scholarly journals A Comparative Study of Top-Down and Bottom-Up Carbon Nanodots and Their Interaction with Mercury Ions

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1265
Author(s):  
Federico Bruno ◽  
Alice Sciortino ◽  
Gianpiero Buscarino ◽  
Maria Laura Soriano ◽  
Ángel Ríos ◽  
...  
Keyword(s):  
Optical Properties ◽  
Carbon Dots ◽  
Carbon Nanodots ◽  
Fluorescent Nanoparticles ◽  
Mercury Ions ◽  
Top Down ◽  
Structural And Optical Properties ◽  
Bottom Up ◽  
Interaction Sites ◽  
Sensing Applications

We report a study of carbon dots produced via bottom-up and top-down routes, carried out through a multi-technique approach based on steady-state fluorescence and absorption, time-resolved fluorescence spectroscopy, Raman spectroscopy, infrared spectroscopy, and atomic force microscopy. Our study focuses on a side-to-side comparison of the fundamental structural and optical properties of the two families of fluorescent nanoparticles, and on their interaction pathways with mercury ions, which we use as a probe of surface emissive chromophores. Comparison between the two families of carbon dots, and between carbon dots subjected to different functionalization procedures, readily identifies a few key structural and optical properties apparently common to all types of carbon dots, but also highlights some critical differences in the optical response and in the microscopic mechanism responsible of the fluorescence. The results also provide suggestions on the most likely interaction sites of mercury ions at the surface of carbon dots and reveal details on mercury-induced fluorescence quenching that can be practically exploited to optimize sensing applications of carbon dots.

Fluorescent Nanotechnology: An Evolution in Optical Sensors

2020 ◽  
Vol 17 ◽  
Author(s):  
Dilawar Hassan ◽  
Hadi Bakhsh ◽  
Asif M. Khurram ◽  
Shakeel A. Bhutto ◽  
Nida S. Jalbani ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Sensors ◽  
Light Emission ◽  
Environmental Contaminants ◽  
Fluorescent Nanoparticles ◽  
Sensing Applications ◽  
Properties Of Materials ◽  
Optical Properties Of Materials ◽  
Fluorescent Nanomaterials

Background: The optical properties of nanomaterials have evolved enormously with the introduction of nanotechnology. The property of materials to absorb and/or emit specific wavelength has turned them into one of the most favourite candidates to be effectively utilized in different sensing applications e.g organic light emission diodes (OLEDs) sensors, gas sensors, biosensors and fluorescent sensors. These materials have been reported as a sensor in the field of tissue and cell imaging, cancer detection and detection of environmental contaminants etc. Fluorescent nanomaterials are heling in rapid and timely detection of various contaminants that greatly impact the quality of life and food, that is exposed to these contaminants. Later, all the contaminants have been investigated to be most perilous entities that momentously affect the life span of the animals and humans who use those foods which have been contaminated. Objective: In this review, we will discuss about various methods and approaches to synthesize the fluorescent nanoparticles and quantum dots (QDs) and their applications in various fields. The application will include the detection of various environmental contaminants and bio-medical applications. We will discuss the possible mode of action of the nanoparticles when used as sensor for the environmental contaminants as well as the surface modification of some fluorescent nanomaterials with anti-body and enzyme for specific detection in animal kingdom. We will also describe some RAMAN based sensors as well as some optical sensing-based nanosensors. Conclusion: Nanotechnology has enabled to play with the size, shape and morphology of materials in the nanoscale. The physical, chemical and optical properties of materials change dramatically when they are reduced to nanoscale. The optical properties can become choosy in terms of emission or absorption of wavelength in the size range and can result in production of very sensitive optical sensor. The results show that the use of fluorescent nanomaterials for the sensing purposes are helping a great deal in the sensing field.

scholarly journals Structural and optical properties of SnO2–Al2O3 nanocomposite synthesized via sol-gel route

2015 ◽  
Vol 33 (4) ◽  
pp. 714-718 ◽  
Author(s):  
Neeraj K. Mishra ◽  
Chaitnaya Kumar ◽  
Amit Kumar ◽  
Manish Kumar ◽  
Pratibha Chaudhary ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Properties ◽  
Sol Gel ◽  
Physical Interaction ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Sensing Applications ◽  
Scanning Electron

AbstractA nanocomposite of 0.5SnO2–0.5Al2O3 has been synthesized using a sol-gel route. Structural and optical properties of the nanocomposite have been discussed in detail. Powder X-ray diffraction and scanning electron microscopy with energy-dispersive X-ray diffraction spectroscopy confirm the phase purity and the particle size of the 0.5SnO2–0.5Al2O3 nanocomposite (13 to 15 nm). The scanning electron microscopy also confirms the porosity in the sample, useful in sensing applications. The FT-IR analysis confirms the presence of physical interaction between SnO2 and Al2O3 due to the slight shifting and broadening of characteristic bands. The UV-Vis analysis confirms the semiconducting nature because of direct transition of electrons into the 0.5SnO2–0.5Al2O3 nanocomposites.

