scholarly journals Spectroscopic characteristics of colloidal solutions of metal nanoparticles

2021 ◽  
Author(s):  
P.A. Krasochko ◽  
R.B. Korachkin ◽  
P.P. Krasochko ◽  
S.N. Gvozdev ◽  
M.A. Ponaskov ◽  
...  
Keyword(s):  
Optical Properties ◽  
Silicon Dioxide ◽  
Plasmon Resonance ◽  
Noble Metals ◽  
Colloidal Solution ◽  
Optical Characteristics ◽  
Colloidal Solutions ◽  
Practical Applications ◽  
Vis Spectroscopy ◽  
Nanoparticles Of Noble Metals

Nanoparticles are finding more and more practical applications in various fields of human activity, including veterinary and medicine. Due to the fact that the effectiveness of activity of colloidal solutions of nanoparticles is directly related to the state of aggregation of nanosized particles, it is urgent to use fast and convenient methods for assessing the physicochemical characteristics of such preparations. Nanoparticles have unique optical properties that depend on their size and shape. They can be determined by the refractive index of the light on the surface of the nanoparticles in a phenomenon known as plasmon resonance, which makes UV-Vis spectroscopy a valuable tool for studying and evaluating the characteristics of nanomaterials. Goal of the study is to study the optical characteristics of several samples of colloids of nanoparticles of noble metals (silver) and bioelements (copper, silicon dioxide) in order to determine the possibility of further application of UV-Vis spectroscopy for evaluation of activity and stability of colloidal solutions of nanoparticles. Commercial preparations based on nanoparticles of noble metals (silver) or bioelements (copper, silicon dioxide) in working dilutions recommended by manufacturers were used to study optical characteristics of the colloidal solutions. Optical density and absorption spectra were determined at the wavelengths (nm): 300-800 nm. The f plasmon surface resonance has been found in all test preparations, while all of them exhibited obvious nonlinear optical properties. The most pronounced plasma resonance peak is found in the colloidal solution of silver nanoparticles within a wavelength of 420 nm. In the case of a colloidal solution of copper nanoparticles, the peak of plasmon resonance was less pronounced and had a red shift (peak at 560 nm). In the colloidal solution of silicon silica, the plasmon resonance was less pronounced than other test preparations, being shifted to the blue side of the spectrum (360 nm).

scholarly journals Optical properties of colloidal solutions of metal nanoparticles

2020 ◽  
Vol 23 (10) ◽  
pp. 47-53
Author(s):  
Petr Krasochko ◽  
Rudolf Korochkin ◽  
Pavel Krasochko ◽  
Sergey Gvozdev ◽  
Mikhail Ponaskov
Keyword(s):  
Optical Properties ◽  
Silicon Dioxide ◽  
Plasmon Resonance ◽  
Noble Metals ◽  
Colloidal Solution ◽  
Physicochemical Characteristics ◽  
Colloidal Solutions ◽  
Plasmon Resonance Peak ◽  
Practical Applications ◽  
Vis Spectroscopy

Nanoparticles are finding more practical applications in various fields of human activity, including veterinary and medicine. Due to the fact that the effectiveness of colloidal solutions of nanoparticles is directly related to their aggregate state, convenient methods for assessing the physicochemical characteristics of such preparations is of high priority. Nanoparticles have unique optical properties that depend on their size and shape. They can be determined by the refractive index of light on the surface of nanoparticles in a phenomenon known as plasmon resonance, which makes the UV-Vis spectroscopy a valuable tool for studying and evaluating the properties of nanomaterials. Optical characteristics of NPs colloidal solutions of noble metals (silver) or bioelements (copper, silicon dioxide) were determined at various wavelengths (nm): 300-800 nm. The surface plasmon resonance has been found in all test preparations, while all of them exhibited obvious nonlinear optical properties. The most pronounced plasmon resonance peak was found in the colloidal solution of silver NPs within a wavelength of 420 nm. In the case of a colloidal solution of copper NPs, the peak of plasmon resonance was less pronounced and had a red shift (peak at 560 nm). In the colloidal solution of silicon dioxide, the plasmon resonance was less pronounced than in other test preparations, being shifted to the blue side of the spectrum (360 nm). UV-Vis spectroscopy of metal NPs requires further studies to assess their stability and influence of various external factors on their activity

scholarly journals Plasmonic Sensing of Aqueous-Divalent Metal Ions by Biogenic Gold Nanoparticles

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Luisa E. Silva-De Hoyos ◽  
Victor Sánchez-Mendieta ◽  
Alfredo R. Vilchis-Nestor ◽  
Miguel A. Camacho-López ◽  
Jésica Trujillo-Reyes ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Plasmon Resonance ◽  
Chemical Interaction ◽  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Colloidal Solutions ◽  
Transmission Electron ◽  
Vis Spectroscopy

