Imagine a vibrant street corner illuminated not by the usual elongated, twisted, or round bulbs, but perhaps by a table on the sidewalk, a wall, or even a fork.
A recent accidental invention revealed last week has elevated LED lighting to a new level, showing its potential as a cheap and long-lasting alternative to traditional bulbs.
LEDs operate on the principle of electroluminescence: electrical energy is converted into light energy when a current flows from the p-type semiconductor to the n-type semiconductor. The junction of these two layers emits variable radiation. The advantages of this type of lighting include the small size of LEDs, which are only a few millimeters in diameter, low energy consumption, and the ability to connect multiple LEDs into long strips or clusters. LEDs are already being used in traffic lights, flashlights, and decorative lighting. They are flexible and operate at a lower cost compared to traditional lights.
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| The white light emitted from Bowers’ rugged lamp. |
Michael Bowers, a graduate student from Vanderbilt University, is working on creating extremely small quantum dots, which are crystals just a few nanometers in size. They are smaller than one-thousandth the width of a human hair. These quantum dots contain between 100 to 1,000 electrons. They are essentially packets of dynamic energy, and the smaller the size, the higher the energy. Each dot in Bowers’ batch is particularly small, containing only 33 to 34 pairs of atoms.
When illuminated or when a current passes through them, they react by emitting light, typically in a vibrant color. However, when Bowers directed a laser beam onto them, something unusual happened.
“I was surprised to see a white glow enveloping the table“, Bowers said, “The quantum dots were supposed to emit blue light, but instead they radiated a brilliant white light“, he explained.
Subsequently, Bowers and other students came up with the idea of embedding the quantum dots in polyurethane and coating this mixture around a blue LED bulb. The rough bulb looks rather unattractive, but it produces white light similar to that of a standard bulb.
The new device emits warm, slightly yellowish white light, twice as bright and with a lifespan 50 times longer than that of a standard 60-watt bulb.
If this process can be developed into commercial products, light will no longer be limited to bulbs. Quantum dot mixtures could be painted onto anything and activated by electricity to create colorful rainbows.
T. An (according to LiveScience)
