MIT researchers created light-emitting plants that can glow for about an hour and recharged in just ten seconds using an LED. To make the glowing plants, they embedded the plants with specially-engineered nanoparticles that are several hundred nanometers in diameter. (For comparison, a human hair is approximately 80,000 nanometers wide.) The nanoparticles, made from a phosphorescent compound, act as "light capacitors" that absorb light and then slowly release it. From MIT News:
"We wanted to create a light-emitting plant with particles that will absorb light, store some of it, and emit it gradually," says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT and the senior author of the new study. "This is a big step toward plant-based lighting."
"Creating ambient light with the renewable chemical energy of living plants is a bold idea," says Sheila Kennedy, a professor of architecture at MIT and an author of the paper who has worked with Strano's group on plant-based lighting. "It represents a fundamental shift in how we think about living plants and electrical energy for lighting."[…]
The particles… can be infused into the plants through the stomata — small pores located on the surfaces of leaves. The particles accumulate in a spongy layer called the mesophyll, where they form a thin film. A major conclusion of the new study is that the mesophyll of a living plant can be made to display these photonic particles without hurting the plant or sacrificing lighting properties, the researchers say.