/solarbytes/media/media_files/2025/02/03/P3H1NyRoNjdoo52WPekb.jpg)
Microscopic analysis reveals salt-induced delamination in Ag/Al paste, accelerating series resistance and structural failure in TOPCon solar cells. Image Source: Science Direct
A study by UNSW, Canadian Solar Inc., Nantong University, and Shanghai Jiao Tong University examines metal contact failures in TOPCon solar cells under DH85 conditions. NaCl contamination on the front side caused a ~92% PCE loss, primarily due to increased series resistance from electrochemical reactions. NaHCO₃ exposure led to a ~5% PCE loss, while rear-side NaHCO₃ contamination resulted in a ~16% loss from recombination. NaCl on the rear side caused a ~4% PCE decline, mainly affecting open-circuit voltage. SEM and EDS revealed cracks, delamination, and Ag oxidation at the Ag-Si interface, weakening metallization stability. XPS analysis confirmed Ag oxidation and Pb reduction, accelerating contact degradation. The study highlights metallization susceptibility to salt exposure, emphasizing risks for TOPCon solar module reliability in humid environments.