Mechanisms Of Nanomaterial Synthesis By Pulsed Laser Heating Under Fluids Plhuf

Download Mechanisms Of Nanomaterial Synthesis By Pulsed Laser Heating Under Fluids Plhuf full books in PDF, epub, and Kindle. Read online Mechanisms Of Nanomaterial Synthesis By Pulsed Laser Heating Under Fluids Plhuf ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!

Mechanisms of Nanomaterial Synthesis by Pulsed Laser Heating Under Fluids (PLHUF)

Author : Venkatanarayana Prasad Sandireddy
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (141 download)

DOWNLOAD NOW!

Book Synopsis Mechanisms of Nanomaterial Synthesis by Pulsed Laser Heating Under Fluids (PLHUF) by : Venkatanarayana Prasad Sandireddy

Download or read book Mechanisms of Nanomaterial Synthesis by Pulsed Laser Heating Under Fluids (PLHUF) written by Venkatanarayana Prasad Sandireddy and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metallic nanoparticles on surfaces have applications in biosensing, reaction monitoring, and solar energy harvesting etc. due their unique properties which are absent in the bulk metal. The size, spacing, shape, areal density and stability are some of the key parameters that determine suitability in applications. Metallic thin film melting in air has been investigated to produce nanoparticles as a relatively inexpensive approach with a predictable size and spacing. However, the main limitation is independent control of particle size and spacing. Recently, Yadavali and Kalyanaraman [1] showed that laser melting of Au films under glycerol lead to the independent control of particle size and spacing. This dissertation is focused on understanding of the behavior of nanoscale Ag metallic systems heated under bulk fluids. Ag thin films, irregular nanostructures, single and bilayer nanopyramids were fabricated using e-beam evaporation and nanosphere lithography then heating either by furnace annealing or nanosecond laser heating in vacuum, air and water-glycerol mixtures. Annealing of Ag/Co bilayer nanopyramids in air at temperature between 373 K to 573 K led to the discovery of the kinetic anchoring mechanism where the high surface energy and lower surface diffusivity of cobalt resulted in the Ag shape stabilization. Nanosecond laser heating of discontinuous Ag nanostructures under water produced a monomodal distribution of nanoparticles with smaller sizes than in air. High pressure gradients generated in the water vapor phase were attributed to this phenomenon. Pulsed laser melting of nanopyramids and thin films under water-glycerol mixtures produced nanoparticles with higher contact angles than in air. This was explained by the change of interfacial energies of quartz and metal surface by introduction of bounding fluids. Finally, nanosecond laser heating of nanopyramids and thin films beyond the boiling temperature of silver led to explosive vaporization in vacuum resulting in formation of small nanoparticles due to re-deposition onto the substrate. Overall, the thermodynamic properties and dispersive properties of the bounding fluid were found to play important roles in the Pulsed Laser Heating Under Fluids or PLHUF process.

Pulsed Laser-Induced Nanostructures in Liquids for Energy and Environmental Applications

Author : Myong Yong Choi
Publisher : Elsevier
ISBN 13 : 0443133808
Total Pages : 338 pages
Book Rating : 4.4/5 (431 download)

DOWNLOAD NOW!

Book Synopsis Pulsed Laser-Induced Nanostructures in Liquids for Energy and Environmental Applications by : Myong Yong Choi

Download or read book Pulsed Laser-Induced Nanostructures in Liquids for Energy and Environmental Applications written by Myong Yong Choi and published by Elsevier. This book was released on 2024-07-26 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulsed Laser Induced Nanostructures in Liquids for Energy and Environmental Applications covers fundamental insights on the mechanism of pulsed laser techniques by considering various experimental conditions to accelerate hypotheses that are appropriate for the production of efficient nanomaterials. In this book, readers will learn about the major advancements in the field of pulsed laser technologies during the past decades, current applications, and future impacts of pulsed laser technologies. This book provides a comprehensive overview of the development of nanostructured catalytic materials via pulsed laser techniques, their use as energy, environment-related applications and their present trend in the industry and market. It also highlights the latest advances related to the application of these nanostructured materials produced via pulsed laser in liquid techniques in various energy (supercapacitor, batteries, and hydrogen production) and environmental remediation (wastewater treatment and conversion of waste into value-added product) processes. Recent progress on several kinds of both photo and electroactive nanomaterials is reviewed, and essential aspects which govern catalytic behaviors, and the corresponding stability, are discussed. Provides basic principles of pulsed laser–matter interaction, with a focus on the resulting material responses compared to other conventional techniques and state-of-the-art applications Offers comprehensive coverage of pulsed laser induced nanomaterials and their potential energy and environmental applications Examines the properties of pulsed laser induced nanostructures that make them so adaptable

