The results have been announced, and the recipients of the 2014 Nobel Prize in Physics are Isamu Akasaki, Hiroshi Amano and Shuji Nakamura. Congratulations to these three fine scientists for this major accomplishment.

As I predicted yesterday, the Nobel Prize has been awarded for a simple and well confirmed advance in technology rather than the higher profile but more speculative and uncertain candidates. The three winners were the leaders of the group of academics and engineers who successfully developed an efficient blue light LED, and development which has allowed for the creation of energy efficient white light sources.

The light emitting diode (LED) was first developed through the 1950s and 1960s using properties of semiconductors to generate light. Where incandescent light sources using a glowing hot piece of metal to produce light, and are therefore very inefficient, and LED produces nothing more than light from the power that is applied to it.

When electrons enter a semiconducting crystal, they have a (relatively) uniform energy. However two crystals with slightly different properties will require the electron to have different energies. As such, if two crystals are joined together, an electron passing from one into the other will lose some of its energy. By selecting the right semiconductors the amount of energy lost will exactly match the energy required to produce a single photon of light. As such all energy lost in the LED is emitted as light with a single colour.

And that was a problem for many applications. Early on in their development, scientists and engineers were able to create LEDs of pure red light, or green light, and later on other colours as well. However blue light was difficult because there are few semiconductors with the right properties, and white light was difficult since it is formed of multiple colours of light and so required multiple semiconductors in a single LED.

Then in 1994,Shuji Nakamura demonstrated a bright blue LED using indium-gallium-nitride as the basic semiconducting crystal. The crystal was made using doping methods that had recently been developed by Isamu Akasaki and Hiroshi Amano, which allowed scientists to modify the properties of this semiconductor in the necessary ways.

So why was it so important to have a bright, blue LED? Why were green and red not sufficient? Isn't it white light we are really after?

The answer is that blue light from this new LED could be passed through a phosphor coating along with yellow light to generate a mixture that appears to human eyes to be white light. In effect, a bright blue LED could be made to look like a bright white LED.

And with bright white LEDs, many possibilities were opened up. Almost immediately manufacturers were generating LED light bulbs, which require less than a tenth of the energy of traditional incandescents, as well as battery powered lamps and small flashlights and signal.

In effect, the development of the bright blue LED has completely revolutionized lighting. No longer do we require a large quantity of electricity that is wasted on heat. Now a small battery, or even an induction coil and a magnet, generates enough electricity for a standard lamp. Finally we can take lights with us wherever we go. Finally we can light our homes and businesses without wasting electricity. The blue LED might just have contributed to saving the planet.

So congratulations to the winners of the 2014 Nobel Prize in Physics!