LARS: Laser Assisted Recycling of Solar Modules

Green and NIR Thresholds, SiNₓ Removal, and Material Recovery

Abstract

High-value photovoltaic (PV) recycling requires opening routes for the PV module stack that provide access to silicon and metallisation rather than only recovering mass. In this work, we present nanosecond laser-assisted recycling of silicon PV modules (LARS), using green and near-infrared (NIR) pulsed lasers to selectively interact with silicon through the transparent laminate stack. The process weakens the cell–encapsulant interface, enables module opening, and simultaneously removes the SiNₓ anti-reflective (AR) coating, thereby avoiding a dedicated HF-based SiNₓ etch in the downstream route. D²-based laser ablation threshold analysis is used to compare 532 nm (“green”) and 1064 nm (“NIR”) nanosecond regimes and to guide process optimisation. Although green, nanosecond-pulsed (ns-pulsed) processing still requires roughly two times lower fluence to achieve delamination, we have achieved a large reduction in fluence needed with NIR ns-pulsed processing. This makes NIR ns-pulsed very relevant industrially, even in comparison to green laser sources, which are substantially more expensive. A subsequent wet-chemical step at the lab scale resulted in a silicon purity up to 99.998%, with 97% yield, and silver purity of 99.7% with 97% yield. These results indicate a strong increase in the potential recovered material value compared with state-of-the-art routes, like shredding. The method has been successfully applied to multiple commercial silicon module architectures, including PERC, TOPCon, Al-BSF, polymer-frontsheet modules, and recent IBC modules, demonstrating versatility. It is also very scalable, since ns-pulsed NIR laser platforms have become substantially cheaper in the last decade.