Synthesized Carbon Nanoparticles Research Articles

Dual emitting carbon nanoparticles for tunable white light emission

Eco-friendly, biomass derived single component luminescent materials with dual emission bands hold immense potential in white light emitting devices (WLED). Compared to WLED fabricated from different color emitting carbon nanoparticles, self-reabsorption and degradation will be negligible in single system white light emitting materials which guarantees stability in long run. Herein, we report a facile, inexpensive and sustainable direct thermal decomposition method to synthesize carbon nanoparticles with dual emission bands. Addition of PVP could efficiently enhance the red emission band of carbon nanoparticles. The excitation dependent broad blue-green emission and excitation independent narrow red emission helps to obtain white light emitting carbon nanoparticles. Upon change in excitation wavelength from 410 nm to 370 nm, white light emissions are obtained with tunable CCT value from 2648 K to 8980 K respectively. By virtue of this tunable warm to cool white light emission, single system WLED can be designed suitable for both indoor and outdoor applications.

A new method for synthesis of carbon nanoparticle and its applications

ABSTRACT In the present study, we synthesized carbon nanoparticles with a different method using chitosan, a natural polymer. As a result, carbon nanomaterials were diffused directly through the intestinal membrane, and carbon nanoparticles were obtained. Surface and chemical characterizations of the obtained carbon nanoparticles were determined by different techniques such as FTIR, DLS, SEM, EDX, and UV-visible. Moreover, the cytotoxic effects of the carbon nanoparticles on Saos-2, MCF-7 cancer cells, and HUVEC non-cancerous cells were evaluated with the MTT test. Although the size of these carbon nanoparticles is not as small as carbon nanodots, these nanoparticles were very effective on cancer cells. Interestingly, our results showed that drug-free carbon nanoparticles were remarkably cytotoxic on MCF-7 and Saos-2 cancer cells. In addition, 5FU loaded carbon nanoparticles (IC50: 12 µg/mL) were 3.5 times more effective than 5FU alone (IC50: 43 µg/mL) on MCF-7 cell lines.

Facile Synthesis of Catalyst Free Carbon Nanoparticles From the Soot of Natural Oils

The growth of carbon nanostructures from vegetable oils using a modified conventional approach is a simple and environmentally friendly technology with controllable features. The goal of this study is to develop a simple and environmentally friendly process for making carbon nanoparticles using commercially available, low-cost vegetable oils. The technique involves the controlled burning of “Mustard”, “Olive”, and “Linseed” oils using the traditional clay lamps and collecting the carbon soot on a ceramic plate. The prepared carbon nanoparticles were purified through sonication and subjected to characterization using powder X-ray diffraction, SEM, Fourier transformed infrared, Thermogravimetric and differential scanning calorimetric analyses. The average particle size of carbon nanoparticles as investigated by powder X-Ray Diffraction analyses was found to be 18, 24, and 57 nm for mustard, olive and linseed oils respectively. SEM analyses revealed the surface morphology of these carbon nanostructures as spherical particles. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) providing knowledge about the thermal stability of these carbon nanoparticles. The synthesized carbon nanoparticles were screened for antibacterial activities against different species (e.g., Pseudomonas aeruginosa, Streptococcus haemolyticus, Proteus refrigere and Staphylococcus aureus) and fruitful results have been obtained.

Green approach to synthesize functional carbon nanoparticles at low temperature

• Carbon nanoparticles were synthesized with tomato extract. • Carbon nanoparticles were formed at 60 °C and under atmospheric pressure. • The mild reaction conditions reduce the energy consumption desired in green synthesis. • The particles detected zinc and presented infrared photothermal response. Carbon nanoparticles have demonstrated their potential to develop materials with advanced applications in which their luminescence and biocompatibility are exploited. In the search for sustainable methods to produce these nanoparticles, natural carbon sources such as plant- and animal-based products and by-products have been used. However, the existing procedures are still performed with high temperature, high pressure, and long reaction times. This report proposes a method to synthesize carbon nanoparticles using a tomato extract as the carbon source, followed by precipitation and calcination at a maximum of 60 °C under atmospheric pressure. This calcination temperature is the lowest reported and contributes to establishing a greener synthesis route. The detected fluorescence of these particles covers the entire region of the visible spectrum. The emission intensity is sensitive to zinc cations, demonstrating that this green method produces useful particles in detecting heavy metals similar to those reported by traditional methods. Furthermore, the aqueous solutions of these particles are photothermic when they are irradiated with red light, also showing their usefulness in biomedical developments. Therefore, this green synthesis at a very low temperature contributes to improving the green methods and boosts the sustainable development of advanced functional materials.

