Navegando por Autor "Barros, Bráulio S."
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Artigo Tb3+/Pr3+ co-doped ZnMoO4 phosphor with tunable photoluminescence and energy transfer processes(Elsevier, 2019-10) Paskocimas, Carlos Alberto; Delmonte, Maurício Roberto Bomio; Lovisa, Laura Ximena; Fernandes, Y.L.R.L.; Garcia, Laurênia Martins Pereira; Barros, Bráulio S.; Silva, Elson Longo da; Motta, Fabiana Villela daZnMoO4:Tb3+, Pr3+ particles in different Tb:Pr ratios (2:0, 1.5:0.5, 1:1, 0.5:1.5 and 0:2) were synthesized by the sonochemical method. These materials were characterized structurally, morphologically and optically by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Ultraviolet–visible absorption spectroscopy and Photoluminescence (PL). From studying the photoluminescent properties, the PL spectra presented 5 D4 → 7 Fj (j = 6, 5, 4 and 3) transitions bands of Tb3+, along with the transitions 3 P0 → 3 H5, 1 D2 → 3 H4, 3 P0 → 3 H6 and 3 P0 → 3 F3 of Pr3+. Time resolved photoluminescence was investigated and an energy transfer (n) mechanism between the matrix and the Tb3+ and Pr3+ ions is simultaneously proposed for better understanding the process efficiency. Parallel to this perspective, the photocatalytic behavior of ZnMoO4:Tb3+, Pr3+ was evaluated. The degradation of methylene blue dye was favored by the effect of increasing the Pr3+concentration. This work deals with the development of inorganic phosphor materials capable of converting UV radiation into light-emitting diode, which can be suitably combined to produce white lightArtigo White light emission from single-phase Y2MoO6: xPr3+ (x = 1, 2, 3 and 4 mol%) phosphor(Elsevier, 2018-11-15) Paskocimas, Carlos Alberto; Lovisa, Laura Ximena; Santiago, Anderson de Azevedo Gomes; Farias, M.B.; Barros, Bráulio S.; Silva, Elson Longo da; Li, Maximo Siu; Delmonte, Maurício Roberto Bomio; Motta, Fabiana Villela daA series of Pr3+ doped with Y2MoO6 was synthesized using the co-precipitation method and the structural, photoluminescent and morphological properties of XRD, scanning electron microscopy (SEM) and photoluminescence spectrometry were investigated. The most intense absorption of its host matrix occurred between 200 and 340 nm due to a charge transfer in O → Mo. The photoluminescence emission results of Y2MoO6: x%Pr3+particles showed some white emission due to a strong contribution of the matrix and the Pr3+dopant. All samples exhibited high color rendering index (>90%), indicating that the light source can reproduce colors. It was possible to obtain a white-emitting single-phase luminescent material from an easy route of production. The investigation indicated that Y2MoO6: x%Pr3+ is a potential candidate for applications with white light emitting diodes