scholarly journals SPECTRAL AND LUMINESCENT PROPERTIES OF CARBON QUANTUM DOTS FUNCTIONALIZED WITH N- AND S-CONTAINING GROUPS

2021 ◽  
Vol 18 (2) ◽  
pp. 12-17
Author(s):  
N.Kh. Ibrayev ◽  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Citric Acid ◽  
Luminescent Properties ◽  
Carbon Quantum Dots ◽  
Quantum Yields ◽  
Dialysis Membrane ◽  
Spectral And Luminescent Properties

In the presented work, carbon quantum dots were obtained by microwave synthesis based on citric acid and Lcysteine. The resulting particles were characterized by electron and probe microscopy, dynamic light scattering and Fourier transform infrared spectroscopy. The spectral and luminescent properties were investigated for the initial solution of carbon quantum dots, as well as solutions obtained as a result of dialysis of the synthesized product. It is shown that all samples exhibit the same optical properties. At the same time, the measurement of quantum yields showed that carbon dots that have passed through the dialysis membrane have the best fluorescent ability.

scholarly journals Tuning the Emission Color of Hydrothermally Synthesized Carbon Quantum Dots by Precursor Engineering

2019 ◽  
Vol 35 (1) ◽  
Author(s):  
Mai Xuan Dung ◽  
Mai Van Tuan ◽  
Pham Truong Long ◽  
Nguyen Thi Mai
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Citric Acid ◽  
Quantum Yield ◽  
Quantum Dot ◽  
Carbon Dots ◽  
Carbon Quantum Dots ◽  
Water Soluble ◽  
Silicon Quantum Dots ◽  
Emission Quantum Yield

