p-Phenylenediamine-derived carbon nanodots for probing solvent interactions

Area of Science:

• Materials Science
• Nanotechnology
• Green Chemistry

Background:

• Carbon nanodots (CNDs) are luminescent nanoparticles (<10 nm) with broad applications in optoelectronics and biology.
• Their low toxicity and facile synthesis align with green chemistry principles.
• p-phenylenediamine-derived carbon nanodots (PD-CNDs) are explored for advanced applications.

Purpose of the Study:

• To synthesize and characterize PD-CNDs using a one-pot hydrothermal method.
• To investigate the luminescent properties and solvatochromic behavior of PD-CNDs.
• To demonstrate the application of PD-CNDs in solvent polarity determination and moisture sensing.

Main Methods:

• One-pot hydrothermal synthesis of PD-CNDs.
• Characterization using X-ray diffraction, spectroscopy, and microscopy.
• Solvatochromic studies across various polar and nonpolar solvents.
• Fluorescence spectroscopy for analyzing luminescent centers and quantum yield.

Main Results:

• Characterization confirmed spherical PD-CNDs (average size 2.8 nm) with amino, carboxyl, hydroxyl, pyridinic, and pyrrolic functional groups.
• PD-CNDs exhibited red-orange fluorescence under UV light, originating from edge states and surface groups.
• The system demonstrated accurate determination of solvent polarity, dielectric constants, and solvent mixture composition.
• Effective moisture sensing in organic solvents with <1% error was achieved.

Conclusions:

• PD-CNDs possess tunable optical properties suitable for sensitive environmental monitoring.
• Their solvatochromic nature enables precise analysis of solvent properties and composition.
• High quantum yield and functionalization suggest broad potential in materials science and sensing applications.