Search query: Luminescent carbon nanodots

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abstract: Similar to its popular older cousins the fullerene, the carbon nanotube, and graphene, the latest form of nanocarbon, the carbon nanodot, is inspiring intensive research efforts in its own right. These surface passivated carbonaceous quantum dots, so called C dots, combine several favorable attributes of traditional semiconductor based quantum dots (namely, size and wavelength dependent luminescence emission, resistance to photobleaching, ease of bioconjugation) without incurring the burden of intrinsic toxicity or elemental scarcity and without the need for stringent, intricate, tedious, costly, or inefficient preparation steps. C dots can be produced inexpensively and on a large scale (frequently using a one step pathway and potentially from biomass waste derived sources) by many approaches, ranging from simple candle burning to in situ dehydration reactions to laser ablation methods. In this Review, we summarize recent advances in the synthesis and characterization of C dots. We also speculate on their future and discuss potential developments for their use in energy conversion/storage, bioimaging, drug delivery, sensors, diagnostics, and composites.
author_names: Sheila N Baker

Gary A Baker
title: Luminescent carbon nanodots: emergent nanolights.
venue: Angewandte Chemie
year: 2010

abstract: A single step hydrothermal mode of carbon nanodots (C dots) synthesis from house hold kitchen garbage such as snake gourd peel extract was successfully carried out. Characterisation of green synthesized C dots were accomplished using UV Visible and FTIR spectroscopy, Spectrofluorimetry and HRTEM. C dots exhibited an appreciable quantum yield of 28.6% Excitation dependent photoluminescence emission properties and pH sensitivity of C dots were also studied in detail. C dots exhibited strikingly selective detection of Fe3+ ions via fluorescence quenching mechanism. Linearity was obtained in a concentration range of 10 100 mM with detection limit of 0.398 mM in accordance with the Stern Volmer relation. The existence of oxygen containing functional moieties in luminescent C dots could be attributed to the effectual complexation between the metal ion and C dots. The selective sensing property of C dots towards Fe3+ ions provide avenue for biochemical analysis related to iron metabolism and diagnosis of anaemia.
author_names: Smrithi Sailaja Prasannakumaran Nair

Nagaraju Kottam

Prasanna Kumar S G
title: Green Synthesized Luminescent Carbon Nanodots for the Sensing Application of Fe3+ Ions
venue: Journal of Fluorescence
year: 2020

abstract: In the present investigation, the authors have adopted a simple and economical method for the synthesis of bright green photoluminescent carbon nanodots (CNDs) from tender coconut water via acid assisted ultrasonic route. Tender coconut water is used as a less expensive and eco friendly carbon precursor to produce well dispersed CNDs possessing a hybrid structural behaviour of both nanocrystalline and amorphous carbon phases. The monodispersed CNDs with spherical morphology and particle size (4 1 nm) were confirmed with the aid of high resolution transmission electron microscopy. The functional groups attached to CNDs are held responsible for the fluorescence nature and mono dispersion that were assessed using Fourier transform infrared spectroscopy. The green fluorescence nature of CNDs was evaluated at a maximum emission at 510 nm with an excitation wavelength of 450 nm, using ultraviolet visible absorption spectrum and photoluminescence spectra. The CNDs with a carbon core and chemical groups over their surface exhibited a fluorescence quantum yield of 60.18% The stability, low cost precursor, rapid reaction and uniform dispersion without chemical functionalisation makes these CNDs synthesised from tender coconut water more advantageous than other sources. This research mainly emphasis on synthesis and characterisation of CNDs with a detailed mechanism for CND formation.
author_names: P S Manoharan

