scholarly journals Green Preparation of Fluorescent Carbon Quantum Dots from Cyanobacteria for Biological Imaging

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 616 ◽  
Author(s):  
Xi Wang ◽  
Pei Yang ◽  
Qian Feng ◽  
Taotao Meng ◽  
Jing Wei ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Source ◽  
Large Scale ◽  
Low Cost ◽  
Average Diameter ◽  
Carbon Quantum Dots ◽  
Water Soluble ◽  
High Concentration ◽  
Wide Range ◽  
Low Cytotoxicity

Biomass-based carbon quantum dots (CQDs) have become a significant carbon materials by their virtues of being cost-effective, easy to fabricate and low in environmental impact. However, there are few reports regarding using cyanobacteria as a carbon source for the synthesis of fluorescent CQDs. In this study, the low-cost biomass of cyanobacteria was used as the sole carbon source to synthesize water-soluble CQDs by a simple hydrothermal method. The synthesized CQDs were mono-dispersed with an average diameter of 2.48 nm and exhibited excitation-dependent emission performance with a quantum yield of 9.24%. Furthermore, the cyanobacteria-derived CQDs had almost no photobleaching under long-time UV irradiation, and exhibited high photostability in the solutions with a wide range of pH and salinity. Since no chemical reagent was involved in the synthesis of CQDs, the as-prepared CQDs were confirmed to have low cytotoxicity for PC12 cells even at a high concentration. Additionally, the CQDs could be efficiently taken up by cells to illuminate the whole cell and create a clear distinction between cytoplasm and nucleus. The combined advantages of green synthesis, cost-effectiveness and low cytotoxicity make synthesized CQDs a significant carbon source and broaden the application of cyanobacteria and provide an economical route to fabricate CQDs on a large scale.

scholarly journals Environment-dependent Emission Tuning in the Multicolor Nitrogen-doped Carbon Quantum Dots

2021 ◽  
Author(s):  
Dineshkumar Sengottuvelu ◽  
Abdul Kalam Shaik ◽  
Satish Mishra ◽  
Mahsa Abbaszadeh ◽  
Nathan Hammer ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solid State ◽  
Large Scale ◽  
Low Cost ◽  
Visible Region ◽  
Carbon Quantum Dots ◽  
One Pot ◽  
Nitrogen Doped ◽  
Emission Changes ◽  
Nitrogen Doped Carbon

Carbon quantum dots (CQDs) are fascinating luminous materials from the carbonaceous family and are increasingly being investigated in many optoelectronic applications due to their unique photoluminescence (PL) characteristics. Herein, we report the synthesis of nitrogen-doped carbon quantum dots (NCQDs) from citric acid and m-phenylenediamine using a one-pot hydrothermal approach. The environment-dependent emission changes of NCQDs were extensively investigated in various solvents, in solid-state, and in physically assembled PMMA-PnBA-PMMA copolymer gels in 2-ethyl hexanol. The NCQDs display bright emission in various solvents as well as in solid-state and a temperature-dependent enhanced emission in gels. In detail, these NCQDs exhibit multicolor PL emission across the visible region and its enhancement upon changing the environment (solutions and polymer matrices). The NCQDs also exhibit excitation-dependent PL and solvatochromism, which are rarely observed in CQDs. Most CQDs are non-emissive in the aggregated or solid-state due to the aggregation-caused quenching (ACQ) effect, limiting their solid-state applications. However, these NCQDs display a strong solid-state emission centered at 568 nm ascribed to the presence of abundant surface functional groups, which helps to prevent the - interaction between the NCQDs and to overcome the ACQ effect in the solid-state. Interestingly, the NCQD containing gels display a significant fluorescence enhancement than the NCQDs in 2-ethyl hexanol solution because of the interaction between the polar PMMA blocks and NCQDs. This research opens up the development of large-scale, low-cost multicolor phosphor for the fabrication of optoelectronic devices, sensing, and bioimaging applications.

scholarly journals Inkjet-Printed CdTe Quantum Dots-Polyurethane Acrylate Thin Films

