Thin Films of Gold Nanoparticles PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Thin Films of Gold Nanoparticles PDF full book. Access full book title Thin Films of Gold Nanoparticles by Jeanne J. Xu. Download full books in PDF and EPUB format.
Author: Jeanne J. Xu
Publisher:
ISBN:
Category : Gold
Languages : en
Pages : 53
Get Book Here
Book Description
Thin films of gold nanoparticles (Au NPs) are of interest because of their unique physicochemical properties. These thin films have potential applications in electrical devices, chemical sensing, and biosensing. Retaining the integrity of the thin film is important for such applications. The purpose of this project is to assess the temporal stability and to explore the mechanisms of degradation of thin films of Au NPs on glass substrates. Thin films were fabricated through a layer-by-layer deposition process. Clean glass substrates were sequentially immersed in solutions of (3-aminopropyl)trimethoxysilane, synthesized Au NPs, and 1-dodecanethiol (DT). The wettability of each layer was characterized with contact angle goniometry. Upon the completion of thin film fabrication, slides were immersed in ultrapure water (nH2O) and changes in wettability were observed over a 7-day period. Although thin films of gold had more hydrophobic surfaces than DT-containing controls lacking Au NPs, there was still a significant decrease in contact angle once the films were immersed in high purity water. Thin film degradation was quantified by a decrease in contact angle. Two possible mechanisms of thin film degradation were investigated: (1) the desorption of DT from thin films by oxidation and (2) the desorption of Au NPs from the thin films. Antioxidant was added to the storage solution to test the oxidation mechanism. Contact angle analysis was used to monitor the changes in wettability of thin films in nH2O with antioxidant. The presence of antioxidant in nH2O improved thin film integrity. Inductively coupled plasma atomic emission spectroscopy was used to determine the change in Au3+ concentration from day 0 and day 7. No substantial change in Au3+ was observed from day 0 to day 7. Between the two mechanisms that were explored, thin film degradation appeared to occur primarily by the oxidation of DT molecules and their desorption into the surrounding medium.
Author: Jeanne J. Xu
Publisher:
ISBN:
Category : Gold
Languages : en
Pages : 53
Get Book Here
Book Description
Thin films of gold nanoparticles (Au NPs) are of interest because of their unique physicochemical properties. These thin films have potential applications in electrical devices, chemical sensing, and biosensing. Retaining the integrity of the thin film is important for such applications. The purpose of this project is to assess the temporal stability and to explore the mechanisms of degradation of thin films of Au NPs on glass substrates. Thin films were fabricated through a layer-by-layer deposition process. Clean glass substrates were sequentially immersed in solutions of (3-aminopropyl)trimethoxysilane, synthesized Au NPs, and 1-dodecanethiol (DT). The wettability of each layer was characterized with contact angle goniometry. Upon the completion of thin film fabrication, slides were immersed in ultrapure water (nH2O) and changes in wettability were observed over a 7-day period. Although thin films of gold had more hydrophobic surfaces than DT-containing controls lacking Au NPs, there was still a significant decrease in contact angle once the films were immersed in high purity water. Thin film degradation was quantified by a decrease in contact angle. Two possible mechanisms of thin film degradation were investigated: (1) the desorption of DT from thin films by oxidation and (2) the desorption of Au NPs from the thin films. Antioxidant was added to the storage solution to test the oxidation mechanism. Contact angle analysis was used to monitor the changes in wettability of thin films in nH2O with antioxidant. The presence of antioxidant in nH2O improved thin film integrity. Inductively coupled plasma atomic emission spectroscopy was used to determine the change in Au3+ concentration from day 0 and day 7. No substantial change in Au3+ was observed from day 0 to day 7. Between the two mechanisms that were explored, thin film degradation appeared to occur primarily by the oxidation of DT molecules and their desorption into the surrounding medium.
Author: Alexandria J. Bear
Publisher:
ISBN:
Category : Gold films
Languages : en
Pages : 84
Get Book Here
Book Description
Author: Stefan Dickert
Publisher:
ISBN:
Category : Cobalt
Languages : en
Pages : 122
Get Book Here
Book Description
Thin films of 7 nm gold nanoparticles were fabricated via a direct write electron beam exposure. The electrons caused the nanoparticles to stick to the substrate and the unexposed areas were rinsed off. After the lift off, the films were annealed. This caused Ostwald ripening. Electrical and structural properties were studied. It was found that the initial film thickness is the crucial factor of the post annealing properties. In case of films thinner than 50 nm, it was found that the particles ripen to form insulating islands hundreds of nanometers in size and seperated from each other. If the film thickness is increased beyond 50 nm, the ripening causes the islands to grow so much, that at least one percolating pathway for charge transport is formed. Metallic conductivity was observed in a wide temperature range (2-350 K). It is possible to create films that display hopping conductivity, if the initial film thickness is at approximately 50 nm. In a second experiment, polystyrene--block-poly(4-vinylpyridine) (PS-P4VP) diblock copolymer was used to create a hexagonal lattice of cobalt nanoparticles. The size scale of the particles was about 12-15 nm with a 25-30 nm separation between them. This artificially arranged array of magnetic "impurities" was covered with a thin metallic film. Copper or palladium were used and the thickness was varied between 13-40 nm. It was found that these nanoengineered films show thermal hysteresis in resistance versus temperature measurements, the shape of which can be manipulated by applying a magnetic field. The effect was more pronounced in the cobalt-copper samples. Further, magnetoresistance measurements showed oscillations as a function of applied field and temperature. Again, the effects shown in the cobalt-copper samples were significantly more pronounced.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 4
Get Book Here
Book Description
This study reports the facile method for the deposition of gold nanoparticles thin film onto a monoporous semi-permeable cellulose membrane through the diffusion of borohydride ions leading to the reduction of AuCl4- ions. The synthesis of gold nanoparticle thin film was deposited on one side of the membrane that was exposed to AuCl4-ions while the other side containing a reducing agent remained clear. [partial abstract].