Metal Oxide Nanoparticle Preparation by Pulsed Laser Ablation of Metallic Targets in Liquid

Author : Valery A. Svetlichnyi
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (115 download)

DOWNLOAD NOW!

Book Synopsis Metal Oxide Nanoparticle Preparation by Pulsed Laser Ablation of Metallic Targets in Liquid by : Valery A. Svetlichnyi

Download or read book Metal Oxide Nanoparticle Preparation by Pulsed Laser Ablation of Metallic Targets in Liquid written by Valery A. Svetlichnyi and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The basic mechanisms of pulsed laser ablation in liquids (PLAL) as a method for the synthesis of nanoparticles (NPs) were considered. Physical and chemical processes occurring during the PLAL that determine the formation, composition and structure of the nanoparticles obtained are described. The influence of the composition and properties of the target material, the solvent and the characteristics of the laser irradiation on the efficiency of the synthesis of nanoparticles is discussed. Separately, an influence of the absorption and scattering (including nonlinear) of laser radiation in the dispersion of nanoparticles on the primary synthetic processes and secondary transformations inside the colloidal solution is examined. The specificity of the characterization of the colloidal solutions of oxide particles produced by PLAL is highlighted. The most promising practical applications of nanomaterials obtained are identified and the examples of their successful use in catalytic research and biomedicine are provided.

Controlling the growth of nanoparticles produced in a high power pulsed plasma

Author : Rickard Gunnarsson
Publisher : Linköping University Electronic Press
ISBN 13 : 9176854663
Total Pages : 69 pages
Book Rating : 4.1/5 (768 download)

DOWNLOAD NOW!

Book Synopsis Controlling the growth of nanoparticles produced in a high power pulsed plasma by : Rickard Gunnarsson

