Eco-Friendly Fluorescent Carbon Nanodots: Characteristics and Potential Applications

Carbon nanodots are zero-dimensional tiny particles of carbon with outstanding characteristics and potential applications. Carbon nanodots are fluorescent materials and possess unique characteristics such as biocompatibility, photostability, low toxicity, sustainable, and eco-friendly. Fluorescent carbon nanodots are emerging nanomaterials that show promising potential in bioimaging, optical sensing, information encryption and storage, photocatalysis, lasers, drug delivery, energy conversion, and photovoltaic applications. Carbon nanodots can be synthesized at very low cost through various sustainable approaches that employ inexpensive renewable resources as starting materials. Carbon nanodots are fascinating carbon-based materials that have received mass attention from past few years for their substantial applications in diverse fields. Carbon nanodots have a huge impact on both health and environmental applications because of their potential to serve as nontoxic replacements to traditional heavy metal-based quantum dots. Herein we highlight the intriguing characteristics and potential applications of fluorescent carbon nanodots in various fields and their perspective in future

Preparation of N-doped carbon dots based on starch and their application in white LED

N-doped carbon dots (CDs) were synthesized simply and economically by a one-step hydrothermal method using starch as a carbon source and ethylenediamine (EDA) as a nitrogen dopant. The prepared CDs possess the properties of excitation-wavelength dependence and emit blue fluorescence under the excitation wavelength of 365 nm. CDs/starch composite was prepared to achieve the solid-state emission of CDs and their application in light emitting diode (LED) as fluorescent materials. White LED, with CIE coordinates of (0.33, 0.37) and correlated color temperature of 5462 K, was obtained by combining CDs/starch and ultraviolet LED light source, indicating that starch-based CDs have the promising potential in the field of optoelectronic devicesPeer reviewe

One-step hydrothermal synthesis of fluorescence carbon quantum dots with high product yield and quantum yield

A one-step hydrothermal synthesis of nitrogen and silicon co-doped fluorescence carbon quantum dots (N,Si-CQDs), from citric acid monohydrate and silane coupling agent KH-792 with a high product yield (PY) of 52.56% and high quantum yield (QY) of 97.32%, was developed. This greatly improves both the PY and QY of CQDs and provides a new approach for a large-scale production of high-quality CQDs. Furthermore, N,Si-CQDs were employed as phosphors without dispersants to fabricate white light-emitting diodes (WLEDs) with the color coordinates at (0.29, 0.32). It is suggested that N,Si-CQDs have great potential as promising fluorescent materials to be applied in WLEDs.Peer reviewe

Bottom-up synthesis of carbon nanoparticles with higher doxorubicin efficacy

open15siembargoed_20180201Bayda, Samer; Hadla, Mohamad; Palazzolo, Stefano; Kumar, Vinit; Caligiuri, Isabella; Ambrosi, EMMANUELE KIZITO; Pontoglio, Enrico; Agostini, Marco; Tuccinardi, Tiziano; Benedetti, Alvise; Riello, Pietro; Canzonieri, Vincenzo; Corona, Giuseppe; Toffoli, Giuseppe; Rizzolio, FlavioBayda, Samer; Hadla, Mohamad; Palazzolo, Stefano; Kumar, Vinit; Caligiuri, Isabella; Ambrosi, EMMANUELE KIZITO; Pontoglio, Enrico; Agostini, Marco; Tuccinardi, Tiziano; Benedetti, Alvise; Riello, Pietro; Canzonieri, Vincenzo; Corona, Giuseppe; Toffoli, Giuseppe; Rizzolio, Flavi

Recent Developments in Synthesis and Photocatalytic Applications of Carbon Dots

The tunable photoluminescent and photocatalytic properties of carbon dots (CDs) via chemical surface modification have drawn increased attention to this emerging class of carbon nanomaterials. Herein, we summarize the advances in CD synthesis and modification, with a focus on surface functionalization, element doping, passivation, and nanocomposite formation with metal oxides, transition metal chalcogenides, or graphitic carbon nitrides. The effects of CD size and functionalization on photocatalytic properties are discussed, along with the photocatalytic applications of CDs in energy conversion, water splitting, hydrogen evolution, water treatment, and chemical degradation. In particular, the enzyme-mimetic and photodynamic applications of CDs for bio-related uses are thoroughly reviewed

An Efficient Synthesis and Photoelectric Properties of Green Carbon Quantum Dots with High Fluorescent Quantum Yield

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)To greatly improve the production quality and efficiency of carbon quantum dots (CQDs), and provide a new approach for the large-scale production of high-quality CQDs, green carbon quantum dots (g-CQDs) with high product yield (PY) and high fluorescent quantum yield (QY) were synthesized by an efficient one-step solvothermal method with 2,7-dihydroxynaphthalene as the carbon source and ethylenediamine as the nitrogen dopant in this study. The PY and QY of g-CQDs were optimised by adjusting reaction parameters such as an amount of added ethylenediamine, reaction temperature, and reaction duration. The results showed that the maximum PY and QY values of g-CQDs were achieved, which were 70.90% and 62.98%, respectively when the amount of added ethylenediamine, reaction temperature, and reaction duration were 4 mL, 180 °C, and 12 h, respectively. With the optimised QY value of g-CQDs, white light emitting diodes (white LEDs) were prepared by combining g-CQDs and blue chip. The colour rendering index of white LEDs reached 87, and the correlated colour temperature was 2520 K, which belongs to the warm white light area and is suitable for indoor lighting. These results indicate that g-CQDs have potential and wide application prospects in the field of white LEDs.Peer reviewedFinal Published versio

