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The use of hydroxyapatite (HAp) based on Aceh's bovine bone has been studied as a candidate for thecoating dental implant materials. In this study, the effect of sintering temperature and viscosity on the thickness ofthe hydroxyapatite layer on the 316L stainless steel plaque was observed. The hydroxyapatite was synthesized frombovine bone and then coated on the plate using the dip-coating method. Then, the plate surface was dried at 110 ºCfor 30 minutes and sintered with various temperatures of 500, 600, 700, and 800 ºC for 1 hour. The plate that hasbeen coated with hydroxyapatite was characterized using a thickness meter to measure the thicknesses of the layer.The water composition of 10 grams/L had a better effect on the thickness of the implant material coated with HApbeef bone compared to the water composition of 4, 6, and 8 (gram/L) (p0.05). On the other hand, the temperaturefactor did not affect changes in the thickness of the implant material (p0.05). The higher water composition (10grams/L) resulted in a decrease in the thickness of the implant material coated with beef bone HAp. KEYWORDS: Hydroxyapatite, sintering temperature, viscosity, dip-coating, thickness, coating dental implant

Additive manufacturing (AM) is a type of manufacturing technologies whereby the material is added a layer upon layer to produce a 3D object. Produced 3D parts are applied in such industry sectors as space, aviation, automotive, building and has excellent future promises. These days, the commercially promised technique for metal manufacturing are laser metal deposition (LMD), direct metal laser sintering (DMLS). Our study concentrated on the investigation of mechanical properties of 17-4 PH stainless-steel parts produced by laser sintering. The effect of the laser sintering process parameters (laser power, scanning speed and energy density) on the ultimate stress, yield stress and Young’s modulus was determined. We showed an evolution of the microstructure. The detected defects were classified. This study allowed to determine optimal process parameters for laser sintering of SS 17-4 PH and to describe mechanical properties of the produced parts as well as helped to show future possibilities of the development of laser sintering technology.

InSn-50Ag composite solder joints doping Ni-coated carbon nanotubes (Ni-CNTs) were fabricated by transient liquid phase (TLP) bonding, and then the effect of Ni-CNTs contents (x = 0, 0.01, 0.03, 0.05, 0.07, 0.1 wt%) on the microstructure and shear property of the composite solder joints was examined. The results showed that the microstructure of Cu/InSn-50Ag-x(Ni-CNTs)/Cu composite solder joints consisted of the interfacial region bamboo-type Cu3(In, Sn), solder center region Ag3In, Ni3Sn4, Ag particles and Ni-CNTs. The appropriate amounts of Ni-CNTs (about 0.07 wt%) are conducive to form a compact composite solder joint and restrain the growth of interfacial Cu3(In, Sn) IMC layer, and the morphologies of IMC layer are determined by Ni-CNTs suppressing atom diffusion and IMC grain orientation. The shear strength of composite solder joints relates to Ni-CNTs content, and the maximum shear strength reaches 42 MPa of Cu/InSn-50Ag-0.07(Ni-CNTs)/Cu. It is regulated by uniform distribution of Ni-CNTs, refined Ag3In grains and interface IMC layer with near-continuous voids. The fracture of the composite solder joints doped Ni-CNTs occurred near to the boundary between the interfacial IMC layer and solder center region, the fracture mechanism is ductile fracture.

In this paper, a plasmonic solar cell using silver nanoparticles is presented. The unit cell structure composes of two layers, each containing a silver nanoparticle deposited on the absorber layer and covered with an indium tin oxide layer. Nanoparticle structure has been used for light-trapping to increase the absorption of plasmonic solar cells. By various light trapping techniques, light can be concentrated in a thin absorber layer. As it will be clarified, through varying the geometry of these nanoparticle structures, the absorption peaks can be directed. All simulation data are obtained using the finite element method. The proposed model achieves two absorption peaks existing at 1.07 μm and 1.17 μm, each with absorptions of around 50%. The parameters of optimized performance have been specified. The results indicate that this model shows an absorption full width at half maximum, reaching 122 nm. Moreover, it can be noticed that the absorption peak can be increased to reach 0.5. The proposed structure has potential applications in the absorption of the infra-red part of the solar spectrum.

The surface of Inconel 738 LC samples has been coated with carbon nanotube and yttria stabilized zirconia utilizing the plasma thermal spray method. Various percentages of carbon nanotubes and yttria stabilized zirconia were utilized in the coating (100 percent nano YSZ, 96 percent nano YSZ +4 percent CNTs, 94 percent nano YSZ +6 percent CNTs, and 92 percent nano YSZ +8 percent CNTs). After coating, a cyclic hot corrosion testing has been conducted, followed by SEM and XRD on all samples. SEM cross-section micrographs were utilized to quantify coating thickness. After 50 hrs of corrosion in 67 percent wt. V2O5 +33 percent wt. Na2SO4 at 950 degree centigrade, the changing weight of absence and coated specimens was measured. The cumulative weight change per surface area of coated specimens at temperatures of 950 °C was found to be 0.0095, 0.0075, 0.006, and 0.0057 mg.cm–2, (E,F,G,H) respectively. The best coating to resist hot corrosion was showed by specimens coated with 92% wt. yttria +8%wt. carbon nanotube. There are no oxides in the base specimens, according to X-rays of coated samples. Images of scanning electron microscopy for the surface layer revealed that it has a significant porosity and that some of the layer of coating s had microcracks.

