(Invited) Alchemy in Nanoplasmonics: New Class of Plasmonic Alloy Nanoparticles

Abstract

It has been believed for more than 150 years that, in the form of spherical nanoparticles (NPs), only the group 11 elements (Cu, Ag, Au) show the localized surface plasmon resonance in the visible region. It is well known that chemical conversion of inorganic NPs via element replacement reactions, such as ion exchange reactions and galvanic replacement reactions, can overcome the difficulties associated with controlling the size, shape, chemical composition, and crystal structure in conventional syntheses [1-3]. Especially, alloying enables us to drastically modulate the electronic properties of metallic NPs. The retained shape of the parent-NPs in element replacement reactions provides an opportunity to obtain non-equilibrium unique structures and even new structures of inorganic NPs, these final structures being known as “pseudomorphs”. Here the nano-pseudomorphic chemistry to give unique alloy NPs, which possess the localized surface plasmon resonance in visible-to-near infrared region, is presented [4]. This is an alchemy in nanoplasmonics in the sense that the plasmonic properties of group 11 elements are reproduced by using non-group 11 elements. [1] Saruyama, M.; So, Y.-G.; Kimoto, K.; Taguchi, S.; Kanemitsu, Y.; Teranishi, T. J. Am. Chem. Soc. 2011, 133, 17598. [2] Kanehara, M.; Arakawa, H.; Honda, T.; Saruyama, M.; Teranishi, T. Chem. Eur. J. 2012, 18, 9230. (Frontispiece) [3] Wu, H.-L.; Sato, R.; Yamaguchi, A.; Kimura, M.; Haruta, M.; Kurata, H.; Teranishi, T. Science 2016, 351, 1306. [4] Sato, R.; Teranishi, T. et al., to be submitted.