Download or read book Controlling the growth of nanoparticles produced in a high power pulsed plasma written by Rickard Gunnarsson and published by Linköping University Electronic Press. This book was released on 2017-12-21 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnology can profoundly benefit our health, environment and everyday life. In order to make this a reality, both technological and theoretical advancements of the nanomaterial synthesis methods are needed. A nanoparticle is one of the fundamental building blocks in nanotechnology and this thesis describes the control of the nucleation, growth and oxidation of titanium particles produced in a pulsed plasma. It will be shown that by controlling the process conditions both the composition (oxidationstate) and size of the particles can be varied. The experimental results are supported by theoretical modeling. If processing conditions are chosen which give a high temperature in the nanoparticle growth environment, oxygen was found to be necessary in order to nucleate the nanoparticles. The two reasons for this are 1: the lower vapor pressure of a titanium oxide cluster compared to a titanium cluster, meaning a lower probability of evaporation, and 2: the ability of a cluster to cool down by ejecting an oxygen atom when an oxygen molecule condenses on its surface. When the oxygen gas flow was slightly increased, the nanoparticle yield and oxidation state increased. A further increase caused a decrease in particle yield which is attributed to a slight oxidation ofthe cathode. By varying the oxygen flow, it was possible to control the oxidation state of the nanoparticles without fully oxidizing the cathode. Pure titanium nanoparticles could not be produced in a high vacuum system because oxygen containing gases such as residual water vapour have a profound influence on nanoparticle yield and composition. In an ultrahigh vacuum system titanium nanoparticles without significantoxygen contamination were produced by reducing the temperature of the growth environment and increasing the pressure of an argon-helium gas mixture within whichthe nanoparticles grew. The dimer formation rate necessary for this is only achievable at higher pressures. After a dimer has formed, it needs to grow by colliding with a titanium atom followed by cooling by collisions with multiple buffer gas atoms. The condensation event heats up the cluster to a temperature much higher than the gas temperature, where it is during a short time susceptible to evaporation. When the clusters’ internal energy has decreased by collisions with the gas to less than the energy required to evaporate a titanium atom, it is temporarily stable until the next condensation event occurs. The temperature difference by which the cluster has to cool down before it is temporarily stable is exactly as many kelvins as the gas temperature.The addition of helium was found to decrease the temperature of the gas, making it possible for nanoparticles of pure titanium to grow. The process window where this is possible was determined and the results presented opens up new possibilities to synthesize particles with a controlled contamination level and deposition rate.The size of the nanoparticles has been controlled by three means. The first is to change the electrical potential around the growth zone, which allows for size (diameter) control in the order of 25 to 75 nm without influencing the oxygen content of the particles. The second means is by increasing the pressure which decreases the ambipolar diffusion rate of the ions resulting in a higher growth material density. By doing this, the particle size can be increased from 50 to 250 nm, however the oxygen content also increases with increasing pressure when this is done in a high vacuum system. The last means of size control was by adding a helium flow to the process where higher flows resulted in smaller nanoparticle sizes. When changing the pressure in high vacuum, the morphology of the nanoparticles could be controlled. At low pressures, highly faceted near spherical particles were produced. Increasing the pressure caused the formation of cubic particles which appear to ‘fracture’ at higher pressures. At the highest pressure investigated, the particles became poly-crystalline with a cauliflower shape and this morphology was attributed to a lowad atom mobility. The ability to control the size, morphology and composition of the nanoparticles determines the success of applying the process to manufacture devices. In related work presented in this thesis it is shown that 150-200 nm molybdenum particles with cauliflower morphology were found to scatter light in which made them useful in photovoltaic applications, and the size of titanium dioxide nanoparticles were found to influence the selectivity of graphene based gas sensors.

Investigation of Fundamental Growth Mechanisms in Pulsed Laser Deposition Synthesis of Nanostructured Materials

Author : William Thomas Mozet
Publisher :
ISBN 13 :
Total Pages : 196 pages
Book Rating : 4.:/5 (974 download)

DOWNLOAD NOW!

Book Synopsis Investigation of Fundamental Growth Mechanisms in Pulsed Laser Deposition Synthesis of Nanostructured Materials by : William Thomas Mozet

Download or read book Investigation of Fundamental Growth Mechanisms in Pulsed Laser Deposition Synthesis of Nanostructured Materials written by William Thomas Mozet and published by . This book was released on 2016 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies are conducted to better understand growth mechanisms in pulsed laser deposition (PLD) synthesis of nanostructured materials, namely graphene and bismuth telluride (Bi2Te3). For graphene, as the substrate temperature increases, the order of the film increases, from an amorphous carbon film to nanocrystalline graphite and few-layer graphene (FLG). By using a high energy laser, the size and type of ablated species can be controlled to create films with smaller nanocrystalline domains. PLD allows the thickness of the films to be directly controlled by the deposition duration. Films can be grown on arbitrary substrates, unlike other methods which utilize surface chemistry. Substrate morphology also affects the samples, with higher surface roughness leading to larger D/G and 2D/G ratios. Polishing substrates prior to deposition can decrease these ratios by up to 15%. Here, the type of carbon source has little impact on sample growth, except in atmospheric growth of graphene, which may not be an optimal condition because of energy loss of the carbon species. In-situ plasma plume analysis is conducted to analyze the species being ablated from the target. Ablated species consist primarily of C+ ions, with some neutral C and C2 species. Ablated C+ ions are at temperatures as high as 12,000 K in vacuum and 10,000 K in 0.1 torr argon. For bismuth telluride, optimal growth conditions are found for the stoichiometric transfer of Bi2Te3, which can vary from system to system. In general, a deposition temperature of 200°C and a deposition pressure of 0.1 to 1.0 torr argon are required for stoichiometric transfer. Using a high energy laser for ablation leads to smaller grain sizes in the nanostructured films. In addition, using a nitrogen atmosphere instead of argon leads to increased gas-phase condensation prior to deposition, resulting in a highly featured surface. When outside of the ideal pressure range, the substrate material can significantly affect the surface morphology of the sample, ranging from smooth films to nanoparticles and nanorods. These morphologies affect the electrical properties of the material. In general, the lowest electrical resistance came from films grown using 532 nm laser irradiation, which leads to larger grain sizes and more featured surfaces. Films grown at slightly reduced pressure, which leads to more featured surfaces, are also low in electrical resistance. These films also have large Seebeck coefficients, both of which lead to a higher thermoelectric figure of merit.

