Control of Ultraviolet Surface Plasmon Absorption of Al Nanoparticles by Changing Particle Size, Shape, Interaction, and Medium Dielectric Constant

Kuiri, Probodh K.

doi:10.1007/s11468-019-01113-6

Cited by 8 publications

(4 citation statements)

References 36 publications

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“…1. The reports highlight that a shift of peak towards UV regions occurs as the particle size decreases and towards the visible region with an increase in sizes 20 . Hence, the flattened peaks obtained at higher concentrations of metal ions could possibly due to the synthesis of large-sized silver nanoparticles.…”

Section: Discussionmentioning

confidence: 90%

Untitled

2021

IJPSR

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Nanoparticles are being constantly exploited by the scientific community due to their versatile properties and applications. However, the synthesis of metallic nanoparticles achieved through conventional physical and chemical techniques is quite expensive and a labor-intensive process with serious consequences like instability of nanoparticles and toxic byproducts. Hence, green synthesis utilizing biological systems, including plants, bacteria, yeast, fungi, and algae proves to be a cost-effective and eco-friendly alternative. Plant extracts are a rich source of many bioactive compounds like secondary metabolites and often act as reducing and capping agents in the synthesis of nanoparticles. The present work deals with the synthesis of silver nanoparticles using aqueous leaf extract of Sauropus androgynous. Prior to the synthesis, phytochemical analysis and antioxidant potential were evaluated. Physical parameters, including silver metal ion concentration and the temperature were optimized for the effective synthesis of silver nanoparticles. The synthesized nanoparticles were characterized via UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray crystallography (XRD). Finally, silver nanoparticles were evaluated for their antibacterial and anti-helminthic activity. Green synthesis of silver nano particles using S. androgynous was optimized at a conc. of 1mM of silver nitrate at a temperature of 70ºC. The characterization of silver nanoparticles revealed a spherical crystallite nature with particle sizes ranging from 16 nm -55nm. The nanoparticles exhibited antibacterial and anti-helminthic activity too. Hence, the green synthesized silver nanoparticle could be considered as a promising therapeutic choice against infectious pathological conditions.

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Section: Discussionmentioning

confidence: 90%

Untitled

2021

IJPSR

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“…For instance, a blue shift is reported, decreasing the gold particle size and with a solvent. 38 In addition, metal deposition reduces the electron–holes recombination thanks to formation of a Schottky barrier improving the productivity. Similar considerations can be extended to platinum and silver, even if the latter has a smaller promoting effect.…”

Section: Resultsmentioning

confidence: 99%

“…This effect is usually visible as absorption feature in the visible range (400–600 nm for Au and Ag nanoparticles), not strictly related to our experimental conditions, but strongly depends on the size and shape of the metal particles and on the dielectric constant of the medium at the interface. For instance, a blue shift is reported, decreasing the gold particle size and with a solvent . In addition, metal deposition reduces the electron–holes recombination thanks to formation of a Schottky barrier improving the productivity.…”

Section: Resultsmentioning

confidence: 99%

Effect of Metal Cocatalysts and Operating Conditions on the Product Distribution and the Productivity of the CO₂ Photoreduction

Conte

Villa

Prati

et al. 2022

Ind. Eng. Chem. Res.

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The CO 2 photoreduction is a promising way to convert one of the most abundant greenhouse gases to valuable chemicals. The photoreduction in the liquid phase is limited by the low solubility of CO 2 in water, but this point is overcome here by using an innovative photoreactor, which allows one to work up to pressures of 20 bar, improving the overall productivity. The photoreduction was performed in the presence of Na 2 SO 3 and using in primis commercial titanium dioxide (P25) and a set of titania catalysts functionalized by surface deposition of either monometallic or bimetallic cocatalysts. The gaseous products were hydrogen and traces of CO, while, in the liquid phase, formic acid/formate, formaldehyde and methanol were quantitatively detected. The pH was observed to shift the products distribution. A neutral environment led mainly to hydrogen and methanol, while, at pH 14, formate was the most abundant compound. The trend for monometallic cocatalysts showed enhanced productivity when using noble metals (i.e., gold and platinum). In order to limit the cost of the catalytic material, bimetallic cocatalysts were explored, adding titania with Au+Ag or Au+Pt. This may open to the possibility of performing the reaction with a smaller amount of the most expensive metals. In the end, we have expressed some conclusions on the cost of the photocatalysts here employed, to support the overall feasibility assessment of the process.

