Figure 2

(a) Vis-NIR long persistent phosphorescence spectrum of ZnGa2O4: Cr/Nd phosphor. The inset shows a conjectural doping pattern of Cr and Nd. (b) XRD patterns for ZnGa2O4: xCr (x = 0.5% and 10%) and ZnGa2O4: xNd (x = 0.5% and 5%) phosphors. (c) Dependence of XRD peak ([PI] labeled in Fig. 2b) position and intensity as a function of Cr and Nd concentration in ZnGa2O4 phosphor. (d–e) 71Ga solid state NMR spectra of ZnGa2O4: xCr (x = 0.5% and 10%) and ZnGa2O4: xNd (x = 0.5% and 10%) samples. All spectra were recorded at a magnetic field of 11.7 T with a sample spinning frequency of 25 kHz.