Recyclable dimethyl isosorbide-assisted full-layer delamination of retired crystalline silicon photovoltaic modules with controlled EVA swelling and interfacial debonding

Abstract

Efficient delamination of retired crystalline silicon photovoltaic (c-Si PV) modules is essential for recovering valuable module materials, but rapid layer separation while suppressing ethylene-vinyl acetate (EVA) over-swelling remains challenging. Here, dimethyl isosorbide (DMI) was used as a recyclable green solvent for full-layer delamination of retired c-Si PV modules under mild conditions. Pure DMI showed the best separation performance, and 80 °C was identified as the optimal treatment temperature. Under this condition, glass, fluorinated coating, backsheet, EVA, and solar cells were completely separated within 30 min, while the fluorinated coating was removed within about 5 min. No obvious macroscopic EVA over-swelling was observed, and the rear Al-containing passivation region and front Ag gridlines of the solar cells were largely preserved. DMI also maintained stable delamination performance after five reuse cycles. Mechanistic analyses indicated that DMI promoted delamination mainly through selective interaction with oxygen-containing motifs in EVA, mild local network perturbation, and continuous penetration along key interfaces. This work provides a mild and recyclable route for selective delamination and recovery of retired c-Si PV module materials.