The concept of back-contact device architecture for perovskite solar cells (PSCs) is a promising alternative to PSCs with the traditional sandwich-type device architecture. The most convenient and low cost method to fabricate back-contact electrodes for PSCs is using microsphere lithography as it can be performed without expensive photolithography tools and cleanroom environment. Deposition of a monolayer of polystyrene microbeads on the surface of cathode substrates (conductive transparent oxide glass substrates covered with a thin layer of SnO2) is achieved through a self-assembly process. The self-assembly process is based on electrostatic attraction forces between negatively charged microbeads and the positively charged cathode surface. The self-assembled monolayer of polystyrene microbeads is used as a sacrificial polymer mask to fabricate the anode layer on top of cathodes. The back-contact electrodes are obtained after removing the sacrificial polymer mask through a lift-off process.

Issues of amorphous oxide semiconductors (AOSs) thin-film transistors (TFTs) mainly focus on improving electrical performance and stability. Currently, the hump, the abnormal transfer characteristic, is also an essential factor of AOSs TFT. The hump phenomenon was observed for AOS-TFTs with a metal capping (MC) layer under various measurement conditions. The mobility in the MC TFT was improved from 14.8 cm2/Vs to 19.2 cm2/Vs compared to that of the conventional TFTs. The improved electrical characteristics in the MC structure are representative of the carrier injection effect and the change of the current path. This reason reveals that the MC structure has a hump phenomenon under the low drain to source voltage ( $V_{DS}$ ). The hump characteristic does not significantly affect the overall MC TFT characteristics (transfer characteristic, improved electrical characteristics through MC structure, etc.). In addition, it was confirmed that it exhibits very stable hump characteristics through repeated measurements and uniformity. It was found that two current paths are formed mainly due to carrier injection from the metal capping layer in the hump phenomenon observed at low $V_{DS}$ . These divided current paths can lead to two on-currents ( $I_{on}$ ) in the transfer curve. Many studies have recently been conducted to fabricate semiconductor devices with multi-values such as 0, 1, and 2. This divided current path could propose a simple method to achieve multi-values with an easy process.

A thin intrinsic hydrogenated amorphous silicon carbide ((i) a-SiCx:H) layer with a wide band gap attracts attention as an alternative passivation layer instead of intrinsic hydrogenated amorphous silicon ((i) a-Si:H) for heterojunction photovoltaic applications. The optical band gap of (i) a-SiCx:H can be widened up to 2.24eV. An increase in the optical band gap makes this layer appropriate as the window material by reducing the parasitic absorption. However, the deposition regime should be investigated to understand the incorporation of carbon. The influence of several deposition parameters such as precursor gasses flow rates and plasma power density on the (i) a-SiCx:H layers were investigated in optical, electrical, and elemental aspects. Relatively high interface trap densities were detected related to carbon piling up at the interface. An increase in the amount of C in the interface affected the passivation quality and fixed charge density of the layer. The ratio of secondary ion intensities measured by time of flight-secondary ion mass spectroscopy presents general hydrogen filling of possible dangling bonds and the bonding preferentiality between the silicon or carbon atoms. The passivation quality of the (i) a-SiCx:H layer partially enhanced by stack layer deposition of (i) a-Si:H/(i) a-SiCx:H resulting effective lifetime above 100 μs.

The need for new materials in various engineering applications are inevitable. The performance measurement ensures the selection of suitable materials for the relevant applications. Corrosion types of failure are gaining attention nowadays, which has shifted the researchers towards developing new materials with enhanced corrosion resistance. In this work, the copper-tin alloy-based hybrid composite was prepared through the powder metallurgy route. The 5 wt% of graphite and 1 wt% of silicon dioxide are used as reinforcement. Further, the corrosion performance of fabricated sample was carried out through two-electrolyte solution. The first one is acidic, i.e. HCl and the second one is salt, i.e. NaCl. It was observed that the electrolyte solution has shown that it is allowing a faster corrosion process and has no side impact on the corrosion profile due to the presence of a passivation layer. A passivation layer is nothing, but it is forming an oxide layer on the surface, which resist the corrosion profile from the side impact.

Ti(C,N)-based cermets with a surface graded layer were obtained by nitrogen sintering under different nitrogen pressures at temperatures from 1300 to 1400 °C. The influence of nitrogen pressure in the range of 50–250 mbar on microstructure and mechanical performance of cermets were then systematically investigated and it was found that coarser solid solution grains formed at the surface of the cemets after sintering the Ti-rich and Ni-poor graded layer. Furthermore, tending with increasing nitrogen pressure, the overall grain sizes and surface region of the cermets became finer, and the surface graded layer thickness increased (the thickest graded layer was 194 μm). The formation of the graded layer and the increase in the thickness of the graded layer were all attributed to the high nitrogen activity on the surface during sintering. Moreover, nitrogen sintering allowed the Ti(C,N)-based cermets to increase the surface hardness of the cermets with a lesser reduction in strength. The maximum surface hardness and TRS (Transverse Rupture Strength) value of cermets after nitrogen sintering was about 14 GPa following a nitrogen pressure of 150 mbar, and 2267 MPa following nitrogen pressure of 100 mbar.

In this work, we experimentally investigate the effects of electric bias on the degradation of few-layer MoS2 back-gated field-effect transistors in ambient air. The devices were fabricated using mechanically exfoliated MoS2 flakes, which were transferred to a Si/SiO2 substrate by a PDMS-based transfer. We report an accelerated electric bias-induced degradation of the devices under investigation and used optical and scanning electron microscopy (SEM) to monitor changes of the morphology of the MoS2 channel. In particular, we found a linear dependency of the degradation on the electric field between the Ti/Au source and drain contacts. In addition, we identify four regions in which morphological changes occur, of which the edges of the MoS2 channel are most affected.

