Tunable luminescence of broadband-excited and narrow line green emitting Y2SiO5:Ce3+, Tb3+ phosphor

WOS: 000366940100046Cerium and terbium activated white emitting yttrium silicate phosphors (Y-2-x-yCe(x)Tb(y)SiO(5)) having average size between 96 and 123 nm were synthesised by a gel-combustion, and their phase and crystal structures, morphologies and ultraviolet (UV)-visible spectroscopic properties were studied. All rare earth doped yttrium silicate (YSO) phosphors are well crystallized powders containing only monoclinic X2-Y2SiO5 phase. No significant changes in the cell parameters were observed with increasing of Tb amount as ionic radii of Tb3+ (0.923 angstrom) and Y3+ (0.9 angstrom) have almost the same. Under different excitations, YSO:Ce3+ exhibits blue emission due to the 5d-4f transitions of Ce3+ ions. The series of emission states at different wavelengths of YSO:Tb3+ associated to f-f transition of Tb3+ ion were detected from luminescence measurements. The emission observed at 544 nm (green) corresponding to D-5(4) -> F-7(5) of Tb3+ is strongest one. Incorporation of variable amounts of Tb3+ in the YSO host lattice determines the modification of emission colour from blue through light blue and eventually to bluish green. A possible energy transfer mechanism taking place from Ce3+ to Tb3+ was also discussed in terms of excitation and emission spectra. (C) 2015 Elsevier B.V. All rights reserved

Synthesis and influence of ultrasonic treatment on luminescence of Mn incorporated ZnS nanoparticles

Manganese (Mn) doping of ZnS phosphors was achieved by precipitation method using different ultrasound (US) maturation times. The structural and luminescence properties of the samples were carried out by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), photoluminescence (PL), and cathodoluminescence (CL). The real amount of manganese incorporated in ZnS lattice was calculated based on ICP-OES results. According with XRD patterns, the phase structure of ZnS:Mn samples is cubic. EDS spectra reveal deviations of the Mn dopant concentration from the target composition. Both 300 K PL and CL emission spectra of the Mn doped ZnS phosphors display intense orange emission at 590 and 600 nm, respectively, which is characteristic emission of Mn ion corresponding to a 4T1→6A1 transition. Both PL and CL spectra confirmed manganese is substitutionally incorporated into the ZnS host as Mn2+. However, it is suggested that the origin of broad blue emission around 400 nm appeared in CL is due to the radiative recombination at deep level defect states in the ZnS. The ultrasound treatment at first enhances the luminescent intensity by ∼3 times in comparison with samples prepared by classical way. This study gives rise to an optimization guideline, which is extremely demanded for the development of new luminescent materials.This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCS – UEFISCDI, project number PN-II-RU-TE-2014-4-1391.Peer Reviewe

Synthesis and influence of ultrasonic treatment on luminescence of Mn incorporated ZnS nanoparticles

Manganese (Mn) doping of ZnS phosphors was achieved by precipitation method using different ultrasound (US) maturation times. The structural and luminescence properties of the samples were carried out by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), photoluminescence (PL), and cathodoluminescence (CL). The real amount of manganese incorporated in ZnS lattice was calculated based on ICP-OES results. According with XRD patterns, the phase structure of ZnS:Mn samples is cubic. EDS spectra reveal deviations of the Mn dopant concentration from the target composition. Both 300 K PL and CL emission spectra of the Mn doped ZnS phosphors display intense orange emission at 590 and 600 nm, respectively, which is characteristic emission of Mn ion corresponding to a 4T1→6A1 transition. Both PL and CL spectra confirmed manganese is substitutionally incorporated into the ZnS host as Mn2+. However, it is suggested that the origin of broad blue emission around 400 nm appeared in CL is due to the radiative recombination at deep level defect states in the ZnS. The ultrasound treatment at first enhances the luminescent intensity by ∼3 times in comparison with samples prepared by classical way. This study gives rise to an optimization guideline, which is extremely demanded for the development of new luminescent materials. © 2017 Elsevier B.V