Figure 1

Atomic structure of (a) the α′-SSO phase (orthorhombic) and (b) the β-SSO phase (monoclinic) upon Eu3+-doping in the SSO host matrix [Drawn using VESTA software after considering the SSO raw crystallographic files (https://www.materialsproject.org/)]; (c) XRD patterns of synthesized SSO:xEu3+ phosphors with various concentrations of Eu3+ ions and reference spectra of SSO, SCO, SiO2 and Eu2O3 with the JCPDS pattern. The bottom panel shows XRD data for the SSO:xEu3+ phosphor (x = 5.0%) and calculations of the crystal structure made using GSAS software.