Sathish Chander Dhanabalan

Muthulakshmi Alagan

Santhoshbalaji Muthuvijayan

Joice Sophia Ponraj

Chandra Kishore Somasundaram
title: Facile synthesis and characterisation of green luminescent carbon nanodots prepared from tender coconut water using the acid assisted ultrasonic route
year: 2020

abstract: 'Nanocarbon science' ignited interest owing to its substantial scope in biomedicine, energy and environment beneficial applications. Carbon dots (C dots) a multi faceted nanocarbon material, emerged as a homologue to graphene and henceforth geared extensive investigation both on its properties and applications. Eximious properties like excitation wavelength tunable fluorescence emission, up converted photoluminescence, photon induced electron transfer, low cytotoxicity, chiroptical behavior, high chemical and photostability set the ground for astounding applications of carbon dots. Abundant availability of raw 'green' precursors complementary to other molecular/graphitic precursors make them environmentally benign, inexpensive and ultimately 'nanomaterials of the current decade' This review focuses on the synthesis of carbon dots not only from natural sources but also from other carbonaceous precursors and contemplates the inherent but controversial properties. We also aim to garner the attention of readers to the recent progress achieved by C dots in one of its prestantious area of applications as nanosensors.
author_names: Nagaraju Kottam

Smrithi S P
title: 'Luminescent carbon nanodots: Current prospects on synthesis, properties and sensing applications'
venue: Methods and applications in fluorescence
year: 2020

abstract: Carbon nanodots (C dots) are fascinating carbon materialsthat are attracting increasing interest because they possessdistinct benefits, such as chemical inertness, a lack of opticalblinking, low photobleaching, low cytotoxicity, and excellentbiocompatibility, compared with organic dyes and othersemiconductor nanodots with heavy metal cores.
author_names: Songnan Qu

Xiaoyun Wang

Qipeng Lu

Xingyuan Liu

Lijun Wang
title: A biocompatible fluorescent ink based on water soluble luminescent carbon nanodots.
venue: Angewandte Chemie
year: 2012

abstract: Carbon nanodots (CDs) with a low cytotoxicity have been synthesized by one step microwave assisted pyrolysis of citric acid in the presence of various amine molecules. The primary amine molecules have been confirmed to serve dual roles as N doping precursors and surface passivation agents, both of which considerably enhanced the fluorescence of the CDs.
author_names: Xinyun Zhai

Peng Zhang

Chang-jun Liu

Tao Bai

Wenchen Li

Liming Dai

Wenguang Liu
title: Highly luminescent carbon nanodots by microwave assisted pyrolysis.
venue: Chemical communications
year: 2012

abstract: The continuous synthesis in controlled gas flame reactors is here demonstrated as a very effective approach for the direct and easy production of structurally reproducible carbon nanodots. In this work, the design of a simple deposition system, inserted into the reactor, is introduced. A controlled flame reactor is employed in the present investigation. The system was optimized for the production of carbon nanoparticles including fluorescent nanocarbons. Blue and green fluorescent carbon could be easily separated from the carbon nanoparticles by extraction with organic solvents and characterized by advanced chemical (size exclusion chromatography and mass spectrometry) and spectroscopic analysis. The blue fluorescent carbon comprised a mixture of molecular fluorophores and aromatic domains; the green fluorescent carbon was composed of aromatic domains (10 20 aromatic condensed rings) bonded and/or turbostratically stacked together. The green fluorescent carbon nanodots produced in the flame reactor were insoluble in water but soluble in N methylpyrrolidinone and showed excitation independent luminescence. These results provide insights for a simple and controlled synthesis of carbon nanodots with specific and versatile features, which is a promising pathway for their use in quite different applicative sectors of bioimaging.
author_names: Carmela Russo

Barbara Apicella

Anna Ciajolo
title: Blue and green luminescent carbon nanodots from controllable fuel rich flame reactors
venue: Scientific Reports
year: 2019

abstract: Abstract Although several methods on the preparation of carbon nanodots (CNDs) emitting throughout the visible have been recently reported, in most of the processes the product suffers from inhomogeneity in size and shape limiting their impact. Here, we report the synthesis of undoped and nitrogen doped luminescent carbon nanodots by rapid pyrolysis using ordered mesoporous silica nanorods as confining templates. A rapid thermal decomposition (pyrolysis) within the confined dimensions of their pores leads to a highly uniform size distribution of CNDs with average sizes below 4 nm. These CNDs are synthesized in an extremely short time period (5 min of reaction) by immersion in a fluidized bed reactor that provides heating homogeneity and ensures fast heat transfer. In addition, a rapid release of the homogeneous CNDs can be easily achieved by a simple ultrasonication filtration step that prevents further chemical action on the mesoporous templates. The emission of both undoped and N doped CNDs in colloidal and solid state (with an efficiency of 1 5% originates from a combination of quantum confinement effects and the presence of oxidized surface states; N doping introduces resonant absorption states which participate in emission. Furthermore, we present a simple model to describe the excitation dependent/ independent mechanism of carbon nanodots.
author_names: M Carmen Ortega-Liebana