Self-activated ‘green’ carbon nanoparticles for symmetric solid-state supercapacitors

Tuning of porosity and surface properties of nanoparticles especially on carbon-based nanomaterials, adopting a ‘greener’ or self-activation synthesis technique for electrical charge storage, is progressing. Herein, we report the self-activation of Teak wood sawdust in a nitrogen atmosphere at different activation temperatures to synthesize carbon nanoparticles. The activated carbon nanoparticles synthesized at 900 °C exhibits a maximum ~ 360 m2 g−1 surface area with ~ 2 nm average pore size diameter. Five electrolytes viz. KOH, KCl, Na2SO4, NaCl, and H3PO4 are used for studying the supercapacitance nature of the activated carbon nanoparticles in a 3-electrode configuration. A maximum specific capacitance of ~ 208 F g−1 @ 0.25 A g−1 is obtained in 1 M KOH as the electrolyte. Two symmetric supercapacitors, aqueous (1 M KOH) and solid-state (PVA/KOH), are fabricated, and their performance difference is compiled. The solid-state symmetric supercapacitor performs in a wider voltage window (1.7 V) with a superior energy density of 27.1 Wh kg−1 at a power density of 178 W kg−1.

Sol-gel synthesized carbon nanoparticles as supercapacitor electrodes with ultralong cycling stability

Recently, high-performance energy storage devices are urgently needed due to the rapid development of miniaturized, portable and high performance electronic equipment. In this work, we present a facile sol-gel technique followed by electrochemical deposition for synthesizing carbon nanoparticles electrode that exhibits the potential to be used as both positive as well as negative supercapacitor material. The technique used here for the synthesis of carbon nanoparticles electrode results in pseudocapacitive behavior instead of typical EDLC. Further, the synthesized carbon nanoparticles electrode exhibits specific capacitance of 73.75 F/g at 0.001 A in potential range of −0.4 to 0.4 V along with excellent cyclic stability even after 9000 GCD cycles. In the positive potential window i.e., from 0 to 0.4 V, the synthesized CNPs electrode exhibits good specific capacitance value of 177.75 F/g at 0.001 A whereas in the negative potential window i.e., from −0.6 to 0 V, it shows specific capacitance of 88 F/g at 0.001 A. These results indicate that the synthesized carbon nanoparticles electrode is a promising material for supercapacitor applications.

Carbon nanodots with tunable luminescence properties synthesized by electrical discharge in octane

We report on the one-step synthesis of luminescent carbon nanodots (C-dots) via an electrical discharge between two graphite electrodes submerged into organic solvent (octane). This is a simple approach for the fabrication of C-dots with tunable photoluminescence (PL) that differs from the other preparation methods, as no post-passivation step is required. The synthesized carbon nanoparticles are of spherical shape and their size is distributed in the range of 2–5 nm and exhibit luminescence sensitive to excitation wavelength.

Soybean-derived blue photoluminescent carbon dots.

Biomass-derived carbon dots (CDs) are biocompatible and have potential for a variety of applications, including bioimaging and biosensing. In this work, we use ground soybean residuals to synthesize carbon nanoparticles by hydrothermal carbonization (HTC), annealing at high temperature, and laser ablation (LA) in a NH4OH solution. The carbon nanoparticles synthesized with the HTC process (HTC-CDs) exhibit photoluminescent characteristics with strong blue emission. The annealing of the HTC-processed carbon particles in the range of 250 to 850 °C causes a loss of the photoluminescent characteristics of the CDs without any significant change in the microstructure (amorphous structure) of the carbon particles. The LA processing of the annealed HTC-processed carbon particles introduces nitrogen-containing surface-functional groups and leads to the recovery of the photoluminescent features that are different from those of the HTC-CDs and dependent on the fraction of nitrogen in the surface-functional groups. The photoluminescence of both the HTC-CDs and LA-CDs is largely due to the presence of N-containing surface-functional groups. The quantum yield of the LA-CDs is more constant than that of the HTC-CDs under continuous UV excitation and does not exhibit a significant reduction after 150 min of excitation. The methods used in this work provide a simple and green strategy to introduce N-surface-functional groups to carbon nanoparticles made from biomass and biowaste and to produce stable photoluminescent CDs with excellent water-wettability.

