title: Light-responsive plasmonic arrays consisting of silver nanocubes and a photoisomerizable matrix.
abstract: We report on the synthesis of novel branched organic-inorganic azo-polyhedral oligomeric silsesquioxane (POSS) conjugates (Azo-POSS) and their use as a stable active medium to induce reversible plasmonic modulations of embedded metal nanostructures. A dense monolayer of silver nanocubes was deposited on a quartz substrate using the Langmuir-Blodgett technique and subsequently coated with an ultrathin Azo-POSS layer. The reversible light-induced photoisomerization between the trans and cis states of the azobenzene-terminated branched POSS material results in significant changes in the refractive index (up to 0.17) at a wavelength of 380 nm. We observed that the pronounced and reversible change in the surrounding refractive index results in a corresponding hypsochromic plasmonic shift of 6 nm in the plasmonic band of the embedded silver nanocubes. The reversible tuning of the plasmonic modes of noble-metal nanostructures using a variable-refractive-index medium opens up the possibility of fabricating photoactive, hybrid, ultrathin coatings with robust, real-time, photoinitiated responses for prospective applications in photoactive materials that can be reversibly tuned by light illumination.
authors: School of Materials Science and Engineering and §Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors: Petr A
authors: PA
authors: Ledin
authors: Michael
authors: M
authors: Russell
authors: Jeffrey A
authors: JA
authors: Geldmeier
authors: Ihor M
authors: IM
authors: Tkachenko
authors: Mahmoud A
authors: MA
authors: Mahmoud
authors: Valery
authors: V
authors: Shevchenko
authors: Mostafa A
authors: MA
authors: El-Sayed
authors: Vladimir V
authors: VV
authors: Tsukruk
keywords: azobenzene conjugates; photoisomerization; plasmonic phenomena; polyhedral oligomeric silsesquioxane