Grant: Discovery Grants Program - Individual

A promising practical approach to nanostructured materials is to use building blocks with the dimensions optimized with respect to desired structural elements, i.e. nanoscale building blocks (NBBs). Discrete NBBs themselves display many unique characteristics, whereas periodic nanostructures built out of NBBs offer a tremendous potential in realizing novel functions. NBB can be compared to Lego: both can build amazingly sophisticated architectures. At the same time, great precision is required for manufacturing (synthesis) of the blocks and a significant diversity of blocks is needed to make them universal structural units (NBBs). The proposed research focuses on the synthesis of NBBs with precisely controlled properties, such as size, shape, chirality, and formation of functional nanocomposites out of these NBBs via self-assembly. Recently, the applicant's group was successful in creating a variety of monodisperse NBBs: silver nanoshapes including decahedra, faceted pentagonal rods, platelets, cubes and right bipyramids, chiral silver nanoclusters, and silica nanospheres for templating. Functional properties of these building blocks include narrow plasmonic absorption of silver decahedra, precisely tuneable from visible to NIR plasmons of faceted rods, and atomic-like discrete absorption and circular dichroism of silver nanoclusters. The immediate research plans are to further diversify the library of the building blocks perfecting silver icosahedra (as the most spherical Platonic shape) and optimize preparation of gold shells using silver galvanic replacement (the metal shells are very versatile NBBs that are currently actively tested in biodiagnostics and medical treatment). Next, more complex core-shell NBBs will be prepared for protection of existing properties and realizing new functions by tailoring the outer layers. These diverse functional NBBs will be assembled into highly-ordered nanostructured functional materials. Advanced applications of the proposed NBBs and nanostructured materials include sensors (based on plasmons and Raman scattering), heterogeneous catalysis (advantageous due to defined surface facets and chirality), metamaterials and plasmonics (optical elements).