How does an LED work and what are the key principles behind its operation?

An LED, or light-emitting diode, works by converting electrical energy into light through a process called electroluminescence. When a voltage is applied to the LED, electrons and electron holes combine in the semiconductor material, releasing energy in the form of photons, which are the particles of light. The key principles behind its operation include the use of a semiconductor material, the movement of electrons and electron holes, and the emission of light as a result of this process.