A turn-on fluorescent solid-sensor for Hg(II) detection.

Area of Science:

• Materials Science
• Chemical Sensors
• Nanotechnology

Background:

• Development of sensitive and selective chemical sensors is crucial for environmental monitoring.
• Hybrid inorganic-organic materials offer unique properties for advanced sensing applications.
• Porous silicon microcavities (PSiMc) provide a versatile platform for sensor fabrication due to their tunable optical properties.

Purpose of the Study:

• To synthesize a rhodamine organosilane derivative (Rh-UTES) for mercury ion detection.
• To covalently immobilize Rh-UTES onto a porous silicon microcavity (PSiMc) to create a hybrid sensor.
• To evaluate the optical sensing performance of the hybrid PSiMc sensor for Hg(2+) ions.

Main Methods:

• One-pot synthesis of the rhodamine organosilane derivative (Rh-UTES).
• Covalent immobilization of Rh-UTES onto PSiMc using triethoxysilane groups.
• Characterization using nuclear magnetic resonance (NMR), infrared (FTIR), scanning electron microscopy (SEM), and specular reflectance.
• Optical performance evaluation using fluorescent spectroscopy and microscopy.

Main Results:

• Successful synthesis and structural confirmation of Rh-UTES.
• Confirmed covalent attachment of Rh-UTES onto the PSiMc surface.
• Significant enhancement in fluorescence emission intensity upon Hg(2+) ion detection (0.12-0.15-fold increase in solid phase).
• PSiMc platform amplified fluorescence emission by 277-fold, improving detection sensitivity.
• Fluorescence microscopy provided a qualitative optical test for Hg(2+).

Conclusions:

• The developed Rh-UTES/PSiMc hybrid sensor exhibits excellent potential for sensitive and selective Hg(2+) detection.
• The combination of Rh-UTES and PSiMc enhances fluorescence properties for improved sensing capabilities.
• This hybrid sensor offers a promising platform for optical detection of heavy metal ions.