Altering of the Electric and Magnetic Dipole Transition Probability of Eu3+ in YPO4 Lattice by Codoping of K+ Ion: Potential Materials for Imaging and Heating

Aqueous, dispersible, luminescent YPO4:Eu3+-K+ and hybrid magnetic-luminescent Fe3O4@YPO4:Eu3+-K+ nanoparticles are prepared at an optimum temperature with a simple synthesis route. The shape of YPO4:Eu3+-K+ nanoparticles is found to be nanorods. Photoluminescence spectrum of a sample upon excitation at 395 nm shows the characteristic peaks of Eu3+ such as magnetic-dipole transition (D-5(0)?->?F-7(1)) at 592 nm, the electric-dipole transition (D-5(0)?->?F-7(2)) at 615 nm, and electric-dipole transition (D-5(0)?->?F-7(4)) at 695 nm. Luminescence intensity increases with K+ doping. Interestingly, their luminescence intensities are almost the same. This could be explained by the polarizability effect of the PO43- group and K+ upon emission of Eu3+. This high intensity at 695 nm will be useful in bioimaging since this wavelength falls in biological window I. This hybrid material shows a hyperthermia temperature under an AC magnetic field, making this material a potential candidate for cancer therapy.