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Top-down synthesis and enhancing device adaptability of graphene quantum dots
Fangyan Sun1, Hrilina Ghosh1, Zhongchao Tan2
1Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Canada.
Nanotechnology
|February 1, 2023
Summary
Non-toxic graphene quantum dots (GQDs) were synthesized from graphite for optoelectronics. These GQDs demonstrate high photocurrent in photodetector devices, showing great potential for future applications.
Area of Science:
- Materials Science
- Nanotechnology
- Optoelectronics
Background:
- Quantum dots (QDs) are crucial for optoelectronics, but toxicity concerns necessitate non-toxic alternatives.
- Graphene quantum dots (GQDs) offer a promising non-toxic option.
Purpose of the Study:
- Synthesize non-toxic graphene quantum dots (GQDs) from graphite.
- Investigate the effect of oxidation conditions on GQD properties.
- Fabricate and test a GQD-based photodetector device.
Main Methods:
- Oxidative cleavage of graphite using sulfuric and nitric acid mixture.
- Hydrogen peroxide oxidation with varying thermal budgets.
- X-ray photoelectron spectroscopy and Raman analysis.
- Post-synthesis neutralization and film formation.
- Fabrication of a photodetector device.
Main Results:
- Graphene quantum dots (GQDs) synthesized in the 1.4-4.2 nm range with tunable size and excellent photoluminescence (PL) intensity.
- Higher temperature oxidation yielded smaller GQDs with lower defect density.
- Neutralized GQDs formed a stable film without altering fluorescence lifetime.
- The GQD photodetector exhibited a high photocurrent and an ON/OFF ratio of 400% under UV illumination.
Conclusions:
- Top-down synthesis provides a viable route to non-toxic GQDs.
- Optimized oxidation conditions enhance GQD photoluminescence and reduce defects.
- GQD-based photodetectors show significant potential for optoelectronic applications.
