One-Step Green Solvothermal Synthesis of Full-Color Carbon Quantum Dots Based on a Doping Strategy

Area of Science:

• Materials Science
• Nanotechnology
• Photochemistry

Background:

• Developing full-color carbon quantum dots (CQDs) with tunable luminescence is crucial for advanced optical applications.
• Improving the photoluminescence quantum yield (PLQY) and spectral properties of CQDs remains a key challenge.

Purpose of the Study:

• To propose a simple, one-pot strategy for synthesizing a range of CQDs with tunable emission colors.
• To investigate the factors influencing luminescence tuning and enhancement in heteroatom-doped CQDs.
• To explore energy transfer mechanisms in mixed CQD solutions and fabricate a white light-emitting diode (WLED).

Main Methods:

• One-pot synthesis of blue, green, yellow-green, and orange-red CQDs doped with heteroatoms.
• Separation of CQDs using column chromatography.
• Characterization of emission peaks, PLQY, and full width at half-maximum (FWHM).
• Fabrication of a white light-emitting diode (WLED) using the synthesized CQDs.

Main Results:

• Successfully synthesized CQDs with emission peaks at 435 nm, 495 nm (88.9% PLQY), 525 nm, and 595 nm (31 nm FWHM).
• Identified abundant C-O/C-O-C electron donor groups as key to improving green CQD PLQY.
• Demonstrated that expanded conjugation (particle size, Cl, N doping) enhances red-shifts in emission spectra.
• Observed and proposed energy transfer mechanisms in concentrated CQD solutions.
• Fabricated a high-efficiency WLED with CIE coordinates (0.361, 0.369), 4534 K CCT, and 90.8 CRI.

Conclusions:

• The developed one-pot strategy offers a simple and effective route to full-color CQDs with tunable properties.
• Heteroatom doping and control over conjugated domains are critical for optimizing CQD luminescence and spectral characteristics.
• The synthesized CQDs are suitable for fabricating high-performance WLEDs, demonstrating their potential in lighting applications.