in Argentina has now developed a predictive approach that changes this starting point. By combining several physical and chemical models, the researchers can identify promising, environmentally friendly solvents even before they are tested experimentally.

“We have found that there are no approaches whatsoever for systematically addressing the problem of toxic solvents in solvent-based solar cells. This led us to consider whether we should completely rethink the search for suitable solvents,” says Prof. Dr. Yana Vaynzof, director of the Institute for Emerging Electronic Technologies (IET) at IFW and holder of the Chair of Novel Electronic Technologies at the Technical University of Dresden.

Using their new approach, the scientists identified previously untapped green solvents—including edible additives used in the food industry—and demonstrated their suitability for the production of perovskite solar cells. The resulting devices performed just as well as those manufactured using conventional toxic solvents. Since this method can also be applied to the search for additional potential solvents, it could reduce the number of experiments required and help researchers explore a much broader range of sustainable alternatives.

The research findings reflect the approach of the REC² Cluster of Excellence, whose goal is to make electronics more sustainable throughout their entire life cycle. It contributes to three of the cluster’s six Responsible Aim Programs: Replace, Reduce, and Recycle. By reducing reliance on toxic substances and the resources required to develop suitable alternatives, this approach could help lower the environmental impact of solar cell manufacturing while promoting the development of more sustainable electronic technologies.

The next step is to investigate the potential of environmentally friendly solvents to improve the recyclability of perovskite solar cells. This predictive approach could also be applied to other solvent-based electronic technologies, thereby opening up new avenues toward more sustainable manufacturing.