Scientists in Taiwan have discovered that gold nanoparticles can induce luminescence in the leaves of plants, making them emit a reddish glow. They came up with the process while searching for a way to create high-efficiency lighting that is similar to LED technology, but without the use of toxic chemicals such as phosphor powder. One use envisioned by lead researcher Dr. Yen-Hsun Su is the cultivation of gold-treated roadside trees that would provide street lighting while saving energy and absorbing carbon dioxide.
Bio-Luminescence and Alternative Energy
Biofuels can be thought of as a sort of first-generation, one-on-one (or gallon-to-gallon) substitute for fossil fuels. Bio-luminescence takes us a step beyond, by incorporating energy generation into an object rather than plying an engine with prefabricated fuel. As Dr. Su explains, chlorophyll can glow when exposed to high wavelength ultra violet light, but gold nanoparticles are excited by shorter wavelengths. By diffusing specially shaped nanoparticles in the leaves of a Bacopa caroliniana plant, Dr. Su’s team was able to induce the chlorophyll to produce a red glow.
Gold and Sustainability
Bio-luminescence is just one example of the roles that gold may play in our sustainable future. At Harvard University, researchers are using gold nanoparticles to develop energy efficient, non-toxic methods for manufacturing fragrances and fabrics, and scientists at the National Institute of Standards and Technology have used gold nanoparticles to “grow” light-emitting nanowires.
Image (altered): Glowing tree and street light by Nagy David on flickr.com.
Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. You can also follow her on Twitter @TinaMCasey and Google+.