Carbon Nanoparticles from Lactose and Baking Soda: Light Absorption and Fluorescence

Fluorescent carbon nanoparticles were prepared using an α-lactose and baking soda based colloidal synthesis route. The existence of the synthesized carbon nanoparticles (CNPs) was detected using th...

Interactions between europium and terbium ions and products of starch thermal decomposition: Spectroscopic and quantum chemical study

Addition of lanthanide ions to carbon nanoparticles produced from biological polymers such as starch may significantly improve luminescent characteristics of such nanoparticles. We have synthesized carbon nanoparticles from starch in the presence of europium and terbium ions and studied their dimensions and optical properties. We also did a quantum chemical calculation of possible compounds formed in a solution obtained after hydrothermal treatment of starch in the presence of europium and terbium ions. After 3 h of alkaline hydrolysis of starch at a temperature of 160 °C in the autoclave in the presence of Tb3+ and Eu3+ ions, we observed the formation of nanoparticles with varying size that have luminescent properties different from those of initial substances. Quantum chemical calculations of potential products show that a Eu complex with starch residues (1:5 ratio) is the most thermodynamically possible, and the Eu complex with levoglucosan is the least possible. The probability of europium and terbuim complexation with potential hydrocarbon ligands increases with the appearance of additional bonds that impart stability to the compounds. Of the compounds studied, the most effective donors are complexes with starch units, with the donor properties weakening as the number of links increases.

Boron and nitrogen co-doped carbon dots as a sensitive fluorescent probe for the detection of curcumin.

In this present study, a fluorescent probe was developed to detect curcumin, which is derived from the rhizomes of the turmeric. We used a simple and economical way to synthesize boron and nitrogen co-doped carbon dots (BNCDs) by microwave heating. The maximum emission wavelength of the BNCDs was 450nm at an excitation wavelength of 360nm. The as-prepared BNCDs were characterized by multiple analytical techniques such as transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and infrared spectroscopy. The synthesized carbon nanoparticles had an average particle diameter of 4.23nm. The BNCDs exhibited high sensitivity to the detection of curcumin at ambient conditions. The changes of BNCDs fluorescent intensity show a good linear relationship with the curcumin concentrations in the range 0.2-12.5μM. This proposed method has been successfully applied to detect the curcumin in urine samples with the recoveries of 96.5-105.5%.

Solvothermal Fabrication of Nitrogen-Doped Carbon Nanoparticles as Efficient Catalyst for Oxygen Reduction in KOH Electrolyte

In this study, CCl4, metallic K and melamine were adopted as precursors to prepare nitrogen-doped carbon nanoparticles via a facile solvothermal method, where the CCl4 served as carbon source, K as strong reduction agent, and melamine as N source. The specific surface area of the synthesized carbon nanoparticles is 184.1 m2 g-1 with about 3.7 at.% N doping content. In addition, the electrochemical measurements indicate that the difference of half-wave potential of carbon nanoparticles is only 46 mV relative to commercial 20 %Pt/C and a 4e transfer dominates the oxygen reduction reaction process. The high activity for oxygen reduction could be ascribed to the successful N doping, especially the pyridinic N and graphinic N, and the hierarchical porosity structure containing mesorpores and macropores, which are favorable for the O2 dissociation and electron/ion transport during the reaction.

Fluorescent carbon nanoparticles obtained from charcoal via green methods and their application for sensing Fe3+ in an aqueous medium.

Two green methods (microwave and hydrothermal) were employed for the preparation of water dispersible fluorescent carbon nanoparticles (CNPs) from activated charcoal. Microwave and hydrothermally synthesized carbon nanoparticles, (MW-CNPs) and (HT-CNPs), respectively were characterized by microscopic and spectroscopic techniques. A detailed study of their fluorescence characteristics was made. MW-CNPs and HT-CNPs were tested for metal ion selectivity in aqueous medium. MW-CNPs showed selectivity for Fe3+ among the tested metal ions and important studies such as for interference, linear range and limit of detection were carried out. The application of MW-CNPs for detection of Fe3+ in water was demonstrated.

