Search

Abstract The paper reports an investigation on the mechanical durability of textured thermoplastic surfaces together with their respective wetting properties. A range of laser-induced topographies with different aspect ratios from micro to nanoscale were fabricated on tool steel inserts using an ultrashort pulsed near infrared laser. Then, through micro-injection moulding the topographies were replicated onto polypropylene surfaces and their durability was studied systematically. In particular, the evolution of topographies on textured thermoplastic surfaces together with their wetting properties were investigated after undergoing a controlled mechanical abrasion, i.e. reciprocating dry and wet cleaning cycles. The obtained empirical data was used both to study the effects of cleaning cycles and also to identify cleaning procedures with a minimal impact on textured thermoplastic surfaces and their respective wetting properties. In addition, the use of 3D areal parameters that are standardised and could be obtained readily with any state-of-the-art surface characterisation system are discussed for monitoring the surfaces' functional response. Graphical abstract Unlabelled Image Highlights • The mechanical durability of textured surfaces is studied. • Laser-induced topographies were replicated onto polypropylene surfaces. • The surface energy and the Wenzel/Cassie-Baxter state of the textured surfaces were quantified. • The hydrophobicity decreased with the progressive abrasion of the topographies. • Standardised 3D areal parameters were correlated with surface wettability. [ABSTRACT FROM AUTHOR]

Abstract Ni-based composite coatings reinforced with in-situ titanium-doped NbC particles were fabricated on Cr12MoV steel plate utilizing laser cladding technology. The microstructure and mechanical properties of the coatings were investigated, as well as the effect of different Nb/Ti mole ratio on the distribution characteristics and formation mechanism of titanium-doped NbC particles. The (Ti, Nb)C distributed homogeneously in the coatings. According to the EBSD results, the coating with Nb/Ti = 1:1 showed strong texture characteristics, and the grains size of the bottom was smaller due to faster heat dissipation. As lower surface energy and lattice misfits of TiC and NbC, (Ti, Nb)C was easily synthesized and the pre-formed TiC particles were the most favorable attachment sites. According to the analysis results of SEM, EPMA and TEM, when Nb/Ti = 1:1, (Ti, Nb)C was a multiple carbide with a NbC structure. In addition, the various morphologies of reinforcing phases were relevant to the solidification rates, temperature gradient and composition distribution. The micro-hardness and wear resistance of coating with Nb/Ti = 1:1 exhibited significantly improvement compared with other coatings. Graphical abstract Unlabelled Image Highlights • The micro-hardness and wear resistance of coating with Nb/Ti = 1:1 exhibited clear improvement. • The (Ti, Nb)C particle in the coating with Nb/Ti = 1:1 exhibited a multiple carbide with a NbC structure. • The coating with Nb/Ti = 1:1 showed strong texture characteristics, and the grains size of the bottom was smaller. • The microstructure evolution mechanism of in-situ titanium-doped NbC reinforced Ni45 coating was studied. [ABSTRACT FROM AUTHOR]

Abstract In the present work, SERS substrates were successfully prepared on solid supports of silicon wafer, gold coated and bare-microscope glass slides. The multifaceted substrates consist of Localized Surface Plasmon Resonance metallic clusters immobilized on the supports. The two-step synthesis was achieved by self-assembly of metallic Ag or Au nanoparticles on the supports followed by in-situ growth of a bulk Au layer. Bimetallic substrates showed higher SERS activity compared to monometallic Au substrates. The gold coated and bare-microscope glass slides with bimetallic substrates had 2.5 × 107 and 2.0 × 107 enhancement factors, respectively. The prepared substrates showed good SERS capability. Graphical abstract Unlabelled Image Highlights • Bimetallic SERS substrates fabricated on solid supports showed enhanced 4-MBA signals and quantification capability. • SERS substrate performance dependent on the roughness, type and size of the LSPR metallic clusters [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Antioxidant functionalized silica-coated TiO 2 nanorods were prepared for the first time. • AO-KH550-SiO 2 -TiO 2 enhanced the thermal and photo stability of PP. • AO-KH550-SiO 2 -TiO 2 exhibited excellent anti- extraction property. • AO-KH550-SiO 2 -TiO 2 could block UV light and capture radicals. Abstract Rutile TiO 2 is commonly used as UV shielding agent because of the absorption of UV light. In this research, we integrated the function of rutile TiO 2 nanoparticles and antioxidants (AO), and prepared a kind of multifunctional TiO 2 nanoparticles with the capacity of both UV absorption and antioxidation. Firstly, rutile TiO 2 nanorods were prepared and encapsulated by SiO 2 to decrease its photocatalytic activity. Then, antioxidant functionalized silica-coated TiO 2 nanorods (AO-KH550-SiO 2 -TiO 2) were successfully synthesized by using aminosilane coupling agent (KH550) as a bridge. By melt blending method, AO-KH550-SiO 2 -TiO 2 were incorporated into PP matrix. The results indicated that AO-KH550-SiO 2 -TiO 2 could improve both photo stability and thermal stability of PP. PP/AO-KH550-SiO 2 -TiO 2 film broke after 220 h UV irradiation, and the broken time of PP/TiO 2 film was only 80 h. And the oxidation induction time of PP/AO-KH550-SiO 2 -TiO 2 sample was 4.7 min, while PP/TiO 2 sample showed no antioxidation effect. In addition, AO-KH550-SiO 2 -TiO 2 exhibited excellent anti-extraction property. This novel design of AO-KH550-SiO 2 -TiO 2 may open up a new avenue for fabricating multifunctional nanoparticles and facilitating their practical application. [ABSTRACT FROM AUTHOR]

Graphical abstract Fabrication and microstructural characterization of nanostructured eutectic surface layers on conventionally sintered Al 2 O 3 -ZrO 2 ceramic via the laser rapid solidification. Highlights • Nanostructured surface layer is grown epitaxially on the as-sintered Al 2 O 3 -ZrO 2 polycrystalline ceramics. • The microstructural evolutions of nanostructured surface layer were initially explored. • The geometrical evolution of molten pool in response to laser remelting parameters was established. Abstract In the present work, nanostructured surface layers of Al 2 O 3 -ZrO 2 eutectic with a thickness of approximate 1000 μm and free of cracks and pores were produced on the surface of conventionally-sintered Al 2 O 3 -ZrO 2 ceramic via the laser irradiation rapid solidification process. The molten pool geometry and microstructure were characterized by scanning electron microscopy and Raman spectroscopy. The geometrical evolution of molten pool in response to laser power and laser scanning velocity was established, where the top view of molten pool exhibits a circular shape at low velocities and gradually evolves into an oval-shaped surface at high velocities. Singular Al 2 O 3 -ZrO 2 eutectic colonies with a size of 100–200 μm, which is formed around a spontaneously nucleated dendritic ZrO 2 core, are found on the surface of laser-remelted layer. The eutectic colony has an interphase spacing of 190–280 nm. The variation of eutectic spacing with growth rate is essentially linear on the logarithmic scale as λ = K V - 0.4 by binary regression analysis. Predicted by the Jackson-Hunt theory on eutectic solidification (JH theory), the eutectic spacing is consistent with the inverse-square-root dependence on growth rate with a proportionality constant of 3.32. The eutectic colonies consist of α -Al 2 O 3 , t -ZrO 2 and m -ZrO 2 phases, where α -Al 2 O 3 and t -ZrO 2 are the dominant phases and the m -ZrO 2 phase increases with the decrease of laser scanning velocity. [ABSTRACT FROM AUTHOR]

