A novel recycling approach: separation and analysis of TCO-coated glass from discarded CdTe PV modules

The ubiquitous adoption of photovoltaic (PV) modules as a renewable energy source for electricity generation has led to significant increase in their deployment. Among thin film-based Photovoltaics (PVs), Cadmium Telluride (CdTe) modules are efficient and widely used but face challenges on end-of-life (EoL) owing to incorporation of toxic materials. Present study introduces new strategies to recover transparent conducting oxides (TCO)-coated glass from discarded CdTe PV modules while separating toxic materials. The recycling process involves a straight forward approach comprising mechanical and chemical treatments. Standard oxidising solutions of H₂SO₄ and H₂O₂ were utilized to recover TCO-coated glass. The laser-scribed fluorine-doped tin oxide (FTO) glass was successfully recovered without compromising its properties. The recovered FTO exhibits very low average resistivity (10^–4 Ω-cm) and sheet resistance (13.70 Ω/sq.). The recovered FTO showed uniform transmission measured on 4 cm² area in the visible spectrum having average transmission ~ 80%, with a bandgap of ~ 3.68 eV, making it suitable for reuse in thin-film PV modules and optoelectronic devices. The residual solution was analysed using ICP-OES and ICP-MS to assess element concentration and neutralize toxicity. Further, the cost analysis has also been carried out for FTO-coated glass recovery.