Fluorescent sensor for Cr(VI) based in functionalized silicon quantum dots with dendrimers

Area of Science:

• Nanotechnology
• Materials Science
• Environmental Chemistry

Background:

• Development of highly luminescent nanoparticles for sensing applications.
• Need for selective and sensitive detection of heavy metals like Chromium (VI).
• Utilizing silicon quantum dots (SiQDs) and dendrimer coatings for enhanced properties.

Purpose of the Study:

• Synthesize luminescent silicon quantum dots coated with hydroxyl PAMAM dendrimer (SiQDs@PAMAM-OH).
• Optimize synthesis parameters for maximum fluorescence intensity.
• Evaluate the potential of SiQDs@PAMAM-OH as a nano-sensor for Cr(VI) detection.

Main Methods:

• One-step hydrothermal synthesis of SiQDs@PAMAM-OH using 3-Aminopropyl)triethoxysilane (APTES) and PAMAM dendrimer.
• Characterization using Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), and X-ray Photoelectron Spectroscopy (XPS).
• Fluorescence spectroscopy to determine excitation/emission wavelengths and optimize synthesis parameters (APTES/PAMAM-OH ratio, pH, ionic strength).

Main Results:

• Achieved highly luminescent SiQDs@PAMAM-OH with excitation/emission peaks at 370/446 nm.
• Demonstrated selective detection of Cr(VI) with a low limit of detection (2.7 μM) and high sensitivity (0.2 μM).
• Validated the nano-sensor's performance in real samples, including tanning effluent and certified waters.

Conclusions:

• Successful synthesis of novel SiQDs@PAMAM-OH nanoparticles.
• Established a sensitive and selective method for Cr(VI) detection using the developed nano-sensor.
• Showcased the potential of SiQDs@PAMAM-OH for environmental monitoring and industrial applications.