TOPCon modules exhibit substantial deterioration during damp heat testing when contrasted with PERC modules.

The report by scientists from the University of New South Wales sheds light on the challenges facing tunnel oxide passivated contact (TOPCon) solar modules, particularly in damp heat environments. Their findings suggest that TOPCon modules experience significant degradation compared to passivated emitter and rear contact (PERC) modules under similar conditions.

The study, titled 'Buyer aware: Three new failure modes in TOPCon modules absent from PERC technology,' conducted extensive testing on both TOPCon and PERC modules with varying components. Despite variations in materials, TOPCon modules consistently exhibited higher power loss ranging from 4-65% relative, compared to just 1-2% relative in PERC modules over 1,000 hours of damp heat testing.

The researchers attributed the poor performance of TOPCon modules to electrochemical reactions involving moisture. They identified three types of failures observed in TOPCon modules: point-localised failure, failure at connection points of ribbons and busbars, and failure throughout the entire area of cells and modules.

While the specific contaminant responsible for the decline in output remains unclear, the presence of sodium and chlorine, possibly from human fingertips during assembly and transportation, was speculated to have an adverse effect on TOPCon cells, making them particularly vulnerable.

The implications of these findings are significant, especially considering the expected increase in the use of TOPCon modules in the global solar sector. With predictions that PERC technology will gradually phase out in favor of other technologies like TOPCon, urgent research efforts are needed to enhance the reliability of TOPCon cells against moisture and other contaminants. The researchers emphasize the importance of further investigation into the performance of TOPCon modules in humid environments to address these challenges effectively.