The chemical interaction between biogenic gold nanoparticles (AuNPs) and several metal (II) ions can be regarded as a practical, twofold, colorimetric, and plasmon resonance sensing method for the recognition of some divalent metal ions in aqueous solutions. The green synthesized AuNPs, using Camellia sinensis as a reducing agent, were characterized by a surface plasmon resonance (SPR) using UV-Vis spectroscopy, infrared spectroscopy, and transmission electron microscopy. The AuNP colloidal solutions obtained have a pink-reddish color with SPRs centered between 529 and 536 nm. AuNPs with spherical, triangular, and hexagonal shapes were found by TEM analyses. Despite their divergent morphologies, these AuNPs can be employed as colorimetric and plasmon resonance sensors for detection of Ca2+, Sr2+, Cu2+, and Zn2+, primarily, in aqueous solutions. Sensibility studies based on molar concentrations were also performed for these metal ions. Furthermore, solid biogenic AuNPs/cellulosic biocomposites were prepared with the aim of developing portable, fast, and dependable colorimetric sensors; nevertheless, these biocomposites resulted to be good adsorbent materials of metal ions.

scholarly journals Laser-Based Synthesis of Au Nanoparticles for Optical Sensing of Glyphosate: A Preliminary Study

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 989 ◽  
Author(s):  
Antonella Laura Sortino ◽  
Maria Censabella ◽  
Gabriella Munzi ◽  
Simona Boninelli ◽  
Vittorio Privitera ◽  
...  
Keyword(s):  
Optical Properties ◽  
Au Nanoparticles ◽  
Synthesis Methods ◽  
Colloidal Solutions ◽  
Nanosecond Pulsed Laser ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Fine Control ◽  
The Stability ◽  
Simple Economic

Nowadays, Au nanoparticles (AuNPs) capture great interest due to their chemical stability, optical properties, and biocompatibility. The success of technologies based on the use of AuNPs implies the development of simple synthesis methods allowing, also, the fine control over their properties (shape, sizes, structure). Here, we present the AuNPs fabrication by nanosecond pulsed laser ablation in citrate-solution, that has the advantage of being a simple, economic and eco-sustainable method to fabricate colloidal solutions of NPs. We characterized the stability and the absorbance of the solutions by Ultraviolet-Visible (UV-Vis) spectroscopy and the morphology of the AuNPs by Transmission Electron Microscopy. In addition, we used the AuNPs solutions as colorimetric sensor to detect the amount of glyphosate in liquid. Indeed, glyphosate is one of the most widely used herbicides which intensive use represents a risk to human health. The glyphosate presence in the colloidal AuNPs solutions determines the aggregation of the AuNPs causing the change in the color of the solution. The variation of the optical properties of the colloidal solutions versus the concentration of glyphosate is studied.

scholarly journals Electrical and Optical Properties of Silicon Oxide Lignin Polylactide (SiO2-L-PLA)

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1354
Author(s):  
Jacek Fal ◽  
Katarzyna Bulanda ◽  
Julian Traciak ◽  
Jolanta Sobczak ◽  
Rafał Kuzioła ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electrical Properties ◽  
Injection Molding ◽  
Silicon Dioxide ◽  
Silicon Oxide ◽  
Logarithmic Scale ◽  
Melt Mixing ◽  
Three Samples ◽  
Vis Spectroscopy ◽  
Mass Fractions

This paper presents a study on the electrical properties of new polylactide-based nanocomposites with the addition of silicon-dioxide–lignin nanoparticles and glycerine as a plasticizer. Four samples were prepared with nanoparticle mass fractions ranging between 0.01 to 0.15 (0.01, 0.05, 0.10, and 0.15), and three samples were prepared without nanoparticle filler—unfilled and unprocessed polylactide, unfilled and processed polylactide, and polylactide with Fusabond and glycerine. All samples were manufactured using the melt mixing extrusion technique and injection molding. Only the unfilled and unprocessed PLA sample was directly prepared by injection molding. Dielectric properties were studied with broadband spectroscopy in a frequency range from 0.1 Hz to 1 MHz in 55 steps designed on a logarithmic scale and a temperature range from 293.15 to 333.15 K with a 5 K step. Optical properties of nanocomposites were measured with UV-VIS spectroscopy at wavelengths from 190 to 1100 nm. The experimental data show that the addition of silicon-dioxide–lignin and glycerine significantly affected the electrical properties of the studied nanocomposites based on polylactide. Permittivity and electrical conductivity show a significant increase with an increasing concentration of nanoparticle filler. The optical properties are also affected by nanofiller and cause an increase in absorbance as the number of silicon-dioxide–lignin nanoparticles increase.