Highlights • Ophthalmic polymers were structured by direct laser interference patterning. • Two-beam interference set-up was used to produce linear line-like patterns. • Single- and multi-pulse laser processing was studied. • Refractive index changes similar to those reported with the ULI technique were obtained. • The processing yield achieved is more than two orders of magnitude higher compared to ULI. Abstract The fabrication of diffractive elements in ophthalmic polymers to induce refractive index changes which may be applied for refractive correction is of great interest in the fields of Optics and Ophthalmology. In this work, poly-hydroxyethyl-methacrylate and silicone hydrogel polymers used as soft contact lenses were structured with linear periodic patterns by means of Direct Laser Interference Patterning (DLIP). As the laser source, a Q-switched laser system emitting 10 ns pulses at a wavelength of 266 nm was used to generate the periodic modulation on the surface of the polymer materials. The experiments were carried out employing a two-beam interference setup, studying the features of the laser processed areas as a function of both the laser fluence and the interference period. The topography of the structured areas was investigated using optical confocal microscopy. Compositional and structural modifications on the materials were studied by means of micro-Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Finally, periodic patterns were characterized through diffractive techniques under illumination of a continuous-wave 632.8 nm He-Ne laser to determine the diffractive properties of the DLIP periodic patterns and the refractive index change induced by the laser processing. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The surface of BiVO 4 is modified by KH550 for the closer contact with RGO. • Ag 3 PO 4 is deposited on the surface of BiVO 4 /RGO by electrostatic self-assembling. • BiVO 4 /RGO/Ag 3 PO 4 shows enhanced photocatalytic activity under visible light. • The contact of BiVO 4 , Ag 3 PO 4 and RGO promotes migration of photoinduced carriers. • BiVO 4 /RGO/Ag 3 PO 4 composite possesses better photo-stability than bare Ag 3 PO 4. Abstract A novel BiVO 4 /RGO/Ag 3 PO 4 ternary composite photocatalyst was fabricated through a two-step method of solvothermal assisted in situ ion sequential deposition method. The morphological structure, composition and optical properties were characterized by SEM, XRD, FT-IR, XPS, PL and UV–vis. The photocatalytic activities were assessed by the photocatalytic degradation process of Rhodamine B (RhB) and 4-nitrophenol (4-NP), and its photocatalytic mechanism was analyzed by conducting active radicals trapping experiments. The as-obtained BiVO 4 /RGO/Ag 3 PO 4 composite photocatalysts exhibited enhancement in photocatalytic activities compared with the pure BiVO 4 , Ag 3 PO 4 and BiVO 4 /Ag 3 PO 4 composite photocatalysts, which can degrade 98.2% of RhB and 82.1% of 4-NP in 45 min under the simulated sunlight irradiation when the mass ratio of Ag 3 PO 4 to BiVO 4 /RGO composites was 0.6:1. The photo-generated holes (h+) and the superoxide radicals (O 2 −) radicals were the dominant active species during the photocatalytic degradation process. The enhancement in photocatalytic performance can be ascribed to the synergistic effect of BiVO 4 and Ag 3 PO 4 , and the incorporation of reduced graphene oxide (RGO) which can promote the transfer and separation of photogenerated carriers at their interfaces. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The transparent and stable reactive silver ink was prepared. • The highly conductive and flexible printed silver films was fabricated at 70 °C. • The silver film displayed excellent adhesive strength and mechanical flexibility. Abstract To solve the problems of high sintering temperatures (∼200 °C), particle aggregation, nozzle clogging, and poor shelf life of silver nanoparticle inks, we prepared a transparent and stable reactive silver ink for fabricating printed electronics. The ink mainly consisted of ammonia and formic acid ligands, silver acetate, and hydroxyethyl cellulose (HEC) adhesive agent. The highly conductive and flexible silver films were fabricated by printing and low temperature sintering the reactive silver ink, and the effects of sintering temperature and sintering time on the electrical properties of the printed silver films were investigated. Consequently, the printed silver film sintered at 70 °C exhibits good electrical properties with a resistivity of 12.1 μΩ·cm, which is only seven times higher than that of bulk silver (1.65 μΩ·cm). Moreover, the silver film also displays excellent adhesive strength and mechanical flexibility in terms of bending and twisting. [ABSTRACT FROM AUTHOR]

Sensitive and selective detection of target analyte is very important in many fields such as commodity inspection and quality monitoring. In this work, we constructed a MIPs@AgNPs surface-enhanced Raman scattering (SERS) sensor by in-situ preparation of silver nanoparticles (AgNPs) inside molecularly imprinted polymers (MIPs) matrix for bisphenol A (BPA) detection. In-situ formed AgNPs are evenly distributed and closely packed in the matrix, which is beneficial for hot spot formation and analyte-AgNPs affinity. Our MIPs@AgNPs sensor shows good BPA selectivity against structurally related molecules such as bisphenol AF (BPAF) and diethylstilbestrol (DES). Excellent sensitivity of this MIPs@AgNPs sensor is demonstrated with the detection limit of at least 5 × 10 −8  mol L −1 for BPA. This sensor is reliable for the quantitative detection of BPA in real samples, validated with results of HPLC. Regeneration of this kind of SERS sensor can be easily realized by solvent rinsing and NaBH 4 reduction. Together with the advantages of ease-of-fabrication, selective recognition, sensitivity and reusability, this kind of MIPs@AgNPs SERS sensor will have a promising practical applications. [ABSTRACT FROM AUTHOR]

The MoS 2 /GO hybrid composite thin film is prepared by a facile solution mixing process. To reduce the composite film spin-coated on a SiO 2 (300 nm)/Si substrate, thermal annealing at 600 °C for 1 h in a N 2 atmosphere is used. The thermally reduced GO (rGO) composite film is subjected to line patterning through a soft lithographic patterning method, and the patterned MoS 2 /rGO composite thin film is re-transferred onto a PET film from the Si substrate. The patterned MoS 2 /rGO composite thin film has a thickness of about 10 nm and the transmittance of the patterned MoS 2 /rGO composite thin film on the PET substrate is 93%. The NO 2 gas sensor device is fabricated and its basic characteristics are systematically investigated. The patterned MoS 2 /rGO composite thin film gas sensor has a sensitivity at least four times higher than the pure rGO thin film gas sensor. In addition, the characteristics of the sensor device are also maintained at a bending radius of 14 mm. This transparent and flexible patterned MoS 2 /rGO composite thin film can be used as a highly sensitive gas sensor that will detect a concentration as low as 0.15 ppm of harmful gases such as NO 2 . [ABSTRACT FROM AUTHOR]

In recent years, the fabrication of superamphiphobic materials has become a hot topic, especially the material with wear abrasion resistance. In this study, the anti-abrasion and self-cleaning superamphiphobic materials were successfully fabricated by employing kaolin particles and silanes via a simple drop coating method. The as-prepared materials show excellent superamphiphobicity to water, ordinary liquids and kinds of oils, even the hexadecane with surface tension as low as 27.5 mN·m −1 . With respect to the mechanical durability, the fabricated material can still maintain its superamphiphobicity even after 180 cm abrasion using sandpaper. The excellent investigation results concerning to chemical durability, self-cleaning property, repellent to corrosion liquids, resistant to ultraviolet radiation and water dripping prove that the fabricated material is robust and multifunctional, which will increase more opportunities for practical applications. Apart from these general applications, the as-fabricated materials can be easily applied to various substrates. These multifunctional properties and the facile preparation method are expected to provide unique benefits for a wide range of applications in resistance mechanical abrasion and large-scale production. [ABSTRACT FROM AUTHOR]

