But do you know that the humble leaf can someday be a source of light energy? Scientists at the Laboratory of Organic Electronics at Linköping University have created a material that releases an electrical impulse when light shifts from sunshine to shade and vice versa.
Magnus Jonsson, docent and principal investigator for the research group, said he and his team drew their inspiration from sunshine and shade fluctuations. From this, they created a combination of materials that developed changes in the heat between sunshine and shade and produced electricity.
Previous to this, the research team, along with scientists from the University of Gothenburg, created small nanoantennas that absorb sunlight and generate heat. In a 2017 article in Nano Letters, they revealed that the antennas could decrease cold downdraughts and save energy when applied to window glass. This is because the antennas, whose size is tens of nanometers, react to nearby infrared light and create heat.
Mina Shiran Chaharsoughi, a Ph.D. student in the research team, improved on the technology by coming up with a tiny optical generator which combined small antennas with a pyroelectric film.
"Pyroelectric" refers to electrical voltage that develops when a material is heated or cooled. The temperature change generates an electric current in the circuit.
The antennas the researchers developed are made up of small gold nanodiscs, 0.16 micrometers in diameter. Researchers put them on a substrate and coated them with polymeric film so they can acquire pyroelectric properties.
Jonsson states that the nanoantennas can be made for large areas. Billions of the small discs can be evenly spread out on the surface of any material. In their case, the spacing between discs is around 0.3 micrometers. The researchers used gold and silver for the nanoantennas, but they can also be made from aluminum or copper.
The antennas generate heat which is converted to electricity with the help of the polymer. But first, the polymer must be polarized to create a dipole with a clear difference between positive and negative charge, across it. The extent of polarization influences the strength of the power generated.
Chaharsoughi explains that they force polarization into the material, which stays polarized for a long time.
She demonstrated the effect vividly by holding a twig with leaves in the air coming from a fan. The movement of leaves created sunshine and shade on the optical generator. This, in turn, created small electrical pulses and set an external circuit in motion.
Jonsson admits their research, published in Advanced Optical Materials, is still in its nascent stage. But she believes natural changes between sunshine and shade in trees have the potential to be a source of energy.
The said study shows just one of the many ways we can harness natural light in our daily lives. Natural light is always there. But this is no reason for us to take it for granted.
We can make the most of it by drawing the curtains and pulling up the blinds to let natural light from the sunshine in. It not only gives us vitamins, it also makes us appreciate the sights and sounds of nature more.
You can try painting your walls in lighter shades and giving it a matte finish to reflect the daylight. Try re-arranging furniture to let it promote the flow of light. Bookshelves and tall cabinets should be perpendicular to the window wall so they don't keep light from entering your house.
Your garden may be beautiful. But overgrown plants, bushes, and hedges may block natural light from streaming through your windows.
Natural sunlight is an ally in many ways. It keeps us mentally and physically healthy. It's a source of endless energy. Learning how to make the most of it shows that we appreciate its immense benefits.
You can read more articles that talk about innovative ways to generate various forms of renewable energy at Research.news.