Electroactive subwavelength gratings (ESWGs) from conjugated polymers for color and intensity modulation.

Subwavelength gratings with electroactive polymers such as poly(3-hexylthiophene) (P3HT) and poly(3,4-propylenedioxythiophene-phenylene) (P(ProDOT-Ph)) controlled the color intensity for various visible colors of diffracted light in a single device. Under the illumination of a white light, at a fixed angle of incidence, the color intensity of the diffracted light was reversibly switched from the maximum value down to 15% (85% decrease) by applying -2 to 2 V due to electrochemical (EC) reaction. All spectral colors including red, green, and blue were generated by changing the angle of incidence, and the intensity of each color was modulated electrochemically at a single EC device.

Color combination of conductive polymers for black electrochromism.

Conducting polymers that absorb three primary colors, red, green, and blue (RGB), were introduced with a yellow electrochromic polymer (Y) for the preparation of black electrochromic devices. Red poly(3-hexylthiophene) (P3HT) and blue poly(3,4-ethylenedioxythiophene) (PEDOT) were coated on one side of the electrode as a cathodically coloring electrochromic (EC) layer, while green poly(aniline-N-butylsulfonate) (PANBS) and yellow EC poly{[1,3-bis(9',9'-dihexylfluoren-20-yl)azulenyl]-alt-[2",7"-(9",9"-dihexylfluorenyl]} (PDHFA) were coated on the opposite electrode to complete a complementary EC device. The yellow PDHFA layer effectively compensated for absorption below 450 nm and above the 600 nm region, which was lacking in the RGB electrode.

Self-assembled CNT circuits with ohmic contacts using Pd hexadecanethiolate as in situ solder.

An easy and elegant method of CNT nanocircuit fabrication using a metal organic precursor of Pd, namely, Pd hexadecanethiolate, is presented. This precursor directs the self-assembly of individual CNTs spanning a gap between Au electrodes. This is achieved by first patterning the precursor along the edges of the gap electrodes, as it enables direct patterning by e beam.

Femtoliter silver cups as surface enhanced Raman scattering active containers.

Femtoliter capacity Ag cups formed by the pulsed laser ablation of an Ag foil have been tried out as substrates for surface enhanced Raman scattering (SERS) measurements. The cups are formed as the impinging droplets from the laser plume undergo a flow pattern before freezing into cup-like structures, resulting in a surface roughness (approximately 35 nm) that makes them ideal for SERS studies. The internal volume of the cups is in the femtoliter (10(-15) l) range, well suited for small-scale reactions, particularly in biological studies.

Highly conducting patterned Pd nanowires by direct-write electron beam lithography.

Palladium hexadecylthiolate is shown to serve as a negative-tone direct-write electron resist to produce nanopatterns down to 30 nm. The written patterns do not deviate much from the precursor in composition, while a post-treatment at 230 degrees C in air produced metallic Pd nanowires with residual carbon less than 10% and resistivity close to the bulk value, a desirable property of interconnects in nanocircuitry. The as-written patterns contain small nanocrystals (<5 nm) in a hydrocarbon matrix, which upon annealing aggregate to form well-connected networks of larger nanocrystals (5-15 nm), thus giving rise to metallic conductivity.

Electron resist behavior of Pd hexadecanethiolate examined using X-ray photoelectron spectroscopy with nanometric lateral resolution.

Electron resist behavior of Pd hexadecanethiolate is studied by varying the e-dosage from 2-280 muC.cm(-2). The e-beam exposed resist is characterized using energy dispersive spectroscopy, infrared spectroscopy, and X-ray photoelectron spectroscopy with nanometric lateral resolution.

A SERS-active nanocrystalline pd substrate and its nanopatterning leading to biochip fabrication.

Nanocrystalline metallic Pd films have been produced by thermolysis of Pd hexadecanethiolate deposited on a Si surface. The particle size was in the range of 50-60 nm based on electron and atomic force microscopy. The Pd surface produced was found to be surface-enhanced Raman scattering (SERS) active with an enhancement factor of approximately 10(5).

Gold nanostructuring on Si substrate by selective electroless deposition.

Gold deposition on Si(111) substrates has been carried out by electroless process from KAuCl4 in a fluorinated solution and the resulting nanostructures have been characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Deposition carried out under normal plating conditions produces an Au film with (111) orientation. The effect of additives such as poly(vinylpyrrolidone) (PVP) and mercaptoundecanoic acid (MUA) to the plating solution has been examined.