We demonstrate mirror-finished superhydrophobic aluminum surfaces fabricated via the formation of anodic alumina nanofibers and subsequent modification with self-assembled monolayers (SAMs). High-density anodic alumina nanofibers were formed on the aluminum surface via anodizing in a pyrophosphoric acid solution. The alumina nanofibers became tangled and bundled by further anodizing at low temperature because of their own weight, and the aluminum surface was completely covered by the long falling nanofibers. The nanofiber-covered aluminum surface exhibited superhydrophilic behavior, with a contact angle measuring less than 10°. As the nanofiber-covered aluminum surface was modified with n-alkylphosphonic acid SAMs, the water contact angle drastically shifted to superhydrophobicity, measuring more than 150°. The contact angle increased with the applied voltage during pyrophosphoric acid anodizing, the anodizing time, and the number of carbon atoms contained in the SAM molecules modified on the alumina nanofibers. By optimizing the anodizing and SAM-modification conditions, superhydrophobic behavior could be achieved with only a brief pyrophosphoric acid anodizing period of 3 min and subsequent simple immersion in SAM solutions. The superhydrophobic aluminum surface exhibited a high reflectance, measuring approximately 99% across most of the visible spectrum, similar to that of an electropolished aluminum surface. Therefore, our mirror-finished superhydrophobic aluminum surface based on anodic alumina nanofibers and SAMs can be used as a reflective mirror in various optical applications such as concentrated solar power systems. [ABSTRACT FROM AUTHOR]

Despite the success of previous methods for fabricating underwater superoleophobic surfaces, most of the surfaces based on soft materials are prone to collapse and deformation due to their mechanically fragile nature, and they fail to perform their designed functions after the surface materials are damaged in water. In this work, the nanosecond laser-induced oxide coatings on hydrophilic bulk metals are reported which overcomes the limitation and shows the robust underwater superoleophobicity to a mechanical challenge encountered by surfaces deployed in water environment. The results show that the surface materials have the advantage that the underwater superoleophobicity is still preserved after the surfaces are scratched by knife or sandpaper and even completely destroyed because of the hydrophilic property of damaged materials in water. It is important that the results provide a guide for the design of durable underwater superoleophobic surfaces, and the development of superoleophobic materials in many potential applications such as the oil-repellent and the oil/water separation. Additionally, the nanosecond laser technology is simple, cost-effective and suitable for the large-area and mass fabrication of mechanically durable underwater superoleophobic metal materials. [ABSTRACT FROM AUTHOR]

In the fabrication of a high-temperature superconducting coated conductor, the surface roughness and texture of buffer layers can significantly affect the epitaxially grown superconductor layer. A biaxially textured MgO buffer layer fabricated by ion beam assisted deposition (IBAD) is widely used in the coated conductor manufacture due to its low thickness requirement. In our previous study, a new method called energetic particle self-assisted deposition (EPSAD), which employed only a sputtering deposition apparatus without an ion source, was proposed for fabricating biaxially textured MgO films on non-textured substrates. In this study, our aim was to investigate the deposition mechanism of EPSAD-MgO thin films. The behavior of the surface roughness (evaluated by R q ) was studied using atomic force microscopy (AFM) measurements with three scan scales, while the in-plane and out-of-plane textures were measured using X-ray diffraction (XRD). It was found that the variations of surface roughness and textures along with the increase in the thickness of EPSAD-MgO samples were very similar to those of IBAD-MgO reported in the literature, revealing the similarity of their deposition mechanisms. Moreover, fractal geometry was utilized to conduct the scaling analysis of EPSAD-MgO film's surface. Different scaling behaviors were found in two scale ranges, and the indications of the fractal properties in different scale ranges were discussed. [ABSTRACT FROM AUTHOR]

The purpose of this work was to optimize a single-step fabrication process of silicon (Si) cones-like nanostructures on Si(111) reconstructed substrates. The substrate temperature is the most important parameter in the Si/Si growth, due to its high influence over the surface nanostructuring and the occurrence of well defined nanocones. We investigate the effect of different substrate temperatures on the density and size distributions of Si nanocones formed during the molecular beam epitaxy (MBE) deposition of Si/Si(111) 7 × 7 reconstructed surfaces. The nanocones were characterized using scanning tunnelling microscopy (STM) and the height and the bottom area distributions of the Si nanocones were assessed. It was found that the obtained distributions are interrelated suggesting the self-similarity of the nanostructures grown during the deposition protocol. [ABSTRACT FROM AUTHOR]

The large-scale surface enhanced Raman scattering (SERS) cotton fabrics were fabricated based on traditional woven ones using a dyeing-like method of vat dyes, where silver nanoparticles (Ag NPs) were in-situ synthesized by ‘dipping-reducing-drying’ process. By controlling the concentration of AgNO 3 solution, the optimal SERS cotton fabric was obtained, which had a homogeneous close packing of Ag NPs. The SERS cotton fabric was employed to detect p -Aminothiophenol (PATP). It was found that the new fabric possessed excellent reproducibility (about 20%), long-term stability (about 57 days) and high SERS sensitivity with a detected concentration as low as 10 −12 M. Furthermore, owing to the excellent mechanical flexibility and good absorption ability, the SERS cotton fabric was employed to detect carbaryl on the surface of an apple by simply swabbing, which showed great potential in fast trace analysis. More importantly, this study may realize large-scale production with low cost by a traditional cotton fabric. [ABSTRACT FROM AUTHOR]

A comparison of processes and wettability characteristics was presented for injection molded superhydrophobic polypropylene surfaces from two fabricating strategies. One is the biomimetic replication of patterns from indocalamus leaf in nature. The contact angle of water sitting on this PP surface was measured as 152 ± 2°, with comparable wetting behavior to natural indocalamus leaf surface. The other strategy is the fabrication of superhydrophobic structure by combining methods that produce structures at different length scales. Regarding both the machinability of mold inserts and function-oriented design, three micro-quadrangular arrays and one hierarchical micro-nano cylinder array were designed with the goal of superhydrophobicity. Particularly, a simple approach to the fabrication of hierarchical structures was proposed by combining the anodized plate and the punching plate. The function-oriented design targets as superhydrophobicity were all reached for the designed four structures. The measured contact angles of droplet for these structures were almost consistent with the calculated equilibrium contact angles from thermodynamic analysis. Among them, the contact angle of droplet on the surface of designed hierarchical structure reached about 163° with the sliding angle of 5°, resulting in self-cleaning characteristic. The superhydrophobicity of function-oriented designed polymer surfaces could be modified and controlled, which is exactly the limitation of replicating from natural organisms. [ABSTRACT FROM AUTHOR]

