Plasma-Tailored Carbon Dots with Atomic-Level sp²/sp³ Hybridization for Programmable Band Structures and Optothermal...

Area of Science:

• Materials Science
• Nanotechnology
• Plasma Physics

Background:

• Precise control over sp²/sp³ hybridization in carbon nanomaterials is crucial for tailoring electronic and optical properties.
• Current methods for hybridization control often lack energy efficiency and environmental friendliness.
• Developing sustainable and precise methods for carbon nanomaterial functionalization is a significant challenge.

Purpose of the Study:

• To present a modular plasma nanoengineering approach for atomic-level control of hybridization in carbon dots (CDs).
• To demonstrate the ability to tune the sp²/sp³ ratio and consequently, the optical and thermal properties of CDs.
• To explore the potential of these engineered CDs for sensor applications.

Main Methods:

• Utilized ambient-pressure microplasmas for nanoengineering carbon dots (CDs).
• Adjusted plasma energy through discharge current and capillary confinement to control the sp²/sp³ hybridization ratio.
• Characterized the synthesized CDs using microscopic and spectroscopic techniques to analyze their properties.

Main Results:

• Achieved atomic-level control of sp²/sp³ hybridization in CDs, enabling tunable optical bandgaps (2.75-3.1 eV).
• Demonstrated phase-dependent optothermal responses and stable photoluminescence (PL)-based thermal sensitivity up to 1.38% °C^-1.
• Identified an optimal sp² content (≈84%) that enhances phonon-exciton coupling and PL thermal control.

Conclusions:

• The catalyst-free, low-temperature plasma nanoengineering approach offers a scalable and sustainable method for creating customizable carbon nanomaterials.
• Engineered CDs exhibit superior thermal sensitivity compared to traditional materials, suitable for advanced sensing.
• This technique opens pathways for developing wearable, implantable, and optoelectronic sensors.