Glucose-Derived Fluorescent Carbon Dots: Effect of Synthesis Temperature on Structural Evolution

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Carbon dots (CDs) are versatile nanomaterials with tunable optical properties.
• Controlling the synthesis of CDs is crucial for optimizing their performance.
• Glucose is a readily available and sustainable precursor for CD synthesis.

Purpose of the Study:

• To investigate the effect of synthesis temperature on the structural and optical properties of glucose-derived carbon dots (CDs).
• To explore the potential of tuning CD properties through controlled pyrolysis.

Main Methods:

• Solvent-free pyrolysis of glucose at temperatures ranging from 160 °C to 250 °C.
• Thermogravimetric analysis (TGA) and spectroscopic techniques (FTIR, Raman) for structural characterization.
• X-ray photoelectron spectroscopy (XPS) for surface chemical analysis.
• Photoluminescence (PL) and time-resolved PL spectroscopy for optical property evaluation.

Main Results:

• Synthesis temperature significantly impacted CD structure, progressing from amorphous to turbostratic graphitic forms.
• Higher temperatures led to increased carbonization, reduced oxygen content (O/C ratio decreased from 0.76 to 0.44), and enhanced sp² hybridization.
• Spectroscopic analysis confirmed the loss of oxygen-containing groups and the formation of conjugated domains.
• Photoluminescence studies showed excitation-dependent emission, with redshift and broadening observed at higher temperatures, indicating surface trap state contributions.

Conclusions:

• The pyrolysis temperature is a critical parameter for controlling the structural evolution and photophysical properties of glucose-derived CDs.
• Tunable structural and optical properties make these CDs promising for applications requiring specific photoluminescence characteristics.
• This solvent-free method offers a scalable approach for producing customized carbon dots.