A combined hydrothermal-calcination approach is developed to synthesize hierarchical β -Bi 2 O 3 /g-C 3 N 4 direct Z-scheme photocatalyst with enhanced visible light photoactivity for Rhodamine B (RhB) degradation. First, Bi 2 O 2 CO 3 microflowers were hydrothermally prepared using Bi(NO 3 ) 3 ·5H 2 O as feedstocks, and then a series of β -Bi 2 O 3 /g-C 3 N 4 direct Z-scheme photocatalysts were synthesized via a facile calcination method using Bi 2 O 2 CO 3 and g-C 3 N 4 as precursors. The samples were systematically characterized by various characterization technologies including X-ray diffraction, scanning and transmission electron microscopes, Fourier transform infrared spectroscopy and N 2 absorption-desorption equipment. It was found that the g-C 3 N 4 content in the precursors played a key role in affecting the photocatalytic activity of the final products. The β -Bi 2 O 3 /g-C 3 N 4 heterojunction exhibited higher photocatalytic activity than single active components ( β -Bi 2 O 3 and g-C 3 N 4 ), indicating the presence of a synergistic effect between two active components in β -Bi 2 O 3 /g-C 3 N 4 heterojunction. Among all as-prepared catalysts, the 70 wt.% g-C 3 N 4 /Bi 2 O 2 CO 3 exhibits the highest activity for RhB degradation, and the apparent reaction rate constant k (42.2 × 10 −3  min −1 ) is 3.1 and 1.7 times as high as that of pure β -Bi 2 O 3 (13.5 × 10 −3  min −1 ) and g-C 3 N 4 (25.2 × 10 −3  min −1 ), respectively. The enhanced photocatalytic performance of β -Bi 2 O 3 /g-C 3 N 4 heterostructure photocatalysts is mainly due to the high surface area, closely contacted interfaces between the β -Bi 2 O 3 and g-C 3 N 4 component, and the formation of direct Z-scheme structure in the β -Bi 2 O 3 /g-C 3 N 4 composites. [ABSTRACT FROM AUTHOR]

In the present study, two-stage process for the fabrication of superhydrophobic Ni-Cu-TiO 2 nanocomposite coatings on the copper substrate has been introduced. Surface modification was performed on the electrodeposited coatings by myristic acid-ethanol solution to achieve superhydrophobicity. Additionally, in order to further study the roughness effect, instead of addition of copper ions in electrodeposition bath, three substrates were roughened by electrochemical etching method. Water repellency properties were studied through measurement of static and dynamic contact angles, and performing bouncing test, self-cleaning and water-jet evaluation. The samples were electrodeposited in various current densities, and the highest corrosion resistance and water repellency properties were obtained for the sample which was electrodeposited in two consecutive steps and modified by a fatty acid called myristic acid (which significantly reduces surface energy of the coating). The highest water contact angle (161°) and the lowest contact angle hysteresis (3°) were obtained for the sample which was coated by 10 mA/cm 2 (144 min) and 20 mA/cm 2 (18 min), respectively. Since this approach does not require any sophisticated equipment and materials, it shows promising future in the fabrication of superhydrophobic coatings. [ABSTRACT FROM AUTHOR]

This research work focused on the fabrication of nickel-doped diamond-like carbon (DLC) films and their characteristics including of surface morphology, microstructure, and electrochemical aiming at applications in non-enzymatic glucose detection. Novel nanodiamond target was employed in unbalanced magnetron radio-frequency co-sputtering process to prepared high quality Ni-doped DLC thin film at room temperature. TEM analysis reveals a highly uniform distribution of Ni crystallites in amorphous carbon matrix with fraction ranged from 3 to 11.5 at.% which is considered as active sites for the glucose detection. Our cyclic voltammetry measurements using 0.1 M H 2 SO 4 solution demonstrated that the as-prepared Ni-doped DLC films possess large electrochemical potential window of 2.12 V, and this was also observed to be significantly reduced at high Ni doping level owing to lower sp 3 fraction. The non-enzymatic glucose detection investigation indicates that the Ni-doped DLC thin film electrode prepared under 7 W of DC sputtering power on Ni target possesses good detecting performance, high stability, and high sensitivity to glucose concentration up to 10 mM, even with the existence of uric acid and ascorbic acid. The peak current was observed to be proportional to glucose concentration and scanning rate, demonstrating highly reversibility redox process of the film electrode and glucose. [ABSTRACT FROM AUTHOR]

Recently, controlling the wettability of a metallic surface so that it is either superhydrophobic or superhydrophilic has become important for many applications. However, conventional techniques require long fabrication times or involve toxic chemicals. Herein, through a combination of pulse laser ablation and simple post-processing, the surface of aluminum was controlled to either superhydrophobic or superhydrophilic in a short time of only a few hours. In this study, grid patterns were first fabricated on aluminum using a nanosecond pulsed laser, and then additional post-processing without any chemicals was used. Under heat treatment, the surface became superhydrophobic with a contact angle (CA) greater than 150° and a sliding angle (SA) lower than 10°. Conversely, when immersed in boiling water, the surface became superhydrophilic with a low contact angle. The mechanism for wettability change was also explained. The surfaces, obtained in a short time with environmentally friendly fabrication and without the use of toxic chemicals, could potentially be applied in various industry and manufacturing applications such as self-cleaning, anti-icing, and biomedical devices. [ABSTRACT FROM AUTHOR]

The membrane carbon materials with hierarchical porous architecture are attractive because they can provide more channels for ion transport and shorten the ions transport path. Herein, we develop a facile way based on “confined nanospace deposition” to fabricate N-dopi-ng three dimensional hierarchical porous membrane carbon material (N-THPMC) via coating the nickel nitrate, silicate oligomers and triblock copolymer P123 on the branches of commercial polyamide membrane (PAM). During high temperature treatment, the mesoporous silica layer and Ni species serve as a “confined nanospace” and catalyst respectively, which are indispensable elements for formation of carbon framework, and the gas-phase carbon precursors which derive from the decomposition of PAM are deposited into the “confined nanospace” forming carbon framework. The N-THPMC with hierarchical macro/meso/microporous structure, N-doping (2.9%) and large specific surface area (994m 2 g -1 ) well inherits the membrane morphology and hierarchical porous structure of PAM. The N-THPMC as electrode without binder exhibits a specific capacitance of 252 F g -1 at the current density of 1 A g -1 in 6 M KOH electrolyte and excellent cycling stability of 92.7% even after 5000 cycles. [ABSTRACT FROM AUTHOR]

Different parameters such as morphology, porosity, crystalline phase or doping agents affect the self-cleaning performance of photocatalytic TiO 2 -based coatings. However, also environmental conditions have been found to play a major role on the photocatalytic self-cleaning property. Substrate temperature is a significant environmental variable that can drastically affect this process. This variable becomes of great importance especially for outdoor applications: many self-cleaning photocatalytic materials have been designed to be exposed to outdoor environments and consequently, can be exposed to variable temperatures depending on the season of the year and the typical weather of the geographical zone. Thus, understanding the influence of the most common outdoor temperatures on the self-cleaning performance of TiO 2 -based coatings is essential for the fabrication of any kind of photocatalytic self-cleaning materials (fabricated by coating technology) that is expected to be subjected to outdoor environments. In this work, the photocatalytic activity was studied by Fourier Transformed Infrared (FTIR) Spectroscopy varying the temperature in the 0 to 30 °C range for dense and mesoporous TiO 2 coatings. The temperature conditions at which these coatings present better performances were identified, providing a deeper insight for the practical application of TiO 2 -based self-cleaning coatings. [ABSTRACT FROM AUTHOR]