Surface Plasmon Resonance Effect on the Optical Properties of TiO2 Doped by Noble Metals Nanoparticles

2012 ◽  
Vol 18-19 ◽  
pp. 177-185 ◽  
Author(s):  
M. Torrell ◽  
R.C. Adochite ◽  
L. Cunha ◽  
N.P. Barradas ◽  
E. Alves ◽  
...  
Keyword(s):  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Noble Metals ◽  
Structural Changes ◽  
Resonance Effect ◽  
Wide Band ◽  
Protective Atmosphere ◽  
Visible Range

Nanocomposite thin films composed of a TiO2 matrix doped with noble metals nanoparticles (MNPS), Au and Ag, were deposited on Si (100) and glass substrates by dc magnetron sputtering. The samples were annealed in a protective atmosphere at temperatures ranging from 200 to 700 °C. The main goal of this work is to characterize and compare the Surface Plasmon Resonance (SPR) behaviour in both systems. The studies have been focused on the growth of the nanoclusters and on their role on the optical properties of the films. Size, shape and distribution of the nanoclusters embedded on the titanium oxide dielectric matrix are reported as key factors on the SPR behaviour in both systems (Au:TiO2 and Ag:TiO2). The MNPs grew due to diffusion mechanisms, which were led by the annealing treatments, even at the highest annealing temperatures. Evidences of the correlation between the nanocomposite film structural changes and the evolution of the optical properties due to the SPR activity are reported. The SPR phenomenon manifests itself as a wide band on the visible range on the absorption spectra, and it is confirmed by an important change on the surface colour tones of the samples.

Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20402
Author(s):  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Color Difference ◽  
Band Gap Energy ◽  
Polybutylene Terephthalate ◽  
Γ Irradiation ◽  
Gap Energy ◽  
Vis Spectroscopy ◽  
Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

Comparative evaluation of the potentiating effect of nanoparticles of noble metals in the antimicrobial compositions

2019 ◽  
pp. 5-15
Author(s):  
Konstantin I. Gurin ◽  
◽  
Valentina S. Menukhova ◽  
Ivan P. Pogorelskiy ◽  
Vladimir S. Lobastov ◽  
...  
Keyword(s):  
Comparative Evaluation ◽  
Noble Metals ◽  
Nanoparticles Of Noble Metals

scholarly journals Synthesis of PVA/CeO2 Based Nanocomposites with Tuned Refractive Index and Reduced Absorption Edge: Structural and Optical Studies

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1570
Author(s):  
Shujahadeen B. Aziz ◽  
Elham M. A. Dannoun ◽  
Dana A. Tahir ◽  
Sarkawt A. Hussen ◽  
Rebar T. Abdulwahid ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Absorption Edge ◽  
Ceo2 Nanoparticles ◽  
Poly Vinyl Alcohol ◽  
Optical Parameters ◽  
Single Oscillator Model ◽  
Vis Spectroscopy ◽  
The Impact ◽  
Host Polymer

In the current study, polymer nanocomposites (NCPs) based on poly (vinyl alcohol) (PVA) with altered refractive index and absorption edge were synthesized by means of a solution cast technique. The characterization techniques of UV–Vis spectroscopy and XRD were used to inspect the structural and optical properties of the prepared films. The XRD patterns of the doped samples have shown clear amendments in the structural properties of the PVA host polymer. Various optical parameters were studied to get more insights about the influence of CeO2 on optical properties of PVA. On the insertion of CeO2 nanoparticles (NPs) into the PVA matrix, the absorption edge was found to move to reduced photon energy sides. It was concluded that the CeO2 nanoparticles can be used to tune the refractive index (n) of the host polymer, and it reached up to 1.93 for 7 wt.% of CeO2 content. A detailed study of the bandgap (BG) was conducted using two approaches. The outcomes have confirmed the impact of the nanofiller on the BG reduction of the host polymer. The results of the optical BG study highlighted that it is crucial to address the ɛ” parameter during the BG analysis, and it is considered as a useful tool to specify the type of electronic transitions. Finally, the dispersion region of n is conferred in terms of the Wemple–DiDomenico single oscillator model.

scholarly journals Optical Characterization of Ultra-Thin Films of Azo-Dye-Doped Polymers Using Ellipsometry and Surface Plasmon Resonance Spectroscopy

Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 41
Author(s):  
Najat Andam ◽  
Siham Refki ◽  
Hidekazu Ishitobi ◽  
Yasushi Inouye ◽  
Zouheir Sekkat
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Spectroscopic Ellipsometry ◽  
Plasmon Resonance ◽  
Complex Refractive Index ◽  
Resonance Spectroscopy ◽  
Doped Polymers

The determination of optical constants (i.e., real and imaginary parts of the complex refractive index (nc) and thickness (d)) of ultrathin films is often required in photonics. It may be done by using, for example, surface plasmon resonance (SPR) spectroscopy combined with either profilometry or atomic force microscopy (AFM). SPR yields the optical thickness (i.e., the product of nc and d) of the film, while profilometry and AFM yield its thickness, thereby allowing for the separate determination of nc and d. In this paper, we use SPR and profilometry to determine the complex refractive index of very thin (i.e., 58 nm) films of dye-doped polymers at different dye/polymer concentrations (a feature which constitutes the originality of this work), and we compare the SPR results with those obtained by using spectroscopic ellipsometry measurements performed on the same samples. To determine the optical properties of our film samples by ellipsometry, we used, for the theoretical fits to experimental data, Bruggeman’s effective medium model for the dye/polymer, assumed as a composite material, and the Lorentz model for dye absorption. We found an excellent agreement between the results obtained by SPR and ellipsometry, confirming that SPR is appropriate for measuring the optical properties of very thin coatings at a single light frequency, given that it is simpler in operation and data analysis than spectroscopic ellipsometry.

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