Imagine covering your electric airplane with a light-collecting, energetic coating that generates enough juice to extend the battery-only range of your electric airplane. That possibility comes to mind from seeing recent articles about Heliatek’s organic solar cells, which demonstrated a solar-collecting efficiency of 13.2 percent. That’s only about one-third of what the best silicon solar cells can do, but those tend to be relatively thick, heavy, and brittle. Heliatek has managed to make a six-layer thin-film cell in which the active layers are only 250 nanometers (0.00000984252 inches) thick. Sandwiched within protective layers and weighing less than a kilogram per square meter (a few ounces per square foot) HeliaFilm™ can be wrapped around a radius of 10 centimeters (just under four inches). Performance figures are for opaque cells. Transparent cells which could be placed on windows or canopies have a transparency level up to 50 percent and an efficiency of six percent. HeliaFilm® is available in lengths from 0.3 to 2.0 …
