A study of the structure, luminescence and cytotoxicity of new green-emitting terbium-doped CaS nanophosphors

CaS nanoparticles have attracted significant attention due to their wide range of optoelectronic applications. The synthesis of CaS nanophosphors doped with different terbium concentrations through a simple wet chemical co-precipitation method using triethanolamine (TEOA) as a capping agent is reported here. X-ray diffractogram ensured that the nanoparticles were crystallized in the cubic phase with space group\(Fm\overline{3}m\). Morphology and particle size of the TEOA-capped CaS:Tb nanophosphors were determined using scanning electron microscopy and transmission electron microscopy. The optical properties of the samples were studied by photoluminescence spectroscopy and UV–Vis absorption measurements. The prepared nanoparticles exhibited green luminescence, which is attributed to ⁵D₄–⁷F_J transitions of terbium ions incorporated into the CaS lattice. The existence of various functional groups in the synthesized products was identified by Fourier transform infrared spectroscopy. The lifetime decay measurements showed that the lifetime of the samples was in the nanosecond range. Cytotoxicity analysis of the nanoparticles was carried out on L929 fibroblast cells, which confirmed that the nanoparticles are biocompatible across a wide range of concentrations. Our findings indicate that CaS:Tb nanophosphor could be a potential candidate as a green-emitting phosphor in optoelectronics and biomedical field.