Silicon carbide (SiC), a non-oxide ceramic with superior thermo-mechanical stability, chemical and radiation resistive properties, finds extensive utilization in optical instruments for terrestrial and space applications. However, its inherent porous texture (α-HCP) becomes a deterrent for high-performance optical telescopes, although several techniques of surface alterations over sintered or reaction-bonded SiC are available. In the present work, the physical vapour deposition (PVD) technique is adopted to deposit a thick (∼5 μm) Silicon dioxide (SiO2) clad layer on a sintered and optically polished SiC (SSiC) substrate. SiO2 clad layer coated SSiC (SDO-SSiC) substrate reduces the surface porosity of SSiC which is found to be suitable for optical mirror application. Finally, an Al based reflective and oxides protective coatings are deposited on SiO2 clad layer to achieve reflective behaviour. The surface figure of 75 nm PV (peak-to-valley) and less than 2 nm surface micro-roughness values are achieved which meets the stringent optical telescope specifications for terrestrial and space applications. The structural and nano-mechanical properties of presently developed SiO2 clad layer-based SiC telescopic mirror have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-Ray Analysis (EDX), atomic force microscopy (AFM), and nanoindentation techniques. The optical properties are investigated by optical profilometry and wavelength based spectrometric (both in visible and infrared ranges) techniques. Finally, space worthiness studies viz., thermo-vacuum, thermal storage, thermal shock and relative humidity tests have been carried out successfully. The process of cleaning, grinding and polishing at each substrate preparation stage and coatings are also reported comprehensively.

The consequence of coupling wear (erosion/abrasion) and corrosion is not just simply the sum of wear in the absence of corrosive medium and corrosion in absence of wear. The so-called synergistic effect implies that corrosion is accelerated due to the removal of the passivating layer because of wear. On the other hand, corrosion can accelerate abrasion when the electrochemical dissolution yields a brittle surface layer which can be subsequently removed by abrasion. The synergism between wear and corrosion is complex and the interaction between mechanical and chemical factors governing tribocorrosion is not yet fully understood. This review aims at providing a general and thorough summary of the wear-corrosion interaction focused on stainless steels due to the technological relevance of these materials. It is taken into consideration the influence of the key parameters affecting wear-corrosion, such as the stainless steel type, slurry characteristics (temperature, pH, solid concentration), the erodent properties (particle size and shape), etc. The different models to describe wear-corrosion and the most used apparatus for tribocorrosion testing are also reviewed.

The optimization of thickness and surface roughness of the TiO2 layer as an efficient electron transporting layer (ETL) plays a significant role on the performance improvement of perovskite solar cells (PSCs). In the present investigation, TiO2 pastes synthesized with various concentrations under hydrothermal conditions were utilized to deposit the TiO2 films of tunable porosities as the ETLs of PSCs. Also, the PSCs were fabricated with a structure of FTO/block-TiO2 (b-TiO2)/m-TiO2/CH3NH3PbI3 (MAPbI3)/CuInS2 (CIS)/carbon as a low-cost architecture. Moreover, the effect of the TiO2 paste concentration was studied on the performances of PSCs under fully ambient conditions. The optimal TiO2 layer was constructed with 20 wt% TiO2 paste concentration, which resulted in the formation of a hole‐free, smooth, and compact ETL layer. The champion perovskite solar cell fabricated with the 20 wt% TiO2 paste concentration showed the highest power conversion efficiency (PCE) of 13.09% (JSC = 20.80 mA cm−2, VOC = 0.98 V and FF = 0.64) but the champion PSC device made with the 10 wt% TiO2 paste exhibited the lowest PCE = 8.05% (JSC = 19.83 mA cm−2, VOC = 0.91 V and FF = 0.45). These results illustrated that the optimal 20 wt% TiO2 paste caused ∼163% enhancement in the PCE of the device. Consequently, it could be suggested for application in fabrication of cost-effective and large scale PSCs.

Reducing the loading of noble Pt-based catalyst is vital for the commercialization of proton exchange membrane fuel cell (PEMFC). However, severe mass transfer polarization loss resulting in fuel cell performance decline will be encountered in ultra-low Pt PEMFC. In this work, mild oxidized multiwalled carbon nanotubes (mMWCNT) were adopted to construct the catalyst layer, and by varying the loading of carbon nanotubes, the catalyst layer structure was optimized. A high peak power density of 1.23 W·cm−2 for the MEA with mMWCNT was obtained at an ultra-low loading of 120 μg·cm−2 Pt/PtRu (both cathode and anode), which was 44.7% higher than that of MEA without mMWCNT. Better catalyst dispersion, low charge transfer resistance, more porous structure and high hydrophobicity of catalyst layer were ascribed for the reasons of the performance improvement.

The commercialization of Solid oxide fuel cells (SOFCs) has always been limited by the poor catalytic activity and the severe degradation of cathode in the intermediate and low operating temperature. Here we report a Gd0.8Ce0.2O1.9−δ (GDC) coated La0.8Sr0.2Co0.2Fe0.8O3-δ (LSCF) composite cathode material, which can significantly improve the electrochemical performance and durability of LSCF cathode. The effects of different GDC coating thickness on the electrochemical performance and long-term working stability of LSCF cathode are investigated, and the optimal coating thickness is established. The polarization impedance of GDC coated LSCF (LSCF@GDC) cathode with 9 nm of GDC coating is 0.08 Ω cm2 at 800 °C, which is only one quarter of that of the raw LSCF cathode, and the degradation rate of constant current polarization with 100 mA cm−2 is only 0.42%/100 h at 700 °C, which is far less than that of the raw LSCF cathode. The X-ray photoelectron spectroscopy (XPS) results show that the degree of Sr segregation decreases with the increase of the thickness of the coated GDC layer. The potential LSCF@GDC composite material is expected to increase the operability of SOFCs and accelerate its commercialization.

