Ballistic-diffusive approximation for the thermal dynamics of metallic nanoparticles in nanocomposite materials

2015 ◽  
Vol 117 (11) ◽  
pp. 114304 ◽  
Author(s):  
A. H. Shirdel-Havar ◽  
R. Masoudian Saadabad
Keyword(s):  
Metallic Nanoparticles ◽  
Nanocomposite Materials ◽  
Thermal Dynamics ◽  
Diffusive Approximation

Fabricating Nanocomposite Catalysts through Interfacial Fusion of Metallic Nanoparticles

2009 ◽  
Vol 1217 ◽  
Author(s):  
Yong-Jae Choi ◽  
Tsan-Yao Chen ◽  
Chi-Kai Chiu ◽  
Tzy-Jiun Mark Luo
Keyword(s):  
Functional Groups ◽  
Soft Lithography ◽  
Mobile Phase ◽  
Metallic Nanoparticles ◽  
Nanocomposite Materials ◽  
Nanoporous Silica ◽  
Polymer Phase ◽  
Bulk Materials ◽  
Silica Colloids ◽  
Nanocomposite Catalysts

AbstractFusion of metallic nanoparticles at both surfaces of silica colloids and nanoporous bulk materials has been utilized as an effective method to integrate inorganic and organic components into nanocomposite materials. When performed on substrates that have been modified with hydrophobic functional groups, aminosilica colloids doped with metallic nanoparticles through the ethylenediamine functional groups adhere to the substrates and self-assemble into nanocomposite film with its thickness to be the function of the time. On the contrary, without metal-bound functional groups, fusion of metallic nanoparticles can be induced at the interface of nanoporous silica when polymer is utilized as the mobile phase for metal nanoparticles inside of silica. Formation, mobilization, and fusion of metallic nanoparticles within the polymer phase can be simultaneously induced at 160 ˚C, during which reactions alter the physical appearance of the materials from transparent to silver metallic color. These two methods can combine with soft-lithography method to create functional structures that exhibit enhanced electrochemical property.

scholarly journals Nanosecond-resolution photothermal dynamic imaging via MHZ digitization and match filtering

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiaze Yin ◽  
Lu Lan ◽  
Yi Zhang ◽  
Hongli Ni ◽  
Yuying Tan ◽  
...  
Keyword(s):  
Metallic Nanoparticles ◽  
Modulation Frequency ◽  
Dynamic Imaging ◽  
Pulse Excitation ◽  
Label Free ◽  
Thermal Dynamics ◽  
Mid Infrared ◽  
Excitation Beam ◽  
Match Filtering ◽  
Lock In

AbstractPhotothermal microscopy has enabled highly sensitive label-free imaging of absorbers, from metallic nanoparticles to chemical bonds. Photothermal signals are conventionally detected via modulation of excitation beam and demodulation of probe beam using lock-in amplifier. While convenient, the wealth of thermal dynamics is not revealed. Here, we present a lock-in free, mid-infrared photothermal dynamic imaging (PDI) system by MHz digitization and match filtering at harmonics of modulation frequency. Thermal-dynamic information is acquired at nanosecond resolution within single pulse excitation. Our method not only increases the imaging speed by two orders of magnitude but also obtains four-fold enhancement of signal-to-noise ratio over lock-in counterpart, enabling high-throughput metabolism analysis at single-cell level. Moreover, by harnessing the thermal decay difference between water and biomolecules, water background is effectively separated in mid-infrared PDI of living cells. This ability to nondestructively probe chemically specific photothermal dynamics offers a valuable tool to characterize biological and material specimens.

Economically Viable Fabrication Method of Nanocomposite Materials From Linear Arrays of Metallic Nanoparticles and Nanorods on Tubular Halloysite Templates

2012 ◽  
Author(s):  
E. Abdullayev ◽  
A. Joshi ◽  
W. Wei ◽  
Y. Zhao ◽  
Y. Lvov
Keyword(s):  
Electron Microscopy ◽  
Metallic Nanoparticles ◽  
Large Scale ◽  
Thermal Reduction ◽  
Nanocomposite Materials ◽  
Fabrication Method ◽  
Simple Method ◽  
Linear Arrays ◽  
Antibacterial Performance ◽  
Transmission Electron

In this work, we report a simple fabrication method for metal nanoparticles and nanorods on halloysite supports. Silver nanorods of 15 nm diameter were synthesized by thermal decomposition of silver acetate within halloysite lumen. Nanorods had crystalline nature with [111] axis oriented ∼ 68° from the halloysite tubule main axis. Linear arrays from gold, iron, cobalt and palladium nanoparticles on halloysite external surface were also synthesized by chemical and thermal reduction method. Samples were analyzed by high-resolution transmission electron microscopy and field-emission scanning electron microscopy. These in situ syntheses offer a simple method for large scale fabrication of metallic nanorods and core-shell ceramic nanocomposites, which can be used as antimicrobial additives in plastic composites, nanoelectronic and optical materials with biocompatibility and environmentally friendly. Antimicrobial thin films were prepared based on halloysite-silver nanocomposites and tested on E. Coli and S Aureus bacterial culture. Antibacterial performance of the nanocomposite material was superior to the other conventional antimicrobial additives (silver doped bioactive glasses and carbon nanotubes). Radiation protection coatings based on fabricated nanocomposite materials is under development.

