Banca de DEFESA: ADRIANO ALMEIDA DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE: ADRIANO ALMEIDA DA SILVA
DATA: 15/02/2024
HORA: 14:00
LOCAL: Presencial - AUDITÓRIO DA FÍSICA/CCN
TÍTULO: Investigação das propriedades térmo-ópticas de nanopartículas de ouro e prata obtidas por síntese verde a partir do extrato da folha de anacardium occidentale l. (cajueiro).
PALAVRAS-CHAVES: nanopartículas metálicas; síntese verde; propriedades ópticas; lente térmica; varredura Z
PÁGINAS: 46
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
RESUMO:

Abstract:The study of metallic nanostructures with gold (Au) and silver (Ag)
nanoparticles has currently aroused interest, due to their high surface area due
to their manometric size, with high potential for application in several areas.
Nanoparticles exhibit properties that depend on their size, geometry, and
volume fraction, and can be used in different applications, such as electronic
devices, biosensors, photocatalysis, photodynamic and photonic therapy. In this
work, the thermo-optical properties of gold nanoparticles (AuNPs) and silver
(AgNPs) in different concentrations, prepared through green synthesis, using
the leaf extract of Anacardium occidentale L. (cashew tree) were investigated.
UV-Vis, DLS, TEM, Thermal Lens and Z-scan techniques were used for
characterization. The formation of nanoparticles was confirmed through the
presence of localized surface plasmon resonance bands (RPSL), characteristic
of metallic nanostructures. DLS measurements showed that the nanoparticles
have a hydrodynamic diameter below 55 nm and high stability due to their
surface potential of -17.8 mV. In studies of thermo-optical properties, AgNPs
showed an increase in thermal diffusivity with increasing concentration. On the
other hand, AuNPs showed a reduction in this parameter with increasing
concentration, so AgNPs and AuNPs can be used to control thermal diffusivity
in nanofluids. From the Z-scan technique, it was observed that the nonlinear
refractive index is amplified with the increase in intensity of the RPSL peak, and
the nonlinear absorption of two photons. Therefore, the investigated parameters
indicated that gold and silver nanoparticles are good heat conductors and can
be applied in thermal sinks.

MEMBROS DA BANCA:
Presidente - 1780191 - FRANCISCO ERONI PAZ DOS SANTOS
Externo ao Programa - 048.317.544-71 - GUSTAVO OLIVEIRA DE MEIRA GUSMÃO - UESPI
Externo ao Programa - 064.149.554-42 - SUZIETE BATISTA SOARES GUSMÃO - UFPI
Externo à Instituição - RENATO BARBOSA COSTA - UPE