Scratching the surface of LeTID

Aug 4, 2020 01:26 PM ET
  • The devices behind light-elevated temperature-induced deterioration are still not completely comprehended, yet it is known to cause considerable efficiency losses for modules in the field. Researchers in China are investigating the causes of the sensation, as well as are currently concentrated on the surface area of the materials and the user interfaces in between the silicon and passivation layers.
Scratching the surface of LeTID
Image: PI Berlin

First recognized in 2012, light-elevated temperature-induced deterioration (LeTID) is known to possibly create performance losses as high as 10% over a duration of years for modules in the field, and also has actually been observed in the majority of p-type silicon PV innovations. This makes it a significant headache for plant owners and also module producers alike.

However, the mechanisms behind this degradation are complicated, and also scientists have so far not been able to isolate the precise reason. In new research study into the impacts of LeTID, researchers led by the Chinese Academy of Sciences checked out LeTID effects on the surface of a solar cell, as well as at the user interfaces between silicon as well as the passivation layers.

The team used deep degree short-term spectroscopy, a specialized approach for observing active issues in semiconductor materials, to view destruction actions of the surface area passivation in a variety of in a different way dealt with multicrystalline silicon examples, consisting of both light weight aluminum oxide and also combined light weight aluminum oxide/silicon nitride passivation layers.

They explained their operate in "Surface relevant deterioration sensations in P-type multi-crystalline silicon at raised temperature level and lighting," which was just recently released in Solar Energy.

Bulk to surface

The experiments revealed a reduction in provider lifetime for the samples after light saturating at 80 C as well as 0.46 kilowatt hours per square centimeter. The number of user interface states-- defects in the material that can minimize efficiency-- enhanced after the light soaking. According to the scientists, this suggests that decreased passivation high quality caused by the increase in user interface states could be a contributing factor in LeTID.

The reason for this increase, however, is most likely in the mass of the product rather than its surface area, and the paper suggests that the increase in user interface states might be to diffusion of impurities in the mass to the surface during the LeTID device. "It might be concluded that the rise of interface states is one root cause of [the] LeTID sensation, but the major reason may be the issues in bulk," the scientists stated.

Even with this, the group ended that additional work concentrating on the surface as well as user interface degradation will be valuable in much better understanding LeTID. "The source of the LeTID sensation is extremely intricate," they said. "And much more extensive research on surface-related degradation need to be executed."



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