An optical probe possessing upconversion luminescence and Hg(2+)-sensing properties

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Upconversion luminescence (UCL) nanomaterials offer unique optical properties for sensing applications.
• Developing selective and sensitive probes for heavy metal ions like mercury (Hg2+) is crucial for environmental and biological monitoring.
• Rhodamine B hydrazide (RB-hydrazide) is a potential chelating agent for metal ions.

Purpose of the Study:

• To create a novel chromophoric upconversion nanosystem for selective detection of mercury ions (Hg2+).
• To functionalize upconversion nanorods with Rhodamine B hydrazide for enhanced sensing capabilities.

Main Methods:

• Synthesis of β-NaYF4 nanorod core-shell structures coated with silica.
• Covalent grafting of Rhodamine B hydrazide (RB-hydrazide) onto the nanorod surface.
• Characterization using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX), Fourier-transform infrared spectroscopy (FTIR), and photoluminescence spectroscopy.
• Evaluation of the nanosystem's sensitivity and selectivity towards Hg2+ under 980 nm excitation.

Main Results:

• The functionalized nanorods exhibited sensitive and selective upconversion luminescence response to Hg2+.
• The RB-hydrazide-Hg complex formation efficiently quenched the green upconversion emission.
• The nanosystem demonstrated high selectivity for Hg2+ over other common metal ions.

Conclusions:

• The developed chromophoric upconversion nanosystem shows significant potential as a fluorescence probe for Hg2+ detection.
• The covalent grafting strategy provides a robust platform for designing advanced optical nanosensors.
• This approach offers a promising avenue for developing sensitive and selective heavy metal ion detection tools.