This paper investigated the silicon substrate orientation dependence on the electrical properties of high-κ HfN gate insulator formed by electron-cyclotron-resonance (ECR) plasma sputtering. The effect of N2/4.9%H2 forming-gas annealing (FGA) was studied. By using N2/4.9%H2 FGA at 500°C for 20 min, the interfacial layer (IL) formation was not formed and led to the zero-interface layer (ZIL). The EOTs of 0.47 and 0.51 nm with leakage current of 1.1 and 1.4 A/cm2 (@VFB -1 V) were obtained on p-Si(100) and p-Si(110), respectively. The density of interface states (Dit) with the order of 1011 cm-2eV-1 was obtained on both p-Si(100) and p-Si(110). This suggests that the direct deposition of HfN film with ZIL prevented the degradation of electrical characteristics on the p-Si(100) and p-Si(110) substrate in comparison to the case of oxide-based hafnium gate insulator.

In this paper we present a multilayer device based on a-Si:H/a-SiC:H that operates as photodetector and optical filter. The use of such device in protein detection applications is pertinent in Fluorescence Resonance Energy Transfer (FRET) measurements that demand the detection of visible fluorescent signals located at specific wavelengths bands. This device was designed to operate in the visible range with a selective sensitivity dependent on the applied electrical bias. Several nanosensors were tested with a commercial spectrophotometer to judge the performance of the FRET signals using glucose solutions of different concentrations. Two nanosensors (FLIPglu-90μM and FLIPglu-600μM) were tested with a commercial spectrofluorimeter to judge the performance of the FRET signals by using glucose solutions of different concentrations. These measurements were carried out by using these nanosensors both in the free form and immobilized form on inner epidermis of onion bulb scale. The proposed device was used to demonstrate the possibility of FRET signals detection, using visible signals of similar wavelength and intensity. The device sensitivity was tuned to enhance the wavelength band of interest using adequate electrical biasing.

We demonstrate fluidically tuned fluorescence enhancement on the colorimetric substrate with the plasmonic effects induced by the periodic gold nanocup arrays. The fluorescence enhancement by the plasmonic effect has been studied extensively by varying the geometries of nanostructures or the morphology of nanoparticles. In this study, however, the fluorescence enhancement without changing these parameters but simply by varying surrounding media on the colorimetric plasmonic surface is accomplished. The dynamic responses of fluorescence from self-assembled monolayer of dyes on the surface were monitored by flowing various fluids with different refractive indices. The dependence of the radiative decay rate as well as the scattering cross-section on the surrounding dielectric properties results into the selective enhancement of the fluorescence intensity, having a maximum at different surrounding refractive index for different fluorophores with different emission band centers.

The colored component of several important ancient pigments, including Egyptian blue and Han blue, are based on alkali earth copper tetrasilicate materials. In recent work, we have found that these layered materials can be chemically exfoliated into their constituent monolayers to provide alkali earth copper tetrasilicate nanosheets—defined by nanometer thickness and lateral dimensions that are on the order of several microns. The facile exfoliation of these materials into nanosheets is especially surprising in view of their long history on artifacts under a variety of environmental conditions, and we have examined the issue of whether archaeological samples are affected by this exfoliation mechanism. We have characterized the properties of these nanosheets by an array of analytical techniques, including powder x-ray diffraction, photoluminescence measurements, and Raman spectroscopy. In all cases, we observe differences between nanosheet and bulk samples that originate from the loss of coupling between layers when going from three-dimensional to two- dimensional structures. Both CaCuSi4O10 nanosheets (derived from Egyptian blue) and BaCuSi4O10 nanosheets (derived from Han blue) have strong near-infrared luminescence properties like their bulk counterparts, yet they are amenable to modern solution processing methods. We have demonstrated ink jet printing with CaCuSi4O10 nanosheet inks, as well as the fabrication of nanosheet-based papers. Potential applications for these materials include NIR-based biomedical imaging and security inks.

The metal-catalyzed step-growth radical polymerization was achieved to enable two systems for preparing tailored polymeric structures, i.e., sequence-regulated vinyl copolymer and periodically-functionalized polymer. The former is a novel strategy for preparing sequence-regulated vinyl copolymers by step-polymerization of sequence-regulated vinyl oligomers prepared from common vinyl monomers as building blocks. The later deals the simultaneous chain- and step-growth radical polymerization, which resulted in the polymers with periodic functional groups.

