4. LED features

4.1 Component efficiency

The energy efficiency η _e of an LED is a complex quantity and the result of several factors:

• η _f , the internal efficiency, which is the ratio of the average energy of the photon produced (equal to hν) to the total energy that the electron-hole pair acquires from the external energy source (equal to eV) ;

• η _ext , the external quantum efficiency, which is the ratio of the number of photons emitted to the number of electrons...