Reproducible and controllable incorporation and immobilization of catalysts and other active particles onto silicone microreactor channels is still challenging. In this work, we present an innovative fabrication protocol to attain affordable, custom-designed photocatalytic microreactors in a fast and simple manner. In this protocol, a 3D-printed ABS microreactor mold is first dip-coated with the photocatalyst, and subsequently, the catalytic layer is transferred onto the microchannel walls by indirect immobilization during the silicone casting and scaffold removal step. Serpentine-shaped microreactors have been satisfactorily fabricated with Au@POM-impregnated TiO2 nanoparticles (Au@POM/TiO2; Au 0.18 % w/w, POM: H3PW12O40) as the integrated photocatalytic layer. The suitability of our fabrication method has been validated on the basis of the excellent photocatalytic performance shown by the microreactors in a model test reaction such as the continuous-flow photoreduction of 4-nitrophenol to 4-aminophenol with NaBH4 and monitored by UV-Vis spectroscopy. Financial support from Gobierno de Navarra (grants PC025-26 and PI030) an Spanish Ministerio de Ciencia, Innovación y Universidades, and the European Regional Development Fund (ERDF/FEDER) (grant RTI2018-096294-B-C31) is gratefully acknowledged. I.P. and S.R. thank Obra Social la Caixa, Fundación Caja Navarra and Universidad Pública de Navarra (UPNA) for their research contracts in the framework of the programs 'Ayudas Postdoctorales' and 'Captación del Talento'. L.M.G. thanks Banco de Santander and UPNA for their financial support under 'Programa de Intensificación de la Investigación 2018' initiative. Centro Tecnológico Lurederra is gratefully acknowledged for its partnership in the project FOREST (PC025-026).

Conventional electrodeposition is used to develop Ni-Al2O3 nano-composite over the Al-2618 surface through nickel-plated immersion. Scratch investigation was carried out with respect to various process parameters such as immersion temperature, packing of particles and current density. The scratch resistance of electrodeposition composition was determined with the Ducom TR102-Scratch testing device and it was fortified with Rockwell C diamond stylus (0.2 mm rad.). Microscopic analysis was made of the morphology and scratch stages of the electrodeposited layer. The results indicates coating layer narrowly imitates the surface contour, as well as the toughness of a substance is influenced by its strength. Also the better adhesive strength could be achieve by higher temperatures, moderate particle loading and current density.

Thick cladding of copper is required for diverse applications, however, only a handful of processes can be used for bulk material cladding. This study has been undertaken to suggest a better alternative method for cladding thick layer of copper on aluminium substrate. Cladding of 3 mm thick layer of copper on 6 mm thick aluminium substrate has been successfully performed using friction stir welding process (FSW). Detailed microscopic study, XRD and microhardness evaluation of the samples proved the quality of clad layer. Interestingly even after three FSW passes no substrate material could reach near the top of clad layer.

Flexible printed electronic technology makes it possible to fabricate low-cost digital microfluidic (DMF) chips. Inkjet printing on flexible substrates is one of the most cost-effective fabrication processes for DMF chips. Based on inkjet printing technology and simplified coating methods of dielectric and hydrophobic layers, we fabricated low-cost flexible DMF chips (FDMFCs) on PET sheet and on matte photo paper. The surface quality, conductivity and spatial output resolution of the silver lines under different number of printings, different line widths and line gaps on the two types of FDMFCs were comprehensively analyzed. The traditional square dispensing electrodes were optimized to reduce the volume error of the droplets generated during the repeated dispensing operations. Droplets can be driven to implement all the operations on various configurations of FDMFCs by electrowetting-on-dielectric, including closed configuration, open configuration, hybrid configuration composed of closed and open regions on a single chip, and open curved configuration, which are defined as full-range droplet actuation. The droplet motion between closed and open regions in two position modes of the top plate was deeply studied. Droplet operation experiments prove that the motion performance of droplets can be comparable to that of chips processed by traditional technology, and the rapid prototyping technology of the FDMFCs can make the performance of droplet operation mainly depend on the conductivity of the electrode layer and the electrode gap and greatly weaken the influence of the substrate surface quality on the FDMFCs.

The aim of this work is to enhance the operation life of steel (CF8M) used in turbines. The steel during its operation in power plant undergo severe wear due to erosion. This decreases the life of component as well adds the maintenance cost of hydro-plant. To overcome this problem of erosion and wear, HVOF thermal spray technique is selected to apply the protective layer of WC-Co-Cr on the substrate material. Wear test were done on slurry erosion test rig at different slurry concentrations, slurry jet impingement angles and spray nozzle stand-off distances for coated and uncoated substrates. The orthogonal L4 array was used to design the experimentation after selecting suitable maximum and minimum values of parameters. The wear loss measurements were taken in terms of weight loss after completion of every cycle. The SEM analysis of as such coated samples and eroded samples was done to know the morphology of the surfaces. It was found that the wear resistance of WC-10Co-4Cr coated against slurry erosion on CF8M steel was better than the uncoated substrate.

