Jéssica M.M. Dias

Electrochemical synthesis of TGA-capped CdTe and CdSe quantum dots

The electrochemical preparation of Te2− and Se2− ions was carried out in NaOH aqueous solution, with high yield and good stability, and applied in the preparation of negatively charged CdTe and CdSe quantum dots (QDs). A CdCl2 aqueous solution containing thioglycolic acid (TGA) stabilizer was mixed with the electrochemically generated Te2− or Se2− ions in a quite reproducible and clean one pot process, without the use of chemical reducing agents. The CdTe and CdSe QDs had good stability and high luminescence with an average size of d = 3.9 nm and 2.6 nm, respectively, the quantum yields and lifetimes were also determined. Hg2+ was efficiently quantified in the presence of the synthesized TGA-capped CdTe and CdSe, making possible the application of these QDs as chemical sensors.

Electrochemical synthetic route for preparation of CdTe quantum-dots stabilized by positively or negatively charged ligands

An electrochemical route for the generation of Te2− ions in an aqueous solution, with high yield and great stability, was developed and applied for the preparation of CdTe quantum dots (QDs) stabilized by negatively or positively charged ligands. An aqueous Cd(ClO4)2 solution containing mercaptopropionic acid (MPA) or cysteamine (Cys) stabilizers was directly added to the electrochemically generated aqueous telluride ion solution. This one pot process is quite reproducible and clean (no chemical reducing agents), allowing control of reduced species generation. The CdTe QDs showed good stability and high luminescence with particle average sizes of d = 3.1 nm (MPA) or 2.7 nm (Cys). Macrophages were efficiently labeled with MPA-capped CdTe QDs as well as with Cys-capped CdTe QDs.

Synthesis and spectroscopic characterization of a fluorescent pyrrole derivative containing electron acceptor and donor groups.

The synthesis and fluorescence characterization of a new pyrrole derivative (PyPDG) containing the electron donor-acceptor dansyl substituent is reported. The effects of temperature and solvent polarity on the steady-state fluorescence of this compound are investigated. Our results show that PyPDG exhibits desirable fluorescent properties which makes it a promising candidate to be used as the photoactive material in optical thermometry and thermography applications. Further, the electrochemical and emission properties of polymeric films obtained from the oxidation polymerization of PyPDG are also analyzed.