Effect of Dopant Concentrations on the Luminescent Properties of LiAl5O8:Fe Phosphors

The structural and optical properties of pure and Fe‐doped LiAl 5 O 8 are investigated using the modified sol–gel method, using anhydrous glucose as the polymerizing agent. The structural and optical properties are identified using X‐ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and X‐ray excited optical luminescence (XEOL). The XRD diffraction patterns confirm the formation of a LiAl 5 O 8 phase with different Fe concentrations. The effect of Fe 3+ ions as a dopant on the luminescent properties of LiAl 5 O 8 is studied and is discussed in detail. The results reveal a red emission upon excitation at 267 and 391 nm. A maximum emission intensity is observed for 1 mol% of Fe. PL and XEOL emission spectra exhibit 4 T 1g ( 4 G) → 6 A 1g ( 6 S) and 4 E 1g + 6 A 1g ( 4 G) → 6 A 1g ( 6 S) transitions typical of the Fe 3+ ion. In addition, an 2 E → 4 A 2 transition centered at ≈714 nm is attributed to the presence of Cr 3+ ions in the host lattice as a contaminant in starting materials. The coordinated Commission Internationale de l'Eclairage (CIE) is calculated from the emission spectra, and points to the possibility of applying this study as a red–pink emitting match.