scholarly journals An Alternative Route to Obtain Carbon Quantum Dots from Photoluminescent Materials in Peat

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1492 ◽  
Author(s):  
Rafael Souza da Costa ◽  
Wiliam Ferreira da Cunha ◽  
Nizamara Simenremis Pereira ◽  
Artemis Marti Ceschin
Keyword(s):  
Quantum Dots ◽  
Aromatic Compounds ◽  
Elemental Carbon ◽  
Low Cost ◽  
Carbon Quantum Dots ◽  
Raw Material ◽  
Transmission Electron ◽  
Photoluminescent Materials ◽  
Average Size ◽  
Green Coloration

Peat, an organic compound easily found in the soil (easy to acquire), has more than 50% elemental carbon in its composition and can be used as raw material to produce carbon quantum dots (CQDs, C-dots, Carbon Dots). In this work we describe two simple and low-cost routes for the acquisition of these photoluminescent materials based on peat. The final products were characterized by Fourier transform infrared spectroscopy (FTIR), absorption (UV-Vis) and emission (PL) spectra and high-resolution transmission electron microscopy (HRTEM). The produced CQDs have an average size of 3.5 nm and exhibit coloration between blue and green. In addition, it is possible to produce photoluminescence by means of the aromatic compounds also present in the composition of the peat, in turn exhibiting an intense green coloration. The results indicate great versatility of peat for the production of photoluminescent materials.

scholarly journals The Synthesis of Highly Fluorescent Carbon Quantum Dots from Tartaric Acid

2020 ◽  
Vol 10 (6) ◽  
pp. 7337-7342
Keyword(s):  
Quantum Dots ◽  
Tartaric Acid ◽  
Low Cost ◽  
Photovoltaic Cell ◽  
Carbon Quantum Dots ◽  
Fluorescent Properties ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Bio Compatibility ◽  
Fluorescent Carbon

Carbon quantum dots (C-dots) have attracted tremendous interest because of their advantageous characteristics of cost-effectiveness and fluorescent nature. In this study, we developed a simple, economical, and effective method for the green synthesis of fluorescent carbon quantum dots using low-cost hydrothermal treatment of Tartaric acid as a carbon source. The as-synthesized C-dots were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), UV–Vis absorption spectroscopy, Spectrofluorophotometry, Fourier transform infrared spectroscopy (FT-IR). The synthesized C-dots possess stable fluorescent properties, good, bio-compatibility, and high quantum yield. The C-dots are highly crystalline, with longitudinal dimensions of 3.128 ± 0.17 nm. The XRD and TEM analysis indicates that the synthesized C-dots have a nearly spherical morphology and narrow size distribution. The results suggest that the proposed C-dots could be utilized for photovoltaic cell, bioimaging, drug delivery, and biosensor applications.

scholarly journals The Effect of Amino-functionalization on Photoluminescence Properties of Sugarcane Bagasse-derived Carbon Quantum Dots

2021 ◽  
Vol 21 (1) ◽  
pp. 62
Author(s):  
Muhammad Wahyu Nugraha ◽  
Nonni Soraya Sambudi ◽  
Laksmi Dewi Kasmiarno ◽  
Norashikin Ahmad Kamal
Keyword(s):  
Quantum Dots ◽  
Particle Size ◽  
Sugarcane Bagasse ◽  
Low Cost ◽  
Carbon Quantum Dots ◽  
Photoluminescence Intensity ◽  
One Pot ◽  
Transmission Electron ◽  
Amino Functionalization ◽  
Natural Carbon

In the present study, amino-functionalized carbon quantum dots (N-CQDs) were prepared from sugarcane bagasse using a simple one-pot hydrothermal method. Both ethylenedinitrilotetraacetic (EDTA) & ethylenediamine (EDA) were used as carbon and amino sources, respectively. The emerging utilization of natural carbon precursors is critically essential considering its low cost, eco-friendly, and unexploited by-products (e.g., sugarcane bagasse), which may have sustainable economic and strategic benefits. The as-prepared N-CQDs were characterized using High-Resolution Transmission Electron Microscope (HRTEM), Fourier Transform Infrared Spectroscopy (FTIR), UV-vis absorption spectroscopy, and photoluminescence spectroscopy. The influences of amine groups were investigated. The as-prepared N-CQDs photoluminescence intensity increased and quenched significantly with EDTA and EDA amino-functionalization, respectively, with the highest quantum yield at 21.21%, 2.4 times higher than non-functionalized CQDs. Furthermore, the amino-functional groups can alter the CQDs structure and particle size ranging from 4.197±1.058 nm to 9.704±1.428 nm. Hence, the N-CQDs produced exhibit highly tunable photoluminescence and particle size potentially applicable in diverse applications.

