Broadband orange-emitting Sr_(3)Si_(8)O_(4)N_(10):Eu^(2+)phosphor discovered by a modified single-particle-diagnosis approach

Discovery of new phosphors with desired properties is of great significance for developing high optical quality solid-state lighting.The single-particle-diagnosis approach is an effective way to search novel phosphors by analyzing tiny single crystals screened from the fired powder mixtures.In this work,a broadband orange-emitting phosphor of Sr(3)Si_(8)O_(4)N_(10):Eu^(2+)for solid state lighting was discovered by this method.The new oxonitridosilicate crystallizes in the monoclinic space group of P2_(1)/n(No.14)with cell parameters of a=4.8185 A,b=24.2303 A,c=10.5611 A,β=90.616°,and Z=4.The crystal structure of SrsSigO4Nio was determined from the single-crystal X-ray diffraction(XRD)data of a single crystal,which is made up of a three-dimensional framework consisting of vertex-sharing SiN_(4)and SiN_(3)O tetrahedra.Sr^(2+)ions occupy five crystallographic sites and have coordination numbers between 6 and 8 with one ordered Sr and other four disordered Sr atoms.The multiple Sr sites lead to a broadband emission centered at 565-600 nm and a bandwidth of 128-138 nm.The internal and external quantum efficiencies(IQE/EQE)of the title phosphor are 48.6%and 29.1%under 450 nm excitation,respectively.To improve the accuracy and speed of distinguishing phosphor particles in fired powder mixtures,a microscopic imaging spectroscopy is developed and demonstrated to modify the single-particle-diagnosis method.