In Situ Time‐Dependent and Progressive Oxidation of Reduced State Functionalities at the Nanoscale of Carbon Nanoparticles for Polarity‐Driven Multiscale Near‐Infrared Imaging

Srivastava, Indrajit; Misra, Santosh K.; Tripathi, Indu; Schwartz-Duval, Aaron S.; Pan, Dipanjan

doi:10.1002/adbi.201800009

Cited by 21 publications

(31 citation statements)

References 42 publications

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] These nanodots have a multitude of intriguing advantages such as their water solubility, low toxicity, high biocompatibility, easy synthesis techniques, and complementary energy and charge transfer properties. [16][17][18][19][20][21][22][23][24][25] However, despite considerable efforts, many questions remain about the intrinsic mechanisms governing their photoluminescence (PL) and its subsequent capability to participate in photoinduced charge-transfer processes. 26,27 For charge-transfer processes, having a precise control over the interactions between the two components is of prime importance.…”

Section: Introductionmentioning

confidence: 99%

Influence of Electron Acceptor and Electron Donor on the Photophysical Properties of Carbon Dots: A Comparative Investigation at the Bulk‐State and Single‐Particle Level

Srivastava

Khamo

Pandit

et al. 2019

Adv Funct Materials

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Carbon dots (CDs) are extensively studied to investigate their unique optical properties such as undergoing electron transfer in different scenarios. This study presents an in-depth investigation to study the ensemble-averaged state/bulk state and single-particle level photophysical properties of CDs that have been passivated with electron-accepting (CD-A) and electron-donating molecules (CD-D) on their surface. Our ensemble-averaged state experiments including UV-Vis absorbance titrations, time-resolved photoluminescence (PL) spectra, and 2D emission studies depicted that both CD-A or CD-D had a blue-shift in emission, with a drastic increase in emission intensity, and consequently higher quantum yields, and that acceptor populations (CD-A) dominate overall photophysical properties. Interestingly, transmission electron microscopy and atomic force microscopy revealed that the mixing of donor and acceptor particles (CD-A+ CD-D) leads to a formation of at least two associated geometries, which was dependent on time, concentration, intramolecular electron/charge transfer and hydrogen bonding. On the other hand, single-particle studies revealed that the instantaneous intensity of CDs was comparable, but that CD-A and CD-D have a larger on-time duty cycle, attributed to an increase of blinking frequency. On-and off-time power-law analysis further revealed that CD-A has a larger off-time distribution slope than bare CDs, This article is protected by copyright. All rights reserved. 3 while their on-time distribution is similar. CD-D exhibits an increase in both on-and off-time distribution slope compared to bare CDs. These results indicate that the electron donor provides additional bright and dark states, while the electron acceptor primarily provides bright states, which can explain the increased blinking frequency in CD-A and CD-D at the single-particle level. Singleparticle studies, however, did not reveal an "acceptor-dominating" scenario based on analysis of instantaneous intensity, bleaching kinetics, and photoblinking, indicating that the direct interaction of CD-A and CD-D may affect their photophysical properties in the bulk state due to formation of hierarchical structural assemblies. We anticipate that these fundamental results will further provide insights towards our understanding of the complex mechanism associated with CD emission, which is one of the key contributors to their successful application. As an immediate application of these CDs, we have shown that they can be used as a sensing array for metal ions and can serve as a powerful toolbox for the technological application of CDs.

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Section: Introductionmentioning

confidence: 99%

Influence of Electron Acceptor and Electron Donor on the Photophysical Properties of Carbon Dots: A Comparative Investigation at the Bulk‐State and Single‐Particle Level

Srivastava

Khamo

Pandit

et al. 2019

Adv Funct Materials

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“…Carbon dots (CDs) have been receiving considerable attention due to their important properties, such as low toxicity, chemical inertness, water solubility, easy functionalization, and excellent biocompatibility relative to traditional organic dyes and inorganic semiconductor quantum dots (0D) . As a consequence, CDs find a wide range of promising applications in the fields of optoelectronics devices, catalysts, energy, in vivo, and biological analysis ,,. Moreover, 0D CDs behave like fluorescent dye exhibiting blue or green or multicolor fluorescence (FL) emission under UV light irradiation .…”