The effects of three antioxidants (AlB2–Al–Al2O3 composite powders and Al and Al/Si composite powders) on the oxidation resistance of low-carbon magnesia-carbon refractories were investigated. First, thermodynamic calculations were performed to analyze the product compositions of the oxidized zone of low-carbon magnesia-carbon refractories with three antioxidants. Then, the oxidation zones were analyzed by X-ray diffraction, field emission scanning electron microscopy and energy spectrum analysis. The results show that the thickness of the decarburization layer of low-carbon magnesia-carbon bricks with Al powder, Al/Si composite powders and AlB2–Al–Al2O3 composite powders is 28.33 mm, 25.34 mm and 12.00 mm, respectively, which implies that the AlB2–Al–Al2O3 composite powder was the most effective antioxidant. The reason is that the Mg3B2O6 phase is formed in the products of the oxidation zone, and its melting point is 1360 °C. Therefore, it melts at 1400 °C and shows excellent oxidation resistance by filling the pores and blocking the oxygen channel. The products of the oxidation zone with Al and Al/Si composite powders were MgAl2O4 and Mg2SiO4 with high melting points, and that of the oxidation zone with Al powder was MgAl2O4. These products are still solid particles at 1400 C. The oxygen channel has a weaker blocking effect than the melt, so the oxidation resistance of Al/Si composite powders and Al powders is weaker.

In this study, resistive random-access memory (RRAM)-based crossbar arrays with a memristor W/TiO2/HfO2/TaN structure were fabricated through atomic layer deposition (ALD) to investigate synaptic plasticity and resistive switching (RS) characteristics for bioinspired neuromorphic computing. X-ray photoelectron spectroscopy (XPS) was employed to explore oxygen vacancy concentrations in bilayer TiO2/HfO2 films. Gaussian fitting for O1s peaks confirmed that the HfO2 layer contained a larger number of oxygen vacancies than the TiO2 layer. In addition, HfO2 had lower Gibbs free energy (ΔG°=-1010.8 kJ/mol) than the TiO2 layer (ΔG°=-924.0 kJ/mol), resulting in more oxygen vacancies in the HfO2 layer. XPS results and ΔG° magnitudes confirmed that formation/disruption of oxygen-based conductive filaments took place in the TiO2 layer. The W/TiO2/HfO2/TaN memristive device exhibited excellent and repeatable RS characteristics, including superb 103 dc switching cycles, outstanding 107 pulse endurance, and high-thermal stability (104 s at 125 °C) important for digital computing systems. Furthermore, some essential biological synaptic characteristics such as potentiation-depression plasticity, paired-pulse facilitation (PPF), and spike-timing-dependent plasticity (STDP, asymmetric Hebbian and asymmetric anti-Hebbian) were successfully mimicked herein using the crossbar-array memristive device. Based on experimental results, a migration and diffusion of oxygen vacancy based physical model is proposed to describe the synaptic plasticity and RS mechanism. This study demonstrates that the proposed W/TiO2/HfO2/TaN memristor crossbar-array has a significant potential for applications in non-volatile memory (NVM) and bioinspired neuromorphic systems.

A novel nano-heterojunction photocatalysts of CdS/MoS2 with appropriate interfacial contact was successfully obtained by the facile two-step hydrothermal synthesis. The MoS2 ultrathin layer was well combined with CdS nanosheets and formed the interaction, which facilitated the transfer and separation of charges. The CdS/MoS2 15 wt% possessed much higher H2 evolution photocatalytic performance (35.24 mmol h−1 g−1), exhibiting an 85.95 times enhancement as compared to that of pure CdS (0.41 mmol h−1 g−1). Moreover, the photochemical stability of CdS/MoS2 heterojunctions was excellent, which showed no significant decrease in activity after four cycles of experiments. The finding provides a novel method to integrate the structure of MoS2 with CdS, which exhibits great potential in solar energy conversion.

With increasing demands for microchips and increasing needs in the nano-scale semiconductor manufacturing industry, atomic layer etching (ALE) has been developing into a critical etching process. Unlike its counterpart in the film deposition domain, atomic layer deposition (ALD), which has been extensively studied, ALE has not been fully studied yet from a modeling and operation point of view. Therefore, this work develops microscopic models to characterize the thermal ALE process of aluminum oxide thin films with two precursors (hydrogen fluoride and trimethylaluminum). First, the reaction mechanisms for the two half-cycles for the thermal ALE process are established. Electronically predicted geometries of the Al2O3 structure with two precursors are optimized. Along with the optimized geometries, possible reaction pathways are proposed and calculated by density functional theory (DFT)-based electronic structure calculations. The proposed reaction paths and their kinetic parameters are used in a kinetic Monte Carlo (kMC) algorithm, which is capable of capturing the features of the thermal ALE of aluminum oxide. The kMC simulation provides an etch time for the given steady-state operating conditions, which are validated via comparison with available experimental results. Finally, data sets collected from the kMC simulation are used to train a feed-forward artificial neural network (FNN) model. The trained FNN model accurately predicts an etch time and dramatically reduces the computation time compared to the kMC simulation, thereby making it possible to carry out real-time, model-based operational parameter calculations. In addition, the trained FNN model can be used to establish a feasible range of operating conditions without demanding experimental work.

Molybdenum disulfide (MoS2) is a promising anode material for lithium-ion batteries (LIBs) because of its high theoretical capacity. But its rapid capacity decay due to poor conductivity, structure pulverization, and polysulfide dissolution presents challenges for practical applications. In this work, an innovative cationic surfactant templating route to one-step synthesizing epitaxial few-layer MoS2@N-doped carbon (EF-MoS2@NC) core–shell hollow structures is developed via an electrostatic interaction S+X−I+ pathway. Compared with general hard-template strategies, the soft-template method proposed here is simplified, avoiding the cumbersome coating and template removal process. The internal hollow space and outer NC protective layer can accommodate the large volumetric expansion of MoS2 and preserve the structural integrity of the electrode preventing polysulphide dissolution. When evaluated as anode materials for LIBs, the core–shell EF-MoS2@NC hollow spheres achieve a high discharge capacity of 928 mA h g−1 after 100 cycles at 0.1 A g−1. More importantly, a reversible capacity of 829 mA h g−1 could be obtained at 1.0 A g−1 after 1000 cycles, which demonstrates good stability.