Structure and Optical Properties of Carbon Nanoparticles Generated by Laser Treatment of Graphite in Liquids.

In this paper, we report the one-step synthesis of luminescent carbon nanoparticles (NPs) via laser irradiation of a graphite target in a solvent [H2 O, ethanol, or a 0.008 m aqueous diethylenetriaminepentaacetic acid (DTPA) solution]. This is a simple approach for the fabrication of carbon dots with tunable photoluminescence (PL) that differs from other preparation methods, as no post-passivation step is required. The unfocused beam of the second harmonic (wavelength 532 nm) of the Nd:YAG laser was used in our experiments. The sizes of the prepared NPs were mainly distributed in the range of 1-8 nm with an average value of 3 nm. Carbon NPs of different inner structure were prepared: hexagonal diamond phase in aqueous DTPA solution, orthorhombic carbon phase in ethanol, and amorphous carbon in water. The synthesized carbon NPs have strong luminescence in the visible region, which makes them attractive for numerous biological applications. The photoluminescence of the synthesized NPs was investigated at different excitation wavelengths, from 260 to 450 nm. The highest intensities of the emission bands were detected for an excitation wavelength of 400 nm.

Chemical Networks And Photoluminescence Properties Of Carbon Nanoparticles Derived Via Sol-gel Method

We have synthesized carbon nanoparticles (CNPs) via the sol-gel method using dextrose as carbon source with different concentration of ethanol. The effects of ethanol concentration (0.2 to 2.0 M) on the chemical network, electrochemical and photoluminescence properties of CNPs were examined using Fourier transform infra-red (FTIR) spectroscopy, Raman spectroscopy, cyclic voltammetry and photoluminescence (PL) spectroscopy. Field emission scanning electron microscopy (FESEM) image of CNPs shows CNPs of 40-80 nm were synthesized by sol-gel method. Chemical network study reveals the presence of various bonds such as C-H, C-H2, C-H3 and aromatic carbon present on the surface of the CNPs. Raman spectra shows that increasing of ethanol concentration decreases the crystalline size of CNPs. Cyclic voltammetry analysis shows prominent oxidation peaks at 0.1-0.2 V whereas the reduction peak observed at 0.2 V. The observed room temperature PL peak at 2.9 eV confirms a blue emission from CNPs.

Synthesis of carbon nanoparticles from commercially available liquified petroleum gas

The aim of this study was to synthesize carbon nanoparticles (CNPs) from commercially available liquefied petroleum gas (LPG). In the research procedure, LPG was reacted with air to construct CNPs. To confirm the successful synthesis of CNPs, we conducted several sample analyses: Gas Chromatography-Mass Spectrometry (GC-MS), Transmission Electron Microscope (TEM), X-ray Diffraction (XRD), and Infrared Spectra (FTIR). We also varied LPG and oxygen mole ratios at 0.8; 2.4; 4.8; and 7.2. The GC-MS results indicated the composition of LPG was propane (58.90%), isobutane (18.35%), butane (22.26%), and butane, 2-methyl (0.48%). The TEM results showed that the particles were spheres with sizes of between 25 and 35 nm. The sizes of particles were controllable, depending on the mole ratio. The XRD results showed mole ratios of LPG and oxygen of 0.80 and 2.40 were natural graphite, whereas the mole ratios of 4.80 and 7.20 were hexagonal graphite. FT-IR results showed CNPs have absorption peaks at wave number (i) 752 (C-H bend sp2); (ii) 835 (C=C); (iii) 1274 (C-O-C vibration); (iv) 1400 and 1600 (C-C stretch aromatic); (v) 2800 (C-H sp2); (vi) 2900 (CH sp3); (vii) 3100 (C-H aromatic); and (viii) 3400 cm-1 (O-H). From the FTIR analysis results, the sample contained allotrope graphite due to detection of peaks at 1400 and 1600 cm-1 (C-C stretch aromatic) and 3100 cm-1 (C-H aromatic).

