Banca de QUALIFICAÇÃO: IAGO RAMON DE VASCONCELOS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : IAGO RAMON DE VASCONCELOS
DATE: 14/09/2022
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

ELECTROSYNTHESIS OF SILVER SULFIDE QUANTUM DOTS FOR NANOTHERANOSTICS APPLICATIONS

KEY WORDS:

Quantum Dots; Infrared regio; Cavity cell; Coating; Photothermia.

PAGES: 91
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

In this work, to enhance the diagnosis of tumors by fluorescence and treatment by photothermy, silver sulfide (Ag2S) quantum dots (QDs) were synthesized via electrochemistry using a cavity cell, where the optical properties of the nanocrystals were modulated through the variation of the Ag+/S2- molar ratio and the time of heat treatment after the electrosynthesis. The results obtained point to the successful obtaining of Ag2S QDs, with optical emission in the near infrared region, in wavelengths that varied between em 735 to 916 nm for the proportions 1:1 and 1:4 (Ag+/S2-), respectively. The nanocrystals showed an average diameter ranging between 4.2 nm and 5.5 nm, with a monoclinic crystal structure confirmed by X-ray diffractogram (XRD). Electron diffraction analyzes (SAED) were also performed and interplanar distances were determined by high resolution transmission electron microscopy (HRTEM). When the Ag2S QDs were laser irradiated in the near infrared region (exc = 785 nm), they showed a photothermal response ranging from 27ºC for Ag2S (ratio 6:1) to a maximum of 39ºC (ratio 1:1) when covered with zinc selenide seeds (Ag2S@ZnSe). The proposed system represents a green path for the production of promising nanosystems for application in nanotheranostics, through the electrochemical route and compositional engineering, combining a lower environmental impact with an increase in system efficiency.

BANKING MEMBERS:
Externo à Instituição - CICERO INÁCIO DA SILVA FILHO
Interna - 519.487.700-59 - GIOVANNA MACHADO - UFRGS
Presidente - 1354207 - SEVERINO ALVES JUNIOR