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.