Ion beam induced luminescence studies of sol gel derived Y2O3:Dy3+ nanophosphors

Pure and Dy3+ doped Y2O3 are prepared by sol-gel technique. The samples are annealed at 900 °C to obtain crystalline phase. X-ray diffraction (XRD) patterns confirm cubic phase of Y2O3. The crystallites size is calculated using Scherrer formula and is found to be in the order of 29.67 nm. The particles are found to be spherical in nature and their sizes are estimated to be 35 nm by scanning electron microscope (SEM) technique. Online ionoluminescence (IL) spectra of pure and Dy3+ doped Y2O3 are recorded with 100 MeV Si8+ ions with fluence in the range 0.375-6.75×1013 ions cm−2. Undoped samples do not show IL emission for any of the fluence explored. Four prominent IL emissions with peaks at 488, 670, 767 nm and a prominent pair at 574 and 584 nm are observed in Dy3+ doped samples. These characteristic emissions are attributed to luminescence centers activated by Dy3+ ions due to 4F9/2→6H15/2, 4F9/2→6H11/2,4F9/2→6H9/2+6H11/2 and 4F9/2→6H13/2 transitions respectively. Further, it is found that IL intensity at 574 nm decays rapidly with ion fluence. A broad and weak photoluminescence (PL) emission with peak at ~485 nm and a strong emission at 573 nm are observed in ion irradiated Y2O3:Dy3+. It is found that PL intensity increases with ion fluence up to 3×1010 ions cm−2 and then it decreases with further increase of ion fluence. This may be attributed to lattice disorder produced by dense electronic excitation under swift heavy ion irradiation.