scholarly journals ZnSe Quantum Dots through a Facile one Pot Synthesis Process

2015 ◽  
Vol 34 ◽  
pp. 73-78
Author(s):  
Irtiqa Syed ◽  
Santa Chawla
Keyword(s):  
Quantum Dots ◽  
Band Gap ◽  
Quantum Confinement Effect ◽  
Hexagonal Phase ◽  
Fluorescence Decay ◽  
Synthesis Process ◽  
One Pot ◽  
One Pot Synthesis ◽  
Transmission Electron ◽  
Average Size

A novel one pot synthesis approach in oleic acid medium was employed to obtain monophasic ZnSe quantum dots (QD) of average size 3.7nm. The QDs were well crystalline in hexagonal phase as revealed by x-ray diffraction and high resolution transmission electron microscopy (HRTEM) studies. The ZnSe QDs exhibit sharp emission peak in the blue (465nm) with 385picosecond fluorescence decay time. The theoretical band gap corresponding to 3.7nm ZnSe QDs matched well with the measured 3.11eV band gap of synthesized QDs which thus showed quantum confinement effect.

Ball-Milling Graphite Used for Synthesis of Biocompatible Blue Luminescent Graphene Quantum Dots

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Zhou J ◽  
◽  
Dong Y ◽  
Ma Y ◽  
Zhang T ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ball Milling ◽  
Graphene Quantum Dots ◽  
Raw Material ◽  
Hydroxyl Groups ◽  
High Quality ◽  
Widespread Application ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Graphene Quantum Dots (GQDs) have been prepared by oxidationhydrothermal reaction, using ball-milling graphite as the starting materials. The prepared GQDs are endowed with excellent luminescence properties, with the optimum emission of 320nm. Blue photoluminescent emitted from the GQDs under ultraviolet light. The GQDs are ~3nm in width and 0.5~2 nm in thickness, revealed by high-resolution transmission electron microscopy and atomic force microscopy. In addition, Fourier transform infrared spectrum evidences the existence of carbonyl and hydroxyl groups, meaning GQDs can be dispersed in water easily and used in cellar imaging, and blue area inside L929 cells were clearly observed under the fluorescence microscope. Both low price of raw material and simple prepared method contribute to the high quality GQDs widespread application in future.

scholarly journals Facile Synthesis of Surface-Modified Carbon Quantum Dots (CQDs) for Biosensing and Bioimaging

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3313 ◽  
Author(s):  
Łukasz Janus ◽  
Julia Radwan-Pragłowska ◽  
Marek Piątkowski ◽  
Dariusz Bogdał
Keyword(s):  
Quantum Dots ◽  
Chemical Structure ◽  
Water Solubility ◽  
Organic Dyes ◽  
Carbon Quantum Dots ◽  
Raw Material ◽  
The Novel ◽  
Surface Modified ◽  
Synthesis Approach ◽  
Effective Analysis

Recently, fluorescent probes became one of the most efficient tools for biosensing and bioimaging. Special attention is focused on carbon quantum dots (CQDs), which are characterized by the water solubility and lack of cytotoxicity. Moreover, they exhibit higher photostability comparing to traditional organic dyes. Currently, there is a great need for the novel, luminescent nanomaterials with tunable properties enabling fast and effective analysis of the biological samples. In this article, we propose a new, ecofriendly bottom-up synthesis approach for intelligent, surface-modified nanodots preparation using bioproducts as a raw material. Obtained nanomaterials were characterized over their morphology, chemical structure and switchable luminescence. Their possible use as a nanodevice for medicine was investigated. Finally, the products were confirmed to be non-toxic to fibroblasts and capable of cell imaging.

scholarly journals The Application of Green-Synthesis-Derived Carbon Quantum Dots to Bioimaging and the Analysis of Mercury(II)

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Qianchun Zhang ◽  
Xiaolan Zhang ◽  
Linchun Bao ◽  
Yun Wu ◽  
Li Jiang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Hela Cells ◽  
Photoelectron Spectroscopy ◽  
Water Solubility ◽  
Limit Of Detection ◽  
Carbon Quantum Dots ◽  
Coefficient Of Determination ◽  
Serum Samples ◽  
X Ray ◽  
Transmission Electron

Ginkgo leaves were used as precursors for the hydrothermal synthesis of carbon quantum dots (CQDs), which were subsequently characterized by transmission electron microscopy as well as Fourier-transform infrared, X-ray powder diffraction, and X-ray photoelectron spectroscopy. The prepared CQDs exhibited a fluorescence quantum yield of 11% and superior water solubility and fluorescence stability, as well as low cytotoxicities and excellent biocompatibilities with A549 and HeLa cells; these CQDs were also used to bioimage HeLa cells. Moreover, owing to the experimental observation that Hg2+ quenches the fluorescence of the CQDs in a specific and sensitive manner, we developed a method for the detection of Hg2+ using this fluorescence sensor. The sensor exhibited a linear range for Hg2+ of 0.50–20 μM, with an excellent coefficient of determination (R2 = 0.9966) and limit of detection (12.4 nM). In practice, the proposed method was shown to be highly selective and sensitive for the monitoring of Hg2+ in lake water and serum samples.