Water-soluble, biocompatible, and highly luminescence carbon quantum dots (CQDs) have synthesized successfully from a citric acid (CA) and ethylenediamine (EDA) by using different approaches. Although the emission quantum yield of CQDs could be as high as 80% their emission spectrum is usually dominated by surface fluorophore groups and maximized at about 450 nm. Herein, we examined the effects of acid and amine precursors on the photoluminescence (PL) of resulting CQDs by systematic comparison the optical properties of CQDs obtained from CA, PA (phthalic acid) and EDA, ANL (aniline). UV-vis and PL spectroscopic studies revealed that the absorption onset varied from 325 nm to 400 nm while PL maximum changed from 390 nm to 450 nm by engineering acid and amine precursors. The emission quantum yield was also changed from 9 to 70%, depending on the used acid-amine precursors.  Keywords Carbon quantum dots, hydrothermal synthesis, color tuning, photoluminescence, acid, amine References K. Wang, Z. Gao, G. Gao, Y. Wo, Y. Wang, G. Shen, D. Cui, Systematic safety evaluation on photoluminescent carbon dots, Nanoscale Res. Lett. 8 (2013) 1–9. doi:10.1186/1556-276X-8-122.[2] K. Jiang, S. Sun, L. Zhang, Y. Lu, A. Wu, C. Cai, H. Lin, Red, Green, and Blue Luminescence by Carbon Dots: Full-Color Emission Tuning and Multicolor Cellular Imaging, Angew. Chemie Int. Ed. 54 (2015) 5360–5363. doi:10.1002/anie.201501193.[3] M.X. Dung, P. Mohapatra, J.K. Choi, J.H. Kim, S. Jeong, H.D. Jeong, InP quantum dot-organosilicon nanocomposites, Bull. Korean Chem. Soc. 33 (2012) 1491–1504. doi:10.5012/bkcs.2012.33.5.1491.[4] X. Mai, Q. Hoang, The Large-Scale Synthesis of Vinyl-Functionalized Silicon Quantum Dot and Its Application in Miniemulsion Polymerization, J. Nanomater. 2016 (2016).[5] M.X. Dung, D.D. Tung, S. Jeong, H.D. Jeong, Tuning optical properties of Si quantum dots by ??-conjugated capping molecules, Chem. - An Asian J. 8 (2013) 653–664. doi:10.1002/asia.201201099.[6] M.X. Dung, H.D. Jeong, Synthesis of styryl-terminated silicon quantum dots: Reconsidering the use of methanol, Bull. Korean Chem. Soc. 33 (2012) 4185–4187.doi:10.5012/bkcs.2012.33.12.4185.[7] V.-T. Mai, N.H. Duong, X.-D. Mai, Surface Polarity Controls the Optical Properties of One-Pot Synthesized Silicon Quantum Dots, Chem. Phys. (2018).doi:10.1016/j.chemphys.2018.11.012.[8] V.-T. Mai, Q. Hoang, X. Mai, Enhanced Red Emission in Ultrasound-Assisted Sol-Gel Derived ZnO/PMMA Nanocomposite, Adv. Mater. Sci. Eng. 2018 (2018) 1–8. doi:10.1155/2018/7252809.[9] J. Schneider, C.J. Reckmeier, Y. Xiong, M. Von Seckendorff, A.S. Susha, P. Kasak, A.L. Rogach, Molecular fluorescence in citric acid-based carbon dots, J. Phys. Chem. C. 121 (2017) 2014–2022. doi:10.1021/acs.jpcc.6b12519.[10] F. Ehrat, S. Bhattacharyya, J. Schneider, A. Löf, R. Wyrwich, A.L. Rogach, J.K. Stolarczyk, A.S. Urban, J. Feldmann, Tracking the Source of Carbon Dot Photoluminescence: Aromatic Domains versus Molecular Fluorophores, Nano Lett. 17 (2017) 7710–7716. doi:10.1021/acs.nanolett.7b03863.[11] M. Shamsipur, A. Barati, A.A. Taherpour, M. Jamshidi, Resolving the Multiple Emission Centers in Carbon Dots: From Fluorophore Molecular States to Aromatic Domain States and Carbon-Core States, J. Phys. Chem. Lett. 9 (2018) 4189–4198. doi:10.1021/acs.jpclett.8b02043.[12] T.H.T. Xuan-Dung Mai, Quang-Bac Hoang, Hong Quan To, Phuong Le Thi, The synthesis of highly luminescent carbon quantum dots, (2017) (47)20-26.[13] M.X.D. Lê Thị Phượng, Lê Quang Trung, Đỗ Thị Thu Hòa, Doãn Diệu Thúy, Ảnh hưởng của tỷ lệ Acid/Amine đến cấu trúc bề mặt và hiệu suất phát xạ của chấm lượng tử carbon, (2018) (55) 67-74.[14] M.V.T. Hoàng Quang Bắc, Trần Thu Hương, Đinh Thị Châm, Nguyễn Thị Loan, Nguyễn Thị Quỳnh, Bùi Thị Huệ, Lê Thị Thùy Hương, Mai Xuân Dũng, Nghiên cứu tổng hợp hạt nano huỳnh quang từ một số rau củ quả, (2017) 4(40), 70-73.[15] Y. Song, S. Zhu, S. Zhang, Y. Fu, L. Wang, X. Zhao, B. Yang, Investigation from chemical structure to photoluminescent mechanism: a type of carbon dots from the pyrolysis of citric acid and an amine, J. Mater. Chem. C. 3 (2015) 5976–5984. doi:10.1039/C5TC00813A.[16] T.H. Ngà, B.T. Hạnh, M.X. Dũng, Tính toán lượng tử làm rõ tính chất quang học của chấm lượng tử carbon, Tạp Chí KHoa Học - Đại Học Sư Phạm Hà Nội 2. 56 (2018).[17] S. Zhu, Q. Meng, L. Wang, J. Zhang, Y. Song, H. Jin, K. Zhang, H. Sun, H. Wang, B. Yang, Highly photoluminescent carbon dots for multicolor patterning, sensors, and bioimaging, Angew. Chemie - Int. Ed. 52 (2013) 3953–3957. doi:10.1002/anie.201300519.[18] Q.-B. Hoang, V.-T. Mai, D.-K. Nguyen, D.Q. Truong, X.-D. Mai, Crosslinking induced photoluminescence quenching in polyvinyl alcohol-carbon quantum dot composite, Mater. Today Chem. 12 (2019) 166–172. doi:10.1016/j.mtchem.2019.01.003.

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.

Green and efficient synthesis of carbon quantum dots and their luminescent properties

2019 ◽  
Vol 206 ◽  
pp. 158-163 ◽  
Author(s):  
Langfeng Zhou ◽  
Meng Qiao ◽  
Lei Zhang ◽  
Lu Sun ◽  
Yang Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Luminescent Properties ◽  
Carbon Quantum Dots ◽  
Efficient Synthesis

scholarly journals Temperature Dependence of Quantum Dots-In-Well Infrared Photo Detectors (QDIPs) using Photoluminescence

2019 ◽  
Vol 8 (2S2) ◽  
pp. 254-259
Keyword(s):  
Quantum Dots ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Dark Current ◽  
Infrared Detectors ◽  
Normal Incidence ◽  
Infrared Detection ◽  
Intersubband Transitions ◽  
Inas Quantum Dots ◽  
Photo Detectors

