Banca de DEFESA: ITALO ALEFI LIMA DOS SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE: ITALO ALEFI LIMA DOS SANTOS
DATA: 14/02/2025
HORA: 10:00
LOCAL: Remota (On-line)
TÍTULO: Síntese, propriedades estruturais, vibracionais e elétricas do trióxido de molibdênio (α-MoO3) dopado com Ag e Al
PALAVRAS-CHAVES: α-MoO3. Doping. Ag and Al. Electrical Properties.
PÁGINAS: 57
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
RESUMO:

In this work, we present the result of the synthesis and characterization of pure
α-MoO3 and doped with different concentrations of silver (Ag) and aluminum
(Al) by thermal decomposition of ammonium heptamolybdate in the solvents:
acetone, isopropyl alcohol and methyl alcohol, for times of 2, 4 and 6 hours of
calcination at a temperature of 350 oC. The structural analysis performed by X-
ray diffraction (XRD) confirmed the stable and single-phase orthorhombic phase
of the α-MoO3 samples with successful doping. Quantitative analysis of the
diffraction patterns was performed through Rietveld refinement, identifying the
action of the dopant on the lattice parameters of the crystal structure. After the
incorporation of Ag and Al into α-MoO3, changes in vibrational modes were
identified using Raman spectroscopy and Fourier transform infrared
spectroscopy (FTIR), respectively. UV-Vis diffuse reflectance spectroscopy(DRS) was used to evaluate the optical properties, highlighting the bandgap
variation of the samples, which was between 3.1 and 3.4 eV. The electrical
properties demonstrated that the samples behave as semiconductors, with
those with a lower dopant concentration (1.0% Ag and 0.5% Al) presenting a
better electrical response compared to the pure sample.

MEMBROS DA BANCA:
Interno - 2056226 - CLEANIO DA LUZ LIMA
Externo ao Programa - 689.***.***-04 - EDIOMAR COSTA SERRA - UEMA
Externo à Instituição - 584.***.***-34 - FRANCISCO FERREIRA DE SOUSA - UFPA
Presidente - 1720015 - GARDENIA DE SOUSA PINHEIRO
Interno - 048.***.***-71 - GUSTAVO OLIVEIRA DE MEIRA GUSMÃO - UESPI