Thermophotovoltaic (TPV) systems have attracted attention as promising power generation systems that can directly convert the radiant energy produced by the combustion of fuel into electrical energy. However, there is a fundamental limit of their conversion efficiency due to the broadband distribution of the radiant spectrum. To overcome this problem, several spectrally selective thermal emitter technologies have been investigated, including the fabrication of photonic crystal (PhC) structures. In this paper, we present some design rules based on finite-a difference time-domain (FDTD) simulation results for tungsten (W) PhC emitter. The W 2D PhC was fabricated by a simple nano-imprint lithography (NIL) process, and inductive coupled plasma reactive ion etching (ICP-RIE) with an isotropic etching process, the benefits and parameters of which are presented. The fabricated W PhC emitter showed spectrally selective emission near the infrared wavelength range, and the optical properties varied depending on the size of the nano-patterns. The measured results of the fabricated prototype structure correspond well to the simulated values. Finally, compared with the performance of a flat W emitter, the total thermal emitter efficiency was almost 3.25 times better with the 2D W PhC structure. [ABSTRACT FROM AUTHOR]

The emergence of transition metal dichalcogenides (TMD) as an exciting class of materials with appealing potentials in electronic and optoelectronics has drawn intensive attention in the past few years. Herein, we report the fabrication of NiSe 2 , which has been predicted to be a promising candidate in the field of electrocatalyst, by direct selenylation of the nickel substrate after epitaxial growth of selenium on a nickel foil. With a combination of photoelectron spectroscopy (PES), X-ray diffraction (XRD), scanning electron microscopy (SEM) and density function theory (DFT) calculations, it is possible to identify the phase transition among the previously reported stable Ni-Se phases and the ultimate formation of NiSe 2 species by external annealing at varying temperatures. While SEM reveals the morphology of NiSe 2 film with flat terraces, XRD, XPS and DFT calculations demonstrate that NiSe 2 is the relatively stable phase formed on the Ni substrate from the cohesive energy point of view. Furthermore, valence band spectra point out the nonmetallic level of these different Ni-Se compounds, agreeing well with literature reports. In the end, our report may indicate a feasible approach to synthesize the pure NiSe2 species under solution-free condition and an encouraging step forward towards non-noble electrocatalysts. [ABSTRACT FROM AUTHOR]

We develop a novel multi-level nanoimprinting mold fabrication methodology realizing the uniform pattern height of each level with the deviation less than 2.6%, by applying the unique ‘top-to-bottom’ level patterning protocol in contrast to typical bottom-to-top patterning sequence. This is implemented by performing sequential dry etching of the stack of etch stop layers and organic insulation layers of desired thicknesses, with proper photolithographic masking in between. We demonstrate that the fabrication can be conducted on a flexible substrate without deformation of pattern profile, which then can be utilized in continuous roll-to-roll nanoimprinting of multi-level nanoarchitectures in a single imprinting process without resorting to alignment of each level. Many applications will benefit from our method, particularly requiring large-area multi-level nanoarchitectures such as thin-film transistor arrays in flexible displays. [ABSTRACT FROM AUTHOR]

In this paper we demonstrate for the first time that a fibre laser with a wavelength of 1070 nm and a pulse width of milliseconds can be applied to generate mesoporous nanocrystalline (nc) TiO 2 thin films on ITO coated glass in ambient atmosphere, by complete vaporisation of organic binder and inter-connection of TiO 2 nanoparticles, without thermally damaging the ITO layer and the glass substrate. The fabrication of the mesoporous TiO 2 thin films was achieved by stationary laser beam irradiation of 1 min. The dye sensitized solar cell (DSSC) with the laser-sintered TiO 2 photoanode reached higher power conversion efficiency (PCE) of 3.20% for the TiO 2 film thickness of 6 μm compared with 2.99% for the furnace-sintered. Electrochemical impedance spectroscopy studies revealed that the laser sintering under the optimised condition effectively decreased charge transfer resistance and increased electron lifetime of the TiO 2 thin films. The use of the fibre laser with over 40% wall-plug efficiency offers an economically-feasible, industrial viable solution to the major challenge of rapid fabrication of large scale, mass production of mesoporous metal oxide thin film based solar energy systems, potentially for perovskite and monolithic tandem solar cells, in the future. [ABSTRACT FROM AUTHOR]

A new Pt nanoparticles decorated Gd-doped Bi 2 MoO 6 photocatalyst was synthesized by the hydrothermal process and in-situ reduction method. The crystal structure, morphology, chemical state and optical property of the obtained photocatalysts were investigated. The activities of photocatalysts were also evaluated by the degradation of Rhodamine B, Tetracyclines and 4-Chlorophenol under visible light irradiation, and the results indicated that the Gd/Pt co-modified Bi 2 MoO 6 sample shows better photocatalytic activity. Meanwhile, the results of trapping experiments and Electron Spin Resonance (ESR) spectra demonstrated that the OH radicals can be formed by doping of Gd 3+ ions, and the addition of Pt was conducive to the producing of more • O 2 − and OH radicals. Also the results from the degradation of 4-chlorophenol implied that the formed OH radicals in the system of Gd/Pt-BMO possess stronger oxidizability than • O 2 − radicals for degrading the special organics which are difficult to be mineralized. Additionally, the mechanism about the excellent photocatalytic activity of Gd/Pt co-modified Bi 2 MoO 6 was also discussed. [ABSTRACT FROM AUTHOR]

In this study, hierarchically feather-mimetic structures formed of poly(m-phenylene isophthalamide) (PMIA) nanofibres were prepared by electrospinning and subsequent crystallisation for superwettability applications. X-ray diffraction measurementsand scanning electron microscopy show that a feather-mimetic structure of crystallised nanoflakes was formed following a hydrothermal treatment process. The nanoflakes formed a nanosized fine texture on top of a coarser-textured membrane, which greatly improved the membrane roughness and yielded a hierarchical topography. After fluorination, the membrane exhibited superamphiphobicity, with surface contact angles of 151° and 136° for water and hexadecane, respectively. The method provides new insight for the design and development of functional bionic membranes based on PMIA. [ABSTRACT FROM AUTHOR]

In this work, we propose a new mixed halide precursor composition for MAPbI 3-x Cl x organic/inorganic perovskite (PRV) solar cells. PRV films made with a new precursor composition of (MAI: PbCl 2 : PbI 2 = 2 : 1 : 1) could be crystallized at lower temperature (70 °C) and shorter annealing duration (60 min), whereas previous standard composition (MAI: PbCl 2 = 3 : 1) requires multi-step and high temperature (from 75 °C to 130 °C) annealing for longer durations (∼100 min). By adopting the suggested composition, much uniform surface morphology of PRV light harvester was obtained even though non-polar solvent washing was not introduced yet. Also, when the suitable toluene washing treatment was introduced, PRV surfaces of highly compact and large crystallites with regular distribution were achieved without any pinhole, which offered significant improvements in fill factor (41 → 65%) and power conversion efficiency (5.85 → 9.39%) of PRV cells. The suggested new precursor composition contributing for surface topography can be widely utilized for inverted planar PRV devices with low-temperature and simple processing. [ABSTRACT FROM AUTHOR]

