Researchers at UNSW Sydney have developed a groundbreaking method that reveals how solar cells can self-heal when exposed to sunlight, addressing damage caused by ultraviolet (UV) radiation. This new technique allows scientists to monitor the chemical changes within high-efficiency silicon solar cells while they are operational, providing insights that could significantly improve the testing and design of solar panels.
Revolutionizing Solar Cell Testing
The research, led by Professor Xiaojing Hao and published in Energy & Environmental Science, uncovers the mechanisms behind ultraviolet-induced degradation (UVID), a process that reduces solar cells’ efficiency over time. Previous studies indicated that solar cells could lose up to 10% of their performance after approximately 2,000 hours of UV exposure. This new understanding of how solar cells recover could lead to better manufacturing practices and quality control.
“This new method can be used directly on the production line to quickly check how well solar cells resist UV damage,” said Professor Hao. “It’s useful for future quality control during manufacturing.” This innovative approach not only enhances the performance of solar cells but also provides a framework for developing more effective testing standards.
Understanding Damage and Recovery
Solar cells suffer efficiency losses due to exposure to UV light, but the recovery process had remained largely unexplained. Traditional methods of studying these phenomena involved destructive analysis or indirect measurements. The UNSW team, including Dr. Ziheng Liu, Dr. Pengfei Zhang, and Dr. Caixia Li, utilized a non-destructive technique called ultraviolet Raman spectroscopy. This allows for real-time observation of chemical changes as solar cells are exposed to UV light and visible light during recovery.
“Instead of just measuring how much power the cell produces, we can directly see how the material itself is changing in real time,” said Dr. Liu.
This advancement means researchers can now observe the reconfiguration of chemical bonds involving hydrogen, silicon, and boron atoms, which weakens the performance of solar cells. Notably, the team was able to document these bond changes and the subsequent recovery process under normal light conditions. “This confirms that recovery is not just an electrical effect,” Dr. Liu added. “The material itself is repairing at the atomic level.”
The implications of this research extend beyond theoretical insights. By establishing a clear distinction between reversible changes and permanent degradation, the new monitoring method could refine how solar panels are certified and tested. Current accelerated aging tests may not accurately reflect real-world conditions, potentially leading to misleading assessments of solar cell durability.
“This approach helps distinguish between true long-term degradation and reversible changes,” Dr. Liu explained. “That distinction is essential for accurate lifetime prediction.”
Future Applications in Solar Technology
The potential applications of this research are significant. Traditional UV degradation tests can take days or weeks and often involve destructive methods. In contrast, the Raman-based technique offers rapid assessments, detecting UV sensitivity in seconds while leaving the solar cell intact. This efficiency could enhance production lines by enabling manufacturers to identify potential UV-related issues early in the production process.
Additionally, the study reveals how design choices—such as the thickness of passivation layers or surface coating properties—affect the resilience of solar cells to UV exposure. This knowledge empowers manufacturers to make informed decisions regarding efficiency, durability, and cost, potentially leading to more effective solar panel designs.
As the solar industry continues to evolve, the findings from this research, supported by the ARC Research Hub for Photovoltaic Solar Panel Recycling and Sustainability, provide a clearer understanding of solar cell behavior under real-world conditions. “With better monitoring tools, we can design better tests, better panels, and ultimately more reliable solar energy systems,” Professor Hao concluded.