scholarly journals Stable Copper Tin Sulfide Nanoflower Modified Carbon Quantum Dots for Improved Supercapacitors

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
Zhen Bi ◽  
Lanyan Huang ◽  
Chaoqun Shang ◽  
Xin Wang ◽  
Guofu Zhou
Keyword(s):  
Quantum Dots ◽  
Volume Change ◽  
Electrode Materials ◽  
Rate Capability ◽  
Carbon Quantum Dots ◽  
High Rate ◽  
Electrochemical Performances ◽  
Tin Sulfide ◽  
Transmission Electron ◽  
Tin Sulfides

Copper tin sulfides (CTSs) have widely been investigated as electrode materials for supercapacitors owing to their high theoretical pseudocapacitances. However, the poor intrinsic conductivity and volume change during redox reactions hindered their electrochemical performances and broad applications. In this study, carbon quantum dots (CQDs) were employed to modify CTSs. The structures and morphologies of obtained materials were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD revealed CTSs were composed of Cu2SnS3 and Cu4SnS4, and TEM suggested the decoration of CQDs on the surface of CTSs. With the decoration of CQDs, CTSs@CQDs showed a remarkable specific capacitance of 856 F·g−1 at 2 mV·s−1 and a high rate capability of 474 F·g−1 at 50 mV·s−1, which were superior to those of CTSs (851 F·g−1 at 2 mV·s−1 and 192 F·g−1 at 50 mV·s−1, respectively). This was mainly ascribed to incorporation of carbon quantum dots, which improved the electrical conductivity and alleviated volume change of CTSs during charge/discharge processes.

scholarly journals Formation of ZnO/Zn0.5Cd0.5Se Alloy Quantum Dots in the Presence of High Oleylamine Contents

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 999
Author(s):  
Yi-An Chen ◽  
Kuo-Hsien Chou ◽  
Yi-Yang Kuo ◽  
Cheng-Ye Wu ◽  
Po-Wen Hsiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Particle Size ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Average Size ◽  
Alloy Quantum Dots ◽  
First Time

To the best of our knowledge, this report presents, for the first time, the schematic of the possible chemical reaction for a one-pot synthesis of Zn0.5Cd0.5Se alloy quantum dots (QDs) in the presence of low/high oleylamine (OLA) contents. For high OLA contents, high-resolution transmission electron microscopy (HRTEM) results showed that the average size of Zn0.5Cd0.5Se increases significantly from 4 to 9 nm with an increasing OLA content from 4 to 10 mL. First, [Zn(OAc)2]–OLA complex can be formed by a reaction between Zn(OAc)2 and OLA. Then, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) data confirmed that ZnO is formed by thermal decomposition of the [Zn(OAc)2]–OLA complex. The results indicated that ZnO grew on the Zn0.5Cd0.5Se surface, thus increasing the particle size. For low OLA contents, HRTEM images were used to estimate the average sizes of the Zn0.5Cd0.5Se alloy QDs, which were approximately 8, 6, and 4 nm with OLA loadings of 0, 2, and 4 mL, respectively. We found that Zn(OAc)2 and OLA could form a [Zn(OAc)2]–OLA complex, which inhibited the growth of the Zn0.5Cd0.5Se alloy QDs, due to the decreasing reaction between Zn(oleic acid)2 and Se2−, which led to a decrease in particle size.

Low-Cost Synthesis and Morphology Control of Magnesium Oxysulfate Hydrate Whiskers

2014 ◽  
Vol 936 ◽  
pp. 986-991
Author(s):  
Chuan Hui Gao ◽  
Li Ding ◽  
Yu Min Wu ◽  
Chuan Xing Wang ◽  
Jun Xu
Keyword(s):  
Electron Microscope ◽  
Raw Materials ◽  
Low Cost ◽  
Hydrothermal Process ◽  
Control Agent ◽  
Raw Material ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Magnesium Oxysulfate

A low-cost raw material, bittern obtained from the production process of sea salt, was used to prepare magnesium oxysulfate hydrate (MgSO4·5Mg (OH)2·2H2O, abbreviated as 152MOS) whiskers via hydrothermal synthesis with ammonia and magnesium sulfate as the other starting raw materials. The bittern was firstly filtered and then used directly without de-coloring. X-ray powder diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction (SAED), energy dispersive X-ray spectroscopy (EDX) and scanning electron microscope (SEM) were employed to investigate the composition and morphology of the products. It was found that the 152MOS whiskers synthesized from bittern at 190°C for 3 hours exhibited fanlike morphology. The formation of the fanlike whiskers was inhibited and most of the whiskers presented as single fibers when ethanol was used as crystal control agent in the hydrothermal process. From the two-dimensional steps observed at tips of the whiskers, a possible growth mechanism was speculated that it was the extension of dislocations that made the growth of the whiskers.

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.

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