A hydrothermal route to water-stable luminescent carbon dots as nanosensors for pH and temperature

Carbon dots (CDs) as a class of heavy-metal-free fluorescent nanomaterials has drawn increasing attention in recent years due to their high optical absorptivity, chemical stability, biocompatibility, and low toxicity. Herein, we report a facile method to prepare stable CDs by hydrothermal treatment of glucose (glc) in the presence of glutathione (GSH). With this approach, the formation and the surface passivation of CDs are carried out simultaneously, resulting in intrinsic fluorescence emission. The influence of reaction temperature, reaction time and feed ratio of GSH/glc on the photoluminescence property of CDs is studied. The as-prepared CDs are characterized by UV–Vis, photoluminescence, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and transmission electron microscope, from which their structural information and property are interpreted. These CDs may be useful as pH sensors or as versatile nanothermometry devices based on the pronounced temperature dependence of their steady-state fluorescence emission spectra, which changes considerably over the physiological temperature range (15–60 °C).This work was supported by the National Natural Science Foundation of China (No. 50925207), the Natural Science Foundation of Jiangsu Province, China (BK20140157), Programme of Introducing Talents of Discipline to Universities (111 Project B13025), and the Fundamental Research Funds for the Central Universities (JUSRP11418)

Laser-driven direct synthesis of carbon nanodots and application as sensitizers for visible-light photocatalysis

We present the first successful synthesis of monodisperse carbon nanodots (CNDs) with tunable photoluminescence (PL) carried out by laser pyrolysis of two common volatile organic precursors such as toluene and pyridine. Remarkably, the initial chemical composition of the precursor determines the formation of undoped or N-doped CNDs and their corresponding absorption response in the visible range (expanded for the latter). We demonstrate the control and versatility of this synthesis method to tune the final outcome and its potential to explore a great number of potential solvent candidates. Furthermore, we have successfully exploited these CNDs (both undoped and N-doped) as effective sensitizers of TiO2 nanoparticles in the visible-light driven photo-degradation of a cationic dye selected as model organic pollutant

Direct Covalent Immobilization of new Nitrogen-doped Carbon Nanodots by Electrografting for Sensing Applications

This paper reports a facile strategy to covalently immobilize nanosized carbon dots (CD) onto carbon conductive surfaces for sensing applications. The carbon nanodots designed with surface amine groups (N-CD) can be electrografted onto carbon electrodes and, thus, easily covalently immobilized on these conductive surfaces. They have been synthetized by a carbonization method microwave-assisted using preselected low cost and biocompatible precursors, such as D-fructose as primary carbon source and urea as N-donor reagent to obtain peripheral enriched nitrogen CD. The synthetized nanomaterial has been characterized by different techniques, that confirm the presence of size-regular amorphous structures with blue fluorescence when are irradiated with UV light. The highly stable immobilization of N-CD onto the electrode surfaces by electrografting provides hybrid electrodes with greater relative surface area and improved electron transfer properties, demonstrating to be a great promise for electrochemical sensing. Because of its good electrical conductivity, electrical properties, abundant edges sites and high catalytic activity, N-CD immobilized on carbon electrodes efficient amplify the electrochemiluminiscence (ECL) signal from the luminophore [Ru(bpy)3]2+ in a taurine sensor. A linear concentration range from 126 to 1000 μM, a sensitivity of 7.40ⅹ10-4 μM-1 and a detection limit of 37.8 μM were determined for the taurine sensorThis work has been supported by the Spanish Ministerio de Ciencia, Innovación y Universidades through projects CTQ2017-84309-C2-1-R and RED2018-102412-T, and Comunidad Autónoma de Madrid (S2018/NMT-4349 TRANSNANOAVANSENS-CM Program and 2017-T1/BIO-5435 Atracción de Talento Project). The authors thank Professor Hector Abruña the critical review of this wor

Carbon Nanodots Derived from Natural Products

This review highlights recent improvements, and present situations concerning the practical application of, natural productsbased carbon nanodots (CNDs) in nanomedicine, sensors, drug delivery, bio-imaging, solar cells, photocatalysis and nanoencapsulation. CNDs are zero-dimensional  carbonaceous nanomaterials that have recently drawn much attention because of their unique physicochemical properties, such as excellent  biocompatibility and tunable photoluminescence, easy functionalization, solubility in water, dispersibility, and low toxicity. Additionally, they are  environmentally friendly, abundant, easily accessible, and rich in multiple elements. Since CNDs derived from organic products have unique properties,  we explored and found that the properties of CNDs may depend on the preparation method and the used precursors. This study also informs on the   positioning of natural products in nanotechnology