Biomass based carbon quantum dots in sensor applications: a review (2021-2025)

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Carbon quantum dots (CQDs) derived from natural biomasses have emerged as a significant area of research.
• These CQDs offer a sustainable and versatile platform for various sensing applications.
• Recent years have seen rapid progress in their synthesis and characterization.

Purpose of the Study:

• To critically review advancements in biomass-derived CQDs from 2021-2025.
• To assess their synthesis methods, physicochemical properties, and sensing capabilities.
• To highlight future prospects and challenges in the field.

Main Methods:

• Review of literature on biomass-derived CQDs synthesis and applications.
• Analysis of synthesis routes including hydrothermal, microwave-assisted, and pyrolytic methods.
• Examination of characterization techniques for morphology, structure, and optical properties.

Main Results:

• Biomass precursors (fruit peels, leaves, waste) are efficiently converted into fluorescent CQDs.
• Synthesis times can be as short as 10 minutes using microwave-assisted methods.
• CQDs exhibit quasi-spherical morphology (2-10 nm), partial graphitization, and high quantum yields (up to 30%), especially when doped.
• Demonstrated high sensitivity and selectivity for analytes like Fe³⁺, antibiotics, glyphosate, NH₃, and CH₂O at nanomolar levels.
• Sensing mechanisms include fluorescence quenching, electron transfer, and Förster Resonance Energy Transfer (FRET).

Conclusions:

• Biomass-derived CQDs are promising nanomaterials for next-generation sensors due to their green origin, cost-effectiveness, and ultrasensitive detection capabilities.
• Challenges remain in large-scale production, protocol standardization, and real-time integration.
• Future directions include adopting greener synthesis, establishing regulatory standards, and developing wearable/portable devices.