You may have seen LED lights illuminating a room or strung on Christmas trees. LED lights are popular today because they use much less energy than other bulbs. For a long time, though, scientists couldn’t make white LED light. They were missing blue LED, which combines with red and green LEDs to make white. Scientists knew the chemical that would turn the LED blue, but it was hard to grow large enough crystals to make the light blue. Twenty-five years ago, three professors, including a Japanese-born American, discovered how to develop large crystals.
This year they were awarded the Nobel Prize in Physics because their discovery has made energy-efficient lighting. In places without electricity, LED lamps can even charge cell phones.