Will phosphorescent materials one day light up our cities?
Around 1603, the Italian shoemaker and amateur alchemist Vincenzo Casciarolo attempted to melt a particularly dense stone he had found on the slopes of Mount Paderno, near Bologna. No gold, silver or other precious metal turned out as he had hoped. But after the stone cooled, Casciarolo discovered something interesting: if he exposed the material to the sun and then took it to a dark room, the stone would glow.
This “stone of Bologna” was the first artificially prepared persistent luminescent substance. Many more would follow and today persistent luminescent materials are used for decorations, emergency lighting, ground markings and medical imaging.
Someday they could give us radiant cities that stay cooler and use less electricity.
A new generation of luminescent materials has the potential to cool cities by re-emitting light that would otherwise be converted into heat. They could also reduce energy consumption, as luminescent sidewalks, illuminated road markers or even illuminated buildings could replace some public lighting. Already, some cities in Europe have installed lighted cycle paths, and some researchers have studied using glowing paint for road marking.