Laser Synthesis of Nanomaterials

Author : Mohamed Boutinguiza
Publisher : Mdpi AG
ISBN 13 : 9783036569291
Total Pages : 0 pages
Book Rating : 4.5/5 (692 download)

DOWNLOAD NOW!

Book Synopsis Laser Synthesis of Nanomaterials by : Mohamed Boutinguiza

Download or read book Laser Synthesis of Nanomaterials written by Mohamed Boutinguiza and published by Mdpi AG. This book was released on 2023-03-29 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanomaterials are a large area of research at present. These materials, which have at least one of their dimensions in the nanoscale (i.e., in a length range from 1 nm to 100 nm), have remarkable or unconventional properties, unlike bulk materials. These materials are currently used in many applications; however, new potential uses are being investigated. In this sense, there is large interest in their use in medicine, electronic devices, the production and storage of energy, composite materials, etc. The production of nanomaterials is addressed through physical and/or chemical methods; however, most of these methods exhibit low reproducibility or a low production rate or make use of toxic chemicals. In order to avoid most of these drawbacks, the laser-based synthesis of nanomaterials has emerged as an alternative to overcome these limitations. This family of methods use a laser beam to produce different nanomaterials (e.g., nanoparticles, nanowires or 2D materials) using diverse approaches. Techniques such as those based on laser ablation, laser vaporization, pulsed laser deposition (PLD), laser-chemical vapor deposition (LCVD), etc., are being explored at present to fabricate these nanoscale materials with a controlled size and shape. In this context, here we present research papers addressing the most recent developments in this field to summarize the current state of the art in the synthesis of nanomaterials using laser techniques.

Laser Generation of Nanoparticles in Liquids

Author : Gaétan Laurens
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (113 download)

DOWNLOAD NOW!

Book Synopsis Laser Generation of Nanoparticles in Liquids by : Gaétan Laurens

Download or read book Laser Generation of Nanoparticles in Liquids written by Gaétan Laurens and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser generation of nanoparticles in liquids : new insights on crystal structure control and colloidal stability The great interest of nanoparticles for their original physical and an chemical properties has been supported by the development of numerous methods of synthesis. In the nineties, laser generation of nanoparticles in liquids appeared, including Pulsed Laser Ablation in Liquids (PLAL). The PLAL technique enables to produce surface free particles for plenty of material and solvent combinations. However, the apparent simplicity of its implementation hides complex physico-chemical mechanisms resulting in a lack of control of the final products. We firstly investigated the dynamics of the laser-generated bubbles for which the PLAL extreme conditions present new studied cases of bubbles dynamics not encountered in the field of fluid mechanics. Then, we aim to bring new insights into better control of the nanoparticles morphology and their colloidal stability. A straight way to tune sizes, crystal structures and the colloidal stability consists in the addition of stabilizing agents. Hence, we investigated the mechanisms of stabilization of colloidal gold using complexing ions. We also succeed to synthesis nano-rubies, i.e. chromium doped corundum alumina nanoparticles, unexpected at nanoscale. The stabilization of the metastable crystal structure using ligands is explained thanks to a comprehensive theoretical approach.