Fabrication of red-emitting Eu3+-induced CaS phosphors: a view of optical, in vitro, lifetime, structural and morphological studies for biomedical applications

In the present study, different concentrations of Europium-doped calcium sulfide nanocrystals were synthesized by the simple sol–gel method. Structural properties were analyzed by powder X-ray diffraction studies. Surface morphology was analyzed by atomic force microscopy. The optical band gap was calculated from a Tauc plot drawn from diffuse reflection spectroscopy data. Optical properties were analyzed from photoluminescence spectroscopy, and the peaks were obtained in the visible region with a wavelength in the order of ~ 640 nm. The average lifetime was calculated from the time-resolved fluorescence spectroscopy. The hemocompatibility test results revealed the biocompatible nature of the samples.