What will make our future brighter? For thousands of years our lives have been lit by the Sun, by stars, by fire. Electricity brought new types of lights, ones we can summon at the flick of a switch.
LEDing the way
Not all lights were created equal. Some lights use more energy than others to create a glow. Incandescent globes shine white hot, wasting a lot of electricity as heat. Fluorescent lights use much less electricity, but better still are light emitting diodes, or LEDs.
LEDs are responsible for the light behind lots of computer screens, smartphones and other devices. They are very efficient, creating a lot of light for only a small amount of electricity. The Nobel Prize in Physics this year was awarded for the invention of blue LEDs to Isamu Akasaki and Hiroshi Amano, both from Japan, as well as Shuji Nakamura, from the United States.
The future is blue
Why blue? For 30 years, blue LEDs were the missing part of the puzzle. After red LEDs were invented, green ones soon followed. But blue was tricky, and without blue, we couldn’t make white light. White is made from the three primary colours of light – red, blue and green.
Eventually, scientists cracked the problem and created blue LEDs. They did it by growing crystals of a chemical called gallium nitride. That was made only 20 years ago, but already blue LEDs have become part of the devices many of us use each day.
The best thing about bright LEDs is that they need so little electricity to run. That makes it easy for them to be powered by solar energy. Cheap solar panel torches can give light to the 1.5 billion people in the world who live without access to an electricity grid. It can allow them to read, cook, work and walk around safely after dark.
Many of us take light for granted. How many lights surround you right now? About a quarter of the world’s electricity is used to make light. If we switched to low-energy LEDs, we could make a real difference to the environment. Now that’s a brighter future.
If you’re after more science news for kids, subscribe to Double Helix magazine!