2/7 - Seminar (inorganic): Richard Robinson, Cornell University
Richard Robinson - Robinson Group website
Department of Materials Science
Host: Robert Cava
Chemical and Structural Engineering of Nanomaterials for Energy Devices
In this talk I will discuss our latest results toward realizing nanomaterial energy devices by chemical and structural engineering. I will discuss our synthesis of hyperbranched cobalt phosphides where we have cracked the normally inert tri-n-octylphosphine oxide (TOPO) and use it as a phosphorous source. I will also discuss our work on chemical engineering surfaces of nanoparticles: we have developed a novel surface modification method to link colloidal nanoparticles together through inorganic bridges. Our method completely removes the bulky surfactant ligands from both II-VI and IV-VI semiconducting nanocrystal films using (NH4)2S. Finally, I’ll discuss our new structural characterization tool, where we have developed a microfabricated phonon spectrometer. Non-thermal distributions of phonons are locally excited and detected in silicon micro- and nanostructures by decay of quasiparticles injected into an adjacent superconducting tunnel junction. In our prototype phonon spectrometer we have demonstrated spatial resolution of 200 nm, a frequency resolution of ~20 GHz, and a frequency range from ~80 to ~800 GHz. Our results on Si nanosheets indicate that the Casimir limit is reached at much lower frequencies than previously believed.