Luminescence characteristics of Bi3+, Cr3+ and Bi3+/Cr3+ activated Sr3Y2Ge3O12 phosphors

A series of Sr3Y2Ge3O12 based phosphors were prepared by a solid-state-reaction method. Their phase, microstructure and luminescence characteristics were investigated. The XRD patterns indicate the cubic phase of the prepared phosphors. The elemental mapping images indicate that the elements distribute homogeneously in the prepared phosphors. Upon the ultraviolet light excitation, the Bi3+ activated Sr3Y2Ge3O12 phosphors show narrow cyan emission. Upon the blue light excitation, the Cr3+ activated Sr3Y2Ge3O12 phosphors show broad NIR emission. Energy transfers from Bi3+ to Cr3+ occur in the Bi3+/Cr3+ coactivated Sr3Y2Ge3O12 phosphors, which leads to the generation of NIR emission upon the ultraviolet light excitation.