Laser recycling of silver from silicon and CIGS solar cells through bulk laser debonding and nanoparticles by laser ablation

Mahantesh Khetri& Mool C. Gupta Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA, United States

The results are presented of a study of UV picosecond and IR nanosecond lasers for ablating and debonding silver lines from  monocrystalline Si and CIGS solar cells. The UV laser efficiently removed silver lines by generating nanoparticles, while the IR laser exhibited bulk debonding at lower powers, and transitioning to ablation mode at higher powers for silicon solar cells. The research investigated the influence of ablation media, specifically methanol-water mixtures and deionized water, on silver recovery efficiency. DI water was found to be  a superior ablation medium, producing high-purity (86 wt%) silver nanoparticles and requiring fewer laser passes for complete silver removal compared to the methanol-DI water mixture. In CIGS solar cells, the UV laser induced debonding dominated  at low power and a shifted to laser ablation mode at higher  laser power. This research demonstrates environmentally friendly silver recovery from solar cells in both bulk and nanoparticle form. It significantly contributes to the development of sustainable and economically viable methods for silver recovery, addressing critical challenges in the recycling of photovoltaic materials.