A research of quantity dots-in-well infrared photo detectors (QDIPs) produces helpful outcomes for creating a twocolor QDIP. Quantum dot infrared photo detectors (QDIPs) have been shown to be a main technology in mid-and longwavelength infrared detection owing to their capacity for normal incidence operation and low dark current. This research explores infrared detectors based on intersubband transitions in a novel heterostructure of InAs / In0.15 Ga0.85 As / GaAs quantum dotsin-well (DWELL). The InAs quantum dots are also positioned in an In0.15 Ga0.85 in the DWELL framework, which in turn is well positioned with the In0.1Ga0.9As obstacle in GaAs quantum. Using fourier transform infrared spectroscopy, the optical characteristics of the sample were researched using photoluminescence and photocurrent. Spectrally adjustable reaction was noted at 6.2μm and 7.5μm with prejudice and lengthy wave IR reaction

scholarly journals Preparation and Properties of Cyanobacteria-Based Carbon Quantum Dots/Polyvinyl Alcohol/ Nanocellulose Composite

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1143 ◽  
Author(s):  
Li Xu ◽  
Ying Li ◽  
Shiyu Gao ◽  
Yue Niu ◽  
Huaxuan Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Polyvinyl Alcohol ◽  
Water Resistance ◽  
Composite Films ◽  
Barrier Properties ◽  
Carbon Quantum Dots ◽  
Infrared Light ◽  
Quantum Yields ◽  
Hydroxyl Groups ◽  
Light Barrier

Blue luminescent carbon quantum dots (CQDs) were prepared from cyanobacteria by a hydrothermal method. The PL quantum yields of the obtained CQDs was 5.30%. Cyanobacteria-based carbon quantum dots/polyvinyl alcohol/nanocellulose composite films were prepared, which could emit bright blue under UV light. FTIR characterization showed that the composite films had hydroxyl groups on the surface and no new groups were formed after combining the three materials. The photoluminescence (PL) spectra revealed that the emission of the prepared CQDs was excitation dependent. Studies on the water resistance performance and light barrier properties of the composite films showed that they possessed higher water resistance properties and better UV/infrared light barrier properties. Therefore, we report the cyanobacteria-based carbon quantum dots/polyvinyl alcohol/nanocellulose composite films have the potential to be applied in flexible packaging materials, anti-fake materials, UV/infrared light barrier materials and so on.

Physical Properties of Thin Films of GaAs and AlxGa1-xAs Grown by Solid-Arsenic-Based MOCVD

2014 ◽  
Vol 976 ◽  
pp. 25-29
Author(s):  
Roberto Castillo-Ojeda ◽  
Joel Diaz-Reyes ◽  
Miguel Galván-Arellano ◽  
Ramon Peña-Sierra
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Low Temperature ◽  
Growth Process ◽  
Carbon Incorporation ◽  
Infrared Measurements ◽  
Hall Effect Measurements ◽  
Low Temperature Photoluminescence

We have studied the optical properties of GaAs and AlxGa1-xAs thin films using low-temperature photoluminescence and Fourier transform infrared spectroscopy. The GaAs and its alloys were grown by MOCVD using solid arsenic instead of arsine, as the arsenic precursor. The gallium and aluminium precursors were trimethylgallium (TMGa) and trimethylaluminium (TMAl), respectively. Some difficulties for growing AlxGa1-xAs by solid-arsenic-based MOCVD system are the composition homogeneity of the layers and the oxygen and carbon incorporation during the growth process. The composition homogeneity of the films was evaluated by low-temperature photoluminescence. Infrared measurements on the samples allowed the identification of the residual impurities, which are carbon-substitutional, Ga2O3, molecular oxygen, humidity and two unidentified impurities. Samples grown at temperatures lower than 750°C were highly resistive, independently of the ratio V/III used; the samples grown at higher temperatures were n-type, as it was proved by Hall effect measurements.

Nitrogen-doped carbon dot mediated fluorescence on–off assay for highly sensitive detection of I− and Br− ions

2018 ◽  
Vol 42 (17) ◽  
pp. 14332-14339 ◽  
Author(s):  
Nan Zhou ◽  
Xingwei Zhang ◽  
Yanping Shi ◽  
Zeliang Li ◽  
Zhibiao Feng
Keyword(s):  
Quantum Dots ◽  
Citric Acid ◽  
Carbon Source ◽  
Nitrogen Source ◽  
Carbon Quantum Dots ◽  
Sensitive Detection ◽  
Nitrogen Doped ◽  
Highly Sensitive ◽  
Highly Sensitive Detection ◽  
Nitrogen Doped Carbon

Nitrogen-doped carbon quantum dots (CDs) were synthesized in ethanol media by using citric acid (CA) as the carbon source and ethanediamine (EDA) as the nitrogen source.

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