Optical detection of gadolinium(iii) ions via quantum dot aggregation

CdTe quantum dot aggregation induced by trivalent metal ions is followed using fluorescence, dynamic light scattering and fluorescence correlation spectroscopy.

Ordered Nano-Laminated Films and Fluorescence Dynamic Characterization of Tb-Bisphthalocyanine

Stable monolayers of Tb (III) -ocat-4-n-nonyloxyphthalocyanine (TbPc2) and TbPc2 blended with amphibious arachidic acid (AA) on air-water interface have been obtained and their solid multilayers have been successfully deposited by Langmuir-Blodgett (LB) technique. The characteristics of their structure and fluorescence are disclosed. The multilayer has a periodic layered structure with a layer spacing of 2.2 nm. Fluorescence lifetime results suggest that the excitons exist by photo-excitation in the film of TbPc2.

Fluorescence Quenching of Polycyclic Aromatic Hydrocarbons by Cetylpyridinium Bromide: Discrimination between Alternant and Nonalternant Hydrocarbons

Molecules of polycyclic hydrocarbons (PAHs) that contain between two and five rings undergo quenching processes in the presence of cetylpyridinium bromide (CPB), which can act as quencher and as surfactant. The CPB concentration and the nature of the PAHs notably influence the inhibition mechanisms of fluorescence. Dynamic quenching is predominant for all hydrocarbons in solutions in which CPB is found in the form of monomers. When the quencher forms premicellar aggregates, fluoranthene, benzo[ a]pyrene, and benz[ a]anthracene undergo dynamic quenching, while for the remaining PAHs the dynamic and static processes coexist. In micellar CPB solutions the static quenching mechanism is predominant. The correlations existing between the quenching constant in the premicellar zone and topological and geometrical descriptors of the PAHs show the different behavior of alternant and nonalternant hydrocarbons.