Laishram Priyobarta S, Ningthoujam Premananda S and Thiyam David Singh
The enhancement of the luminescence intensity of the Dy3+ by Ba2+ ions (at different concentrations) codoping into YVO4:2Dy nanoparticles at different annealing temperature of as-prepared, at 500 and 900°C were studied. The XRD study shows the strains are induced when dopant and codopant are incorporated into host matrix. XRD patterns of nanohybrids show the existence of two phases corresponding to YVO4:2Dy and Fe3O4 nanoparticles. TEM image of YVO4:2Dy nanoparticles were spherical shape whereas for YVO4:2Dy/Fe3O4 nanohybrids, the spherical particles are forming chain like structure due to the PEG molecule which binds both YVO4:2Dy and Fe3O4 during nanohybrids formation. Increase in absorption coefficient and decrease in lattice strain values are the major reasons for the enhancement of emission intensity in photoluminescent (PL). Lifetime studies also shows correlation between the calculated energy transfer and diffusion for indirect excitation which is also studied here. High quantum efficiency up to 45% can be achieved. YVO4:2Dy/Fe3O4 nanohybrids is found to achieve hyperthermia temperature 42°C in short time. This nanohybrids shows luminescence in the region of biological window indicating nanohybrids can be used as bioimaging probe. It also shows high viability up to 94% in HeLa cancer cells.