Banca de QUALIFICAÇÃO: ANDERSON SELTON SILVA DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : ANDERSON SELTON SILVA DOS SANTOS
DATE: 31/01/2024
TIME: 09:00
LOCAL: Google Meet
TITLE:

Synthesis of temperature luminescent ratiometric nanosensors based on ZnS:Mn and carbon dots

KEY WORDS:

Semiconductors, nanocomposites, nanothermometry, nanoparticles

PAGES: 60
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

The increasing search for new technologies that can respond to the continuous demands of the world market for temperature sensors is driving research and scientific advances in various areas, especially luminescent
nanomaterials and their compounds with ratiometric emission. In this sense, this work evaluated the structural and optical properties of nanocomposites based on manganese-doped zinc sulphide (ZnS:Mn) and carbon dots (CD) derived from lemon peels (CD-L). The materials were synthesized via coprecipitation at room temperature. CD-L and the ZnS:Mn systems had a spherical morphology and an average size of less than 10 nm. X-ray diffraction (XRD) studies revealed a cubic crystal structure for manganese-doped ZnS, and the incorporation of CD-L does not significantly affect the profile of the main crystallographic planes. The optical properties were also analyzed using diffuse reflectance spectroscopy (DRS), which showed a profile similar to that of the ZnS:Mn host, with a maximum absorption band around 270 nm. In addition, the nanocomposites exhibited dual emission, with maximum fluorescence centered at 594 nm, characteristic of the 4T1 ⟶ 6A1 transitions of the Mn2+ ion in the ZnS matrix, and at 440 nm relative to the CD-L emission. The preliminary results of the thermometric studies for the nanosystems studied, ZnS:Mn(1.0)/CD2 and ZnS:Mn(1.0)/CD4, showed a ratiometric response for use as luminescent nanothermometers, showing that the proposed nanocomposites are strong candidates for nanoscale temperature
sensing.

COMMITTEE MEMBERS:
Externo(a) ao Programa - 1247925 - ANIELLE CHRISTINE ALMEIDA SILVA - nullPresidente - 1869296 - CINTYA D'ANGELES DO ESPIRITO SANTO BARBOSA
Externo(a) à Instituição - FAUSTHON FRED DA SILVA - UFPB
Externo(a) ao Programa - ***.790.304-** - RODRIGO DA SILVA VIANA - UFAL
Interno(a) - 1515173 - SIMONI MARGARETI PLENTZ MENEGHETTI