Synthesis and characterization of rare earth doped ternary spinel matrices using non ceramic routes for luminescent and bio medical applications

Abstract

Synthesis techniques do significantly influence the optical, magnetic, electronic and catalyticproperties of materials, particularly in the nanometric dimension. The prime motive of the presentwork was to check the feasibility of three non-refractory routes - co-precipitation, hydrothermaland auto-combustion – to facilitate nanophosphor synthesis at temperatures well below 1000 oC.Structural, morphological, and optical properties were investigated using X-ray diffraction(XRD), fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM),scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), photoluminescence(PL), and colorimetric analysis.Optimization of synthesis parameters such as temperature and duration of synthesis, pH, post-calcination temperature, etc. were done for all the three synthesis routes in pure ZnAl2O4.Further, the influence of Eu3+ and Tb3+ doping on luminescent behaviour of the ternary spinelwere explored. The study also probed into the possibility of generating a white emission, throughco-doping in ZnAl2O4 matrix, thereby enhancing the material potential for use in lighting anddisplay technologies. The viability of the green auto-combustion procedure, using Moringa oleiferaleaf extract as the natural fuel, was extended towards synthesis of other AB2O4 spinel systems (A– Zn, Mg; B – Al, Cr).Beyond luminescence, the synthesized pristine ZnAl2O4, prepared via the three routes, wereevaluated for photocatalytic degradation of methylene blue dye, where catalyst dosage and pHplayed critical roles. Biomedical potential was examined through in-vitro cytotoxicity analysisagainst Dalton’s lymphoma ascites (DLA) and normal spleen cells. The photocatalytic, cytotoxic,and anti-bacterial response against E. coli. of selected green systems were also done.Overall, the study demonstrates the versatility of rare earth-doped spinel matrices synthesized vianon-ceramic and green routes, underscoring their applicability in luminescent devices,photocatalysis, and biomedical systems. Future recommendations include exploring alternativedopants and microwave assisted synthesis, extending the eco-friendly approach to other spinelsystems, and broadening applications across advanced functional materials.