A group of scientists in Taiwan recently postulated that placing gold nanoparticles within the leaves of trees, causes them to give off a luminous reddish glow. The idea of using trees to replace street lights is an ingenious one – not only would it save on electricity costs and cut CO2 emissions, but it could also greatly reduce light pollution in major cities.
The discovery came about accidentally after the scientists were looking for a way to create high-efficiency lighting similar to LED technology, but without using toxic chemicals such as phosphor powder.
The researchers infused sea urchin shaped nanoparticles of gold inside the leaves of a Bacopa Caroliniana plant. The gold reacted with the chlorophyll, causing the leaves to emit a red glow, essentially creating a bio-LED. Under a high wavelength of ultraviolet light, the gold nanoparticles were able to produce a blue-violet fluorescence to trigger a red emission in the surrounding chlorophyll.
The research is still in its infancy and there are many issues that need to be ironed out, not the least of which is the high price of gold, which makes infusing even tiny amounts quite an expensive proposition.With all these challenges these kind of streetlights are dreams with the attached questions: what happens when the tree sheds leaves?, will gold nanoparticles disrupt the ability of chlorophyll to transfer its energy to the photosynthetic pathway? and so on, but the idea is certainly intriguing and could lead to other more feasible applications.