Synthesis of N-Doped Micropore Carbon Quantum Dots with High Quantum Yield and Dual-Wavelength Photoluminescence Emission from Biomass for Cellular Imaging

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.

Facile Hydrothermal and Solvothermal Synthesis and Characterization of Nitrogen-Doped Carbon Dots from Palm Kernel Shell Precursor

“…Figure 2 shows the instrumentals for the pyrolytic carbonization of palm kernel shell (PKS) in an inert tubular nitrogen gas chamber of a furnace, which produced a black carbonaceous char with an average yield of 30.96% as tabulated in Table 1. The result agrees with other research groups [42,56]. Their analysis shows that the obtained char was about 30%, the char results from the thermal decomposition of cellulose, lignin, and hemicellulose in the PKS precursor.…”

“…The nitrogen gas was purged at a flow rate of 50 ccs/min through the quartz tube during the carbonization period at a temperature of 600 • C for 3 h at a 10 • C/min rise in temperature. Nitrogen gas was kept running for 3 h until the furnace chamber temperature was brought to 40 • C [42,57,65,66]. The percentage yield of the carbonized palm kernel shell (CPKS) materials was determined after the sample temperature reached room temperature by again weighing the carbonized materials using Equation (1) below:…”

You Don’t Learn That in School: An Updated Practical Guide to Carbon Quantum Dots

“…Ren et al [ 50 ] developed N-doped micropore CQDs passivated with formamide utilizing the pulsed laser ablation (PLA) method and using waste Platanus biomass as the carbon precursor. The N-doped micropore CQDs displayed dual-wavelength coexisting fluorescence emissions in the indigo-blue wavelength region, suggesting the transition of the excited electrons from the intrinsic π * orbital to the surface state produced from the saturation passivation.…”

Recent advances in crystalline carbon dots for superior application potential

“…Laser ablation Graphite, 35,38,39 biomass, 61 carbon powder. 62 Fast synthesis, tunable surface states.…”