Phosphor-free white light-emitting diodes*

The multiple color-matching schemes that could improve the color rendering index for phosphor-free white LEDs are discussed. Then we review a few of the recent research directions for phosphor-free white LEDs, which include the development of monolithic GaN-based white LEDs and hybrid integrated GaN-based and AlGaInP-based white LEDs. These development paths will pave the way toward commercial application of phosphor-free white LEDs in the coming years.