Solid-State Fluorescent Carbon Dots with Unprecedented Efficiency from Visible to Near-Infrared Region

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Developing solid-state luminescent materials for light-emitting diodes (LEDs) with bright, long-wavelength emissions is crucial but challenging.
• Aggregation-caused fluorescence quenching in solid-state carbon dots (CDs) limits their efficiency and application range.

Purpose of the Study:

• To engineer novel carbon dots (CDs) with extended wavelength emissions in the solid state.
• To overcome self-quenching issues in solid-state CDs and enhance their fluorescence quantum yields.
• To demonstrate the application of these engineered CDs in white LEDs and plant growth lighting.

Main Methods:

• A novel structure engineering strategy was employed to synthesize solid-state fluorescence-emitted carbon dots (CDs).
• Surface polymer chains were utilized to suppress π-π stacking and aggregation-caused fluorescence quenching.
• The electronic bandgap was tuned by enlarging the sp² carbon core to achieve redshifted emissions.

Main Results:

• The study reports the first self-quenching-resistant solid-state CDs with emissions spanning the visible to near-infrared region.
• Remarkably improved quantum yields of up to 67.7% were achieved, representing the highest value for solid-state CDs.
• Fabrication of white LEDs with adjustable correlated color temperatures (1882–5019 K) and a plant growth LED device demonstrating enhanced plant growth efficiency were achieved.

Conclusions:

• This work presents high-quality, solid-state CD-based phosphors with superior luminescence properties.
• The engineered CDs offer a promising platform for diverse optoelectronic applications, including advanced LED lighting.
• The findings pave the way for efficient solid-state emitters with tunable long-wavelength emissions.