As an emerging technique for surface smoothing, solution deposition planarization (SDP) has recently drawn more attention on the fabrication of the second generation high temperature superconducting (2G-HTS) tapes. In our work, a number of amorphous oxide layers were deposited on electro-polished or mirror-rolled metallic substrates by chemical solution route. Topography evolution of surface defects on these two types of metallic substrates was thoroughly investigated by atomic force microscopy (AFM). It was showed that root mean square roughness values (at 50 × 50 μm 2 scanning scale) on both rough substrates reduced to ∼5 nm after coating with SDP-layer. The smoothing effect was mainly attributed to decrease of the depth at grain boundary grooving on the electro-polished metallic substrate. On the mirror-rolled metallic substrates, the amplitude and frequency of the height fluctuation perpendicular to the rolling direction were gradually reduced as depositing more numbers of SDP-layer. A high J c value of 4.17 MA cm −2 (at 77 K, s.f. ) was achieved on a full stack of YBCO/CeO 2 /IBAD-MgO/SDP-layer/C276 sample. This study enhanced understanding of the topography evolution on the surface defects covered by the SDP-layer, and demonstrated a low-cost route for fabricating IBAD-MgO based YBCO templates with a simplified architecture. [ABSTRACT FROM AUTHOR]

A new type of nanohybrid (GO/THPP/PSA) was noncovalently constructed by anchoring 5, 10, 15, 20-tetrakis-(4-hydroxylphenyl)porphyrin (THPP) and 1-pyrenesulfonic acid hydrate (PSA) in graphene oxide (GO). The assembly mechanism of the nanohybrid was explored in detail. The results showed that THPP and PSA were attached in the GO by π–π stacking interaction and hydrogen bond. Compared with pure GO, GO/THPP or GO/PSA, the GO/THPP/PSA nanohybrid showed better photocatalytic activity for hydrogen evolution. The mechanism of electron transfer in the GO/THPP/PSA nanohybrid was investigated. It was shown that light absorption and separation of electron/hole pairs were improved dramatically due to wider light response and multi-channel electrons transfer in the hybrid. The results could initiate new ideas for constructing other graphene-based functionalized materials with high photocatalytic activity. [ABSTRACT FROM AUTHOR]

There is an increasing interest in harvesting photoejected electrons for highly sensitive photodetectors, by interfacial engineering rather than the classic semiconductors. However, the widely employed device structures involving a p - n junction that causes photogenerated electron-hole separation to enhance the response are usually complex with a high fabrication challenge. Here, we present TiO 2 -based highly efficient ultraviolet (UV) photodetection by achieving its nanocrystal assembled film having high surface defects. The sol-gel derived TiO 2 films have been subjected to a post-growth annealing at 500 °C in air (SA) and vacuum (SB) and one subjected to UV treatment (SC) to tune the surface defects. The UV photoresponse results show that the nanocrystal assembled UV cured TiO 2 film shows as high as 1.7 × 10 3 UV-to-visible rejection ratio and photo-to-dark current ratio of 1.2 × 10 4 under 10 V bias and 10 μW incident light power. Most interestingly, unprecedently high photo-to-dark current ratio of the order of ∼10 4 at as low as 1 V bias condition and only 10 μW incident light without device fabrication has been observed. Moreover, the films show stable response cyclibility under UV radiation. Therefore, simple UV curing improves UV photoresponse properties of TiO 2 film enormously without the need to form conventional devices and opens the pathway for high-performance, low-cost, low-power consumption UV photodetector. [ABSTRACT FROM AUTHOR]

Polymer products with micro/nano-structures have excellent mechanical and optical properties, chemical resistance, and other advantages. Injection molding is one of the most potential techniques to fabricate polymer products with micro/nano-structures artificially in large numbers. In this study, a surface approach to fabricate high aspect ratio nanopillars and micro/nano combined structures was presented. Mold insert with micropillar arrays and nanopillars on its surface was prepared by combing anodic aluminum oxide (AAO) template and etched plate. Anti-sticking modification was done on the template to realize a better demolding quality. The influences of mold temperature and polymer material on the final replication quality were investigated. The results showed that the final replication quality of high aspect ratio nanopillars was greatly improved as compared with the unprocessed template. Polymer with low elongation at break was not suitable to fabricate structures with high aspect ratio via injection molding. For polypropylene surface, the experimental results of static contact angles were almost consistent with Cassie-Baxter equation. When the mold temperature reached 178 °C, hair-like polycarbonate nanopillars were observed, resulting in an excellent hydrophobic characteristic. [ABSTRACT FROM AUTHOR]

With oil spill accidents and oil industrial wastewater increasing, oil/water separation has attracted much attention in recent years. Herein, we report the fabrication of superhydrophilic and underwater superoleophobic thiol-ene/silica hybrid decorated fabrics for oil/water separation via vapor-liquid interfacial reaction. It is based on sol-gel reaction of tetraethyl orthosilicate (TEOS) to generate silica and thiol-ene reaction between poly(ethylene glycol) dimethacrylate (PEGDMA) and trimethylolpropane tris(3-mercaptopropionate) (TTMP) to form crosslinked hydrophilic polymer on polyester fabric under the catalysis of butylamine/ammonia vapor. The chemical structure of the surfaces on thiol-ene/silica hybrid decorated fabric was confirmed by FTIR and XPS, and obvious micro-nano morphology and roughness were observed with SEM and AFM. The water contact angle of the fabric attained 0° in 0.36 s, and the underwater oil contact angle reached up to 160°. Importantly, the fabric exhibited high separation efficiency at 99.5%, fast water flux above 71600 Lm −2 h −1 and excellent recyclability in oil/water separation. Our findings open a new strategy to fabricate organic-inorganic hybrid superhydrophobic and underwater superoleophobic materials for oil/water separation. [ABSTRACT FROM AUTHOR]

Various transparent GaN-doped SnO 2 thin films were deposited on glass substrates by e-beam evaporation using GaN:SnO 2 targets of different GaN weight ratios. It is interesting to find that carrier polarity of the thin films was converted from n-type to p-type with increasing GaN ratio higher than 15 wt.%. The n–p transition in GaN-doped SnO 2 thin films was explained for the formation of Ga Sn and N O with increasing GaN doping level in the films, which was identified by Hall measurement and XPS analysis. A transparent thin film p–n junction was successfully fabricated by depositing p-type GaN:SnO 2 thin film on SnO 2 thin film, and a low leakage current (6.2 × 10 −5 A at −4 V) and a low turn-on voltage of 1.69 V were obtained for the p–n junction. [ABSTRACT FROM AUTHOR]

Based on the self-developed three dimensional micro/nano machining system, the effects of machining parameters and sample material on micro/nano machining are investigated. The micro/nano machining system is mainly composed of the probe system and micro/nano positioning stage. The former is applied to control the normal load and the latter is utilized to realize high precision motion in the xy plane. A sample examination method is firstly introduced to estimate whether the sample is placed horizontally. The machining parameters include scratching direction, speed, cycles, normal load and feed. According to the experimental results, the scratching depth is significantly affected by the normal load in all four defined scratching directions but is rarely influenced by the scratching speed. The increase of scratching cycle number can increase the scratching depth as well as smooth the groove wall. In addition, the scratching tests of silicon and copper attest that the harder material is easier to be removed. In the scratching with different feed amount, the machining results indicate that the machined depth increases as the feed reduces. Further, a cubic polynomial is used to fit the experimental results to predict the scratching depth. With the selected machining parameters of scratching direction d3/d4, scratching speed 5 μm/s and feed 0.06 μm, some more micro structures including stair, sinusoidal groove, Chinese character ‘田’, ‘TJU’ and Chinese panda have been fabricated on the silicon substrate. [ABSTRACT FROM AUTHOR]

