A simple chemical vapor deposition method for the production of highly conductive polymer poly(3,4-ethylenedioxythiophene).

Conductive thin films of Poly(3,4-ethylenedioxythiophene) (PEDOT) have been successfully deposited on a variety of substrates by a simple chemical vapor deposition (CVD) method starting from the liquid monomer (EDOT) and using FeCl3 as a catalyst. Resistivity measurements indicated very good conductivity of the material, comparable with other previously reported values for PEDOT deposited by CVD. Further cyclic voltammetry measurements indicated a value of around -4.7 eV for the HOMO level of PEDOT in the deposited films, in agreement with other reported values. This value is within the bandgap of most semiconductors, and together with the relative low internal resistance makes our material an ideal candidate as a solid-state hole transport material for dye sensitized solar cells.

Growth of E18 rat hippocampal neuronal cells on nanostructured surfaces for enhanced electrical stimulation and recording.

We have prepared gold nanowire arrays inside nanoporous alumina templates with the goal towards neuronal interfacing and electrical recording from neurons. We have investigated biofunctionalization of such gold nanowire arrays (GNWs) and gold nanofilm (GNF) platforms to understand its impact on neuronal attachment and growth. Poly-D-Lysine (PDL) was coated on the nano-templates surfaces for adhesion of neurons which also enhanced the neuronal growth. Optical microscopy and scanning electron microscopy images revealed strong affinity and improved growth of neurons on PDL-coated surfaces. Such results will impact future investigation of stimulation and recording of electrical activity on nanoscale surfaces.

Synthesis of nanomaterials using self-assembled nanotemplates.

Nanoporous alumina templates and titania nanotube arrays have emerged as highly important materials due to their many potential applications in a variety of research areas. The templates are prepared using an electrochemical anodization process starting from metallic Al or Ti films. Several different synthesis routes for the deposition of such templates have been demonstrated in literature. This article provides an overview of the various synthesis routes that may be employed. The templates have diverse applications and may also be utilized in the electrodeposition of nanowire arrays of a variety of materials, such as metals, semiconductors, etc. A brief overview of these deposition methods is also provided.

Engineering low-aspect ratio carbon nanostructures: nanocups, nanorings, and nanocontainers.

The synthesis of carbon nanostructures, with interesting morphologies, has created a revolution in nanotechnology; carbon nanotube is a case in point, but other nanoscale morphologies of graphitic carbon could provide compelling uses. In particular short structures, including very short nanotubes, have proven impossible to be grown by existing techniques due to the difficulty in controlling and terminating growth during initial stages. Here we present architectures engineered from graphitic carbon, having up to 10(5) times smaller length/diameter (L/D) ratios compared to conventional nanotubes, revealing unique morphologies of nanocups, nanorings, and large area connected nanocup arrays. Such highly engineered hollow nanostructures were fabricated using precisely controlled short nanopores inside anodic aluminum oxide templates. The nanocups were effectively used to hold and contain other nanomaterials, for example, metal nanoparticles, leading to the formation of multicomponent hybrid nanostructures with unusual morphologies. The results reported here open up possibilities to integrate new morphologies of graphitic carbon in nanotechnology applications.

High-aspect ratio nano-noodles of alumina and titania.

We report the formation of high-aspect ratio rod-like structures or 'nano-noodles' of alumina or titania. Such structures are formed either by rapid anodization of aluminum/titanium foil or by long-term post-anodization treatment of porous templates. Specifically, the nano-noodle structures form during anodization in highly acidic electrolytes and/or at high anodization voltages, or when porous templates are etched for long periods of time in an acid. Growth mechanism for such structures is also proposed.

Roles of pH and acid type in the anodic growth of porous alumina.

Several theoretical models have been formulated to explain the growth of porous structures in anodized alumina. Using some basic assumptions, these models predict the size and shape of the pores in the anodic porous alumina as functions of pH and voltage. Additionally, they address issues of stability in the pore growth. In this work, we have carried out a systematic experimental investigation to study the stability phase diagram as a function of pH and applied voltage. We also obtain the dependence of pore dimensions on the pH, voltage, and acid type. Based on our results, and insight gained from recent chemical analysis of the porous alumina anodization process, we conclude that the models must include an appropriate weighting factor to account for the oxidation and dissolution mechanism during the pore formation.