LED light tube luminescence principle

The terminal voltage of the PN junction forms a certain potential barrier. When a forward bias voltage is applied, the potential barrier drops, and the majority carriers in the P region and the N region diffuse toward each other. Since the electron mobility is much greater than the hole mobility, a large number of electrons will diffuse toward the P region, forming an injection of minority carriers in the P region. These electrons recombine with holes in the valence band, and the energy obtained during the recombination is released in the form of light energy. This is the principle of PN junction luminescence.