Low-temperature Co-precipitation Synthesis of ZnAl2O4 Nanophosphors Probing Its Luminescent, Antibacterial and Anticancer Potentials

Metal nanoparticles and their binary oxides are well-known for their interactions with biomolecules and their applications in the biomedical field. However, the potential of ternary oxide nanophosphors remains underexplored in these fields due to challenges associated with high-temperature synthesis procedures and the use of toxic chemicals. ZnAl2O4, a ternary oxide matrix, being recognized for its adjustable wide bandgap, impressive surface properties, mechanical strength, thermal stability, and high quantum yield, is chosen for the present work. This study aims to comprehensively investigate the structural, morphological, optical, and cytotoxic properties of zinc aluminate nano phosphors synthesized through a co-precipitation method followed by low-temperature calcination. Analysis using X-ray diffraction spectroscopy (XRD) and Fourier-transform infrared spectroscopy (FTIR) revealed that the formation of the ZnAl2O4 spinel phase initiates at 300 °C and completes at 750 °C.SEM-EDAX measurements provided further confirmation of the compositional integrity of the synthesized sample. The average crystallite size, determined to be 11.47 nm through a W–H plot, along with a higher bandgap value of 4.49 eV compared to bulk ZnAl2O4 from the diffuse reflectance spectra (DRS), attests to the success of the nanophosphor synthesis. The self-activated blue luminescent centers of ZnAl2O4 can be fine-tuned to emit light in the green and red regions of the electromagnetic spectrum through appropriate rare earth (RE) doping, utilizing Tb3+ and Eu3+ respectively. Furthermore, the particles underwent short-term in-vitro cytotoxicity testing using Dalton’s Lymphoma Ascites cells (DLA) and normal cells, demonstrating high activity against DLA cells while maintaining compatibility with normal cells.