Highly luminescent water-soluble AgInS2/ZnS quantum dots-hydrogel composites for warm white LEDs

FRET-based innovative assays for precise detection of the residual heavy metals in food and agriculture-related matrices

Dual functionalized, stable and water dispersible CdTe quantum dots: Facile,one-pot aqueous synthesis, optical tuning and energy transfer applications

Microwave-assisted synthesis of fluorescent silicon quantum dots for ratiometric sensing of Hg (II) based on the regulation of energy transfer

Design of smartphone platform by ratiometric fluorescent for visual detection of silver ions

The sensitive and selective detection of mercury in aqueous solution is of paramount importance as the mercury concentration in drinking water above the threshold level set by world health organization can cause serious health issues to humans. We demonstrate a simple, facile, and cost-effective one pot synthesis route to synthesize MPA (3-mercaptopropionic acid) stabilized CdTe/CdS core-shell quantum dots and its application for detection of mercury using the fluorescence resonance energy transfer with a cationic dye, Rhodamine 6G. The quantum dots prepared via chemical reduction strategy using a combination of reducing agents, namely sodium borohydride and citric acid exhibit a high quantum efficiency (> 20% for solid state). Structural as well as luminescence studies of the prepared quantum dots were found to depend on the pH as well as the size of the quantum dots (hydrodynamic diameter ranging from 9 to 16 nm). Analysis of the fluorescence resonance energy transfer (FRET) between the prepared quantum dots and Rhodamine 6G elucidate that efficient energy transfer happens in the presence of a cetyl trimethyl ammonium bromide (CTAB) surfactant. Though the prepared CdTe/CdS quantum dots exhibit fluorescence quenching with an increase in mercury concentration and act as an “OFF-sensor,” the Rhodamine 6G-quantum dot pair employed here found to be a better approach as the inherent fluorescence of Rh6G is insensitive to mercury concentration. Our studies elucidate that the fluorescence ratio of Rh6G in a FRET pair follows a linear nature for the Stern-Volmer plot in the concentration range of Hg2+ ions (0.1 nM to 2 μM) and provide a LOD of 3.8 nM.

Vinitha Ganiga

Papers

Sensitive detection of mercury using the fluorescence resonance energy transfer between CdTe/CdS quantum dots and Rhodamine 6G

Dual functionalized, stable and water dispersible CdTe quantum dots: Facile,one-pot aqueous synthesis, optical tuning and energy transfer applications