So recently the 2014 Nobel prize in physics has been jointly awarded to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura for the invention of efficient blue light-emitting diodes. “So what’s the big deal with blue LED’s?” you might be asking right now. This short article will take a look at the importance of LED’s in general and why blue light emitting diodes play a special role among LED’s.
First of all, what is an LED? LED or a light-emitting diode is a semiconductor device capable of emitting light with the following advantages when compared to incandescent light sources: lower energy consumption, longer lifetime, improved physical robustness and smaller size. Light-emitting diodes are now used in applications as diverse as automotive headlamps, advertising, general lighting, traffic signals, and camera flashes. Electroluminescence — the phenomena used by LED’s — was discovered back in 1907 by Henry Joseph Round. In 1927 Russian researcher Oleg Vladimirovich Losev published a paper called Luminous carborundum [silicon carbide] detector and detection with crystalsabout, which was the inspiration for the future LED’s. 34 years later, in 1961 Robert Biard and Gary Pittman invented and patented the first infrared LED for Texas instruments. A first visible light LED soon followed by Nick Holonyack, a consulting engineer for General Electric Company. For his work, including 41 patents on related and unrelated inventions, Holonyack is often regarded as the father of the visible light LED’s. The first LED’s were red, however the green, yellow and blue LED’s were invented in the following decades.
By mixing blue, green and red LED’s any colour can be emitted
The mentioned colours of the LED’s played a pivotal role, since they could be combined to emit essentially any colour after the blue LED’s were developed in 1994. This was a crucial step towards the development of efficient and cheap lighting, which is exactly the reason why Isamu Akasaki, Hiroshi Amano and Shuji Nakamura — the men, who made the blue LED’s possible — received this years Nobel prize. The main obstacle in developing the elusive blue diodes was finding the right material to act as the semiconductor in the diode and have the right properties to emit blue light efficiently. The material used for the red and green diodes was gallium arsenide phosphide, however it simply didn’t work for blue. It was not until 1994, when Amano, Nakamura and Akasaki came up with the right material — gallium nitride.
The great thing about all of this that Akasaki, Nakamura and Amano succeeded where many big companies with far greater resources failed. After all, it’s all about the passion and clever workarounds at the end of the day. And now, only 20 years after the development of the blue LED’s cheap and efficient lighting offered by these modern light sources promises a cheaper, brighter and, most importantly, cleaner future.
Sources and more reading:
- There’s An Excellent Reason Why A Blue Lightbulb Just Won the Nobel Prize
- Lightbulb Moment for Nobel Physicists
- LED – Light Emitting Diode
- Nobel Prize Press Release