Herein, we report a facile synthetic protocol to grow thin films of Cu(II) tetrakis(4-carboxyphenyl)porphyrin (CuTCPP) metal-organic frameworks (MOF) from a tetrakis(4-carboxyphenyl)porphyrin (H 2 TCPP) solution and the copper hydroxide (Cu(OH) 2 ) nanoneedle array formed on a Cu substrate at room temperature. The formations of Cu-centered TCPP ligands and crystalline platelet-like Cu MOFs were successfully probed by SEM, XRD, FTIR, UV–vis and XPS. The formation process from Cu(OH) 2 was monitored by using SEM images obtained at different reaction times during the first 24 h, thus suggesting the reaction pathway of Cu(OH) 2 dissolution followed by the reprecipitation of CuTCPP MOFs at a near surface. In addition, the CuTCPP MOFs exhibited a high specific surface area of 408 m 2 /g. [ABSTRACT FROM AUTHOR]

Common producing steps for test strips is complex and fussy. In this work, we proposed a feasible binder-free test strips fabrication method to directly grow enzyme/manganese phosphate nanosheets hybrids on the screen-print electrodes (SPE). Combined with microfluidic packaging technology, the ready-made portable electrochemical biochip shows a wider linear range (1–40 mM, R 2 = 0.9998) and excellent stability (maintained 98% response current after 20 days store and retained 75% response current after continuous 30 days determination) for the detection of glucose. Compared with commercial test strips, the biochip exhibits excellent sensitivity, stability and accuracy, which is indicative of its potential application in real samples. [ABSTRACT FROM AUTHOR]

MoS 2 thin films are obtained by atomic layer deposition (ALD) in the temperature range of 120–150 °C using Mo(CO) 6 and dimethyl disulfide (DMDS) as precursors. A pressure tuned stop-flow ALD process facilitates the precursor adsorption and enables the deposition of MoS 2 on high porous three dimensional (3D) nanostructures. As a demonstration, a TiO 2 /MoS 2 core/shell inverse opal (TiO 2 /MoS 2 -IO) structure has been fabricated through ALD of TiO 2 and MoS 2 on a self-assembled multilayer polystyrene (PS) structure template. Due to the self-limiting surface reaction mechanism of ALD and the utilization of pressure tuned stop-flow ALD processes, the as fabricated TiO 2 /MoS 2 -IO structure has a high uniformity, reflected by FESEM and FIB-SEM characterization. A crystallized TiO 2 /MoS 2 -IO structure can be obtained through a post annealing process. As a 3D photonic crystal, the TiO 2 /MoS 2 -IO exhibits obvious stopband reflecting peaks, which can be adjusted through changing the opal diameters as well as the thickness of MoS 2 layer. [ABSTRACT FROM AUTHOR]

Fabrication of a nanoporous tungsten oxide film via anodizing of tungsten in an ammonium nitrate (NH 4 NO 3 )/ethylene glycol (EG)/water (H 2 O) mixture is reported for use as a visible light-driven photocatalyst. Anodizing of tungsten in a 1.0 M NH 4 NO 3 /EG solution containing less than 0.1 vol% H 2 O resulted in active dissolution of the tungsten substrate. As the H 2 O concentration increased to more than 25 vol%, a thin barrier oxide film was formed on the tungsten substrate. A thick porous tungsten oxide with numerous nanopores measuring several tens of nanometer in diameter was fabricated via anodizing at a moderate H 2 O concentration of 1.0 vol%. The porous oxide consisted of a double-layered structure with an outer porous layer and an inner dense layer, and the outer porous layer became thinner as the NH 4 NO 3 concentration decreased. A uniform porous oxide film from the top surface to the bottom interface was fabricated via anodizing at 20 V in a 0.02 M NH 4 NO 3 /EG solution containing 1.0 vol% H 2 O at 313 K. The porous tungsten oxide exhibited visible light-driven photocatalytic activity for the photocatalytic decomposition of methylene blue. [ABSTRACT FROM AUTHOR]

This report details the development of a simple, non-vacuum, mild route for the fabrication of CFTS and CFTSSe thin films. This work investigates the synthesis of CFTS powder using solid-phase synthesis. Subsequently, the stable colloidal ink was prepared and blade-coated onto Mo-coated substrates followed by an annealing process under an Ar atmosphere. Thin films of this material were converted into CFTS and CFTSSe thin films by sintering and exposing them in sulfur or selenium vapor. The structures of the CFTS and CFTSSe were observed to be consistent with the stannite phase. The crystal lattice parameters of the CFTS and CFTSSe post-annealed films were determined by their respective X-ray diffraction patterns and Raman scattering measurements. The band gaps of CFTS and CFTSSe films, as determined by UV–vis absorption, were estimated to be 1.32 eV and 1.22 eV with an error of ±0.02 eV. The corresponding CFTS and CFTSSe films showed a clear photoresponse without current transients, which is promising for future photovoltaic applications. [ABSTRACT FROM AUTHOR]

Gallium nitride (GaN) nanowires (NWs) were fabricated by metal-assisted photochemical etching (MaPEtch). Gold nanoparticles (AuNPs) as metal catalyst were electrodeposited on the GaN substrate. SEM and HRTEM images show the surface of GaN NWs is smooth and clean without any impurity. SAED and FFT patterns demonstrate GaN NWs have single crystal structure, and the crystallographic orientation of GaN NWs is (0002) face. On the basis of the assumption of localized galvanic cells, combined with the energy levels and electrochemical potentials of reactants in this etching system, the generation, transfer and consumption of electron-hole pairs reveal the whole MaPEtch reaction process. Such easily fabricated GaN NWs have great potential for the assembly of GaN-based single-nanowire nanodevices. [ABSTRACT FROM AUTHOR]

In the present work, copper oxide superhydrophobic surface is fabricated on a copper foil via the chemical bath deposition (CBD) method. The effects of some influential factors such as initial concentrations of Cu (II) ions and the surface energy modifier, solution pH, reaction and modification steps time on the wettability property of copper oxide surface were evaluated using Taguchi L 16 experimental design. Results showed that the initial concentration of Cu (II) has the most significant impact on the water contact angle and wettability characteristics. The XRD, SEM, AFM and FTIR analyses were used to characterize the copper oxide surfaces. The Water contact angle (WCA) and contact angle hysteresis (CAH) were also measured. The SEM results indicated the formation of a flower-like micro/nano dual-scale structure of copper oxide on the substrate. This structure composed of numerous nano-petals with a thickness of about 50 nm. As a result, a copper oxide hierarchical surface with WCA of 168.4°± 3.5° and CAH of 2.73° exhibited the best superhydrophobicity under proposed optimum condition. This result has been obtained just by 10 min hydrolysis reaction. Besides, this surface showed a good stability under acidic and saline conditions. [ABSTRACT FROM AUTHOR]

We present the photoluminescence (PL) emission of Silicon and Germanium nanocrystals (NCs) of different sizes embedded in two different matrices. Formation of the NCs is achieved via solid-state dewetting during annealing in a molecular beam epitaxy ultra-high vacuum system of ultrathin amorphous Si and Ge layers deposited at room temperature on SiO 2 . During the dewetting process, the bi-dimensional amorphous layers transform into small pseudo-spherical islands whose mean size can be tuned directly with the deposited thickness. The nanocrystals are capped either ex situ by silicon dioxide or in situ by amorphous Silicon. The surface-state dependent emission (typically in the range 1.74 eV–1.79 eV) exhibited higher relative PL quantum yields compared to the emission originating from the band gap transition. This red-PL emission comes from the radiative transitions between a Si band and an interface level. It is mainly ascribed to the NCs and environment features deduced from morphological and structural analyses. Power dependent analysis of the photoluminescence intensity under continuous excitation reveals a conventional power law with an exponent close to 1, in agreement with the type II nature of the emission. We show that Ge-NCs exhibit much lower quantum efficiency than Si-NCs due to non-radiative interface states. Low quantum efficiency is also obtained when NCs have been exposed to air before capping, even if the exposure time is very short. Our results indicate that a reduction of the non-radiative surface states is a key strategy step in producing small NCs with increased PL emission for a variety of applications. The red-PL band is then an effective tool for the quality assessment of NCs based structures. [ABSTRACT FROM AUTHOR]

