Squaraine-Based Optical Sensors: Designer Toolbox for Exploring Ionic and Molecular Recognitions

<div><div><div><p>The structural features of a series of diverse Deep Eutectic Solvents (DESs) have been investigated and characterized by means of two fluorescent probes. The spectral and photophysical properties of the latter are strictly dependent on the experienced environment, so that they can provide insights into the polarity, viscosity, hydrogen-bond network, and micro-heterogeneity of the various DESs.</p><p>In fact, the investigated DESs exhibit a variety of properties with regards to their hydrophilicity, acidity, and hydrogen-bond ability, and these details were deeply probed by the two fluorescent molecules. The effect of the addition of water, which is a key strategy for tuning the properties of these structured systems, was also tested. In particular, the excited state dynamics of the probes, measured by femtosecond-resolved transient absorption, proved instrumental in understanding the changes in the structural properties of the DESs, namely reduced viscosity and enhanced heterogeneity, as the water percentage increases. Differences between the various DESs in terms of both local microheterogeneity and bulk viscosity also emerged from the peculiar multi-exponential solvation dynamics undergone by the excited states of the probes.</p></div></div></div>

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Probing the Structural Features and the Micro-heterogeneity of Various Deep Eutectic Solvents and their Water Dilutions by the Photophysical Behaviour of Two Fluorophores

10.26434/chemrxiv.13395683 ◽

2020 ◽

Author(s):

Matteo Tiecco ◽

Irene Di Guida ◽

Pier Luigi Gentili ◽

Raimondo Germani ◽

Carmela Bonaccorso ◽

...

Keyword(s):

Hydrogen Bond ◽

Transient Absorption ◽

Photophysical Properties ◽

Deep Eutectic Solvents ◽

Structural Features ◽

Solvation Dynamics ◽

Structured Systems ◽

Reduced Viscosity ◽

Bond Network ◽

Fluorescent Molecules

<div><div><div><p>The structural features of a series of diverse Deep Eutectic Solvents (DESs) have been investigated and characterized by means of two fluorescent probes. The spectral and photophysical properties of the latter are strictly dependent on the experienced environment, so that they can provide insights into the polarity, viscosity, hydrogen-bond network, and micro-heterogeneity of the various DESs.</p><p>In fact, the investigated DESs exhibit a variety of properties with regards to their hydrophilicity, acidity, and hydrogen-bond ability, and these details were deeply probed by the two fluorescent molecules. The effect of the addition of water, which is a key strategy for tuning the properties of these structured systems, was also tested. In particular, the excited state dynamics of the probes, measured by femtosecond-resolved transient absorption, proved instrumental in understanding the changes in the structural properties of the DESs, namely reduced viscosity and enhanced heterogeneity, as the water percentage increases. Differences between the various DESs in terms of both local microheterogeneity and bulk viscosity also emerged from the peculiar multi-exponential solvation dynamics undergone by the excited states of the probes.</p></div></div></div>

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Fluorescent Nanotechnology: An Evolution in Optical Sensors

Current Analytical Chemistry ◽

10.2174/1573411017666201215121420 ◽

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.

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Influence of the structural features of pyrene-dendronized bodipys on the optical and photophysical properties

MRS Advances ◽

10.1557/s43580-021-00164-4 ◽

2021 ◽

Author(s):

Aldo S. Estrada-Montaño ◽

Pasquale Porcu ◽

Mireille Vonlanthen ◽

Andrea García-Rodríguez ◽

Juan Carlos Carranza Cruz ◽

...

Keyword(s):

Photophysical Properties ◽

Structural Features

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Recent Advancements in Doped/Co-Doped Carbon Quantum Dots for Multi-Potential Applications

C – Journal of Carbon Research ◽

10.3390/c5020024 ◽

2019 ◽

Vol 5 (2) ◽

pp. 24 ◽

Cited By ~ 9

Author(s):

Ganeshlenin Kandasamy

Keyword(s):

Quantum Dots ◽

Optical Sensors ◽

Carbon Nanomaterials ◽

Synthesis Method ◽

Carbon Quantum Dots ◽

Carbon Nanodots ◽

Synthesis Methods ◽

Sensing Applications ◽

Potential Applications ◽

Co Doped

Carbon quantum dots (CQDs)/carbon nanodots are a new class of fluorescent carbon nanomaterials having an approximate size in the range of 2–10 nm. The majority of the reported review articles have discussed about the development of the CQDs (via simple and cost-effective synthesis methods) for use in bio-imaging and chemical-/biological-sensing applications. However, there is a severe lack of consolidated studies on the recently developed CQDs (especially doped/co-doped) that are utilized in different areas of application. Hence, in this review, we have extensively discussed about the recent development in doped and co-doped CQDs (using elements/heteroatoms—e.g., boron (B), fluorine (F), nitrogen (N), sulphur (S), and phosphorous (P)), along with their synthesis method, reaction conditions, and/or quantum yield (QY), and their emerging multi-potential applications including electrical/electronics (such as light emitting diode (LED) and solar cells), fluorescent ink for anti-counterfeiting, optical sensors (for detection of metal ions, drugs, and pesticides/fungicides), gene delivery, and temperature probing.

