67 research outputs found
Nanopatterning on silicon surface using atomic force microscopy with diamond-like carbon (DLC)-coated Si probe
Atomic force microscope (AFM) equipped with diamond-like carbon (DLC)-coated Si probe has been used for scratch nanolithography on Si surfaces. The effect of scratch direction, applied tip force, scratch speed, and number of scratches on the size of the scratched geometry has been investigated. The size of the groove differs with scratch direction, which increases with the applied tip force and number of scratches but decreases slightly with scratch speed. Complex nanostructures of arrays of parallel lines and square arrays are further fabricated uniformly and precisely on Si substrates at relatively high scratch speed. DLC-coated Si probe has the potential to be an alternative in AFM-based scratch nanofabrication on hard surfaces
Single-crystal silver nanowires: Preparation and Surface-enhanced Raman Scattering (SERS) property
Ordered Ag nanowire arrays with high aspect ratio and high density
self-supporting Ag nanowire patterns were successfully prepared using
potentiostatic electrodeposition within the confined nanochannels of a
commercial porous anodic aluminium oxide (AAO) template. X-ray diffraction and
selected area electron diffraction analysis show that the as-synthesized
samples have preferred (220) orientation. Transmission electron microscopy and
scanning electron microscopy investigation reveal that large-area and ordered
Ag nanowire arrays with smooth surface and uniform diameter were synthesized.
Surface-enhanced Raman Scattering (SERS) spectra show that the Ag nanowire
arrays as substrates have high SERS activity.Comment: 5 pages, 4 figure
Fabrication of hydrophobic inorganic coatings on natural lotus leaves for nanoimprint stamps
Hydrophobic inorganic films were obtained by direct deposition of copper or
silicon onto natural lotus leaves by ion beam sputtering deposition technique.
Scanning electron microscopy observations showed a lotus-leaf-like surface
structure of the deposited inorganic films. Hydrophobic nature of the inorganic
films on lotus leaves had been improved compared to the inorganic films
deposited on flat silicon substrates. Water contact angles measured on the
lotus-leaf-like copper and silicon films were 136.3 \pm 8{\deg} and 117.8 \pm
4.4{\deg}, respectively. The hydrophobic lotus-leaf-like inorganic films had
been repeated used as nanoimprint stamps. Negative structures of
lotus-leaf-like inorganic films were obtained on the polystyrene resist layers.Comment: 14 pages, 6 figure
Structural properties and Raman spectroscopy of lipid Langmuir monolayers at the air-water interface
Spectra of octadecylamine (ODA) Langmuir monolayers and egg
phosphatidylcholine (PC)/ODA-mixed monolayers at the air-water interface have
been acquired. The organization of the monolayers has been characterized by
surface pressure-area isotherms. Application of polarized optical microscopy
provides further insight in the domain structures and interactions of the film
components. Surface-enhanced Raman scattering (SERS) data indicate that
enhancement in Raman spectra can be obtained by strong interaction between
headgroups of the surfactants and silver particles in subphase. By mixing ODA
with phospholipid molecules and spreading the mixture at the air-water
interface, we acquired vibrational information of phospholipid molecules with
surfactant-aided SERS effect.Comment: 8 pages, 9 figure
Unveiling the Mechanism of Plasma-Catalytic Low-Temperature Water–Gas Shift Reaction over Cu/γ-Al<sub>2</sub>O<sub>3</sub> Catalysts
The water-gas shift (WGS) reaction is a crucial process for hydrogen production. Unfortunately, achieving high reaction rates and yields for the WGS reaction at low temperatures remains a challenge due to kinetic limitations. Here, nonthermal plasma coupled to Cu/γ-Al2O3 catalysts was employed to enable the WGS reaction at considerably lower temperatures (up to 140 °C). For comparison, thermal-catalytic WGS reactions using the same catalysts were conducted at 140-300 °C. The best performance (72.1% CO conversion and 67.4% H2 yield) was achieved using an 8 wt % Cu/γ-Al2O3 catalyst in plasma catalysis at ∼140 °C, with 8.74 MJ mol-1 energy consumption and 8.5% H2 fuel production efficiency. Notably, conventional thermal catalysis proved to be ineffective at such low temperatures. Density functional theory calculations, coupled with in situ diffuse reflectance infrared Fourier transform spectroscopy, revealed that the plasma-generated OH radicals significantly enhanced the WGS reaction by influencing both the redox and carboxyl reaction pathways
Dipole-tunable interfacial engineering strategy for high-performance all-inorganic red quantum-dot light-emitting diodes
All-inorganic quantum dot (QD) light-emitting diodes (AI-QLEDs) with excellent stability received enormous interest in the past few years. Nevertheless, the vast energy offset and the high trap density at the NiOX/QDs interface limit hole injection leading to fluorescence quenching and hampering the performance. Here, we present self-assembled monolayers (SAMs) with phosphonic acid (PA) anchoring groups modifying NiOX hole transport layer (HTL) to tune energy level and passivate trap states. This strategy facilitates hole injection owning to the well-aligned energy level by interface dipole, downshifting the vacuum level, reducing the hole injection barrier from 0.94 eV to 0.28 eV. Meanwhile, it mitigates the interfacial recombination by passivating surface hydroxyl group (-OH) and oxygen vacancy (VO) traps in NiOX. The electron leakage from QDs toward NiOX HTL is significantly suppressed. The all-inorganic R-QLEDs exhibit one of the highest maximum luminance, external quantum efficiency and operational lifetime of 88980 cd m−2, 10.3% and 335045 h (T50@100 cd m−2), respectively. The as-proposed interface engineering provides an effective design principle for high-performance AI-QLEDs for future outdoor and optical projection-type display applications
Fabrication of surface-patterned ZnO thin films using sol-gel methods and nanoimprint lithography
Surface-patterned ZnO thin films were fabricated by direct imprinting on ZnO
sol and subsequent annealing process. The polymer-based ZnO sols were deposited
on various substrates for the nanoimprint lithography and converted to
surface-patterned ZnO gel films during the thermal curing nanoimprint process.
Finally, crystalline ZnO films were obtained by subsequent annealing of the
patterned ZnO gel films. The optical characterization indicates that the
surface patterning of ZnO thin films can lead to an enhanced transmittance.
Large-scale ZnO thin films with different patterns can be fabricated by various
easy-made ordered templates using this combination of sol-gel and nanoimprint
lithography techniques.Comment: 17 pages, 5 figures; Published in Journal of Sol-Gel Science and
Technology, 201
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