With support from the Macromolecular, Supramolecular, and Nanochemistry program in the Chemistry Division at NSF, the PI will synthesize colloidal elongated gold and silver nanoparticles and will study their integration with semiconductor and polymer materials. Through the controlled assembly of these materials, the project will produce nanoscale nonlinear optical switches and fast single photon sources. Three separate research thrusts will be pursued: (1) Fast nanoscale nonlinear optical switching will be sought by coating an Au bipyramid with or embedding it in a medium exhibiting an optical Kerr effect. Feedback between the intensity-dependent refractive index of the medium and the index-sensitive resonant electric field enhancement can support optical bistability on subpicosecond time scales. (2) Picosecond single photon sources will be designed to take advantage of the large and anisotropic field enhancement of a bipyramid, speeding its radiative rate and defining its polarization state. (3) Since silver is a better plasmonic material than Au at optical frequencies and there are no existing synthesis of small monodispersed Ag antenna with narrow Plasmon resonance, the PI will undertake synthetic strategies to produce monocrystalline Ag nanorods with good shape yield and monodispersity using in particular underpotential deposition (UPD) of lower work function metals to control surface energy and stability.
With support from the Macromolecular, Supramolecular, and Nanochemistry program in the Division of Chemistry at NSF, this project will impact three separate scientific areas: colloidal synthesis, plasmonic materials, and education. Colloidal synthesis is a field still in its infancy and this project will focus on the development of new methods to control both the shape of the particle and its assembly into more complex structures. Electronic processing has changed society profoundly, and the processing of light is already ubiquitous in telecommunications and promises to continue to develop. Ultrafast nanoscale optical switches and single photon sources must be developed as part of this progress, and this project will chemically produce and characterize these two basic but essential elements. The research project will educate two PhD students to become skilled and creative scientists at the frontier in an interdisciplinary research area, intersecting physics and chemistry. The PI will also develop curricular materials and optical demonstrations to bring an understanding of the properties of light and colloidal materials to disadvantaged high school students and to the public at large.