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Lei Du ◽  
Zhejun Liu ◽  
Suhua Jiang
Keyword(s):  
Thin Films ◽  
Quantum Dots ◽  
Water Content ◽  
Large Scale ◽  
Low Cost ◽  
Water Soluble ◽  
Cdte Quantum Dots ◽  
Flexible Displays ◽  
Uv Curable ◽  
Polyurethane Acrylate

We demonstrated the inkjet-printed CdTe quantum dots-polyurethane acrylate thin films and their potential application in the display devices. The water soluble CdTe QDs were synthesized through the wet chemistry and the emission wavelengths can be freely tuned during the preparation process. Combining with the UV curable resin polyurethane acrylate, the QDs inks were prepared and the influence of diluent and water content on the performance of resultant films was studied. The tensile stress of the films cured from the QDs inks with diluent increased from 10.6 MPa to 27.5 MPa and the low water content led to uniform polymer matrix. Furthermore, the existence of diluent and low water content would all improve the fluorescence stability of the thin films. Finally, the thin films can be deposited on different substrates and well controlled to meet the RGB color standard, which will pave the way to a simple, low-cost, large-scale, and highly reliable method for the application of flexible displays.

scholarly journals Synthesis of Copper–nitrogen Codoped Carbon Quantum Dots Using Frangipani as a Carbon Source and Application of Metronidazole Determination

2021 ◽  
Author(s):  
Lan Yuwei Lan ◽  
Yuwei Lan ◽  
Wenbin Bao ◽  
Chunfeng Liang ◽  
Guowei Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Source ◽  
Detection Method ◽  
Fluorescence Probe ◽  
Low Cost ◽  
Copper Acetate ◽  
Carbon Quantum Dots ◽  
Excitation Wavelength ◽  
One Step ◽  
High Fluorescence

Abstract High-fluorescence Cu/N codoped carbon quantum dots (Cu/NCQDs) were prepared by a one-step hydrothermal method using frangipani as the carbon source and copper acetate as the copper source. The Cu/NCQDs exhibited high-intensity, stable blue fluorescence that is independent of the excitation wavelength. Since metronidazole can effectively quench the fluorescence intensity of Cu/NCQDs, a metronidazole fluorescence-detection method using Cu/NCQDs as the fluorescence probe was developed, and the quenching mechanism was studied.The method has the advantages of simplicity, speed, and low cost. Besides,it has a wider linear range and detection limit. Further, the metronidazole content in actual samples was determined by this method, with good results.

Teaching application of watercolor light color technique

2020 ◽  
pp. 002072092093683
Author(s):  
Yin Shi
Keyword(s):  
Art Education ◽  
Large Scale ◽  
Low Cost ◽  
Art Curriculum ◽  
Repeated Practice ◽  
Wide Range ◽  
Light Color ◽  
Teaching Application ◽  
Design Drawing

As a branch of watercolor painting, watercolor light color has been widely used in different fields. In the field of design, designers use the convenience, quickness, transparency and brilliance of watercolor to draw a design drawing. In the field of art creation, watercolor is usually the best choice for painters to go out to sketch and create large-scale drawings. In the field of art education, watercolor tools are easy to carry, low-cost and easy to operate, which can facilitate students’ repeated practice and outside Sketching is helpful to cultivate students’ sense of color and observation ability. Therefore, as a branch of art curriculum, watercolor light color has a wide range of uses and great practicability, which is worth exploring and studying.

scholarly journals Formation of Carbon Quantum Dots via Hydrothermal Carbonization: Investigate the Effect of Precursors

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 986
Author(s):  
Md Rifat Hasan ◽  
Nepu Saha ◽  
Thomas Quaid ◽  
M. Toufiq Reza
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Microcrystalline Cellulose ◽  
Uv Light ◽  
Synthesis Method ◽  
Hydrothermal Carbonization ◽  
Carbon Quantum Dots ◽  
Medical Diagnostics ◽  
Particle Size Range ◽  
Wide Range

