Abstract
Pursuit of a simple, fast, and cost-effective method to prepare highly and dual-wavelength fluorescent carbon quantum dots (CQDs) is a persistent objective in recent years. Here, we fabricated N-doped micropore carbon quantum dots (NM-CQDs) with a high quantum yield and dual-wavelength photoluminescence (PL) emission from sustainable biomass using a pulsed laser ablation method. Interestingly, two coexisting indigo–blue photoluminescence (PL) emissions were clearly observed, elucidating that the excited electrons transited from the intrinsic π* orbital to the surface state (SS) formed from the saturation passivation. The quantum yield (QY) and fluorescence lifetime (FL) of the obtained NM-CQDs were as high as 32.4% and 6.56 ns. Further investigations indicated that the emission behaviors of NM-CQDs were still stable and independent in various conditions such as various excitation wavelengths, salt ionic concentrations, pH values, irradiation times, and temperatures. The obtained NM-CQDs are very suitable for cellular staining images due to strong and stable PL emission and show good internalization in different cells. Therefore, we propose a new and cost-effective preparation strategy for highly fluorescent NM-CQDs with great potential in biomedical imaging and engineering.
Highlights
Carbon quantum dots (CQDs) are a promising material, featuring fluorescent carbon nanoparticles of less than 10 nm in size with a high surface-to-volume ratio [1,2,3]
There are still many challenging issues to be solved, including the following: (1) carbon precursors for the preparation of CQDs by pulsed laser ablation are high-cost and non-renewable [28,30]; (2) the fluorescence quantum yield of CQDs is relatively low in many solvents such as water and ethyl acetate oleamide using the pulsed laser ablation method [27,28], which limits their applications in biomedical imaging and optoelectronics; (3) the PL mechanism of CQDs, especially for dual-wavelength PL mechanism, remains ambiguous
These results indicate that the pored carbon precursor is very suitable for preparing high-quantum yield (QY) CQDs with great potential in biomedical imaging because more surface defects from the pored structure can induce more electron transition pathways, further facilitating the PL emission [31,32]
Summary
Carbon quantum dots (CQDs) are a promising material, featuring fluorescent carbon nanoparticles of less than 10 nm in size with a high surface-to-volume ratio [1,2,3]. There are still many challenging issues to be solved, including the following: (1) carbon precursors for the preparation of CQDs by pulsed laser ablation are high-cost and non-renewable [28,30]; (2) the fluorescence quantum yield of CQDs is relatively low in many solvents such as water and ethyl acetate oleamide (often less than 20%) using the pulsed laser ablation method [27,28], which limits their applications in biomedical imaging and optoelectronics; (3) the PL mechanism of CQDs, especially for dual-wavelength PL mechanism, remains ambiguous. It is necessary to propose a new and cost-effective preparation strategy to obtain pure CQDs with a high quantum yield and dual-wavelength PL emission for an understanding of the PL mechanism and application in biomedical imaging and engineering. We propose a new preparation strategy for highly fluorescent NM-CQDs with great potential in biomedical imaging and engineering
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
