New materials and devices bring white LEDs closer to home
Even though 125 years have passed since Thomas Edison invented the incandescent lightbulb, his basic technology is still the main source of light in most homes today. That may change over the next decade, however, in favor of light-emitting diodes, or LEDs. These devices, long used in digital clocks, consist of a semiconductor chip typically made of a gallium-based material. The chip emits light when a voltage is applied.
Unlike incandescent lightbulbs, LEDs don't waste electricity heating a filament to 2,000°C. Instead, they channel a larger proportion of power directly into light. A LED can last for up