Li-self doping effect on the LiAl5O8 luminescent properties

The influence of Li self-doping effect on the structural and optical properties of LiAl5O8 was investigated. X-ray diffraction (XRD) results indicated the samples present high crystalliny degree and single crystalline phase. Scanning Electron Microscopy (SEM) images showed nanosized particles disposed in agglomerates. X-ray Absorption Near Edge Spectroscopy (XANES) indicated that the Al local geometry is similar for both sets of samples, independent on the Li excess. X-ray Fluorescence (XRF) mapped intrinsic contaminants (Fe and Cr) from the precursors. Photoluminescence (PL) and X-ray Excited Optical Luminescence (XEOL) emission spectra presented broad bands and transitions associated with Fe3+, Cr3+ and defects from the host. XEOL excitation spectra presented positive edge and luminescent grow tendency with the increase of the excitation energy around the Al K-edge. The observed optical transitions by the excitation with X-rays, ultraviolet and visible were more expressive in the red/near infrared range.