Synthesis, Characterization, and Tunable Optical Properties of Hollow Gold Nanospheres†, J. Phys. Chem. B. 110, 19935-19944

Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA.
The Journal of Physical Chemistry B (Impact Factor: 3.3). 11/2006; 110(40):19935-44. DOI: 10.1021/jp062136a
Source: PubMed


Nearly monodisperse hollow gold nanospheres (HGNs) with tunable interior and exterior diameters have been synthesized by sacrificial galvanic replacement of cobalt nanoparticles. It is possible to tune the peak of the surface plasmon band absorption between 550 and 820 nm by carefully controlling particle size and wall thickness. Cobalt particle size is tunable by simultaneously changing the concentration of sodium borohydride and sodium citrate, the reducing and capping agent, respectively. The thickness of the gold shell can be varied by carefully controlling the addition of gold salt. With successful demonstration of ensemble as well as single HGN surface-enhanced Raman scattering, these HGNs have shown great potential for chemical and biological sensing applications, especially those requiring nanostructures with near-IR absorption.


Available from: Tammy Y. Olson, May 29, 2014
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    • "For example, hollow gold nanoparticles are much more efficient than their solid counterparts at heat generation when exposed to near-infrared radiation , which makes them attractive for cancer theranostic applications [5]. The most widespread methods for the synthesis of hollow nanostructures are based on the Kirkendall effect [6] and on galvanic replacement reactions [2] [7] [8]. The latter method allows reproducible synthesis of hollow nanoparticles, but they often exhibit polycrystalline microstructure and high density of defects [8]. "
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    ABSTRACT: A sequence of diffusion-controlled processes, namely, thin film dewetting, dealloying and thermal coarsening was employed for producing of hollow gold nanoparticles. The porous gold nanoparticles on silica substrate were obtained by solid state dewetting of Au–Ag bi-layers followed by selective dealloying of Ag. We studied in detail the last stage of the proposed method enabling the transformation of porous nanoparticles into hollow ones due to curvature-driven surface diffusion. The porous nanoparticles were annealed at 350 °C in air and in vacuum and characterized by high-resolution scanning electron microscopy. The microstructure evolution of the particles during thermal treatment was studied by in-situ X-ray diffraction. The observed decrease of compressive strain in the particles during coarsening was discussed in terms of Weissmüller–Cahn model. Annealing in ambient air resulted in faster coarsening of gold nanoparticles compared to annealing in vacuum. The isolated pores trapped in the particle bulk as well as the pores located at the particle/substrate interface were observed in the particles annealed in air. A qualitative model illustrating the observed coarsening behavior is proposed.
    Acta Materialia 01/2016; 102:108-115. · 4.47 Impact Factor
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    • "Sun et al. [6] first introduced the technique of synthesizing gold nanoboxes in a controllable manner in 2002 through sacrificing silver nanostructure templates in a galvanic reaction with a gold precursor. Further reports by the group have included the enhancement of the homogeneity and stability of the products, in addition to the creation of other hollow/porous particles such as gold nanocages (AuNCs), nanoframes, porous nanorods, etc. [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21]. In their reports, the detailed mechanism of reduction, galvanic replacement and the de-alloying process in the synthesis was proposed and discussed [16,17,22,23]. "
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    ABSTRACT: Compared to solid gold nanoparticles (AuNPs) which have been widely used for the construction of localized surface plasmon resonance (LSPR) sensors, hollow gold nanoparticles have attracted greater attention recently due to the stronger plasmonic effect that they demonstrate. Combining this with the known advantages of the use of fibre optic technology, a portable, reliable and highly sensitive sensor system has been developed and reported in this study and evaluated for various potential sensing applications. In this work, hollow gold nanocages have been designed and the synthesized specifically for the development of a LSPR-based optical fibre sensor, in this case for Refractive Index (RI) measurement. In doing so, different hollow structures of nanogold have been synthesized and characterized and the experimental results obtained show that the sensitivity of the hollow nanostructure-based LSPR sensor, in response to known RI variations, is closely related to the hollowness of the gold nanocages. It was observed that with the decrease of the wall thickness of the nanocages, the sensitivity of the LSPR sensor created increases dramatically and this is due to the strong plasmonic coupling seen between the interior and exterior fields. Compared to the LSPR sensors based on solid-nanoparticles reported earlier by the authors, the nanocage-based sensor created in this work has demonstrated an excellent sensitivity of 1933 nm/RIU, thus showing a significant improvement of at least 3 fold in sensitivity from that prior work.
    Sensors and Actuators B Chemical 02/2014; 191:37-44. DOI:10.1016/j.snb.2013.09.094 · 4.10 Impact Factor
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    • "obtained particles as well as the high aspect ratio of synthesized hollow nanostructures. On the other hand, increasing the plasmon bandwidth of spectrum after removing silica spheres is due to aggregation of nanoparticles and the introduction of new multipole modes [26] as well as polydispersity in particle size or shape of products [28]. Hence, based on our results it can be inferred that among these synthesized nanoparticles, hollow particles are almost the only nanostructures which show optical response to wavelengths within near IR range rather than visible range. "
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    ABSTRACT: In this paper, we report preparation and characterization of monodispersed hollow gold nanoparticles with the average thickness of about 25 nm through the template method. The formation of these hollow nanostructures involves three subsequent steps: preparation and functionalization of silica nanospheres, formation of a thick gold shell around the templates and following selective etching of silica particles by HF solution. In order to obtain monodispersed hollow particles, the optimum amount of trisodium citrate was used as stabilizing agent. The results show that although for both concentrated and diluted HF solution, pure gold nanoparticles were obtained, but the 10 volume percent HF solution destroys the hollow structures and just agglomerated gold particles were generated. Furthermore, by investigation the optical response of the synthesized metallic nanoparticles consisting gold nanoparticles, silica-gold nanoshells and hollow gold nanoparticles, it can be inferred that the hollow structures are capable to absorb wavelengths mainly within near infrared region. Hence, this paper introduces a new strategy to produce the metallic nanostructures with optical response within NIR range which may provide new opportunities for their applications in variety of fields such as photoelectronics, catalysis and cancer therapy.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 09/2013; 436:1069-1075. DOI:10.1016/j.colsurfa.2013.08.028 · 2.75 Impact Factor
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