Silicon solar cells loose their efficiency after exposing to sun rays for some time due to forming of BsO2i. Researchers, L. I. Murin, et al., from institutions in Belarus, the UK, Norway, Sweden, and Portugal, may have reached a different point of view.
The researchers performed their own ab initio calculations to get a clue as to the possible location of local vibrational mode lines due to the doubly positively charged O2i. The calculations also revealed the expected intensity of the dimer’s local vibrational modes for both the neutral and doubly positively charged states. However, the researchers found no trace of the doubly positively charged O2i in their sample set. Although their data did show the existence of the O2i in the neutral charge state, the Bourgoin-Corbett diffusion mechanism cannot occur without dimers in both charge states.Overall, the results cast doubt on the formation of the BsO2i complexes that have been widely thought to cause light-induced degradation of silicon solar cells. The findings also suggest that alternative mechanisms for solar cell degradation deserve a closer look.