Researchers at Chalmers University of Technology in Sweden have recently developed a new process for efficiently recovering precious metals from thin-film solar cells.

Although thin-film cells account for less than 10% of the solar cell market, they demonstrate excellent performance under specific conditions and a wider range of applications, owing to their unique advantages over traditional silicon-based crystalline cells, such as flexibility and adaptability.

The production of CIGS cells, a leading variant of thin-film technology, requires a high demand for indium and silver. However, this process generates significant waste that includes a combination of precious metals and hazardous materials.

Effectively separating these metals from other substances becomes extremely beneficial economically and ecologically as they can be reused for new products.

“It is crucial to remove and recycle contaminants so that the material becomes as clean as possible again. So far, it uses a lot of heat and a large amount of chemicals, which is an expensive process that is also not environmentally friendly,” said Ioanna Teknetzi, a Ph.D. student at the Faculty of Chemistry and Process Engineeringwho together with Dr. Burcak Ebin and Dr. Stellan Holgersson published the new study in the journal Solar Energy Materials and Solar Cells.

The researchers considered both the purity of the recovered materials and the environmental impact during the recycling process. To achieve this, they used a method called washout to separate the metals in the cells. This method uses far fewer chemicals than traditional methods, making the process “milder” for the environment. In addition, researchers have refined the process to minimize impurities in the recovered indium and silver.

The study has shown that it is so possible to recover 100% of the silver and about 85% of the indium, which took place at room temperature without heat input. It takes a day, which is a little longer than traditional methods, but it’s cheaper and better for the environment.

“We hope that our research can serve as a reference for optimizing the recycling process and pave the way for future application of the process on a larger scale,” said Dr. Burcak Ebin.

Details on the study and the new method can be found in this magazine.