We have electrochemically synthesized 3D-porous Ni/MnO x nanocomposites for supercapacitor applications. 3D porous micro-nanostructured networks of nickel were prepared using hydrogen bubbles as a dynamic template at different deposition potentials and times. The prepared nickel films were used then as 3D-porous substrates for anodic deposition of manganese oxide nanostructures. The effects of deposition potential and time on the structure of the prepared nickel scaffolds and especially on the capacitive behavior of the subsequently fabricated 3D-porous Ni/MnO x nanocomposites were investigated. The results show that the areal capacitance and especially the rate capability of prepared Ni/MnO x nanocomposites have improved with increasing the deposition potential or optimizing the deposition time of nickel films in the nanocomposites. The prepared 3D-porous Ni/MnO x nanocomposite, in which the nickel scaffold has been deposited at the potential of −6 V and duration of 90s, show almost the highest capacitive performance among all other prepared nanocomposites. This prepared nanocomposite, with the loading mass of 1.65 mg cm −2 , showed the high areal capacitance of 654 mF cm −2 (396.4 F g −1 ) at the current density of 0.5 mA cm −2 (0.3 A g −1 ) in 0.5 M Na 2 SO 4 solution. This nanocomposite also revealed the highest rate capability; the capacitance retention is about 63% (412 mF cm −2 ) with increasing the discharge rate from 0.5 to 20 mA cm −2 , which is almost twice the observed amount of retention when the deposition potential of Ni films was −2 V (31%) or their deposition time was 45 s (34%). In addition, the prepared nanocomposite exhibited an outstanding cycling stability. The capacitance retention was about 98.91% after performing 2000 charge-discharge cycles. [ABSTRACT FROM AUTHOR]

We have investigated ZnO nanostructures on cotton fabric (CF) s a flexible material for an application of wearable thermoelectric (TE) power generator which requires super-hydrophobicity, UV protection, and high TE efficiency. Field emission scanning electron microscopy images revealed that the formed ZnO nanostructures have a mixture of nanorods and nanosheets and are uniformly coated on the CF. XRD pattern and Raman spectra revealed that the ZnO nanostructure has a wurtzite structure. Contact angle measurements showed that the ZnO-nanostructures-coated CF possessed a high super hydrophobic nature with an angle of 132.5°. ZnO nanocomposite/CF sample exhibited an excellent UV protection factor 183.84. Seebeck coefficient, electrical resistivity and thermoelectric power factor of the ZnO nanostructures on cotton fabric were evaluated to be 28 μV/K, 0.04 Ω-cm, and 22 μW/m K 2 , respectively. [ABSTRACT FROM AUTHOR]

Polymer solar cells (PSCs) have gained immense research interest in the recent years predominantly due to low-cost, solution process-ability, and facile device fabrication. However, achieving high stability without compromising the power conversion efficiency (PCE) serves to be an important trade-off for commercialization. In line with this, we demonstrate the significance of incorporating a CsI/ZnO bilayer as electron transport layer (ETL) in the bulk heterojunction PSCs employing low band gap polymer (PTB7) and fullerene (PC 71 BM) as the photo-active layer. The devices with CsI/ZnO interlayer exhibited substantial enhancement of 800% and 12% in PCE when compared to the devices with pristine CsI and pristine ZnO as ETL, respectively. Furthermore, the UV and UV-ozone induced degradation studies revealed that the devices incorporating CsI/ZnO bilayer possess excellent decomposition stability (∼23% higher) over the devices with pristine ZnO counterparts. The incorporation of CsI between ITO and ZnO was found to favorably modify the energy-level alignment at the interface, contributing to the charge collection efficiency as well as protecting the adjacent light absorbing polymer layers from degradation. The mechanism behind the improvement in PCE and stability is analyzed using the electrochemical impedance spectroscopy and dark I–V characteristics. [ABSTRACT FROM AUTHOR]

Metallic nanostructures can find various applications such as in optoelectronic devices, nanostructure synthesis and catalytic applications and their applicability vary depending on their size, density and configuration dependent properties. In this paper, the dimensional and configurational evolution of self-assembled palladium (Pd) nanostructures is systematically studied on c -plane sapphire with the control of annealing temperature (AT) and annealing duration with the initial Pd layers of various thicknesses. Depending on the AT, two distinct growth regimes are observed based on the concurrent effect of surface diffusion, surface energy minimization and Pd sublimation: i.e. (i) agglomeration of Pd nano-clusters from voids (500 < AT ≤ 650 °C) and (ii) round nanoparticle (NP) fabrication (650 °C < AT ≤ 900 °C). At 950 °C, due to the sublimation of Pd atoms, substantial decrease in the NP dimension is witnessed and results in the ring patterns around the NPs. Additional investigation is performed at 950 °C to reveal the annealing duration effect on the NP evolution. Due to the dual effect of the Oswald ripening and atom sublimation, initially the dimension of NPs is grown and then gradually decays along with the duration, resulting in an inverted ‘V’ pattern evolution in diameter and height. Moreover, the evolution of optical properties such as absorption band and average reflectance are studied with the corresponding reflectance spectra as a function of wavelength over UV, visible and NIR region. The Raman spectra analysis depicts the variation of lattice vibration peak intensity and position based on the surface morphology of the Pd nanostructures. [ABSTRACT FROM AUTHOR]

To enhance the separation efficiency of photo-generated carriers, a p–n junction photocatalyst BiOI/NaNbO 3 has been fabricated by a facile method. The obtained samples were characterized by XRD, SEM, TEM, HRTEM, PL, N 2 sorption–desorption and DRS. DRS results showed that the light absorption edges of BiOI/NaNbO 3 hybrids were red-shifted with the increase of BiOI content. The SEM and TEM images revealed that the BiOI was widely decorated over the surfaces of NaNbO 3 cubes. The formation of p–n heterojunction at their interfaces was proved by the HRTEM image. The visible light-driven photocatalytic activity was evaluated by the degradation of methylene blue (MB) in aqueous solution. Compared with single NaNbO 3 and BiOI, the BiOI/NaNbO 3 hybrid photocatalysts have exhibited significantly enhanced activities. Meanwhile, the mass ratio of BiOI/NaNbO 3 displayed important influence on the MB degradation. The hybrid photocatalyst with BiOI content of 40% performed the optimal activity. This activity enhancement should be attributed to the strong visible light absorption, the high migration and separation efficiency of photo-induced carriers. The photocurrent and PL measurements confirmed that the interfacial charge separation efficiency was greatly improved by coupling BiOI with NaNbO 3 . Controlled experiments proved that the degradation of pollutants was mainly attributed to the oxidizing ability of the generated holes (h + ), ·O 2 − , and ·OH radicals. [ABSTRACT FROM AUTHOR]