Structural and optical properties of iron ions doped near-infrared persistent spinel-type phosphors

In this work, a series of iron ions doped spinel-type compounds AB(2)O(4) were prepared by high temperature solid phase reactions. The phase compositions of all the samples were analyzed using X-ray diffraction (XRD). Thermoluminescence (TL), and persistent luminescence spectra were collected systematically to reveal the trapping and de-trapping processes. Photoluminescence (PL) bands in the near-infrared luminescence band (600-900 nm) were observed for all the Fe3+-doped spinel-type structured materials. It was demonstrated that MgGa2O4:Fe3+ sample showed the best persistent luminescence (PersL) performance among the compounds studied. X-ray Photo Electron Spectroscopy (XPS) and Electron Paramagnetic Resonance Spectroscopy (EPR) tests reveal that the dopant Fe ions have a greater probability of occupying the octahedral sites than tetrahedral sites. Thanks to its long persistence, MgGa2O4:Fe3+ has the potential to be used in the biological or agricultural related applications.