In this work we have investigated the mechanical properties and fracture patterns of some graphene nanowiggles (GNWs). Graphene nanoribbons are finite graphene segments with a large aspect ratio, while GNWs are nonaligned periodic repetitions of graphene nanoribbons. We have carried out fully atomistic molecular dynamics simulations using a reactive force field (ReaxFF), as implemented in the LAMPPS (Large-scale Atomic/Molecular Massively Parallel Simulator) code. Our results showed that the GNW fracture patterns are strongly dependent on the nanoribbon topology and present an interesting behavior, since some narrow sheets have larger ultimate failure strain values. This can be explained by the fact that narrow nanoribbons have more angular freedom when compared to wider ones, which can create a more efficient way to accumulate and to dissipate strain/stress. We have also observed the formation of linear atomic chains (LACs) and some structural defect reconstructions during the material rupture. The reported graphene failure patterns, where zigzag/armchair edge terminated graphene structures are fractured along armchair/zigzag lines, were not observed in the GNW analyzed cases.

In the previous investigation, piezoelectric properties of the ‘Aligned-type’ in which the piezoelectric-ceramic particles are formed in linear aggregates in the rubber, remarkable piezoelectric properties were confirmed. In this investigation, to further enhance the piezoelectric properties of the Aligned-type, the influence of the matrix properties was investigated. The properties on which we focused were the dielectric constant and the Young’s modulus. Four kinds of matrix materials whose dielectric constant and Young’s modulus are different from each other; Silicone gel, Silicone rubber, Urethane rubber and Poly-methyl-methacrylate were investigated. As a result of measurement of the piezoelectric strain constant d 33 of the Aligned-Type, it was confirmed that though the influence of the dielectric constant of the matrix material was small, the lower the Young’s modulus of the matrix was, the higher d 33 was.

Transparent UV protective coatings were developed by incorporating nano-TiO2 into waterborne acrylic systems to provide long-term UV protection for UV sensitive cool color roofing. Water based high crystalline TiO2 nanoparticle suspension was prepared via a gel-sol method at a basic pH. The TiO2 nanoparticles have an average size of 20 nm and are stable against agglomeration. As prepared TiO2 nanosuspension is ready to be well dispersed in commercial waterborne acrylic resin system without extra surface modification. The fabricated TiO2/acrylic nanocomposite coating achieved an UV cut-off below 350 nm with a visible transmission greater than 85% at 700 nm. It is also demonstrated that surface modification of Nano-TiO2 with a SiO2 insulation layer would suppress the catalytic activity of Nano-TiO2 and improve the UV protection for UV and photocatalysis sensitive dyes.

Articular cartilage is prone to degeneration and possesses extremely poor self-healing capacity due to its low cell density and absence of blood vessels. It has extensively reported tissue engineered scaffold can be a promising approach for cartilage repair. However, there still remains an inherent lack of desirable scaffolds that stimulate cartilage regrowth with appropriate functional properties. Therefore, in this study, we develop a biomimetic cartilage substitute comprising of electrospun polycaprolactone (PCL) with cold atmospheric plasma (CAP) modified cell favorable surface and sustained bioactive factor (bovine serum albumin (BSA) or transforming growth factor beta 1 (TGF-β1)) incorporated microspheres inside for improving stem cell chondrogenesis and cartilage regeneration. Scanning electron microscopy (SEM) analysis showed the drug delivery spheres homogeneously distribution in the fibrous scaffold. Furthermore, CAP treatment renders the scaffold’s surface more hydrophilic and results in more specific vitronectin adsorption as illustrated by contact angle and ELISA testing. Our results showed that the CAP treated scaffold can greatly improve growth and chondrogenic differentiation (such as increased glycosaminoglycan (GAG) synthesis) of human bone marrow-derived mesenchymal stem cells (MSCs).

