The elemental composition and XRD profiles of the Zn(Tb)S and the Zn(Tb)S NPs that are post-synthetically modified by varying concentrations of Cd²⁺ are shown in panels (a) and (b), respectively. Panel (b) also includes the XRD profile for the Cd(Tb)S NPs. The trend of lattice parameters as a function of composition of the NPs is shown in panel (c). Panels (d) – (g) summarize the luminescence excitation and emission spectra. The trend in Tb³⁺ emission quantum yield is shown in panel (h). Panels (i) and (j) summarize the trends in shorter lifetime component and average lifetime of the broad emission. Panel (k) shows the relative contributions of shorter-lived surface related and longer-lived core related Tb³⁺ emission components in these NPs. (Adapted with permission from Reference [105], Copyright 2019 American Chemical Society).