The Guardian reports on Swiss scientists who have taken ordinary wood floor planks, coated them with silicon and embedded nanocrystals, and then stepped on them to generate enough electricity to turn on a light bulb:
The wood pieces become electrically charged owing to contact and separation when stepped on via a phenomenon called the triboelectric effect. This effect occurs when electrons can transfer from one object to another, akin to the static electricity produced when you rub a balloon on your hair for a few seconds.
If a material is tribo-positive it tends to lose electrons, and if it is tribo-negative it tends to attract electrons, said the senior study author, Guido Panzarasa, a group leader in the professorship of wood materials science located at Eidgenössische Technische Hochschule Zürich and the Swiss Federal Laboratories for Materials Science and Technology Dübendorf.
To boost wood’s triboelectric properties, the researchers coated one piece of it with a common silicone that gains electrons upon contact, while the other piece was embellished with nanocrystals that have a tendency to lose electrons. After testing different types of wood, they found that radially cut spruce – a common wood for construction in Europe – generated 80 times more electricity than natural wood.
Using a wood floor prototype with a surface area slightly smaller than an A4 piece of paper produced enough energy to drive household LED lamps and small electronic devices such as calculators, the researchers found.
You can read more of the researchers’ work here, in Matter.