The efficiency of thin-film solar cells using a-Si:H is limited by the decrease in a-Si:H layer optical path length and its poor light absorption at red and NIR wavelengths. Metal NP such as Au have been shown to increase the absorption in the active material and then cell performances, by exhibiting localized surface plasmon (LSP) resonances. Our work’s goal is to understand NP influence in such cells, to perform an optimal structure by increasing the amount of light absorbed within the cell using NP scattering and luminescence. Modeling based on Mie theory is first carried out using bulk Palik data for Au spheres with various diameters and refractive medium indexes. Using modeling parameters, Au layers were deposited on glass and SnO2 substrates respectively by thermal evaporation in vacuum and sputtering, followed by thermal annealing (200 ∼ 500°C) in order to promote the NP growth. MEB pictures show quasispherical Au NP shape with a mean size of 150nm. This diameter range switches extinction of NP in scattering regime. Annealing temperature (T) strongly affects the NP morphology. Surface coverage decreases and sphericity appears to increase with T. UV-Visible spectroscopy displays distinct LSP resonances around 600nm after annealing with a red shift while T increases.

The use of generic sorption data in PA requires the transfer of the data to the PA-specific conditions. A site-specific Kd setting approach for PA calculations was tested, comparing two data transfer procedures. First transfer of sorption data can be done through semi-quantitative estimation procedures, by considering differences between experimental and PA geochemical conditions (sorption capacity, radionuclide speciation, competitive reactions, etc.). On the other hand, thermodynamic sorption models allow to estimate Kd variations directly, based on quasi-mechanistic understanding. The present paper focuses on illustrating example calculations regarding the derivation of Kd values, and their uncertainties, of Cs, Ni, Am and Th, for the mineralogical and geochemical conditions of the mudstone system at the Horonobe URL. Clay minerals (illite and smectite) were considered as sorption-relevant minerals in all cases. The Kd setting results were compared with Kd measured for Horonobe mudstone by batch experiments. The results indicate that Kd can be quantitatively evaluated from generic sorption data when adequate data and models are available. The careful evaluation and conjunctive use of calculated and measured Kd values can enhance the reliability of Kd setting and uncertainty assessments.

Semi-flexible polymer networks generate a diverse family of structures. The network generating behaviors of specific semi-flexible biological filaments are well known (i.e. F-actin, microtubules, DNA etc.), however recent developments in tunable synthetic filaments extend the range of accessible structures. A similarly tunable model was developed using the molecular dynamics platform NAMD to provide a guide for generating synthetic filament networks. Structural characteristics of simulated networks may be quantitatively examined using connectivity analysis, radial pair distribution functions and scaling analysis. These methods provide a basis to calculate morphological properties, including mesh size, packing order, network connectivity, avg. cluster size, filaments per bundle, and space-filling dimensionality. An analytic toolset for describing the structure of filament networks is thus provided by detailing these methods.

A facile technique was developed for a long-term increase in silicone elastomer surface hydrophilicity, eliminating the need for post-cure surface treatment (e.g. oxygen plasma or surface grafting). Well-defined silicones (1-4 kDa) with a central vinyl functionality and discrete PEG2, PEG3 and tetrahydrofurfuryl (THF) pendant endgroups were synthesized, characterized and used as comonomers in addition-cure, platinum catalyzed 2-part silicone elastomer formulations. The modified silicone elastomers were optically clear and maintained the mechanical performance characteristic of this class of material with up to 20 wt.% comonomer in the 2-part formulation. Contact angle measurements of deionized water on the silicone elastomer surface showed improved wettability with comonomer content. The elastomer surface shifted from hydrophobic (contact angle ∼120°C) to hydrophilic (contact angle < 90°C) at ∼5 wt.% comonomer loadings for extended time frames (> 5 months). Coefficient of friction measurements of the modified silicone elastomers revealed an increase in surface lubricity with comonomer loadings.

Silver nanoparticle (AgNP) is one of the elegant material because its uses in various fields. In this study, AgNPs have been prepared by using Peltophorum pterocarpum (PP) flower extract as reducing and capping agent and aqueous silver nitrate (aq.AgNO3) as silver precursor. The synthesized nanoparticles were characterized using Ultra Violet - Visible (UV-Vis) spectroscopy, High Resolution Transmission Electron Microscope (HR-TEM) and Fourier Transform Infrared Spectroscopy (FT-IR), which reveals the formation of nanosized particles. The UV-Vis spectrum shows an absorption peak around 430nm. HR-TEM images of AgNPs with clear morphology and well dispersed prepared AgNPs.

