US Patent 10479937 Narrow band red phosphor

A narrow band red phosphor may have a general composition MSxSeyAz:Eu, wherein M is at least one of Mg, Ca, Sr and Ba, A is at least one of C, N, B, P and a monovalent combining group NCN (cyanamide), and may in some embodiments further include one or more of O, F, Cl, Br and I. In embodiments 0.8<x+y<1.25 and 0<z≤0.05, and in some embodiments x, y and z are determined strictly by charge balancing. A white light emitting device may comprise: a blue and/or UV excitation source; a narrow band red phosphor of the present invention; and phosphors with peak emission at shorter wavelengths, such as yellow, green, yellow/green and/or blue.