Banca de QUALIFICAÇÃO: ANDERSON DE AZEVEDO GOMES SANTIAGO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : ANDERSON DE AZEVEDO GOMES SANTIAGO
DATA : 08/06/2017
HORA: 14:00
LOCAL: Sala de aulas do PPGCEM
TÍTULO:

Characterization of the photoluminescent properties of Ba1-xZnxMoO4 synthesized by the ultrasonic pyrolysis spray method

PALAVRAS-CHAVES:

barium molybdate; zinc molybdate; ultrasonic spray pyrolysis; and photoluminescence.

PÁGINAS: 60
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
ESPECIALIDADE: Cerâmicos
RESUMO:

Ba1-xZnxMoO4 (x=0, 0.25, 0.5, 0.75 and 1) powders were synthesized by the ultrasonic pyrolysis spray method, using temperatures of 1000°C and 1100°C. The samples were structurally characterized by the X-ray diffraction technique and morphologically by scanning electron microscopy field emission (SEM-FEG). The optical properties of the samples were studied using Uv-Visible spectroscopy and photoluminescence spectroscopy (PL). The XRD showed that the powders of 0≤x≤0.75 have tetragonal Scheelite crystalline structure of BaMoO4. While powders with x = 1, have triclinic structure of α-ZnMoO4. SEM-FEG micrographs demonstrated that the particles have predominant spherical morphology, varying the particle diameter between 0.1 and 1.5 μm. The gap energies vary between 4.56 eV and 4.17 eV, due to the structural disorder generated by the oxygen vacancies and the displacement of the Mo atoms, promoted by the increase of the intermediate intervals between the conduction and valence bands. The PL emission spectra of the powders have a predominance in the red region, caused by the formation of a mixture of [MoO3] and [MoO4] clusters interspersed by Ba atoms and distortions of [MoO4] clusters.

MEMBROS DA BANCA:
Interno - 1802888 - FABIANA VILLELA DA MOTTA
Presidente - 1883170 - MAURICIO ROBERTO BOMIO DELMONTE
Externo à Instituição - RICARDO LUÍS TRANQUILIN - UFRN