Light-emitting diodes (LEDs) are highly efficient, but they can’t directly produce white light. Though a blue LED can be coated with a phosphor that alters some wavelengths to yield a whitish mix, the resulting light has a bluish cast, and some energy is wasted as heat in the process. A new LED lamp avoids this problem by using an optic coated with quantum dots–bits of semiconductor material a few nanometers in diameter. When excited by a light source, the dots radiate light in wavelengths that vary according to their sizes. The optic–coated with dots in specific sizes and ratios–appears orange when the light is off (left) but radiates white light when the underlying blue LED is on (right). The result: LED lamps that are 50 percent more efficient and produce better-quality white light.
Credit: Bruce Peterson
Product: Array lamp with Quantum Light optic
Cost: About $100 per lamp
Company: Nexxus Lighting, QD Vision
Other products in this section:
How the science of persuasion could change the politics of climate change
Conservatives have to make the case to conservatives, and a growing number of them are.
This battery advance could make electric vehicles far cheaper
Sila Nanotechnologies has pulled off double-digit performance gains for lithium-ion batteries, promising to lower costs or add capabilities for cars and phones.
These boots were made for generating power
Embedded in a boot heel, a microfluidic device based on a 19th-century invention harvests energy from human footsteps.