Why Did A Lightbulb Win The Nobel Prize?
On Tuesday, Oct. 7, The Royal Swedish Academy of Sciences announced that they awarded the prize to Isamu Akasaki of Meijo University in Nagoya, Japan, Hiroshi Amano of Nagoya University in Japan, and Shuji Nakamura of the University of California, Santa Barbara for:
"...having invented a new energy-efficient and environment-friendly light source - the blue light-emitting diode (LED). In the spirit of Alfred Nobel the Prize rewards an invention of greatest benefit to mankind; using blue LEDs, white light can be created in a new way. With the advent of LED lamps we now have more long-lasting and more efficient alternatives to older light sources."
That's all well and good, but it seems like a pretty simple invention - a better light bulb - and simple inventions don't win Nobel prizes. So why was their work so special?
Why is a blue lightbulb worthy of the world's most prestigious physics award? Let's start with all of the important applications that the blue LED led to, specifically.
Important Applications
The blue LED was so highly coveted because with it, companies could combine blue with red and green light to produce white light and compete with the other commercially-available white incandescent lights.
White LED lamps are 50% more efficient at converting electrical energy into light compared to incandescent light bulbs. The result is that LEDs last for about 100,000 hours, which is 100 times longer than your average incandescent lights and 10 times longer than fluorescent lights.
If the U.S. replaced all of its lights with LEDs, it would reduce energy consumption by about 20 percent, Christian Wetzel, a professor of physics at the Rensselaer Polytechnic Institute in Troy, New York told Inside Science. This reduction would mean that utility companies would not need to invest in building new power plants.
That also means a lot less waste: Since the bulbs last longer, we would throw fewer dead light bulbs out. And since LEDs use less energy, it's easier to power them with renewable energy sources like solar power, which has huge applications in areas of the world where power is scarce.
"The LED lamp holds great promise for increasing the quality of life for over 1.5 billion people around the world who lack access to electricity grids: due to low power requirements it can be powered by cheap local solar power," The Royal Swedish Academy of Sciences stated in their press release.
But, today's white LED-emitting technology are more than just better light bulbs.
Multi-color LEDs light up the screens on your smartphone, tablet, and laptop computer. The advent of the blue LED has also led to higher-energy LEDs called ultraviolet LEDs that offer an inexpensive way to sterilize water, which is especially useful in developing countries with limited access to clean drinking water.
Why blue claims the Nobel Prize
But why does the blue LED, specifically, get the prize, as opposed to red or green LEDs?
LEDs, unlike incandescent or fluorescent lights, generate light through a phenomenon called electroluminescence: A material emits light in response to an electric current passing through. The wavelength of the light emitted depends on the materials used.
In 1962, Nick Holonyak, Jr., who was then a consulting scientist at General Electric Company, developed the first visible-light LED: Red. Five years later George Craford invented the green LED. But the blue LED would not come easily.
It took another 27 years to create a blue LED.
The reason it took so long to produce this color of LED was because the technology and materials just weren't there until the 90s.
"At the risk of oversimplifying all of solid-state physics, the key to building any LED is to find the right material to serve as the semiconductor 'die' in the diode," Ethen Siegal writes in Medium. "...while many different types of materials emitted red, yellow and green light, a blue LED was elusive."
The material used to make these other LEDs was gallium arsenide phosphide, but this material can't produce the higher-energy blue light. It was not until 1994, after years of research, when Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura discovered that gallium nitride held the key. The three scientists succeeded where many had failed.
"A lot of big companies really tried to do this and they failed. But these guys persisted and they tried, and tried again, and eventually they actually succeeded," said Per Delsing, the chairman of the Nobel Committee, in an interview.
These LEDs do have one downside: All of this blue light is messing with our sleep.