Carbon quantum dots (CQDs) are nanomaterials with a particle size range of 2 to 10 nm. CQDs have a wide range of applications such as medical diagnostics, bio-imaging, biosensors, coatings, solar cells, and photocatalysis. Although the effect of various experimental parameters, such as the synthesis method, reaction time, etc., have been investigated, the effect of different feedstocks on CQDs has not been studied yet. In this study, CQDs were synthesized from hydroxymethylfurfural, furfural, and microcrystalline cellulose via hydrothermal carbonization at 220 °C for 30 min of residence time. The produced CQDs showed green luminescence behavior under the short-wavelength UV light. Furthermore, the optical properties of CQDs were investigated using ultraviolet-visible spectroscopy and emission spectrophotometer, while the morphology and chemical bonds of CQDs were investigated using transmission electron microscopy and Fourier-transform infrared spectroscopy, respectively. Results showed that all CQDs produced from various precursors have absorption and emission properties but these optical properties are highly dependent on the type of precursor. For instance, the mean particle sizes were 6.36 ± 0.54, 5.35 ± 0.56, and 3.94 ± 0.60 nm for the synthesized CQDs from microcrystalline cellulose, hydroxymethylfurfural, and furfural, respectively, which appeared to have similar trends in emission intensities. In addition, the synthesized CQDs experienced different functionality (e.g., C=O, O-H, C-O) resulting in different absorption behavior.

Toward phosphorescent and delayed fluorescent carbon quantum dots for next-generation electroluminescent displays

2021 ◽  
Author(s):  
Ting Yuan ◽  
Ting Meng ◽  
Yuxin Shi ◽  
Xianzhi Song ◽  
Wenjing Xie ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Quantum Dots ◽  
Carbon Quantum Dots ◽  
High Thermal Stability ◽  
Next Generation ◽  
Low Cytotoxicity ◽  
Tunable Emission ◽  
Fluorescent Carbon

Featuring a combination of size-tunable emission wavelengths, high thermal stability, and low cytotoxicity, carbon quantum dots (CQDs) have opened up a new possibility for next-generation displays.

scholarly journals Synthesis and Properties of Nitrogen-Doped Carbon Quantum Dots Using Lactic Acid as Carbon Source

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 466
Author(s):  
Kaixin Chang ◽  
Qianjin Zhu ◽  
Liyan Qi ◽  
Mingwei Guo ◽  
Woming Gao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Lactic Acid ◽  
Fluorescence Quenching ◽  
Functional Groups ◽  
Fluorescence Intensity ◽  
Carbon Quantum Dots ◽  
Nitrogen Doped ◽  
Ph Values ◽  
Wide Range ◽  
Nitrogen Doped Carbon

Nitrogen-doped carbon quantum dots (N-CQDs) were synthesized in a one-step hydrothermal technique utilizing L-lactic acid as that of the source of carbon and ethylenediamine as that of the source of nitrogen, and were characterized using dynamic light scattering, X-ray photoelectron spectroscopy ultraviolet-visible spectrum, Fourier-transformed infrared spectrum, high-resolution transmission electron microscopy, and fluorescence spectrum. The generated N-CQDs have a spherical structure and overall diameters ranging from 1–4 nm, and their surface comprises specific functional groups such as amino, carboxyl, and hydroxyl, resulting in greater water solubility and fluorescence. The quantum yield of N-CQDs (being 46%) is significantly higher than that of the CQDs synthesized from other biomass in literatures. Its fluorescence intensity is dependent on the excitation wavelength, and N-CQDs release blue light at 365 nm under ultraviolet light. The pH values may impact the protonation of N-CQDs surface functional groups and lead to significant fluorescence quenching of N-CQDs. Therefore, the fluorescence intensity of N-CQDs is the highest at pH 7.0, but it decreases with pH as pH values being either more than or less than pH 7.0. The N-CQDs exhibit high sensitivity to Fe3+ ions, for Fe3+ ions would decrease the fluorescence intensity of N-CQDs by 99.6%, and the influence of Fe3+ ions on N-CQDs fluorescence quenching is slightly affected by other metal ions. Moreover, the fluorescence quenching efficiency of Fe3+ ions displays an obvious linear relationship to Fe3+ concentrations in a wide range of concentrations (up to 200 µM) and with a detection limit of 1.89 µM. Therefore, the generated N-CQDs may be utilized as a robust fluorescence sensor for detecting pH and Fe3+ ions.

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