Effects of In³⁺ doping concentration on the structural, morphological and photoluminescence properties of x% In³⁺:MgAl₂O₄ nanophosphor prepared via citrate sol-gel method

A series of nanocrystalline (0 ≤ x ≤ 1.25%) x% In³⁺:MgAl₂O₄ (IMAO) phosphor powders have been successfully prepared via citrate sol-gel technique. The x-ray diffraction (XRD) results indicated that the IMAO consists of the cubic phase and average crystallite sizes was found to be 9 nm. Scanning electron microscopy (SEM) revealed that the In³⁺ concentration influences the phosphor morphology. Ultraviolet-visible (UV-vis) results showed that the reflectance and absorption of the IMAO depends on the In³⁺ concentration. The prepared samples exhibited the emission at 395 nm, which is attributed to the defects within the host material. The optimum emission intensity was observed at x = 0.3% In³⁺. The critical distance (R_c) calculation suggested that the concentration quenching occurs due to the multipole-multipole interaction. The Commission Internationale de l'Elcairage (CIE) diagram revealed that varying the In³⁺ concentration does not influence the emission colour.