The constraint effect with material parameters mismatch between every parts of planar solid oxide fuel cell (SOFC) plays an important role in the operation life. In this study, the mismatch effect of material creep strength coefficient on creep damage and failure probability of planar SOFC was investigated by finite element method. The results show that the maximum equivalent creep strain and failure probability of SOFC are located in the outer corner of sealant layer. With the increase of the creep strength coefficient of the sealant layer, the maximum creep damage, damage area and failure probability of the sealant layer all increase gradually. The creep strength coefficient of the sealant layer is suggested to be smaller than that of the frame material, which will improve service life of SOFC.

In this investigation, ZnO nanostructures were coated via hydrothermal process on glass substrate surfaces, which were treated by acidic and alkaline solutions. Furthermore, the ZnO structure was doped by different amounts of Al+3 ions to investigate the microstructural variation. Characteristics of the samples by XRD and SEM analyses confirmed the formation of different morphologies and various crystal sizes for the nanostructured ZnO on the substrates including nanoflower, nanorod, and nanopanel morphologies. Furthermore, XRD results showed that the Zn2+ concentration was a crucial factor in changing the grain size. EDS analysis confirmed the uniform distribution of Al dopant, while the FTIR spectra revealed the presence of Al–O and Zn–O stretching bonds in the coatings. The results confirmed that the sample, which was etched by fused NaOH had a uniform and compacted structure. Moreover, it was evident the proposed treatment and synthesis process was successful in the formation of uniform nanostructured ZnO film on the glass substrate without the requirement for seed layer deposition.

Introducing artificial interface layer is a cost-effective strategy to inhibit parasitic reactions and dendritic growth on the zinc anode. However, boosting cation transfer while blocking anions and active water molecules through the interface layer is still a formidable challenge at current stage. Here, a zeolitic imidazolate framework (ZIF) based multi-functional interface layer is fabricated to prevent active water molecules reaching the deposition sites while increasing the cation concentration at the interface based on the coordinative self-concentration mechanism and electrokinetic effects, thus effectively inhibiting parasitic reactions and dendrite growth. Specifically, a super-saturated interfacial electrolyte layer is formed in the ZIF-11 layer because a large amount of water and large solvated molecule are removed in advance, eventually inhibiting the generation of hydrogen and basic zinc sulfate. Simultaneously, a thin electric double layer on the wall of the channel inside the interface layer can be formed due to the intense adsorption of zinc ions by the abundant zincophilic nitrogen-containing functional groups in the interface layer, leading to smooth electrokinetic surface conduction and stable deionization shock in the channel. These electrokinetic effects will jointly guide the distribution of zinc ions, thereby forming a uniform shock electrodeposition on the anode surface. Accordingly, the ZIF-11@Cu-Zn based symmetric cells can operate stably for 1800 hours, nearly 18 times longer than that of Cu-Zn based symmetric cells at 0.5 mA cm−2. And the ZIF-11@Cu-Zn based aqueous Zn-ions hybrid supercapacitors (AC||ZIF-11@Cu-Zn ZHCs) exhibit a reversible capacity of 58.6 mA h g−1 and the capacity retention is about 96.23 % after 5000 cycles. Moreover, AC||ZIF-11@Cu-Zn ZHCs can still run effectively for 5,000 cycles even paired with the cathode with commercial-grade loading of 23.3 mg cm−2.

CdCl2 treatment is crucial in the fabrication of highly efficient CdS/CdTe thin-film solar cells. This study reports a comprehensive analysis of thermal evaporated CdS/CdTe thin-film solar cells when the CdTe absorber layer is CdCl2 annealed at temperatures from 340 to 440 °C. Samples were characterized for structural, optical, morphological and electrical properties. The films annealed at 400 °C showed better crystallinity with a cubic zinc blende structure having large grains. Higher refractive index, optical conductivity, and absorption coefficient were recorded for the CdTe films annealed at 400 °C with CdCl2. Optimum photoactive properties for CdS/CdTe thin-film solar cells were also obtained when samples were annealed at 400 °C for 20 min with CdCl2, and the best device exhibited VOC of 668.4 mV, JSC of 13.6 mA cm-2, FF of 53.9 % and an efficiency of 4.9 %.

This paper presents the use of AZTS, a non-toxic and earth abundant material as buffer layer in CZTS solar cells due to its good lattice match. We have performed simulation on the experimentally fabricated AZTS/CZTS hetero-junction device by adding CZTS as back surface field (BSF) layer. In this work, first we have reconstructed the AZTS/CZTS experimentally designed solar cell then BSF layer is added to boost the solar cell performance in SCAPS simulator. Several parametersof AZTS buffer layer such as generation/recombination rate and doping concentration are varied during simulationto enhance the performance of investigated solar cells structures. It has been noticed that addition ofBSF layer increasesthe efficiency of AZTS/CZTS solar cell from 4.51% to 5.05% along with improvement of both Voc and FF.

In this letter, a threshold switching (TS) selector with Ag doping-based nano-polycrystalline ZnO switching layer (SL) having (002) preferred orientation has been manifested, without incorporating an active Ag metal layer, using a facile co-sputtering deposition technique. The TS selectors with extremely controlled doping of ~0.14 at. % Ag concentration showed remarkable electroforming (EF)-free selection behavior such as gigantic selectivity (~1011), extreme-low off-current (~10 fA), high on-current density (~1.6 MA/cm2), ultra-steep switching slope (~0.8 mV/decade), satisfactory endurance (>106), fast switch-on speed (~38 ns) and relaxation speed (~64 ns), and high device yield (~90%). Furthermore, selector devices showed reproducible selection behavior with stable threshold voltage (Vth) having merely 8% variances.

