lighting principle of LED
First we know what light are different ways of changing energy from one form into another. this photoelectric transformation is implemented by diode. that happens when two atomic nuclei collide with each other, releasing energy in the form of photons. i picked on simple work to illustrate these LED principles.

LED–Light Emitting Diode, it is Semi-conductor electronic components that can lighting, and LED is a current injected device whose characteristic and life are greatly dependent on the performance of LED-used current supply. the recombination of photogenerated holes and electrons to radiating copious amounts of light when led is also observed under forward voltages .

Restraining the complex of the electrons and cavities on the reversal voltage .

And we’re talking about numbers of release energy, because it is the fundamental condition that light wavelength .(From a physical standpoint, there ought to be as many colours as there are different wave lengths)。
Calculating formula of wavelength：