Researchers at the University of South Wales have developed a way to monitor how solar cells are damaged by ultraviolet radiation and how they naturally recover, which could help cut the cost of making solar modules and improve their efficiency.
The research team, led by Scientia Professor Xiaojing Hao, said the research could significantly transform how solar panels are tested, designed and certified for long-term use.
“This new method can be used directly on the production line to quickly check how well solar cells resist UV damage, making it useful for future quality control during manufacturing,” Professor Hao said.
The efficiency and performance of silicon solar cells degrade over time due to their constant exposure to ultraviolet radiation, with previous studies showing the drop in performance to be as high as 10 per cent after the equivalent to 2,000 hours exposure to UV radiation.
Photovoltaic experts have understood that this degradation in efficiency can be recovered under certain conditions, such as exposure to sunlight during normal operations.
However, this recovery has not been observed in terms of electrical output, and it remained a mystery what was actually happening inside the material without cutting the solar cells apart.
To address the problem, the UNSW used ultraviolet Raman spectroscopy, which utilises lasers to reveal a material’s molecular vibrations, to monitor chemical bond changes in operating cells exposed first to UV light and during recovery under visible light.
“This technique works a bit like a camera. 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 Ziheng Liu, corresponding author of the research paper published in Energy & Environmental Science.
The technique showed that UV light initially alters chemical bonds involving hydrogen, silicon, and boron atoms near the cell surface.
When the cell was later exposed to normal visible light, the researchers saw the chemical structure return to its original state.
The monitoring method has major implications for the solar industry and could help improve certification tests for solar panels.
The researchers say the method could be used to screen new materials, processing conditions, or design changes before cells are built into full solar panels.
It could also allow manufacturers to identify potential UV-related issues early in production.