Christmas isn’t far off now, and whether you’re celebrating it or not, you’ve may well have started seeing Christmas lights starting to appear adorning houses and Christmas trees. How do these lights actually work, and how can they be made to produce such an array of colours? This graphic takes a look at the chemistry.
LED stands for light-emitting diode, and they come in a whole range of colours, from reds and oranges to blues and violets. Though they may look small, they’re packing some serious science – in fact, the 2014 Nobel Prize in physics went to scientists who worked on discovering how to make efficient blue LEDs.
It makes sense to start by explaining how LEDs can produce light in the first place. LEDs are made of semiconducting materials, materials which conduct electricity under some conditions but not others. Several different semiconducting materials can be used in LEDs, but a lot of them are gallium-based, for example gallium nitride and gallium phosphide.