Order and disorder around Cr$^{3+}$ in chromium doped persistent luminescence AB$_2$O$_4$ spinels

Neelima Basavaraju; Kaustubh R. Priolkar; Didier Gourier; Aurélie Bessière; Bruno Viana

doi:10.1039/c5cp01097g

paper

Order and disorder around Cr $^{3 +}$ in chromium doped persistent luminescence AB $_{2}$ O $_{4}$ spinels

arXiv:1503.07979 · doi:10.1039/c5cp01097g

Abstract

X-ray absorption near edge structure (XANES) spectroscopy technique is used to better understand the charging and decharging processes of the persistent luminescence in the Cr $^{3 +}$ doped AB $_{2}$ O $_{4}$ spinels (A = Zn, Mg and B = Ga and Al) with low photon energy excitation by visible light. Cr K edge XANES spectra have been simulated for different near neighbour environments around the Cr $^{3 +}$ recombination centres and compared with the experimental curve. In Cr $^{3 +}$ :ZnGa $_{2}$ O $_{4}$ compound, the Cr $^{3 +}$ local structure corresponds mostly to that of a normal spinel ( $\sim$ 70\%), while the rest comprises of distorted octahedral environment arising from cationic site inversion and a contribution from chromium clustering. This local structure is strongly different in Cr $^{3 +}$ :MgGa $_{2}$ O $_{4}$ and Cr $^{3 +}$ :ZnAl $_{2}$ O $_{4}$ where, for both cases, chromium clustering represents the main contribution. The strong correlation between the intensity of persistent luminescence and \% of Cr in clusters leads us to infer that presence of Cr clusters is responsible for decrease of the intensity of the visible light induced persistent luminescence in the Cr $^{3 +}$ doped AB $_{2}$ O $_{4}$ spinels.

in Phys. Chem. Chem. Phys. (2015)

Order and disorder around Cr3+ in chromium doped persistent luminescence AB2​O4​ spinels

Abstract

References in corpus (2)

Order and disorder around Cr $^{3 +}$ in chromium doped persistent luminescence AB $_{2}$ O $_{4}$ spinels