Author: Mark William Sugden
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Author: Soo Ai Ng
Publisher:
ISBN:
Category :
Languages : en
Pages : 240
Get Book Here
Book Description
Author: Zaheer Abbas Khan
Publisher: GRIN Verlag
ISBN: 3668243042
Category : Science
Languages : en
Pages : 114
Get Book Here
Book Description
Doctoral Thesis / Dissertation from the year 2011 in the subject Materials Science, Asian Insitute of Technology, language: English, abstract: A novel approach of multilayered thin film based on layer-by-layer deposition using colloidal nanoparticles was carried out in this work. The films were made by the self-assembly of oppositely charged metal and dielectric nanoparticles, alternately capped with polymers. Synthesized colloidal suspensions of gold nanoparticles (~20nm) and silica nanoparticles (~30nm) were used as the building blocks for the self-organisation of the films. Capping with PDDA and chitosan was used effectively to control the optical absorption of the surface plasmon resonance peaks of the gold nanoparticles. Using different combinations of layer formation, absorption characteristics in the near-ultraviolet (NUV), green and blue region were controlled through capping and varying the thickness of the film. Capping with chitosan or PDDA reduced the absorption peak of the coated silica nanoparticles in a similar fashion. Peak absorption in the UV range was achieved by assembling bare silica nanoparticles layers onto layers of gold nanoparticles. Transmission color was controlled (less than 1% color distance per added bi-layer) by changing the film thickness. Optical modeling of multilayer thin films constructed with oppositely charged nanoparticles helped us to understand phenomenon such as surface plasmon resonance, absorbance, transmittance and reflectance. Maxwell-Garnett effective medium theory in this case is applied in quasi-static limit to multilayer composite consisting of host material silica and inclusion material gold nanoparticles. Maxwell Garnett optical simulations is correlated with experimental spectra obtained for the thin film composites. The thickness of layers, size and spacing of metal inclusion is varied to alter the optical properties for the required device applications. The multilayered thin film of gold and silica resembles a structure consisting of large charge sheets of metal separated by a dielectric layer. When the applied electric potential reaches a threshold value, it drives the electrons to tunnel through the charge sheets producing a rectification effect. Therefore current-voltage measurements of the multilayer thin films were performed to calculate the threshold voltages. The electrical capacitance in these multilayer devices was modified with the change in thickness of the dielectric layers between two conducting layers and calculated by capacitance-voltage measurements of multilayer stack. [...]
Author: Nicholas A. Joy
Publisher:
ISBN:
Category : Detectors
Languages : en
Pages : 166
Get Book Here
Book Description
Author: Gero Decher
Publisher: John Wiley & Sons
ISBN: 3527646760
Category : Technology & Engineering
Languages : en
Pages : 1157
Get Book Here
Book Description
This second, comprehensive edition of the pioneering book in this fi eld has been completely revised and extended, now stretching to two volumes. The result is a comprehensive summary of layer-by-layer assembled, truly hybrid nanomaterials and thin fi lms, covering organic, inorganic, colloidal, macromolecular, and biological components, as well as the assembly of nanoscale fi lms derived from them on surfaces. These two volumes are essential for anyone working in the field, as well as scientists and researchers active in materials development, who needs the key knowledge provided herein for linking the field of molecular self-assembly with the bio- and materials sciences.
Author: Gubicza, Jen?
Publisher: IGI Global
ISBN: 1466658533
Category : Technology & Engineering
Languages : en
Pages : 359
Get Book Here
Book Description
X-ray line profile analysis is an effective and non-destructive method for the characterization of the microstructure in crystalline materials. Supporting research in the area of x-ray line profile analysis is necessary in promoting further developments in this field. X-Ray Line Profile Analysis in Materials Science aims to synthesize the existing knowledge of the theory, methodology, and applications of x-ray line profile analysis in real-world settings. This publication presents both the theoretical background and practical implementation of x-ray line profile analysis and serves as a reference source for engineers in various disciplines as well as scholars and upper-level students.
