Study on the fluorescence of double-emission carbon quantum dots by improved intercept method

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Dual-emission carbon quantum dots (DCQDs) exhibit unique fluorescence properties.
• Understanding the fluorescence mechanism is crucial for their application.
• Existing methods may not fully capture the complexities of DCQD fluorescence.

Purpose of the Study:

• To investigate the fluorescence mechanism of DCQDs using an improved intercept method.
• To synthesize high-quantum-yield DCQDs.
• To explore the relationship between DCQD properties, band gap, and environmental factors like pH and Fe3+ concentration.

Main Methods:

• Hydrothermal synthesis of DCQDs using sulfadiazine precursor.
• Characterization of DCQD morphology, chemical, and fluorescence properties.
• Application of the improved intercept method to estimate band gap from UV-vis spectra.
• Investigation of fluorescence emission changes with excitation wavelength and pH.
• Analysis of Fe3+ ion concentration effects on DCQD band gap.

Main Results:

• DCQDs possess a graphene-like structure with well-resolved lattice fringes.
• DCQD fluorescence intensity and emission show reversible changes between acidic and alkaline conditions.
• The improved intercept method aligns well with observed emission wavelength shifts at different excitation wavelengths.
• Fe3+ ions significantly influence specific band gaps of DCQDs, suggesting surface defect involvement in quenching.

Conclusions:

• The improved intercept method is effective for elucidating DCQD fluorescence mechanisms.
• DCQDs demonstrate tunable fluorescence and potential for Fe3+ detection.
• This method offers a new avenue for researching carbon quantum dot fluorescence.