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Theory of the Optical Properties of a DNA-Modified Gold Nanoparticle System  [PDF]
Sung Yong Park,David Stroud
Physics , 2003, DOI: 10.1016/j.physb.2003.08.019
Abstract: We describe a simple model for the melting and optical properties of a DNA/gold nanoparticle aggregate. The aggregate is modeled as a cluster of gold nanoparticles on a periodic lattice connected by DNA bonds, and the extinction coefficient is computed using the discrete dipole approximation. The optical properties at fixed wavelength change dramatically at the melting transition, which is found to be higher and narrower in temperature for larger particles, and much sharper than that of an isolated DNA link. All these features are in agreement with available experiments.
Tunable variation of optical properties of polymer capped gold nanoparticles  [PDF]
M. Haridas,S. Srivastava,J. K. Basu
Physics , 2008, DOI: 10.1140/epjd/e2008-00135-x
Abstract: Optical properties of polymer capped gold nanoparticles of various sizes (diameter 3-6 nm) have been studied. We present a new scheme to extract size dependent variation of total dielectric function of gold nanoparticles from measured UV-Vis absorption data. The new scheme can also be used, in principle, for other related systems as well. We show how quantum effect, surface atomic co - ordination and polymer - nanoparticle interface morphology leads to a systematic variation in inter band part of the dielectric function of gold nanoparticles, obtained from the analysis using our new scheme. Careful analysis enables identification of the possible changes to the electronic band structure in such nanoparticles.
Optimization of Optical Properties of Polycarbonate Film with Thiol Gold-Nanoparticles  [PDF]
Claudio Larosa,Enrico Stura,Roberto Eggenh?ffner,Claudio Nicolini
Materials , 2009, DOI: 10.3390/ma2031193
Abstract: A new nanostructured composite film based on thiol gold nanoparticles dispersed in polycarbonate and prepared by evaporating a solution of 1-dodecanthiol gold nanoparticles and polycarbonate was developed for applications as optical lenses. Lenses with superior mechanical properties, coloring and UV ray absorption and with the same transparency as the matrix were obtained. The supporting highly transparent polycarbonate matrix and the chloroform solution of thiol gold nanoparticles, 3 nm mean size, was mixed according to a doping protocol employing different concentrations of thiol gold nanoparticles vs. polycarbonate. The presence of nanoparticles in the polymer films was confirmed by the spectrophotometric detection of the characteristic absorbance marker peak at 540–580 nm. The nanostructured films obtained show a better coverage in the UV-vis range (250–450 nm) even at very low doping ratios, of the order of 1:1,000. These results offer a very promising approach towards the development of efficient nanostructured materials for applications to optical lenses.
Optical Properties of Linoleic Acid Protected Gold Nanoparticles
Ratan Das,Siddartha S. Nath,Ramendu Bhattacharjee
Journal of Nanomaterials , 2011, DOI: 10.1155/2011/630834
Abstract: Linoleic acid-protected gold nanoparticles have been synthesized through the chemical reduction of tetrachloroaurate ions by ethanol in presence of sodium linoleate. The structure of these nanoparticles is investigated using transmission electron microscopy, which shows that the Au nanoparticles are spherical in shape with a narrow size distribution which ranges from 8 to 15 nm. Colloidal dispersion of gold nanoparticles in cyclohexane exhibits absorption bands in the ultraviolet-visible range due to surface plasmon resonance, with absorption maximum at 530 nm. Fluorescence spectra of gold nanoparticles also show an emission peak at 610 nm when illuminated at 450 nm. UV-Vis spectroscopy reveals that these nanoparticles remain stable for 10 days.
Optical and Structural Properties of Ultra-thin Gold Films  [PDF]
Anna Kossoy,Virginia Merk,Denis Simakov,Kristjan Leosson,Stéphane Kéna-Cohen,Stefan A. Maier
Physics , 2014, DOI: 10.1002/adom.201400345
Abstract: Realizing laterally continuous ultra-thin gold films on transparent substrates is a challenge of significant technological importance. In the present work, formation of ultra-thin gold films on fused silica is studied, demonstrating how suppression of island formation and reduction of plasmonic absorption can be achieved by treating substrates with (3-mercaptopropyl) trimethoxysilane prior to deposition. Void-free fi lms with deposition thickness as low as 5.4 nm are realized and remain structurally stable at room temperature. Based on detailed structural analysis of the fi lms by specular and diffuse X-ray reflectivity measurements, it is shown that optical transmission properties of continuous ultra-thin films can be accounted for using the bulk dielectric function of gold. However, it is important to take into account the non-abrupt transition zone between the metal and the surrounding dielectrics, which extends through several lattice constants for the laterally continuous ultra-thin films (film thickness below 10 nm). This results in a significant reduction of optical transmission, as compared to the case of abrupt interfaces. These findings imply that the atomic-scale interface structure plays an important role when continuous ultra-thin films are considered, e.g., as semi-transparent electrical contacts, since optical transmission deviates significantly from the theoretical predictions for ideal films.
A comparative study of electrochemical and optical properties of rhenium deposited on gold and platinum
Zerbino, Jorge O.;Castro Luna, Ana M.;Zinola, Carlos F.;Méndez, Eduardo;Martins, M. E.;
Journal of the Brazilian Chemical Society , 2002, DOI: 10.1590/S0103-50532002000400016
Abstract: rhenium-containing films were grown on gold and platinum after different potentiostatic and potentiodynamic polarizations in the - 0.20 v to 0.70 v range (vs rhe) in aqueous acid perrhenate. experimental data were obtained using cyclic voltammetry and ellipsometry, from which the thickness and optical indices of the electrodeposited rhenium layer were calculated. metallic rhenium deposition on gold takes place at potentials within the hydrogen evolution reaction. rhenium oxide on platinum is formed in the hydrogen adatom potential domain, whereas metallic rhenium is deposited concurrently with the hydrogen adsorption and evolution reactions on the same metal.