Inkjet printing of TiO2 potentially offers a high degree of control over the deposition of TiO2 suspensions. Previous use of inkjet printing for TiO2 depositions have focused on producing TiO2 films with uniform density. A multi-ink printing system offers the possibility of depositing TiO2 films with variable density using a single deposition method.

For this research, inkjet printing of TiO2 films with a graded density profile was explored as a means of improving dye sensitized solar cells (DSSCs) performance. Varying pore volume as a means to produce density variations in TiO2 layers was explored. To control the pore volume, several TiO2 suspensions were developed with different pore-forming additives. DSSCs with printed TiO2 films having three density layers showed an average improvement in the conversion efficiency of 127% versus those with a single layer and 45% versus those with dual- layer TiO2. Short-circuit current densities of cells with tri-layer films increased an average of 62% over those with a single layer and 17% over those with dual-layer TiO2. It was also shown that DSSCs with inkjet printed TiO2 layers performed better than those with spin-coated TiO2 layers.

The results effectively demonstrated the potential for using inkjet printing as a sole deposition method to produce TiO2 films with non-uniform density leading to improved DSSC performance. One possibility for further study is to create further layer variations through simultaneous printing of different suspensions.

The synthesis of bimetallic magnetic nanoparticles is very challenging because of the agglomeration and non-uniform size. In this paper, we present the synthesis of monodispersed 3-5 nm sized thiolated bimetallic alloyed Au/Co nanoparticles with decahedral and icosahedral shape, their characterization using Cs-corrected scanning transmission electron microscopy (STEM) and magnetic measurements using superconducting quantum interference device (SQUID) magnetometer. The Z-contrast imaging and energy dispersive X-ray spectroscopy (EDS) mapping showed an inhomogeneous alloying with minor segregation between Au and Co at nanoscale and the SQUID measurement exhibited the ferromagnetic behavior.

We show that high-efficiency and low-degradation hydrogenated amorphous silicon (a-Si:H) p-i-n solar cells can be obtained by depositing absorber layers in a triode-type plasma-enhanced chemical vapor deposition (PECVD) process. Although the deposition rate is relatively low (0.01-0.03 nm/s) compared to the conventional diode-type PECVD process (∼0.2 nm/s), the light-induced degradation in conversion efficiency of single-junction solar cell is substantially reduced (Δη/ηini∼10%) due to the suppression of light-induced metastable defects in the a-Si:H absorber layer. So far, we have attained an independently-confirmed stabilized efficiency of 10.11% for a 220-nm-thick a-Si:H solar cell which was light soaked under 1 sun illumination for 1000 hours at cell temperature of 50°C. We further demonstrate that stabilized efficiencies as high as 10% can be maintained even when the solar cell is thickened to >300 nm.

Imprinting is a well-established technique to induce recognition features in both organic and inorganic materials for a variety of target analytes. In this study, ion imprinted polysiloxanes with varying percentage of coupling agent i.e. 3-chloro propyl trimethoxy silane (CPTM) were synthesized by sol-gel method for imprinting of Cr3+. The imprinting of Cr3+ in cross-linked siloxane network was investigated by FT-IR which indicates the metal ion is coordinated with oxygen atoms of polysiloxanes. SEM images revealed that imprinted polysiloxanes possess uniform particles of submicron size. It was experienced that by increasing the concentration of CPTM up to 10% (v/v) substantially improves the binding capacity of polysiloxanes which allows us to recognized Cr3+ down to 50µg/L. Furthermore, the selectivity of Cr3+-imprinted polysiloxanes was evaluated by treating them with other competing metal ions of same concentration i.e. Cr6+, Pb2+ and Ni2+. In this regard, polysiloxanes showed much higher binding for imprint ion i.e. Cr3+ in comparison to above mentioned metal ions. Finally, the regenerated polysiloxanes were studied in order to reuse them thus, developing cost effective biomimetic sensor coatings.