Section: Introductionmentioning

confidence: 99%

Green Synthesis of Carbon Dot Weak Gel from Pear Juice: Optical Properties and Sensing Application

Mondal

Srivastava

2018

ChemistrySelect

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Herein, we report for the first time a low-cost and eco-friendly carbon dot weak gel (CDWG) in the absence of any gelling agent from a pear juice as a green precursor. Our findings showed that the volatile nature of acetone, basic media, and cellulose content in pear juice played key roles in the formation of CDWG. This fabrication strategy of CDWG from a green precursor in absence of gelling agent could be more advantageous over CD-hybrids gel. Further, the fabricated gel exhibited excitation dependent red shifted multicolor (blue-green-yellow-orange) emission due to the presence of characteristic hydrophilic surface in CDs. The other unique feature of the work involved utilization of inherent fluorescent property of CDs in establishing optical interaction between 0D CDWG and 2D reduced graphene oxide (G) and graphene oxide (GO). It may be concluded that the quenching is mainly guided by the electron rich CDs and electron acceptance ability, large specific surface area of G and GO. It is also interesting to note that the introducing of gel property in CDs exhibit improved sensing efficiency and limit of detection of CDWG (1.5 μg ml À 1 ) for G. Further, such optical sensing could be beneficial for the fabrication of optoelectronics, photovoltaic devices and sensing of bio-molecules and metal ions.[a] J.

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“…The ζ-potential values for LnCNPs were found to be positive and greater than +20 mV for all three LnCNPs ( Figure 2 a), confirming sufficient colloidal stability when suspended in water. 46 Interestingly, our synthetic procedure resulted in LnCNPs with varying ζ-potentials. Therefore, a differential degree of counterionic–ligand interaction between the viruses/bacteria and LnCNPs is anticipated leading to distinct fluorescence fingerprints for each of the microorganisms.…”

Section: Resultsmentioning

confidence: 98%

Monitoring the Viral Transmission of SARS-CoV-2 in Still Waterbodies Using a Lanthanide-Doped Carbon Nanoparticle-Based Sensor Array

Alafeef

Dighe

Moitra

et al. 2021

ACS Sustainable Chem. Eng.

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The latest epidemic of extremely infectious coronavirus disease 2019 (COVID-19) has created a significant public health concern. Despite substantial efforts to contain severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) within a specific location, shortcomings in the surveillance of predominantly asymptomatic infections constrain attempts to identify the epidemiological spread of the virus. Continuous surveillance of wastewater streams, including sewage, offers opportunities to track the spread of SARS-CoV-2, which is believed to be found in fecal waste. To demonstrate the feasibility of SARS-CoV-2 detection in wastewater systems, we herein present a novel facilely constructed fluorescence sensing array based on a panel of three different lanthanide-doped carbon nanoparticles (LnCNPs). The differential fluorescence response pattern due to the counterion–ligand interactions allowed us to employ powerful pattern recognition to effectively detect SARS-CoV-2 and differentiate it from other viruses or bacteria. The sensor results were benchmarked to the gold standard RT-qPCR, and the sensor showed excellent sensitivity (1.5 copies/μL) and a short sample-to-results time of 15 min. This differential response of the sensor array was also explained from the differential mode of binding of the LnCNPs with the surface proteins of the studied bacteria and viruses. Therefore, the developed sensor array provides a cost-effective, community diagnostic tool that could be potentially used as a novel epidemiologic surveillance approach to mitigate the spread of COVID-19.

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In Situ Time‐Dependent and Progressive Oxidation of Reduced State Functionalities at the Nanoscale of Carbon Nanoparticles for Polarity‐Driven Multiscale Near‐Infrared Imaging

Cited by 21 publications

References 42 publications

Influence of Electron Acceptor and Electron Donor on the Photophysical Properties of Carbon Dots: A Comparative Investigation at the Bulk‐State and Single‐Particle Level

Influence of Electron Acceptor and Electron Donor on the Photophysical Properties of Carbon Dots: A Comparative Investigation at the Bulk‐State and Single‐Particle Level

Green Synthesis of Carbon Dot Weak Gel from Pear Juice: Optical Properties and Sensing Application

Monitoring the Viral Transmission of SARS-CoV-2 in Still Waterbodies Using a Lanthanide-Doped Carbon Nanoparticle-Based Sensor Array

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