Onions could be secret to efficient solar cells

In Finland, researchers at the University of Turku and Aalto University have found that the skin of red onions could hold the key to effective UV protection of solar cells. Currently, petroleum-based films made of  polyvinyl fluoride and polyethylene terephthalate are used to protect solar cells from UV damage.

The group, which also included the Netherlands’ Wageningen University, found that nanocellulose dyed with red onion skin extract outperformed even market-standard commercial PET-based UV filter. 

According to the study, developing biobased materials often involves a trade-off between UV protection and light transmission in visible region. Lignin, for example, has a dark brown color that limits its use in transparent films.  The film treated with red onion dye exceeded 80% light trans-mission at longer wavelengths.