Onion-skin Dye May Find Use In Greener UV-Protected Solar Cells

Solar cells frequently encounter high levels of harmful ultraviolet light because they capture the maximum possible sunlight.A new eco-friendly coating could protect them from these UV rays, using its active ingredient extracted from onion skin.

Currently, manufacturers apply clear films made from petroleum-based materials to the surface of solar cells for UV protection.However, the extraction and processing of petroleum are not sustainable processes, nor is the disposal of film-coated cells after they have reached the end of their life.

Exploring Bio-Based Alternatives to Petroleum Films

For this reason, scientists have been looking for bio-based alternatives to petroleum-based films.One promising material is nanocellulose, which researchers compose from small cellulose fibers obtained from plant sources, such as agricultural and forestry waste.

However, this material alone cannot provide the necessary protection.

With that in mind, Finnish and Dutch researchers recently experimented with three different additives: cross-linked iron ions, nanoparticles of a plant-based biopolymer called lignin, and an anthocyanin dye extract obtained from red onion skin. Previous studies have shown that these substances possess UV-blocking properties.

In laboratory tests, researchers applied sheets of nanocellulose film treated with each of the additives to dye-sensitized solar cells, which they then exposed to a UV lamp for 1,000 hours.This time is equivalent to approximately one year of sunlight exposure in a Central European climate.

Effectiveness of Onion-Dye Film in UV Protection

The results showed that the onion-dye film performed the best, blocking 99.9% of UV light with wavelengths up to 400 nanometers. Additionally, it allowed over 80% of visible light transmission at longer wavelengths, maintaining this efficiency throughout the testing period. Visible light is the source that solar cells use to generate electricity.

In fact, these figures surpassed the figures that researchers achieved with commonly used UV-blocking PET (polyethylene terephthalate) films, which are also petroleum-based

Future Potential for Biodegradable Solar Cells

Researchers hope that in the future, they can use the onion-dye nanocellulose film not only in conventional solar cells but also in cells designed to be fully biodegradable, such as those that power remotely located environmental sensors.

Scientists from the University of Turku and Aalto University in Finland, along with Wageningen University in the Netherlands, conducted the study, which they recently published in the journal ACS Applied Optical Materials.

Read the original article on: New Atlas

Read more: Bacteria Feed on Toxic and Persistent PFAS Chemicals