Former group members

Hideo Hata
My main research interest focuses on producing new layered intercalation compounds through manipulating the interface of anionic layered host materials and anionic guests. By intercalating basic or cationic polyelectrolytes, the layer charge of the anionic host can be controlled. The process stems from the principle of layer-by-layer polyelectrolyte adsorption, which is overcompensation of the layer charge. Acidic dyes, anionic nanoparticles, and environmental contaminants such as ClO₄^- and TcO₄^- can act as guest molecules in these new cationic hosts.

Nina Kovtyukhova
My most ambitious goal is to contribute to bridging a gap between the single device level and the circuit level in nanoscale electronics. This can be achieved by preparing electronically functional films built-in metal nanowires. Nanowire-based circuit architecture is the core of chemically assembled nanocomputing design. My approach is based on combining wet layer-by-layer self-assembly of ultrathin films with template-directed synthesis of metal nanowires. By applying the layer-by-layer self-assembly to replication of a nanoporous membrane, one can prepare tubules of desired composition and thickness, which are stuck to the pore walls. Metal electroplating inside the tubules leads to metal nanowires coated with inorganic or inorganic/organic ultrathin films, which reveal current rectifying, switching, or insulating behavior. By performing the layer-by-layer self-assembly on the exposed tips of nanowires inside the membrane pores, which is followed by plating metal on the top of the film, it is possible to prepare nanowires with nanoparticle semiconductor, semiconductor/polymer or polymer films embedded between two metal segments of the wire. Encouraging, electrical properties of the both in- and on-wire devices are similar to those of planar micron-sized devices prepared by conventional layer-by layer self-assembly of the same films on planar substrates.

Shoichi Kubo
My research interests include development of photo-functional materials. In the past, I have worked on photonic crystals fabricated by self-assembly of mono-dispersed spheres. I'm now trying to make new systems which can exhibit unique optical properties such as negative or low refractive indices and non-linear absorption. Gold and silver nanoparticles are good candidates to realize such systems because they have plasmon resonance frequencies in the visible and near IR, and can interact with light at these wavelengths. Their optical properties in combination with other matrices, such as liquid crystals, are under investigation.

Yanyan Cao
Self-assembly of protein based nanosized structures.

Brian Kelly
I am interested in studying the effects confinement has on 1-D metal nano-particles (wires); specifically electron transport properties and crystallinity. Experiments have shown that single metal nano-wires, such as Pb, Sn, and Bi exhibit properties that differ from bulk metals.

Yoji Kobayashi
My research uses electrostatic layer-by-layer assembly techniques to prepare inorganic proton conducting membranes for intermediate temperature fuel cells. This method can be used, for example, to deposit layered perovskite films on a Pd foil substrate. The benefit of this method is that very thin membranes can be made, permitting materials of even modest proton conductivity to be used. Furthermore, various chemical modifications can be made on a layer-by-layer (angstrom) scale to improve proton conductivity.

Tom Larrabee
I am interested in the self-assembly of nanorod/nanoparticle structures. Particularly, lyophilic and lyophobic interactions, particle-particle interactions, and particle-surface interactions. Surface patterning, such as soft-lithography, is being used to direct particle organization. Fundamentalstudies involving mixed SAMs are underway, as well as experiments related to molecular electronics applications

Anna Lee
My research is focused on improving the energy conversion efficiency of dye-sensitized solar cells (DSSCs) by constructing 3-dimensional photonic crystals (PC) on top of collidal TiO₂ films. The difficulty with DSSCs is their poor light absorbance at wavelengths longer than 600 nm. I am studying how the periodic microstructure of PCs having a stop band in the 550 - 700 nm range affects the utilization of long wavelength light in DSSCs. I also plan to incorporate dye-sensitized colloidal O₂-evolving catalysts into the modified DSSCs to investigate the direct photoelectrolysis of water.

Brad Lewis
In my research I look at the use of nano-structured materials for the conversion of visible light into chemical and electrical energy. Currently I am attempting to prepare arrays of CdSe nanowires for use in photovoltaic solar cells. I have also looked at the photosensitization of, and the electron transfer in layered metal oxide semiconductor (LMOS) based nanostructures to be used as visible light water splitting catalysts.

Josh Schottenfeld
I work on synthesis and characterization of novel non-oxide perovskites. The synthesis involves heating various inorganic precursors to high temperatures in an ammonia atmosphere. Typical characterization consists of power X-ray diffraction, internal UV-Vis reflectance and measuring catalytic activity.

Yang Wang
I am interested in developing a class of nano- and microscale motors, which are powered by catalytic reactions, and applying them to nanomachinery, nanoscale delivery vehicles, and so on.