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Modelling the emission of dyes under the influence of metallic nanoparticles

Grant number: 12/20653-6
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): April 01, 2013
Effective date (End): February 29, 2016
Field of knowledge:Physical Sciences and Mathematics - Physics - Condensed Matter Physics
Principal researcher:Paula Homem-de-Mello
Grantee:Edison Franco Junior
Home Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil


In the 1960s, experimental studies and modeling showed that electrodynamics based on flat metal surfaces can cause decrease in the fluorescence signal of chromophores when these molecules are close to the surface. Moreover, it was found that rough surfaces and nanoparticles can amplify the optical properties, especially the Raman scattering, which gave rise to technical Surface-Enhanced Raman Scattering (SERS). It was shown that it is possible to switch between brightness enhancement and quenching of fluorescence only by varying the distance metal chromophore and therefore to determine the conditions under which each effect is favored. These properties are useful for many areas, such as analytical, biosensors, electronics and materials science. However, there is still no systematic study in the literature, including various compositions, sizes and shapes of nanoparticles. On the other hand, computer simulations are a natural way for in-depth study of fluorophore-nanoparticle interaction, and there are already some papers in the literature. Instead of that, there are computational limitations to treat nanoparticles, and clusters usually replace them. The validity of this substitution has been little explored. So, this project aims to determine how to make changes in the fluorescence spectra of dyes in the presence of metal nanoparticles, using a computer simulations in two main approaches: (a) using "discrete" metal clusters, for which will be evaluated the minimum number of metal atoms that we have to include to obtain the effects on fluorescence spectra, and (b) using a polarizable dielectric to simulate the effects of a nanoparticle. We intend also to conduct systematic experimental studies, in which fluorophores and nanoparticles (composition, shape and size) will be evaluated. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
FRANCO-JUNIOR, EDISON; LOPES, ANA CAROLINA G.; SUFFREDINI, HUGO B.; HOMEM-DE-MELLO, PAULA. Simple model to study heterogeneous electrocatalysts. Journal of Power Sources, v. 273, p. 360-367, JAN 1 2015. Web of Science Citations: 0.
LUCAS, FRANCISCO WILLIAN DE S.; MASCARO, LUCIA H.; FILL, TAICIA P.; RODRIGUES-FILHO, EDSON; FRANCO-JUNIOR, EDISON; HOMEM-DE-MELLO, PAULA; DE LIMA-NETO, PEDRO; CORREIA, ADRIANA N. Diclofenac on Boron-Doped Diamond Electrode: From Electroanalytical Determination to Prediction of the Electrooxidation Mechanism with HPLC-ESI/HRMS and Computational Simulations. Langmuir, v. 30, n. 19, p. 5645-5654, MAY 20 2014. Web of Science Citations: 17.

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