Nguyen Xuan Chung

Rens Limpens

Leyre Gomez

Jose L Hueso

Jesus Santamaria

Tom Gregorkiewicz
title: Uniform luminescent carbon nanodots prepared by rapid pyrolysis of organic precursors confined within nanoporous templating structures
year: 2017

abstract: Carbon nanodots (CNDs)@BaSO4 hybrid phosphors are fabricated in an easy and low cost process by sequentially assembling Ba2+ and SO42 ions onto the surface of carbon nanodots through electrostatic attraction. CNDs act as the nucleus to attract these reactive ions and provide the luminescent centers in the hybrid phosphors. This strategy is versatile for a variety of negatively charged CNDs with different emission colors. The advantage of the resultant hybrid phosphors is that their luminescence exhibits excellent thermal and photostability, as well as remarkable resistance to strong acid/alkali and common organic solvents. These merits allow for the fabrication of CNDs based light emitting diodes using the CNDs@BaSO4 hybrid phosphors as a color conversion layer.
author_names: Ding Zhou

Yuechen Zhai

Songnan Qu

Di Li

Pengtao Jing

Wenyu Ji

De-Zhen Shen

Andrey L Rogach
title: Electrostatic Assembly Guided Synthesis of Highly Luminescent Carbon Nanodots@BaSO4 Hybrid Phosphors with Improved Stability.
venue: Small
year: 2017

abstract: Abstract Synthesized carbon dots (C dots) from Dioscorea hispida (Gadong tuber) starch were modified with passivating agents such as O O bis(3 aminopropyl)polyethylene glycol 1500 (PEG 1500N and branched polyethyleneimine (BPEI) to increase the functional efficiency of C dots to be used in biological investigations. After surface modification, the C dots decreased in size from 6 25 to 3 20 nm without changing their morphology. The modified C dots were fluorescent, and the fluorescence peak gradually shifted to a longer excitation wavelength (from 420 to 500) Upon modification, thereby elucidating a competitive quantum yield of 15% (C dots PEG 1500N and 12.6% (C dots BPEI) The UV visible spectrum of the C dots modified with PEG 1500N contained an absorption peak at 290 nm, whereas, that of the C dots modified with BPEI contained peak at 360. Fourier transform infrared analysis showed a peak at 1700 cm 1 (C dots PEG 1500N and 1697 cm 1 (C dots BPEI) that corresponds to the amide HCONH carbonyl bond, indicating that PEG 1500N and BPEI had been successfully passivated on the surface of C dots. To examine photothermal response, irradiation was carried out for 5 min using three different instruments which is UV lamp (365 nm) visible lamp and laser (532 nm, 1 W/cm 2 where temperature for each sample increased respectively. C dots demonstrated not losing their luminescent properties upon irradiation to UV lamp and laser for 30 min. Contrary, the intensity of fluorescence reduced when it exposed to the visible lamp for the same period. In vitro studies of the modified C dots with zebrafish Danio rerio revealed that C dots PEG 1500N is non toxic while C dots BPEI is highly toxic to the fish embryos. Significantly, this study has successfully demonstrated that Gadong tuber starch can be used as a starch based modifier for C dots; which possibly can be utilized as a nanocarrier with thermal sensing properties.
author_names: Regina Sisika A Sonthanasamy

Shazrul Fazry

Bohari Mohd Yamin

Azwan Mat Lazim
title: Surface functionalization of highly luminescent carbon nanodots from Dioscorea hispida with polyethylene glycol and branched polyethyleneimine and their in vitro study
venue: Journal of King Saud University Science
year: 2019