Recycling solar panels is crucial to mitigating the environmental impact of the growing volume of end-of-life photovoltaic waste and to conserve valuable resources, while achieving high purity in recovered materials ensures their effective reuse in the manufacturing of new solar panels, contributing to a sustainable and circular economy. This study proposes a two-step leaching process to recover Ag and Al from the silicon fraction of EoL photovoltaics (PVs). In the first-stage laboratory scale tests, 99% Al was extracted using 5% HCl at room temperature (19 °C) for 3 h The Al was precipitated as oxide from the solution. The silicon residue was then leached with 0.5 M HNO₃ at 85 °C for 2 h, extracting 99% Ag and producing Si with 99.83% purity. The silver was precipitated to produce metallic Ag with >99.9% purity. Then, 95.63% of Pb in the nitric acid effluent was removed using ion exchange resins. Further, methods to mitigate the effluent solutions were recommended and the entire process was presented in a flowsheet.

Hydrogen has been long known for its ability to passivate defects in silicon devices. However, multiple recent studies on understanding the mechanism behind light- and elevated temperature-induced degradation (LeTID) have proposed that hydrogen plays an important role in this degradation mechanism. Despite its important role in photovoltaic applications, the quantitative assessment of hydrogen is difficult and seldom reported. In this work, we applied hydrogen effusion mass spectroscopy to quantify the hydrogen released from hydrogenated silicon nitride (SiN _x :H) and atomic layer deposited (ALD) aluminum oxide (AlO _x ) dielectric films at elevated temperatures. We demonstrate that the amount of hydrogen effused from these layers strongly correlates with the extent of LeTID observed in the multicrystalline silicon wafers passivated with these monolayers and their stacks. It is shown that the hydrogen effusion scales linearly with the SiN _x :H thickness, similar as the extent of LeTID. The effusion measurements on the AlO _x /SiN _x :H stack revealed that the presence of the AlO _x film modifies the total amount of hydrogen that is effused, whereas it was found to slow the hydrogen in-diffusion. This result is consistent with the LeTID extent determined after contact firing where ALD AlO _x layers were found to act as a hydrogen diffusion barrier, strongly reducing LeTID when placed in between c-Si and SiN _x :H and increasing LeTID when placed on top of SiN _x :H.

A method for the determination of 22 trace impurities in solar grade silicon after dissolution in a mixture of HF and HNO₃ and subsequent matrix evaporation is reported. The presented method involves a simple, inexpensive, one-vessel sample preparation apparatus design. The recoveries of B, Na, Mg, Al, P, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Mo, Sb, W, and Tl at 250 μg kg⁻¹ level are in the range of 93 to 108%. After careful selection of monitored isotopes and their respective resolutions, a sector field mass spectrometer has been used to carry out the measurements. Limits of determination down to 120 ng kg⁻¹ have been obtained using a calibration by three-point standard addition. The method was tested on diluted NIST SRM 57b silicon powder as well as on synthetic test samples and also applied successfully on raw solar grade silicon samples in an interlaboratory comparison including NAA.

Recycling solar panels is crucial to mitigating the environmental impact of the growing volume of end-of-life photovoltaic waste and conserving valuable resources, while achieving high purity in recovered materials ensures their effective reuse in the manufacturing of new solar panels, con-tributing to a sustainable and circular economy. This study proposes a two-step leaching process to recover Ag and Al from the silicon fraction of EoL photovoltaics (PVs). In the first stage laboratory scale tests, 99% Al was extracted using 5% HCl at room temperature for 3 hrs. The Al was precip-itated as oxide from the solution. The silicon residue was then leached with 0.5 M HNO3 at 80°C for 2 hrs extracting 99% Ag and producing Si with 99.83% purity. The silver was precipitated to produce metallic Ag with >99.9% purity. Methods to mitigate the effluent solutions were recom-mended and the entire process was presented in a flowsheet.