LEDs create light as negatively charged electrons in the circuit interact with positively charged "electron holes." When an electron enters a hole, they combine energies and emit some as light. But electrons often zip past holes without merging, which is why LEDs tend to be dim. But a film of DNA taken from salmon sperm, Steckl found, creates an energy barrier that slows electrons enough that the holes can better attract electrons, merging with them more often and emitting more light. (Any DNA would work, but salmon sperm is easily acquired.)
Because "BioLEDs" use cheap renewable materials instead of precious rare metals, Steckl expects that in a decade or so, they will be common in TVs, cellphones and other gadgets with a display—which sounds pretty good to the world's salmon fishermen. "They're so excited," he says, "that I can't keep them at bay."