Banca de DEFESA: FLÁVIA SANTOS DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : FLÁVIA SANTOS DA SILVA
DATE: 29/04/2024
TIME: 14:00
LOCAL: REMOTO
TITLE:

Synthesis and Characterization of carbon dots multicolored from 1,3,6 Trinitropyrene

KEY WORDS:

Carbon nanodots; fluorescence; solvatochromism; solar cells.

PAGES: 85
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Inorgânica
SUMMARY:

The Carbon Dots (CDs) are zero-dimensional fluorescent nanomaterials that have physical, chemical and optical characteristics that make these materials potential for application in various areas, such as biomedical, environmental and energy conversion. Recent studies seek to understand the luminescence mechanism of these materials and the influence of property parameters on the properties of these materials, to make the properties more predictable and result in Carbon Dots with interesting properties. In the present work, the synthesis of Carbon Dots was carried out using the precursor of 1,3,6 - Trinitropyrene, previously synthesized through the nitration of pyrene, the synthesis of CDs was carried out using the solvothermal method, varying two synthesis parameters, the first parameter was the synthetic time, varying in 2 h, 6 h and 12 h of occurrence for each synthesis and the second parameter was the synthesis solvent. Toluene, N, N dimethylformamide and a mixture between N, N dimethylformamide and water in a 2:1 ratio, variations of these settings resulted in 9 samples. Structural and optical characterization of the CDs obtained was carried out. The CDs were dispersed in different solvents and it was found that there was a solvatochromic effect in the samples with deviations in the emission wavelengths with the variation in the polarity of the solvents in which the CDs were dispersed. They were tested on solar cells, but these did not yield significant results, possibly due to CD not being well adsorbed to TiO2 after sensitization, which can be attributed to the absence of good functional groups to anchor CD to TiO2. The Carbon Dots presented quantum yields ranging from 18.8% to 58.9%, emissions at different wavelengths were observed in the CDs both with the variation of the synthesis solvent and with the variation of the solvent used to disperse the Carbon Dots after syntheses. The effect of synthetic time was mainly observed in the XRD patterns of the samples, indicating that the different synthetic times lead to important changes in the nanoparticle core. It was confirmed that the choice of synthetic and post-synthetic configurations are of great relevance for adjusting the properties of Carbon Dots.

BANKING MEMBERS:
Externa à Instituição - ELLEN RAPHAEL - UEA
Externo à Instituição - JEFFERSON LUIS FERRARI - UFU
Presidente - 1443844 - MARCO ANTONIO SCHIAVON