Phosphors for solid state lighting

Abstract

After an introduction of the basic concepts for solid-state-lighting, i.e. multi-chip LEDs and phosphor-conversion LEDs based on blue or near-UV pump LEDs, white LED phosphors are discussed regarding their match to different application requirements. Since the US Energy Star requirements have set first 'standards' for LED lighting, we evaluate different phosphor solutions for white LEDs mainly regarding these requirements. Efficient daylight LED for outdoor applications can be realized using yellow orthosilicates or garnets. Looking at cool white or even warm white LEDs with CRI 75+ blends of garnets and red nitrides are first choice. Solutions based on garnets and nitrides are superior, where CRI and/or color stability is important. Finally, the strong and package-dependent effect of particle size and scattering on color and efficiency is discussed.