Color tunability of nanophosphors by changing cations for solid-state lighting

X3MgSi2O8: Eu2+, Mn2+ (X=Ba, Sr, Ca) phosphors with the mean particle size of 200 nm and the spherical shape are synthesized through combustion method. They show three emission colors under near-ultraviolet light: the blue and green colors from Eu2+ ions and the red color from Mn2+ ions. Three emission bands show the different emission colors with changing X2+ cations. These color shifts are discussed in terms of two competing factors of the crystal field strength and the covalency. These phosphors with maximum excitation of around 375 nm can be applied as color-tunable phosphors for white-light-emitting diode based on ultraviolet/phosphor technology.