A German-Turkish research team has developed a solvent-free method using ultrasonic cavitation to delaminate crystalline silicon PV modules at end-of-life, completely separating the glass and front EVA layer while partially releasing c-Si fragments. The proposed approach achieved a delamination efficiency of 82.2% on a mass basis, highlighting ultrasonic cavitation as a sustainable alternative for PV module recycling.
Researchers from Germany’s Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) and Turkey’s Ege University have developed a new approach for end-of-life delamination of photovoltaic modules, using ultrasonic cavitation to completely separate the glass and the front layer of ethylene vinyl acetate (EVA), and partially release c-Si fragments from the back EVA layer.
Ultrasonic cavitation occurs when high-frequency sound waves pass through a liquid, creating small bubbles that quickly form and collapse. This collapse releases intense local pressure and heat, causing powerful mechanical and chemical effects. It can generate shock waves, microjets and localized heating, which can break down solids or remove contaminants. Ultrasonic cavitation is widely used for cleaning delicate objects, promoting chemical reactions and improving the emulsification or dispersion of nanoparticles. Essentially, it uses imploding air bubbles to create strong microscopic forces for cleaning, mixing or material handling.
“This study introduces ultrasonic cavitation as an alternative solvent-free delamination mechanism,” said corresponding author Aslı Birtürk. pv magazine. “It is the second method in a series of environmentally friendly, solvent-free approaches for PV delamination, developed during my doctoral studies under the supervision of Prof. Melih Soner Celiktas. first methoddeveloped in 2024, achieved a mass-based delamination efficiency of 98.4% using only distilled water and no chemical solvents.”
Birtürk added that both studies are proof-of-concept process evaluations investigating sustainable delamination strategies for PV modules at end-of-life. “There is potential to further scale up these proof-of-concept methods from laboratory to pilot scale, taking into account life cycle assessment (LCA), optimizing operational parameters for industrial applicability and improving recovery rates for critical raw materials (CRMs),” she added.
In their latest research, the scientists started by making small pieces of c-Si PV module measuring 2.5 cm x 2.5 cm and weighing 25 g. They were placed in a jacketed glass reactor containing 100 ml of distilled water set at 85 C. Ultrasonic cavitation was initiated using an ultrasonic probe at 20 kHz and 50% amplitude. The samples were exposed to ultrasonic cavitation for 20, 40 and 60 hours, with intermediate checks performed at the end of each hour.
In addition, the group used computational fluid dynamics (CFD) to understand how cavitation physically interacts with materials. They further used scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy for material characterization. An LCA was carried out to evaluate the environmental impact of the process.
“A remarkable finding was that delamination could be achieved without any chemical additives, mainly caused by mechanical effects,” Birtürk said. “The important role of EVA deformation and associated emission benefits were particularly encouraging results. It is both a surprise and not, but we demonstrated the chemical-free delamination effect in two separate papers.”
The researcher added that “a mass-based delamination efficiency of 82.2% was achieved with this method. The process works by mechanically weakening the interfacial EVA layer, and the experimental results show that the deformation behavior of EVA plays a dominant role in the clean separation. The life cycle assessment indicates a net emissions benefit of -5.75 kg CO₂ equivalent, highlighting the environmental potential of this approach.”
Their findings were presented in “Solvent-free ultrasonic approach for end-of-life delamination of crystalline silicon PV modules”, published in Sustainable materials and technologies.
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