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“…The details of the theoretical model can be found elsewhere [34,35]. This theory was successfully employed to calculate the OA data for Au [34,36], Ag [37], and Al [38] NPs. Also this model was extended to calculate the OA spectra of alloys' metal NPs [39,40].…”

Section: Theoretical Model and Discussionmentioning

confidence: 99%

Control of Spectral Shift of Plasmon Resonance of Ag-PVP Nanocomposite By Varying The PVP Shell Thickness In Core-Shell Structure

Sao

Kuiri

Nath

2021

Preprint

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Metal-polymer nanocomposite materials have interesting physical, chemical, and optical properties which were highly utilized in electronic, optical,and biomedical applications. Here, we have experimentally and theoretically studied the crucial role of polymer Polyvinylpyrrolidone (PVP) on the localized surface plasmon resonance (LSPR) spectra of silver (Ag) nanoparticles (NPs). In this work, we have synthesized PVP stabilized Ag NPs in Ethelene Glycol (EG) medium and observed a large blueshift (20 nm)of LSPR peak and tunable plasmonic properties of PVP coated Ag NPs by only varying the concentration of PVP. A reduction of Ag NP size from 13 nm to 5 nm with the increase in PVP concentration from 0.125 mM to 3 mM is seen. We found that the observed large blueshift of the LSPR bands with the varying in PVP concentration is not just due to the reduced Ag NP size but due to the combined effect of thickness of the PVP shell and radius of the Ag NP core. The polymer PVP used in the synthesis process of Ag NPs plays role of a surface modifier and forms a protective shell/layer surrounding the (core) particle. This is supported by the theoretical optical absorption data obtained from a modified effective medium theory. To accommodate such a large blueshift of the LSPR bands we have considered the Ag-PVP core-shell structure. The LSPR peak shift in the core-shell nanostructure is well accommodated by varying the effective shell thickness of PVP while taking the core size of Ag NPs as measured experimentally for each case. This clearly indicates that the observed large blueshift of SPR band of Ag NPs cannot be justified by considering the decrease in Ag NP size alone. It is also confirmed that the shell thickness of PVP plays a crucial role in explaining the blueshift of the SPR band of Ag NPs. This study can help to understand the optical response especially plasmonic properties of other metal NPs coated with organic polymers.

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Control of Ultraviolet Surface Plasmon Absorption of Al Nanoparticles by Changing Particle Size, Shape, Interaction, and Medium Dielectric Constant

Cited by 8 publications

References 36 publications

Untitled

Untitled

Effect of Metal Cocatalysts and Operating Conditions on the Product Distribution and the Productivity of the CO₂ Photoreduction

Control of Spectral Shift of Plasmon Resonance of Ag-PVP Nanocomposite By Varying The PVP Shell Thickness In Core-Shell Structure

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Control of Ultraviolet Surface Plasmon Absorption of Al Nanoparticles by Changing Particle Size, Shape, Interaction, and Medium Dielectric Constant

Cited by 8 publications

References 36 publications

Untitled

Untitled

Effect of Metal Cocatalysts and Operating Conditions on the Product Distribution and the Productivity of the CO2 Photoreduction

Control of Spectral Shift of Plasmon Resonance of Ag-PVP Nanocomposite By Varying The PVP Shell Thickness In Core-Shell Structure

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Product

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Effect of Metal Cocatalysts and Operating Conditions on the Product Distribution and the Productivity of the CO₂ Photoreduction