Direct white-light from core-shell-like sphere with Sr3Mg- Si2O8： Eu2＋, Mn2＋ coated on Sr2SiO4：Eu2

A method of color mixture for white light is presented with Sr3MgSi2O8：Eu2＋, Mn2＋ shell coated on Sr2SiO4：Eu2＋ core by spray pyrolysis procedure. Upon near ultraviolet （NUV） excitation, a 550 nm band emission of Eu2＋ from core host combines with the simultaneous emissions of Eu2＋ at 457 nm and Mn2＋ at 683 nm based on energy transfer in the shell lattice to generate warm white light with color rendering index （CRI） of 91. With such a core-shell-like structure, the re-absorption of blue light from shell layer can be effectively suppressed, and the chemical stability of the phosphor is verified experimentally to be superior to that of the Sr2SiO4：Eu2＋. This new proposed phosphor provides great potential in the color mixture of blending-free phosphor converted white NUV light emitting diode （LED） devices.