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Highly Fluorescent and Stable Black Phosphorus Quantum Dots in Water
Liyuan Long1, Xianghong Niu2,3, Kun Yan1
1National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, 210093, P. R. China.
Small (Weinheim an Der Bergstrasse, Germany)
|October 12, 2018
Summary
Researchers developed fluorescent black phosphorus quantum dots (BPQDs) using liquid exfoliation and passivation. These BPQDs show strong, stable photoluminescence in water, enabling potential biomedical applications.
Area of Science:
- Materials Science
- Nanotechnology
- Quantum Dots
Background:
- 2D black phosphorus (BP) possesses desirable optical and electronic properties.
- Challenges in BP nanostructure research include low yield, instability in water, and weak photoluminescence (PL).
Purpose of the Study:
- To develop a high-yield method for producing fluorescent black phosphorus quantum dots (BPQDs).
- To investigate the photoluminescence properties and stability of BPQDs in aqueous solutions.
- To explore the potential applications of BPQDs in bioimaging and biomedical fields.
Main Methods:
- Liquid exfoliation of black phosphorus.
- Surface passivation of black phosphorus quantum dots.
- Photoluminescence spectroscopy and quantum yield measurements.
- Stability tests under ambient conditions.
- Theoretical calculations to understand PL mechanisms.
Main Results:
- High-yield production of fluorescent BPQDs achieved through liquid exfoliation and passivation.
- BPQDs exhibit strong photoluminescence (PL) in both ethanol and water, with a 70% quantum yield in water.
- Stable PL observed for 150 days under ambient conditions, surpassing conventional organic dyes and heavy-metal nanostructures.
- Intense and stable PL attributed to intrinsic band-to-band states and surface states from passivation.
- Polar water molecules enhance PL by reducing nonradiative centers and increasing surface fluorescent groups.
Conclusions:
- The developed method yields highly fluorescent and stable black phosphorus quantum dots (BPQDs).
- BPQDs demonstrate superior photostability and quantum yield in aqueous solutions, making them suitable for bioimaging.
- Negligible biotoxicity and clear cell imaging indicate significant potential for biomedical and display applications.
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