Tubes of Light

Nanotubes—carbon cylinders 100,000 times thinner than a human hair—may turn out to make efficient solar panels. Georgia Tech scientist Jud Ready made a grid of millions of nanotubes and coated them with a light-absorbing semiconductor material. When sunlight shines on the grid, each tiny nanotube "tower" converts the light to electricity, just like in a conventional solar panel. However, the nanotubes get an energy bonus because light ricochets from one tower to the next, increasing the amount of light that gets absorbed. Ready's solar cells also have the advantage of being compact and lightweight, which may make them suitable for use in weather satellites or space stations, where size and weight are critical. To gain wider use, however, somebody will have to figure out a way to manufacture them more cheaply. Currently the nanotube grids entail tricky chemistry in a 700-degree° Celsius furnace.