We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10 13 per square centimeter and with room-temperature mobilities of ∼10,000 square centimeters per volt-second can be induced by applying gate voltage.

http://science.sciencemag.org/content/sci/306/5696/666.full.pdf

Electric Field Effect in Atomically Thin Carbon Films

We describe a simple process for the fabrication of ultrathin, transparent, optically homogeneous, electrically conducting films of pure single-walled carbon nanotubes and the transfer of those films to various substrates. For equivalent sheet resistance, the films exhibit optical transmittance comparable to that of commercial indium tin oxide in the visible spectrum, but far superior transmittance in the technologically relevant 2- to 5-micrometer infrared spectral band. These characteristics indicate broad applicability of the films for electrical coupling in photonic devices. In an example application, the films are used to construct an electric field-activated optical modulator, which constitutes an optical analog to the nanotube-based field effect transistor.

http://science.sciencemag.org/content/sci/305/5688/1273.full.pdf

Transparent, Conductive Carbon Nanotube Films

We demonstrate logic circuits with field-effect transistors based on single carbon nanotubes. Our device layout features local gates that provide excellent capacitive coupling between the gate and nanotube, enabling strong electrostatic doping of the nanotube from p-doping to n-doping and the study of the nonconventional long-range screening of charge along the one-dimensional nanotubes. The transistors show favorable device characteristics such as high gain (>10), a large on-off ratio (>10(5)), and room-temperature operation. Importantly, the local-gate layout allows for integration of multiple devices on a single chip. Indeed, we demonstrate one-, two-, and three-transistor circuits that exhibit a range of digital logic operations, such as an inverter, a logic NOR, a static random-access memory cell, and an ac ring oscillator.

/pdf/logic-circuits-with-carbon-nanotube-transistors-vw5igdkjzb.pdf

Logic circuits with carbon nanotube transistors

Gold nanorods: Synthesis, characterization and applications

This Account reports the synthesis and characterization of dendrimer-encapsulated metal nanoparticles and their applications to catalysis. These materials are prepared by sequestering metal ions within dendrimers followed by chemical reduction to yield the corresponding zerovalent metal nanoparticle. The size of such particles depends on the number of metal ions initially loaded into the dendrimer. Intradendrimer hydrogenation and carbon−carbon coupling reactions in water, organic solvents, biphasic fluorous/organic solvents, and supercritical CO2 are also described.

http://rcrooks.cm.utexas.edu/research/resources/Publications/rmc113.pdf

Dendrimer-Encapsulated Metal Nanoparticles: Synthesis, Characterization, and Applications to Catalysis

The potentiostatic electrochemical template synthesis of nanowires (Ni, Co, Cu, Au, and polyporrole) in polycarbonate track-etched membranes with nominal pore diameters dN between 10 and 200 nm is ...

Template synthesis of nanowires in porous polycarbonate membranes: electrochemistry and morphology

This paper describes a new data set available to academic researchers at the following website: http://mktsci.pubs.informs.org . These data are comprised of store sales and consumer panel data for 30 product categories. The store sales data contain 5 years of product sales, pricing, and promotion data for all items sold in 47 U.S. markets. In two U.S. markets, the store level data are supplemented with panel-level purchase data and cover the entire population of stores. Further information is available regarding store characteristics in these markets. We address several potential applications of these data, as well as the access protocol.

The data set described in this paper is maintained by IRI. Any fees charged by IRI for the distribution of the data set will be used for the continual maintenance and updating of the data. Scholarships to cover IRI's fees for those who need it are available through the INFORMS Society for Marketing Science ISMS. Please see the website above for further details.

https://pubsonline.informs.org/doi/pdf/10.1287/mksc.1080.0450

Database Paper---The IRI Marketing Data Set

We explore the electric-field effect of carbon nanotubes (NTs) in electrolytes. Due to the large gate capacitance, Fermi energy (EF) shifts of order ±1 V can be induced, enabling to tune NTs from p to n-type. Consequently, large resistance changes are measured. At zero gate voltage, the NTs are hole-doped in air with |EF|≈0.3–0.5 eV, corresponding to a doping level of ≈1013 cm−2. Hole-doping increases in the electrolyte.

Electrochemical carbon nanotube field-effect transistor

Emerging alternative photovoltaic technologies such as dye sensitized solar cells (DSSCs) and organic solar cells (OSCs) have recently gained much attention as well as maturity and are on the step of being commercialized. Bulk heterojunction hybrid solar cells containing inorganic nanoparticles and semiconducting polymers are still lagging behind in respect of device performance although they have theoretically the potential to exhibit better performances than devices containing solely organic compounds. In this article we review the recent state of the art development of bulk heterojunction hybrid solar cells. Critical factors limiting the solar cell device performance are highlighted and strategies for further device improvement are demonstrated by giving recent examples from literature.

Bulk-heterojunction hybrid solar cells based on colloidal nanocrystals and conjugated polymers

We report on bulk-heterojunction hybrid solar cells based on blends of non-ligand-exchanged CdSe quantum dots (QDs) and the conjugated polymer poly(3-hexylthiophene) with improved power conversion efficiencies of about 2% under AM1.5G illumination after spectral mismatch correction. This is the highest reported value for a spherical CdSe QD based photovoltaic device. After synthesis, the CdSe QDs are treated by a simple and fast acid-assisted washing procedure, which has been identified as a crucial factor in enhancing the device performance. A simple model of a reduced ligand sphere is proposed explaining the power conversion efficiency improvement.

Michael Krüger

Papers

Template synthesis of nanowires in porous polycarbonate membranes: electrochemistry and morphology

Database Paper---The IRI Marketing Data Set

Electrochemical carbon nanotube field-effect transistor

Bulk-heterojunction hybrid solar cells based on colloidal nanocrystals and conjugated polymers

Improved efficiency of hybrid solar cells based on non-ligand-exchanged CdSe quantum dots and poly(3-hexylthiophene)