Centuries ago, the methods to produce light were rudimentary and problematic until now, with several options in the list. LED, the acronym of Light Emitting Diodes, are semiconductors with special properties and then, to know its origins we need to revisit the work of Michael Faraday in 1833, the year in which he shares the experiment with silver sulfide observing a change in resistance due to temperature. After that, several scientists were trying to discover more electricity properties in reference with certain materials. Nick Holonyak presents the discovery of LEDs in 1962.
LED is then a special class of diode because it emits light. A diode is something called a P-N junction, with very useful characteristics in terms of electronic engineering. It's one of the most used parts, almost always present in every circuit board. But LEDs emit light, and the question is... why? Electroluminescence was tested in lab around 1907 by a British researcher, employing silicon.
So, different materials could emit photons (if they really exist, but let's call them that way) in presence of electricity. That's what happens with this special type of diode —with unconventional periodic elements— due to the presence of atom lattices with lack of electrons, a process that could be created artificially but was present in Nature billion years ago! The idea is not from us of course.
Then, electrons arrive and the result is light! It's a great step in terms of energy optimization and possibilities because the light is now separated from vacuum or any form of crystal tube. In recent times there are even LED clothes! Besides they last much more than a conventional light bulb and consume much less energy giving the same light.