Development of an electrode modified on the basis of carbon nanoparticles and reduced graphene oxide for simultaneous determination of isoproterenol, uric acid and tryptophan in real samples

Abstract In this research, the electrochemical properties of a carbon paste electrode modified by synthesized carbon nanoparticles (CNPs), reduced graphene oxide (RGO), and a novel derivative of hydroquinone, (Z)-4-(naphthalen-1-ylimino methyl) benzene-1, 2-diol, (NYB) were studied by cyclic voltammetry. The modified electrode was used as an electrochemical sensor for catalytic oxidation of isoproterenol (IP), and it exhibited an excellent electrocatalytic activity for IP with a good electrochemical performance, low overpotential and high conductivity. It was found that under optimum conditions (pH = 7.0) in cyclic voltammetry, the oxidation potential of IP would decrease to about 324 mV at the modified electrode as compared to an unmodified carbon paste electrode. Differential pulse voltammetry (DPV) exhibited two linear dynamic ranges of 0.5 to 80.0 μM and 80.0 to 1000.0 μM for IP. Also, the selectivity of the prepared electrochemical sensor was checked for determination of IP in the presence of uric acid (UA) and Tryptophan (Try). The detection limit for IP was found to be 0.065 μM.

Binding analysis of carbon nanoparticles to human immunoglobulin G: Elucidation of the cytotoxicity of CNPs and perturbation of immunoglobulin conformations

The chemical compositions, sizes and fluorescent properties of synthesized carbon nanoparticles (CNPs) were characterized. Escherichia coli (E. coli) cells were used as a model to study the cytotoxicity of CNPs, and the results of the cellular uptake of CNPs yielded excellent results: the CNPs demonstrated good biocompatibility and were non-toxic to the growth of the E. coli cells. Moreover, to assess the potential toxicity of CNPs to human health, the binding behavior of CNPs with human immunoglobulin G (HIgG) was examined by fluorescence quenching spectroscopy, synchronous fluorescence spectroscopy and circular dichroism spectroscopy under physiological conditions. The fluorescence quenching constants and parameters for the interaction at different temperatures had been calculated according to Scatchard. The thermodynamic parameters, such as enthalpy change (ΔH), entropy change (ΔS) and free energy change (ΔG), were calculated, and the results indicated strong static quenching and showed that van der Waals forces, hydrogen bonds and hydrophobic interactions were the predominant intermolecular forces stabilizing the CNP–HIgG complex. Synchronous fluorescence and circular dichroism spectra provided information regarding the conformational alteration of HIgG in the presence of CNPs. These findings help to characterize the interactions between CNPs and HIgG, which may clarify the potential risks and undesirable health effects of CNPs, as well as the related cellular trafficking and systemic translocation.

"Turn On" Fluorescence Determination of Nitrite Using Green Synthesized Carbon Nanoparticles.

Although several methods have been reported for the determination of nitrite, development of simple, rapid,cost-effective, and sensitive sensors still remains a great challenge.Here, a simple yet very sensitive fluorescent method for the rapid determination of nitrite has been developed. The fluorescent assay is based on the aggregation of PEG6000 coated carbon nanoparticles (PCNs) in the presence of NO2(-) ions resulting in fluorescence enhancement. The assay response was linear in a concentration range of 3.84 × 10(-8) M to 4.97 × 10(-9) M with a detection limit of 2.32 × 10(-9) M. The proposed sensor exhibited good selectivity towards NO2(-) and was successfully applied for the determination of nitrite in milk, borewell water and soil samples.

Fluorescent chemosensor for pyridine based on N-doped carbon dots

Fluorescent carbon dots (CDs) and its nitrogen doped (N-CDs) nanoparticles have been synthesized from lactose as precursor using a bottom-up hydrothermal methodology. The synthesized nanoparticles have been characterized by elemental analysis, FTIR, Raman, TEM, DLS, XPS, and steady-state and life-time fluorescence. The synthesized carbon nanoparticles, CDs and N-CDs, have a size at about 7.7±2.4 and 50±15nm, respectively, and quantum yields of 8% (CDs) and 11% (N-CDs). These techniques demonstrated the effectiveness of the synthesis procedure and the functionalization of the CDs surface with amine and amide groups in the presence of NH3 in aqueous media. The effect of excitation wavelength and pH on the luminescent properties was studied. Under the optimal conditions, the nitrogen doped nanoparticles can be used as pyridine sensor in aqueous media because they show an enhancement of its fluorescence with a good linear relationship. The analytical method is simple, reproducible and very sensitive for pyridine determination.