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A team from the School of Photovoltaic and Renewable Energy Engineering at the University of New South Wales (UNSW) in Australia has reinvented the design of screen-printed contacts to reduce costs and silver consumption, without sacrificing the efficiency of tunnel oxide passivated contact (TOPCon) solar cells.
New UNSW research, published in July 2024, has proposed an established process to help scale TOPCon solar power even further.
The researchers say their approach to solar cell construction, described in “ Ultra-Lean Silver Screen-Printing for Sustainable Terawatt-Scale Photovoltaic ,” published in RRL Solar , could reduce the silver content of TOPCon from between 12 mg/W and 15 mg/W to 2 mg/W. This would keep the solar industry’s silver consumption below 20% of global supply as PV expands.
The authors of the study say the efficiency of the cells using their method is 24.04%, and that cells manufactured in partner Chinese facilities have achieved an efficiency of 26.7%.
The study involved partners from metal pulp production and photovoltaic manufacturing. It was led by Brett Hallam, an associate professor in the School of Photovoltaic Engineering and Renewable Energy at UNSW.
“The industry, by and large, hasn’t been forward-thinking,” Hallam says. In 2021, Hallam conducted research into what technology PV manufacturers should adopt, beyond passivated emitter rear contact (PERC) solar. The study, “Design Considerations for Multi-terawatt Scale Manufacturing of Existing and Future Photovoltaic Technologies: Challenges and Opportunities Related to Silver, Indium and Bismuth Consumption,” was published in Energy and Environmental Science .
In this article, Hallam dismissed expectations that more efficient heterojunction solar (HJT) would replace PERC, arguing that the indium required in the indium tin oxide layer – a transparent and conductive oxide – would only allow 200 GW of production before the worlds indium reserves were exhausted.
“There’s always a big push for solar cell efficiency,” Hallam said, as people see “the cliff edge that’s looming with the exponential growth in installations needed to mitigate climate change.”
The teams eureka moment came in 2020, thanks to the doctoral research of Yuchao Zhang, co-author of the two aforementioned papers. |
