UNSW says its ultraviolet Raman spectroscopy shows how UV light breaks chemical bonds inside solar cells and how normal sunlight helps reverse part of this damage
The method can be used on production lines to quickly assess UV resistance, helping screen materials, processes, and designs before full module assembly
The team says this technique supports more accurate performance and lifetime estimates for solar modules
Researchers at the University of New South Wales (UNSW) Sydney have devised a new test method that can closely track how ultraviolet (UV) radiation damages solar cells and how that damage can be naturally reversed under sunlight.
Solar panels are known to lose some performance due to UV light, but they can regain part of it when used normally, explain the scientists. While they could see the power come back, understanding what was changing inside the solar cell was not possible.
To view the changes happening inside the solar cell, UNSW says it has developed a new, non-destructive monitoring technique called ultraviolet Raman spectroscopy. It identifies a material by shining a laser on it and analyzing how the light scatters to reveal the material’s molecular vibrations.
By using this method, the team was able to see UV light reconfiguring certain chemical bonds involving hydrogen, silicon, and boron atoms, thereby weakening performance. It also enabled them to see hydrogen atoms migrating back toward the surface, repairing broken bonds, returning the chemical structure to its original state.
The technique allows engineers to monitor chemical bonding near the solar cell surface when exposed to UV light as well as during recovery under visible light. This, they explain, allows them to see exactly how UV exposure alters the chemical structure inside the cells as degradation occurs.
“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,” said Scientia Professor Xiaojing Hao.
By directly observing these changes, the researchers can better understand why there is a drop in performance under prolonged UV light. Just as importantly, they can also study how exposure to normal sunlight helps the cells recover over time.
“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,” explains Dr Ziheng Liu, the Corresponding Author of the Energy & Environmental Science paper.
“This approach helps distinguish between true long-term degradation and reversible changes,” added Liu. “That distinction is essential for accurate lifetime prediction.”
It can be used to screen raw materials, processing conditions, or design changes before cells are built into full solar panels.
UVID challenge is very real for solar modules as it leads to higher-than-expected power losses, thereby impacting a project’s financial health. UNSW cites previous studies to claim that the drop in module performance can be as high as 10% after the equivalent of 2,000 hours of exposure to UV radiation during accelerated testing.
A 2025 study by the US National Laboratory of the Rockies (NLR), previously National Renewable Energy Laboratory, observed UV-induced degradation in n-type modules and called for stricter standards and a better understanding of degradation mechanisms (see NREL Research Flags Higher UV Degradation In n-Type Modules).
UNSW says its findings are expected to support the development of improved manufacturing and treatment processes that reduce long-term degradation. Over time, this could lead to more durable and reliable solar panels with longer operational lifetimes, according to the team.
The UNSW research is published in Energy & Environmental Science journal under the title A non-destructive UV Raman characterisation platform to enable insight into the mechanism of reversible ultraviolet-induced degradation (UVID) in TOPCon solar cells.