Radiation-induced graft polymerization is introduced to effectively fabricate proton exchange membrane based on 12.5 μm fluorinated ethylene propylene (FEP) film. The graft side chains penetrate FEP film and distribute inside the bulk matrix evenly. The membranes exhibit hydrophilic/hydrophobic microphase-separated morphology as well as good thermal stability. The influences of irradiation parameters on the membrane property are investigated and the resulting membranes (named FEP-g-PSSA) exhibit excellent physicochemical properties. Membrane with 27.48% degree of graft and 130.1 mS cm−1 proton conductivity is employed for fuel cell performance measurement. Under optimized operate conditions (80 °C, 75% relative humidity), the power density could reach up to 0.896 W cm−2, inspiring for fuel cell application. The mass-transport-controlled polarization of membrane electrode assembly (MEA) based on FEP-g-PSSA membrane is higher than Nafion® 211 within the whole current density range and the gap is widening with increasing current density. At 2.0 A cm−2, the mass transfer polarization of FEP-g-PSSA reaches up to 0.204 V, far higher than Nafion® 211 (0.084 V). By promoting the compatibility between the ionomer in the catalyst layer and FEP-g-PSSA membrane and optimizing the membrane/catalyst layer/gas diffusion layer interfaces, the fuel cell performance could be significantly enhanced, making the FEP-g-PSSA membranes promising in fuel cell application.

Interface recombination is one of the factors limiting the performance of Cu(In,Ga)Se_2 (CIGS). Especially in the absence of band grading at the front and rear surface, interface passivation approaches become important to improve device performance. The integration of an oxide layer as passivation layer at the front surface of the CIGS requires meticulous considerations in order not to impact the further steps of the solar cell production. In this article, a novel approach is reported to try to tackle the problem of interface recombination at the front surface of CIGS without affecting further solar cell production steps. In this approach, an Al_2O_3/HfO_2 multi-stack layer with contact openings is applied. NaCl template patterning with preliminarily selected parameters was used to create a homogeneous pattern of contact opening on the CIGS surface and allow the current flow in the device. After the removal of the NaCl islands, the holes in the multi-stack (openings) were visualized by scanning electron microscopy. In addition, energy-dispersive X-ray spectroscopy (EDS) was performed before and after chemical bath deposition of the buffer layer. The EDS result confirmed that the undesired etching of the Al_2O_3 layer during buffer layer deposition was prevented by using a thin HfO_2 layer. Solar cells were produced by using preliminarily selected parameters for the multi-stack design. As a result, without having a significant negative impact on the solar cell parameters, a device design was achieved which is almost comparable with the reference device. In addition, options for future improvement and development are discussed. European Union's H2020 Research and Innovation Program [715027]

Resistive type superconducting fault current limiter (R-SFCL), based on REBCO coated conductor, is of great help to enhance the safety and stability of power system. When the fault current appears, the current is transferred from the superconducting layer to the metal layers with large resistance in the REBCO coated conductor, so as to limit the current. However, the interface resistance affects the current distribution between different metal layers. What's more, the inhomogeneity effect of REBCO coated conductor has great influence on the quench characteristics of R-SFCL. In this work, the current transfer model of REBCO coated conductor is established, and the influence of interface resistance on current distribution is analyzed. The inhomogeneity effect of resistivity parameters and critical current of REBCO coated conductor is analyzed. One non-inductive bifilar coil is fabricated for DC impulse current test, and the influence of inhomogeneity effect of REBCO coated conductor on quench characteristics is verified.

The corrosion resistance of the Cathode Electro-deposition (CED) production line’s conveyor chain can be improved by performing electroplating with zinc metal on the alloy steel. The zinc coating over the steel conveyor chain link is better suitable for the Pre-treatment (PT) and CED line. The PT and CED line is naturally both acidic and high temperature at the same time and both enhance the rate of corrosion over any material. The process of zinc coating over the alloy steel used in the conveyor chain link enhances the rust inhibition property without altering the hardness. This is made possible through the sub-micron thickness addition of zinc over the base metal. Corrosion test was conducted in 3.5% NaCl solution according to ASTM STD G1 03 and the results of two specimens (I pin and chain link) were observed and reported. The corrosion rate was greatly improved by the sub-micron thickness of the zinc layer added on the conveyor chain link. The weight loss rate for 5 weeks test time reduced from 2.41% to 0.73% after zinc coated. Weight loss of new zinc coated material improved by 1.67% from the existing chain link material. The corrosion rate of the chain-link improved by 71% from the existing chain link. The results presented in the paper can contribute to the body of knowledge of corrosion behaviour of metals in acidic and temperature environment, which in turn enable more accurate prediction of failures of CED line conveyor chains.

Solar water evaporation technology has become one of the promising ways for seawater desalination by excellent energy capture and efficient solar-thermal conversion. However, some challenges still restrict its further industrial development, such as low flexibility, non-portability, and insufficient energy utilization, salt crystallization problems. In this work, hierarchical MoS2 nanosheets coupled with MXene (MoS2-MXene) is constructed and formed into a film with foldability and portability for solar water evaporation. Improved evaporation rate (2.5 kg m−2 h−1) is observed due to enhanced energy capture from a folded 3D solar evaporation system. Meanwhile, the outstanding evaporation performance (3.2 kg m−2 h−1) is realized because of gradient heating from a hydrophobic MoS2-MXene@PF (MoS2-MXene@Paraffin) under one sun. During the evaporation of high-concentration NaCl solution (20 wt%), the hydrophobic layer is observed to become a salt crystallization site for salt generation. After long-term and multiple testing, no salt crystallization was found at the evaporation site, maintaining a stable evaporation rate. More interesting, MoS2-MXene@PF can be also succeeded as a solar thermal pack for storing heat through the phase change material paraffin (PF). This work provides a new solution to realize excellent energy capture for solar desalination and solar thermal storage.

