Reactive Silver Ink as a Novel Low-Temperature Metallization: Monitoring Corrosion

Reactive silver ink (RSI) forms low-resistivity (<;5μΩ.cm) metallization at temperatures below 100 °C-enabling lower resistive losses for thermally sensitive solar cells while drastically reducing Ag usage compared to other low-temperature Ag pastes. However, before adoption of the technology many reliability related questions must be addressed. Ag-based metallizations are susceptible to corrosion by acetic acid formed in encapsulated modules, resulting in increased resistive losses. Here we report on corrosion of three types of metallizations; high-firing-temperature Ag paste (HT Ag Paste), low-temperature Ag paste (LT Ag Paste), and RSI. We develop a method for exposing these metallizations to dilute acetic acid in concentrations comparable to those found in field- and damp heat-exposed modules. We find that HT Ag and RSI are quickly affected by acetic acid exposure after only 24 h. Interestingly, Raman spectroscopy suggests the formation of AgCl or AgCH₃COO on HT Ag Paste, dissolution of AgCH₃COO from RSI, and LT Ag Paste remains relatively unchanged throughout 2936 h of exposure to diluted acetic acid.