A Unified Approach to Study the Thermal Dynamics in Multilongitudinal Mode Semiconductor Lasers

2001 ◽  
Vol 20 (2) ◽  
pp. 159-169 ◽  
Author(s):  
M. Ganesh Madhan ◽  
P. R. Vaya ◽  
N. Gunasekaran
Keyword(s):  
Semiconductor Lasers ◽  
Unified Approach ◽  
Thermal Dynamics

Plasmon-assisted interaction of Si with light, for cancer hyperthermia and electromagnetic energy harvest

2020 ◽  
Vol 92 (2) ◽  
pp. 20101
Author(s):  
Behnam Kheyraddini Mousavi ◽  
Morteza Rezaei Talarposhti ◽  
Farshid Karbassian ◽  
Arash Kheyraddini Mousavi
Keyword(s):  
Silicon Nanowires ◽  
Metallic Nanoparticles ◽  
Near Infrared ◽  
Optical Transition ◽  
Electromagnetic Energy ◽  
Energy Harvest ◽  
Absorption Enhancement ◽  
Ir Absorption ◽  
Absorption Mechanism ◽  
Near Ir

Metal-assisted chemical etching (MACE) is applied for fabrication of silicon nanowires (SiNWs). We have shown the effect of amorphous sheath of SiNWs by treating the nanowires with SF6 and the resulting reduction of absorption bandwidth, i.e. making SiNWs semi-transparent in near-infrared (IR). For the first time, by treating the fabricated SiNWs with copper containing HF∕H2O2∕H2O solution, we have generated crystalline nanowires with broader light absorption spectrum, up to λ = 1 μm. Both the absorption and photo-luminescence (PL) of the SiNWs are observed from visible to IR wavelengths. It is found that the SiNWs have PL at visible and near Infrared wavelengths, which may infer presence of mechanisms such as forbidden gap transitions other can involvement of plasmonic resonances. Non-radiative recombination of excitons is one of the reasons behind absorption of SiNWs. Also, on the dielectric metal interface, the absorption mechanism can be due to plasmonic dissipation or plasmon-assisted generation of excitons in the indirect band-gap material. Comparison between nanowires with and without metallic nanoparticles has revealed the effect of nanoparticles on absorption enhancement. The broader near IR absorption, paves the way for applications like hyperthermia of cancer while the optical transition in near IR also facilitates harvesting electromagnetic energy at a broad spectrum from visible to IR.

Green synthesis of mixed metallic nanoparticles using room temperature self-assembly

2017 ◽  
Vol 13 (2) ◽  
pp. 4671-4677 ◽  
Author(s):  
A. M. Abdelghany ◽  
A.H. Oraby ◽  
Awatif A Hindi ◽  
Doaa M El-Nagar ◽  
Fathia S Alhakami
Keyword(s):  
Self Assembly ◽  
Metallic Nanoparticles ◽  
Room Temperature ◽  
Bimetallic Nanoparticles ◽  
Reduction Process ◽  
Nano Particles ◽  
Nano Structure ◽  
Small Shift ◽  
Molar Ratios ◽  
Vis Spectroscopy

Bimetallic nanoparticles of silver (Ag) and gold (Au) were synthesized at room temperature using Curcumin. Reduction process of silver and gold ions with different molar ratios leads to production of different nanostructures including alloys and core-shells. Produced nanoparticles were characterized simultaneously with FTIR, UV/vis. spectroscopy, transmission electron microscopy (TEM), and Energy-dispersive X-ray (EDAX). UV/vis. optical absorption spectra of as synthesized nanoparticles reveals presence of surface palsmon resonance (SPR) of both silver at (425 nm) and gold at (540 nm) with small shift and broadness of gold band after mixing with resucing and capping agent in natural extract which suggest presence of bimetallic nano structure (Au/Ag). FTIR and EDAX data approve the presence of bimetallic nano structure combined with curcumin extract. TEM micrographs shows that silver and gold can be synthesized separately in the form of nano particles using curcumin extract. Synthesis of gold nano particles in presence of silver effectively enhance and control formation of bi-metallic structure.

Metallic Nanoparticle Synthesis by Green Chemistry

2018 ◽  
Vol 11 (6) ◽  
pp. 4287-4294
Author(s):  
Anikate Sood ◽  
Shweta Agarwal
Keyword(s):  
Green Chemistry ◽  
Green Synthesis ◽  
Biomedical Research ◽  
Metallic Nanoparticles ◽  
Nanoparticle Synthesis ◽  
Synthesis Methods ◽  
Metallic Nanoparticle ◽  
Medical Field ◽  
Advantages And Disadvantages ◽  
Gold Silver

Nanotechnology is the most sought field in biomedical research. Metallic nanoparticles have wide applications in the medical field and have gained the attention of various researchers for advanced research for their application in pharmaceutical field. A variety of metallic nanoparticles like gold, silver, platinum, palladium, copper and zinc have been developed so far. There are different methods to synthesize metallic nanoparticles like chemical, physical, and green synthesis methods. Chemical and physical approaches suffer from certain drawbacks whereas green synthesis is emerging as a nontoxic and eco-friendly approach in production of metallic nanoparticles. Green synthesis is further divided into different approaches like synthesis via bacteria, fungi, algae, and plants. These approaches have their own advantages and disadvantages. In this article, we have described various metallic nanoparticles, different modes of green synthesis and brief description about different metabolites present in plant that act as reducing agents in green synthesis of metallic nanoparticles. 

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