Structural and photoluminescence properties of Eu3+ doped alpha-Ag2WO4 synthesized by the green coprecipitation methodology

Autor(es)

Pinatti, Ivo M. ^[1] ; Nogueira, Icamira C. ^[2] ; Pereira, Wyllamanney S. ^[1] ; Pereira, Paula F. S. ^[3] ; Goncalves, Rosana F. ^[4] ; Varela, Jose A. ^[3] ; Longo, Elson ^[3] ; Rosa, Ieda L. V. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Chem, LIEC, INCTMN, BR-13565905 Sao Carlos, SP - Brazil

^[2] PPGEM, IFMA Inst Fed Educ Ciencia & Tecnol Maranhao, Sao Luis, MA - Brazil

^[3] State Univ Sao Paulo, UNESP, Inst Chem, INCTMN, LIEC, BR-14800900 Araraquara, SP - Brazil

^[4] Univ Fed Sao Paulo, UNIFESP, BR-09972270 Diadema, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: DALTON TRANSACTIONS; v. 44, n. 40, p. 17673-17685, 2015.
• Citações Web of Science: 21

Resumo

Europium doped silver tungstates alpha-Ag2-3xEuxWO4 (x = 0, 0.0025, 0.005, 0.0075 and 0.01 mol) were synthesized by the coprecipitation method at 90 degrees C for 30 minutes. These crystals were structurally characterized by means of X-ray diffraction (XRD), Rietveld refinement, and micro-Raman (MR) and Fourier transformed infrared (FT-IR) spectroscopies. Field emission scanning electron microscopy (FE-SEM) images were employed to observe the shape of the crystals. The optical properties were investigated by ultraviolet-visible (UV-vis) absorption and photoluminescence (PL) measurements. The XRD pattern indicated structural organization at a long range for all undoped and Eu-doped samples, while MR and FT-IR revealed that the presence of the Eu3+ ions favors the structural organization at a short range. The Rietveld refinement showed that all the crystals are monophasic with an orthorhombic structure and the Pn (2) over barn space group. The refined lattice parameters and atomic positions were employed to model the WO6 and AgOn (n = 2, 4, 6 and 7) polyhedra in the unit cell. FE-SEM analysis revealed nanorod-like microcrystals with growth of metallic silver on the surface. Further, the UV-vis absorption spectra indicated the existence of intermediary energy levels within the band gap. PL spectra showed a broad band related to the {[}WO6] group and characteristic narrow peaks due to the f-f transitions of Eu3+ as a result of efficient energy transfer from the matrix. Also, the emission line shape transitions from D-5(0) to F-7(J) (J = 0-4) levels of the Eu3+ were noticed. Among the samples, the most intense photoluminescence results were observed for the alpha-Ag2-3xEuxWO4 (x = 0.0075) sample. Lifetime decays support that the Eu3+ ions occupy at least two crystallographic sites. CIE coordinates confirmed the colors of the emission spectra which classify this material as a potential phosphor in the visible range. (AU)

• Processo FAPESP: 13/23995-8 - Síntese do Tungstato de Prata dopado com o Eu3+ e estudo das suas propriedades ópticas, fotoluminescentes e fotocatalíticas
• Beneficiário: Ivo Mateus Pinatti
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 08/57872-1 - Instituto Nacional de Ciências dos Materiais em Nanotecnologia
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs