Optical transition probabilities of white light emitting Sr2SiO4:Dy3+ nanophosphors for lighting applications using Judd-Ofelt analysis

Dysprosium doped strontium silicate (Sr2-xSiO4:xDy(3+), x = 0-7 mol%) are prepared by solution combustion synthesis and their luminescent behaviour is investigated. X-ray diffraction (XRD) reveals the structure to be orthorhombic in nature and different structural parameters are calculated. The photoluminescence excitation and emission spectra are thoroughly discussed. The emission spectra excited at 350 nm showed the characteristic blue and yellow emission, the admixture of which gives probable white emission. Further, the absorption spectrum is used to systematically study the spectral intensities of Sr2-xSiO4:xDy(3+) (x = 0.008) nanophosphors using Judd-Oflet (JO) theory. The JO parameters thus obtained followed the trend Omega(2) > Omega(6) > Omega(4) that revealed the field surrounding the ions lack inversion symmetry and is also confirmed by asymmetric ratios. JO parameters are also used to study different radiative properties. The magnitude of the calculated peak emission cross section for the transition F-4(9/2) -> H-6(13/2) is 1.02 x 10(-20) cm(2), a value suitable for laser applications. An energy transfer quenching mechanism indicates that the mode of non-radiative transition is dominated by dipole-dipole interactions. Color coordinates and color correlated temperature with respect to different Dy3+ concentrations are studied in detail.