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Spin-Dependent Photoluminescence in Carbon-Based Quantum Dots.
Erin S Grant1, Joseph F Olorunyomi2,3, Sam C Scholten1
1Department of Physics, School of Science, RMIT University, Melbourne, Australia.
Advanced Materials (Deerfield Beach, Fla.)
|February 24, 2026
Summary
Researchers observed magnetic field-induced photoluminescence (PL) modulation in carbon-based quantum dots (CQDs) at room temperature. This discovery enables new possibilities for quantum sensing and imaging in biological samples.
Area of Science:
- Quantum Technologies
- Materials Science
- Nanotechnology
Background:
- Spin-dependent photoluminescence (PL) modulation in nanomaterials is crucial for quantum technologies.
- Carbon-based quantum dots (CQDs) are versatile luminescent nanomaterials but lack observed room-temperature spin-dependent PL.
Purpose of the Study:
- To investigate and demonstrate room-temperature, spin-dependent photoluminescence modulation in carbon-based quantum dots (CQDs).
- To explore the potential of CQDs for nanoscale quantum sensing and imaging applications.
Main Methods:
- Synthesized CQDs from 19 different amino acids using pyrolysis.
- Applied magnetic fields (~10 mT) under ambient conditions to observe magneto-PL effects.
- Utilized electron spin resonance (ESR) to analyze the spin-dependent PL mechanism.
Main Results:
- Observed significant magneto-PL effects (up to ~1%) in the majority of synthesized CQDs, persisting in both dry and solution states.
- Detected ESR with a g-factor of ~2, indicating a radical pair mechanism is likely responsible.
- Demonstrated that paramagnetic species reduce magneto-PL contrast by increasing spin relaxation.
Conclusions:
- Achieved room-temperature, spin-dependent PL modulation in CQDs, a previously elusive property.
- The findings suggest CQDs can be utilized for in situ quantum sensing and imaging of biological samples.
- This work enhances the functionality of biocompatible CQDs for advanced quantum applications.
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