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Photochemistry of Squaraine Dyes. 8. Photophysical Properties of Crown Ether Squaraine Fluoroionophores and Their Metal Ion Complexes

The Journal of Physical Chemistry ◽

10.1021/j100088a033 ◽

1994 ◽

Vol 98 (37) ◽

pp. 9291-9296 ◽

Cited By ~ 51

Author(s):

Suresh Das ◽

K. George Thomas ◽

K. J. Thomas ◽

Prashant V. Kamat ◽

M. V. George

Keyword(s):

Crown Ether ◽

Metal Ion ◽

Photophysical Properties ◽

Metal Ion Complexes ◽

Squaraine Dyes

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Porous Silicon Nanostructured Materials for Sensing Applications: Molecular Assembling and Electrochemical or Optical Evaluation

MRS Proceedings ◽

10.1557/opl.2016.21 ◽

2016 ◽

Vol 1812 ◽

pp. 77-82

Author(s):

J. Márquez ◽

M. De la Cruz-Guzmán ◽

L.F. Cházaro ◽

G. Palestino

Keyword(s):

Porous Silicon ◽

Optical Sensors ◽

Detection Threshold ◽

Environmental Pollutants ◽

High Sensitivity ◽

Hybrid Nanostructures ◽

Specular Reflectance ◽

Sensing Applications ◽

Fluorescent Ligands ◽

Hybrid Devices

ABSTRACTPorous silicon (PSi) combines the potential of miniaturization with a very large surface area. The PSi surface can be chemically modified resulting in a high sensitivity (low detection threshold) device for chemical and biomolecular sensing. In previous work, we have shown that redox proteins and fluorescent ligands can be infiltrated into PSi (PSiMc) structures. The hybrid devices have shown interesting new properties produced by the coupling of the individual properties of PSi nanostructures and the modifiers. In this work, we have obtained a PSiMc/redox protein bioelectrode, which presents a quasi-reversible electrochemical response. This effect was attributed to the semiconducting nature of the PSi substrate and to the functional groups of the crosslinking molecules (MPTS), which together produce a capacitive effect on the device. On the other hand, the chemical modification of PSiMc with fluorescent ligands allowed us to fabricate fluorescent PSi hybrid nanostructures, which were tested for the detection of environmental pollutants such as heavy metals (specifically Hg2+). We found that the selectivity of this optical device depends on the selected recognizing molecule. The captured metal induces the formation of a metallic complex that shows higher fluorescence compared with the sensor device. These results demonstrate the viability of using porous silicon as optical sensors and electrochemical biosensors. The infiltration of fluorescent recognizing molecules and proteins into the PSi matrix were evaluated by specular reflectance, FTIR spectroscopy, fluorescence spectroscopy and cyclic voltammetry.

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Photophysical properties and pH sensing applications of luminescent salicylaldehyde derivatives

Research on Chemical Intermediates ◽

10.1007/s11164-015-2343-4 ◽

2015 ◽

Vol 42 (5) ◽

pp. 5027-5048 ◽

Cited By ~ 16

Author(s):

Jiaoyan Liu ◽

Jinghui Cheng ◽

Xiaofeng Ma ◽

Xiangge Zhou ◽

Haifeng Xiang

Keyword(s):

Photophysical Properties ◽

Ph Sensing ◽

Sensing Applications ◽

Salicylaldehyde Derivatives

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Lossy double negative guiding layer optical sensors

Opto-Electronics Review ◽

10.2478/s11772-011-0031-5 ◽

2011 ◽

Vol 19 (3) ◽

Cited By ~ 2

Author(s):

H. Khozondar ◽

S. Taya ◽

M. Shabat ◽

E. Mehjez

Keyword(s):

Optical Sensors ◽

Double Negative ◽

Electric Permittivity ◽

Refractive Index Sensitivity ◽

Cladding Layer ◽

Left Handed ◽

Sensing Applications ◽

Index Sensitivity ◽

Layer Waveguide ◽

Waveguide Sensor

AbstractWe proposed a three-layer waveguide as an optical sensor for homogeneous sensing applications. A guiding layer of the proposed structure is considered as lossy left-handed material (LHM) with simultaneously the complex negative electric permittivity ɛ and the complex negative magnetic permeability µ. We also assume a cladding layer to have an intensity-dependent refractive index. Sensitivity of the proposed optical waveguide sensor is derived and its dependence on different parameters of a waveguide is studied.

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