Stimulation of cysteine-coated CdSe/ZnS quantum dot luminescence by meso-tetrakis (p-sulfonato-phenyl) porphyrin
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2018
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Interaction between porphyrins and quantum dots (QD) via energy and/or charge transfer is usually accompanied
by reduction of the QD luminescence intensity and lifetime. However, for CdSe/ZnS-Cys QD water solutions, kept
at 276 K during 3 months (aged QD), the significant increase in the luminescence intensity at the addition of meso tetrakis (p-sulfonato-phenyl) porphyrin (TPPS4) has been observed in this study. Aggregation of QD during the storage
provokes reduction in the quantum yield and lifetime of their luminescence. Using steady-state and time resolved fluorescence techniques, we demonstrated that TPPS4 stimulated disaggregation of aged CdSe/
ZnS-Cys QD in aqueous solutions, increasing the quantum yield of their luminescence, which finally reached
that of the fresh-prepared QD. Disaggregation takes place due to increase in electrostatic repulsion between QD at
their binding with negatively charged porphyrin molecules. Binding of just four porphyrin molecules per single QD
was sufficient for total QD disaggregation. The analysis of QD luminescence decay curves demonstrated that
disaggregation stronger affected the luminescence related with the electron-hole annihilation in the QD shell.
The obtained results demonstrate the way to repair aged QD by adding of some molecules or ions to the
solutions, stimulating QD disaggregation and restoring their luminescence characteristics, which could be
important for QD biomedical applications, such as bioimaging and fluorescence diagnostics. On the other
hand, the disaggregation is important for QD applications in biology and medicine since it reduces the size
of the particles facilitating their internalization into living cells across the cell membrane.
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Luminescence stimulation, Electrostatic interaction, Cysteine-coated quantum dot, Disaggregation, TPPS4 porphyrin
Citação
G. PARRA, Gustavo et al. Stimulation of cysteine-coated CdSe/ZnS quantum dot luminescence by meso-tetrakis (p-sulfonato-phenyl) porphyrin. Nanoscale Research Letters, Berlim, v. 13, p. 1-8, 2018. DOI: 10.1186/s11671-018-2449-x . Disponível em: https://link.springer.com/article/10.1186/s11671-018-2449-x. Acesso em: 5 maio 2023.