scholarly journals Novel properties and applications of carbon nanodots

2018 ◽  
Vol 3 (6) ◽  
pp. 565-597 ◽  
Author(s):  
Lian Xiao ◽  
Handong Sun
Keyword(s):  
Optical Properties ◽  
Carbon Dots ◽  
Carbon Nanodots

Overview of the optical properties and versatile applications of carbon dots.

scholarly journals Fluorescent carbon dots: rational synthesis, tunable optical properties and analytical applications

RSC Advances ◽  
2017 ◽  
Vol 7 (65) ◽  
pp. 40973-40989 ◽  
Author(s):  
Yifan Wang ◽  
Yanwu Zhu ◽  
Shaoming Yu ◽  
Changlong Jiang
Keyword(s):  
Optical Properties ◽  
Carbon Dots ◽  
Sensing Applications ◽  
Analytical Applications ◽  
Tunable Optical Properties ◽  
Fluorescent Carbon Dots ◽  
Fluorescent Carbon

This review summarizes current advances on the design and the employment of fluorescent carbon dots in sensing applications, especially from the point of analytical view.

scholarly journals Top-down and bottom-up approaches to transparent, flexible and luminescent nitrogen-doped carbon nanodot-clay hybrid films

Nanoscale ◽  
2017 ◽  
Vol 9 (29) ◽  
pp. 10256-10262 ◽  
Author(s):  
Konstantinos Dimos ◽  
Francesca Arcudi ◽  
Antonios Kouloumpis ◽  
Ioannis B. Koutselas ◽  
Petra Rudolf ◽  
...  
Keyword(s):  
Carbon Nanodots ◽  
Hybrid Films ◽  
Top Down ◽  
Bottom Up ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon

Transparent, flexible and luminescent hybrid films composed of 2D-ordered nitrogen-doped carbon nanodots and clays are synthesized via top-down and bottom-up approaches.

Structural and Optical Properties of N-Doped and B-Doped Carbon Dots

2020 ◽  
Vol 61 (5) ◽  
pp. 818-825 ◽  
Author(s):  
A. E. Tomskaya ◽  
I. P. Prosvirin ◽  
M. N. Egorova ◽  
S. A. Smagulova ◽  
I. P. Asanov
Keyword(s):  
Optical Properties ◽  
Carbon Dots ◽  
Structural And Optical Properties ◽  
Doped Carbon Dots

scholarly journals Fluorescent Carbon Nanodots as Sensors of Toxic Metal Ions and Pesticides

2021 ◽  
Vol 6 (1) ◽  
pp. 21
Author(s):  
Federico Bruno ◽  
Alice Sciortino ◽  
Gianpiero Buscarino ◽  
Marco Cannas ◽  
Franco Mario Gelardi ◽  
...  
Keyword(s):  
Optical Properties ◽  
Carbon Dots ◽  
Low Cost ◽  
Synthesis Method ◽  
Toxic Metal ◽  
Size Exclusion ◽  
Carbon Nanodots ◽  
Molar Ratios ◽  
Wide Range ◽  
Fluorescent Carbon

Carbon nanodots (CDs) are a new class of fluorescent carbon-based nanomaterials characterized by a plethora of morphologies and sizes. Among these, we can include two different types of CDs, namely, graphitic and diamond-like. This wide range of structures opens up the possibility to design different CDs, with tunable optical properties accordingly to the synthesis method and precursors used. We prepared two different CDs following a bottom-up approach by thermally induced decomposition of organic precursors (namely, citric acid and urea in different molar ratios), and using purification by Size Exclusion Chromatography (SEC). Obtained CDs were characterized by Raman, absorption and fluorescence (PL) spectroscopies to understand structural and optical properties, and by atomic force microscopy (AFM) to elucidate morphology. They feature graphitic and diamond-like carbon structures with highly efficient visible emissions. Their sensing towards Cd and Hg heavy metals has been tested by PL experiments. We found a PL quenching in the presence of concentrations of metal salts starting from 0.5 μM and a selectivity towards the interacting ions, depending on the CDs structure, enabling using them for sensing. Furthermore, preliminary experiments suggest that these dots can also be used in principle as sensors of common pesticides. Considering the advantages of carbon dots with respect to other nanomaterials, such as non-toxicity, low cost and ease of synthesis, we consider these results to be very promising in view of exploiting the optical response of carbon dots to fabricate in the near future a variety of pollutant-sensing devices.

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