Actually, when electric current enters the diode, the electrons on one side of the diode become excited and move to a higher energy state, absorbing electrical energy. When they move across the diode to the other side, they drop back to a lower energy state. When this happens, they release that energy in the form of a photon, which we interpret as visible light.

So LEDs turn electrical energy directly into light energy, which is why they are so efficient. An incandescent bulb, on the other hand, simply heats the filament to the point where it is so hot that it gives off light, just like metal can be heated to give off light.

Just my 2 cents...