A comparative study of electrochemical and optical properties of rhenium deposited on gold and platinum  [cached]
Zerbino Jorge O.,Castro Luna Ana M.,Zinola Carlos F.,Méndez Eduardo
Journal of the Brazilian Chemical Society , 2002,
Abstract: Rhenium-containing films were grown on gold and platinum after different potentiostatic and potentiodynamic polarizations in the - 0.20 V to 0.70 V range (vs rhe) in aqueous acid perrhenate. Experimental data were obtained using cyclic voltammetry and ellipsometry, from which the thickness and optical indices of the electrodeposited rhenium layer were calculated. Metallic rhenium deposition on gold takes place at potentials within the hydrogen evolution reaction. Rhenium oxide on platinum is formed in the hydrogen adatom potential domain, whereas metallic rhenium is deposited concurrently with the hydrogen adsorption and evolution reactions on the same metal.
Calculated Optical Properties of Dielectric Shell Coated Gold Nanorods

CAO Min,WANG Meng,GU Ning,

中国物理快报 , 2009,
Abstract: Optical absorption spectra of dielectric shell coated gold nanorods are simulated using the discrete dipole approximation method. The influence of the aspect ratio, shell thickness, dielectric constant of the shell, and surrounding medium on the longitudinal resonance mode is investigated. It is found that the coated dielectric shell does not affect the trend in the dependence of resonance position on the aspect ratio, while it broadens the resonant line width and reduces the sensitivity of plasmon resonance in response to changes of the surrounding medium. Furthermore, the difference of dielectric constants between the shell and surrounding medium plays an important role in determining the resonance position. The screening effect of the dielectric shell tends to be less apparent for a thicker shell thickness.
Microwave-Mediated Rapid Synthesis of Gold Nanoparticles Using Calotropis procera Latex and Study of Optical Properties  [PDF]
Ratul Kumar Das,Punuri Jayasekhar Babu,Nayanmoni Gogoi,Pragya Sharma,Utpal Bora
ISRN Nanomaterials , 2012, DOI: 10.5402/2012/650759
Abstract: We report a microwave-mediated simple and rapid method of gold nanoparticles (GNPs) synthesis using latex of Calotropis procera. UV-Vis spectroscopic studies indicated the formation of GNPs. The GNPs were stable at room temperature (25°C) for six months. Transmission electron microscope (TEM) micrographs of the synthesized GNPs showed the formation of spherical nanoparticles with an average size of 13 ± 5?nm. SAED and XRD confirmed the crystalline nature of GNPs. Fourier transform infrared (FTIR) analysis indicated the presence of organic coating on the nanoparticles. Cytotoxicity of the GNPs was tested on HeLa and A549 and found to be nontoxic which was indicating that latex of Calotropis procera provided the nontoxic coating on GNPs, thus can be used as biomedical and pharmacological applications. 1. Introduction Gold nanoparticles (GNPs) have been of immense interest for their unique chemical and physical properties and potential technological applications in various fields ranging from catalysis to disease diagnosis [1–15]. Conventional methods of GNPs synthesis mostly rely on the use of synthetic chemicals and prolonged heating [16–19]. Owing to the increased awareness for potential toxicity of GNPs associated with biological applications, alternative methodologies for biocompatible GNPs synthesis are gaining importance. Replacement of toxic chemicals as a reducing and stabilizing agent is the prime concern of this new approach. Reports about the successful synthesis and subsequent stability of GNPs by using different biomaterials sourced from plant and microbes are now increasing day by day [20–27]. On the other hand, microwave (MW) dielectric heating is a fast emerging and widely accepted new processing technology for a variety of inorganic synthesis and biomedical applications [28–33]. Compared to the conventional heating, MW irradiation shortens reaction times and improve yield without causing any appreciable alteration in the composition of products of a chemical reaction. In contrast to general heating treatment, MW synthesis favors homogeneous heating through the entire bulk of the reaction mixture in a container, leading to a more homogeneous and easy nucleation of noble metal nanoparticles [34–37]. We found that latex of the plant C. procera, a multifarious plant having many remedial properties, can act as both reducing and capping agent in the GNPs synthesis through conventional heating [38]. This motivated us to further explore the synthesis of GNPs through MW irradiation. We found remarkable shortening in the reaction time and GNPs of
Quantum mechanical ab initio calculations of the structural, electronic and optical properties of bulk gold nitrides  [PDF]
Mohammed S. H. Suleiman,Daniel P. Joubert
Physics , 2013, DOI: 10.1140/epjb/e2015-60292-1
Abstract: In the present work, the atomic and the electronic structures of Au3N, AuN and AuN2 are investigated using first-principles density-functional theory (DFT). We studied cohesive energy vs. volume data for a wide range of possible structures of these nitrides. Obtained data was fitted to a Birch-Murnaghan third-order equation of state (EOS) so as to identify the most likely candidates for the true crystal structure in this subset of the infinite parameter space, and to determine their equilibrium structural parameters. The analysis of the electronic properties was achieved by the calculations of the band structure and the total and partial density of states (DOS). Some possible pressure-induced structural phase transitions have been pointed out. Further, we carried out GW0 calculations within the random-phase approximation (RPA) to the dielectric tensor to investigate the optical spectra of the experimentally suggested modification: Au3N(D0_9). Obtained results are compared with experiment and with some available previous calculations.
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