%0 Journal Article %J ACS Appl Mater Interfaces %D 2015 %T Light-responsive plasmonic arrays consisting of silver nanocubes and a photoisomerizable matrix. %A Ledin, Petr A %A Russell, Michael %A Geldmeier, Jeffrey A %A Tkachenko, Ihor M %A Mahmoud, Mahmoud A. %A Shevchenko, Valery %A El-Sayed, Mostafa A. %A Tsukruk, Vladimir V. %X 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. %B ACS Appl Mater Interfaces %V 7 %P 4902-12 %8 2015 Mar 4 %G eng %N 8 %1 http://www.ncbi.nlm.nih.gov/pubmed/25671557?dopt=Abstract %R 10.1021/am508993z %0 Journal Article %J Nanoscale %D 2015 %T Silver nanocube aggregation gradient materials in search for total internal reflection with high phase sensitivity %A Konig, Tobias A. F. %A Ledin, Petr A %A Russell, Michael %A Geldmeier, Jeffrey A %A Mahmoud, Mahmoud. A. %A El-Sayed, Mostafa A. %A Tsukruk, Vladimir V. %X We fabricated monolayer coatings of a silver nanocube aggregation to create a step-wise optical strip by applying different surface pressures during slow Langmuir-Blodgett deposition. The varying amount of randomly distributed nanocube aggregates with different surface coverages in gradient manner due to changes in surface pressure allows for continuous control of the polarization sensitive absorption of the incoming light over a broad optical spectrum. Optical characterization under total internal reflection conditions combined with electromagnetic simulations reveal that the broadband light absorption depends on the relative orientation of the nanoparticles to the polarization of the incoming light. By using computer simulations, we found that the electric field vector of the s-polarized light interacts with the different types of silver nanocube aggregations to excite different plasmonic resonances. The s-polarization shows dramatic changes of the plasmonic resonances at different angles of incidence (shift of 64 nm per 10[degree] angle of incidence). With a low surface nanocube coverage (from 5% to 20%), we observed a polarization-selective high absorption of 80% (with an average 75%) of the incoming light over a broad optical range in the visible region from 400 nm to 700 nm. This large-area gradient material with location-dependent optical properties can be of particular interest for broadband light absorption, phase-sensitive sensors, and imaging. %B Nanoscale %V 7 %P 5230-5239 %G eng %U http://dx.doi.org/10.1039/C4NR06430E %R 10.1039/C4NR06430E %0 Journal Article %J ACS nano %D 2014 %T Electrically Tunable Plasmonic Behavior of Nanocube-Polymer Nanomaterials Induced by a Redox Active Electrochromic Polymer %A König, Tobias AF %A Ledin, Petr A %A Kerszulis, Justin %A Mahmoud, Mahmoud A. %A El-Sayed, Mostafa A. %A Reynolds, John R %A Tsukruk, Vladimir V. %B ACS nano %@ 1936-0851 %G eng %! ACS Nano