Colloids and Surfaces A: Physicochem. Eng. Aspects 443 (2014) 102–108 Contents lists available at ScienceDirect Colloids and Surfaces A: Physicochemical and Engineering Aspects jo ur nal ho me p ag e: www.elsevier.com/locate/colsurfa Preparation of silver hollow nanostructures by plasmon-driven transformation Sławomir Stasie ´ nko, Jan Krajczewski, Sebastian Wojtysiak, Krzysztof Czajkowski, Andrzej Kudelski ∗ Department of Chemistry, University of Warsaw, Pasteur 1, PL-02-093 Warsaw, Poland h i g h l i g h t s • Silver hollow nanostructures were synthesized by plasmon-driven transformation. • In contrast to typical methods, no auxiliary template structures are used. • Plasmon-driven transformation was carried out in the presence of oxygen and citrate. g r a p h i c a l a b s t r a c t a r t i c l e i n f o Article history: Received 14 September 2013 Received in revised form 26 October 2013 Accepted 29 October 2013 Available online 5 November 2013 Keywords: Plasmon resonance Synthesis Nanomaterials with hollow interiors Nanoshells a b s t r a c t Herein we demonstrate the synthesis of silver spherical hollow nanostructures by the plasmon-driven transformation (PDTr) of partially agglomerated silver sol. The PDTr process was carried out in the pres- ence of oxygen and trisodium citrate using intensive 550–650 nm light. In contrast to typical methods of the synthesis of metallic hollow nanostructures, no auxiliary template structures are used. Therefore, the obtained nanoshells should be less contaminated, which may be beneficial to their catalytic and optical properties. The method is believed to open up a straightforward route to the fabrication of nanoshells from metals which support surface plasmon resonance. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Metal nanomaterials with hollow interiors have found appli- cations in areas including biomedical imaging [1], photothermal cancer treatment [2,3], drug delivery [4], surface-enhanced Raman scattering [5,6], and catalysis [7–12]. Because of their lower densi- ties, which usually translate to a higher surface area than their solid counterparts, the hollow nanoparticles are especially promising in catalysis [10–12]. For instance, Pt hollow nanospheres are twice as active for methanol oxidation as solid Pt nanoparticles of roughly the same size [10]. Some hollow nanostructures also exhibit surface ∗ Corresponding author. Tel.: +48 22 8220211x278; fax: +48 22 8225996. E-mail address: akudel@chem.uw.edu.pl (A. Kudelski). plasmonic properties superior to their solid counterparts [13–17]. For example, the position of the surface plasmon resonance (SPR) band for gold nanoshells can be changed by varying the shell diam- eter and its thickness in a significantly broader wavelength range than the SPR band of solid spherical gold nanoparticles [14–17]. The observed significant red-shift of the strong SPR band for very thin gold nanoshells significantly facilitates biomedical applica- tions of such nanostructures, since it allows to tune maximum absorption/scattering of nanoparticles to the transparent window of biological tissues (800–1200 nm) [15–17]. Hollow nanostructures from noble metals are typically fab- ricated by the template-assisted selective etching of core–shell nanoparticles [12,18], or by the galvanic replacement reaction [18–22]. In the first approach the “auxiliary” core particle is over- laid with a shell of a noble metal and then the core is selectively 0927-7757/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.colsurfa.2013.10.063