Optical properties of composite membranes containing arrays of nanoscopic gold cylinders

Foss, Colby A.; Hornyak, Gabor L.; Stockert, Jon A.; Martin, Charles R.

doi:10.1021/j100198a004

Cited by 216 publications

(181 citation statements)

References 10 publications

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“…oscillation of randomly orientated nanorods predicted by Gans' theory is in agreement with the results of Martin and coworkers, 9,[23][24][25][26] who also find a blue-shift of the plasmon maximum using Maxwell-Garnett theory. On the other hand, the absorption maximum of the longitudinal mode red-shifts with increasing gold nanorod aspect ratio.…”

Section: Resultssupporting

confidence: 90%

Simulation of the Optical Absorption Spectra of Gold Nanorods as a Function of Their Aspect Ratio and the Effect of the Medium Dielectric Constant

1999

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Gold nanorods with different aspect ratios are prepared in micelles by the electrochemical method and their absorption spectra are modeled by theory. Experimentally, a linear relationship is found between the absorption maximum of the longitudinal plasmon resonance and the mean aspect ratio as determined from TEM. It is shown here that such a linear dependence is also predicted theoretically. However, calculations also show that the absorption maximum of the longitudinal plasmon resonance depends on the medium dielectric constant in a linear fashion for a fixed aspect ratio. Attempts to fit the calculations to the experimental values indicate that the medium dielectric constant has to vary with the aspect ratio in a nonlinear way. Chemically, this suggests that the structure of the micelle capping the gold nanorods is size dependent. Furthermore, comparison with the results obtained for rods of different aspect ratios made by systematic thermal decomposition of the long rods further suggests that the medium dielectric constant is also temperature dependent. This is attributed to thermal annealing of the structure of the micelles around the nanorods.

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Section: Resultssupporting

confidence: 90%

Simulation of the Optical Absorption Spectra of Gold Nanorods as a Function of Their Aspect Ratio and the Effect of the Medium Dielectric Constant

1999

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“…These differences in the optical absorption spectra cannot be explained by the effective medium theory, 16 which does account for the color changes observed in other metalceramic composite films. 17 The results of Fig. 5 indicate a dramatic change in the band gap energy of the Bi nanowires as a function of wire diameter.…”

mentioning

confidence: 93%

Bismuth quantum-wire arrays fabricated by a vacuum melting and pressure injection process

1998

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Ultrafine bismuth nanowire arrays were synthesized by injecting its liquid melt into nanochannels of a porous anodic alumina template. A large area (1 cm 3 1.5 cm) of parallel wires with diameters as small as 13 nm, lengths of 30-50 mm, and packing density as high as 7.1 3 10 10 cm 22 has been fabricated. X-ray diffraction patterns revealed these nanowires, embedded in the insulating matrix, to be essentially single crystalline and highly oriented. The optical absorption spectra of the nanowire arrays indicate that these bismuth nanowires undergo a semimetal-to-semiconductor transition due to two-dimensional quantum confinement effects.Highly regular metal and semiconductor nanowire arrays embedded in a dielectric matrix have attracted a great deal of research attention because of their potential applications in electronic and optical devices and promise for studying one-dimensional (1D) quantum properties. The quantum confinement of carriers in two dimensions will significantly change their electronic energy states and make the properties of these 1D systems very different from their bulk counterparts. A promising approach to fabricate nanowire systems is to fill an array of nanochannels with the media of interest. Porous anodic alumina, 1-3 which has hexagonally packed nanometer-sized channels, is one such possible host template. Besides its desirable geometry, the wide band gap energy of alumina makes it an excellent host material for quantum wires. Anodic alumina has previously been used to synthesize a variety of metal and semiconductor nanowires, such as Ni, Pd, Au, Pt, and CdS, through chemical or electrochemical processes. [4][5][6][7] However, the diameters of those nanowires have not reached the quantum confinement regime. In order to exhibit strong quantum confinement characteristics, the wire diameter should be smaller than the exciton diameter, which is given by d ex 2eh 2 (m 21 e 1 m 21 h )͞e 2 , where e is the static dielectric constant, and m e and m h are the effective masses of electrons and holes, respectively. Bismuth, which is a semimetal and has a very small electron effective mass (m e ഠ 0.014m 0 at the band edge along a) Author to whom correspondence should be addressed. the trigonal direction, and m e ഠ 0.0036m 0 for heavy electrons along the bisectrix direction), is considered a good candidate to study quantum confinement effects in the 1D system. Our theoretical calculations estimate that Bi makes a transition from a semimetal to a 1D semiconductor at a wire diameter of about 45 nm or 81 nm if the wire is oriented along the trigonal direction or the bisectrix direction, respectively. 8In this paper, Bi quantum-wire arrays were fabricated by a novel vacuum melting and pressure injection technique which can produce continuous, dense nanowire arrays, as required by many practical electronic applications. High-pressure injection of molten metal has been used to fill a single glass nanotube, 9 and more recently, porous anodic alumina having channel diameters larger than 200 nm. 10 The injec...

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“…Among various preparation techniques of nanowires and nanoparticles, the templates synthesis [6] is one of the promising methods, in which uniform void spaces of porous materials are used as a host to confine wires and particles as a guest [3,7]. Mesoporous silicas such as siliceous FSM-16 [8,9], MCM-41 [10], SBA-15 [11], and organosilica HMM-1 [12] have a two dimensional (2D) hexagonal structure (p6mm symmetry) of 1D-channels less than 10 nm in diameter and a high surface area up to 1000 m 2 g -1 .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and electronic property of platinum nanowire and nanoparticle in mesoporous silica template

et al. 2006

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Optical properties of composite membranes containing arrays of nanoscopic gold cylinders

Cited by 216 publications

References 10 publications

Simulation of the Optical Absorption Spectra of Gold Nanorods as a Function of Their Aspect Ratio and the Effect of the Medium Dielectric Constant

Simulation of the Optical Absorption Spectra of Gold Nanorods as a Function of Their Aspect Ratio and the Effect of the Medium Dielectric Constant

Bismuth quantum-wire arrays fabricated by a vacuum melting and pressure injection process

Synthesis and electronic property of platinum nanowire and nanoparticle in mesoporous silica template

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