Mixed phase of iron telluride based thin films consisting of nanopebbles has been grown successfully over conducting stainless steel (SS) substrate through successive ionic layer adsorption reaction (SILAR) process. Crystal structural and elemental states through XPS revealed clear indication of FeTe: Fe2TeO5 mixed phase growth and well supported through FTIR studies. Agglomeration of embedded quantum dots forming nanopebbles like surface architecture resulting in enhanced hydrophilic nature evident through contact angle and higher surface roughness by atomic force micrographs found beneficial as more electroactive surface area for electrolyte ions to interact. This helped to achieve a significant specific capacitance of 591 F/g (166 mF/cm2) @3 mV/s potential scan rate and, 107 F/g (30 mF/cm2) @0.4 mA/cm2 in NaCl electrolyte. Performed electrochemical impedance spectroscopy (EIS) studies explored clear insight of the solution and charge transfer resistances, and relaxation time constant. Iron telluride based thin film clearly demonstrates very high value of pseudo capacitive contribution than the electric double layer due to the intrinsic pseudocapacitive behavior of mixed phase.

In this work, the high temperature friction mechanism of the tetrahedral amorphous carbon (ta-C) film was elucidated. The multilayer ta-C film with alternating hard and soft sub-layers exhibited a low friction coefficient of 0.14 at 400 °C before a sudden failure occurred at 4600 cycles. The wear failure was attributed to the gradual consumption of the ta-C film at the contact region. The design of a hard or soft top layer effectively regulated the high temperature friction properties of the multilayer ta-C. The addition of a hard top layer contributed to a low friction coefficient (0.11) and a minor wear rate (4.0 × 10−7 mm3/(N m)), while a soft top layer deteriorated the lubrication effect. It was proposed that the passivation of dangling bonds at the sliding interface dominated the low-friction mechanism of the ta-C film at high temperature, while the friction induced graphitization and the formation of sp2-rich carbonaceous transfer layer triggered C C inter-film bonding, resulting in serious adhesion force and lubrication failure. Moreover, the multilayer ta-C film with hard top layer obtained excellent friction performance within 500 °C, while the high temperature induced oxidation and volatilization of carbon atoms led to the wear failure at 600 °C.

Preparation and growth mechanism of anodization of Ti and Al has been widely concerned for two decades, but the research on anodic ZrO2 is relatively lacking. In this paper, anodic TiO2 and ZrO2 nanotubes were prepared in glycerol electrolyte containing 0.35 M NH4F and 4 vol% H2O under different anodizing voltages. We had successfully prepared the anodic ZrO2 nanotubes (AZNTs) with a complete top and a “bulb” at the bottom under 60 V, and with the increase of the applied anodizing voltage, the “bulb” cavity also increased. However, under the same anodizing conditions, the surface of anodic TiO2 nanotubes (ATNTs) is a cluster of nano-tip morphology, and the bottom of the ATNTs is a conventional hemisphere shape. In addition, both AZNTs and porous anodic zirconia (PAZ) were found to coexist in the anodic ZrO2 layer prepared at 60 V. Here, we used the oxygen bubble model and ionic current and electronic current theories to analyze the reason of the special morphology. It is confirmed that the porous anodic oxides are actually evolved from nanotubes. In other words, the structure is essentially the same.

Laser-assisted 3D printing process of fabricating carbon fibre reinforced plastic parts by sandwiching fibres between plastic layers was developed to improve the bond strength of the fibres to the plastic layers. Here, bundled carbon fibres are placed on the 3D-printed lower plastic layer, and the upper plastic layer is deposited on the fibres. Next, the two layers sandwiching the fibres are laser-heated using a blue diode laser beam. The plastic colour changed the heating temperature at the interface between the fibres and the plastic layer due to the transmittance and absorption phenomena; the translucent layer having high transmittance was most appropriate. The strength and rigidity of the 3D-printed carbon fibre reinforced plastic parts were improved by laser heating. Carbon fibre reinforced plastic parts having closed cross-sections are manufactured and strengthened by optimising the sandwiched fibre orientation. Besides, a tailored part locally reinforced by the carbon fibres is easily 3D-printed, and the deformation behaviours are observed.

LiCoO2 with a cut-off voltage of 4.6 V (versus Li/Li+) could increase by about 28% of energy density compared with the commercial 4.45 V LiCoO2 cathode. However, severe issues such as oxygen evolution and dramatic phase transition strangle the practical application of 4.6 V LiCoO2. We herein develop a one-step wet chemical coating method at room temperature to stabilize the interface of LiCoO2 under high voltage. Through the treatment of LiCoO2 particles by LiAlH4 solution, the oxygen framework of the surface was reconstructed forming a composite coating layer which is featured a morphology with an inside-out transition structure from order to disorder. Benifited from the Al-containing composite layer, an excellent cycling performance has been obtained on the treated commerical samples, delivering a capacity retention of 70.4% even after 1000 cycles. The key to the improvement of electrochemical performance is to restrain the loss of lattice oxygen which is further elucidated by the results from differential electrochemical mass spectroscopy (DEMS). The interface evolution in different depths was carefully investigated delineating the relationship between the fluorated interface and the enhanced performance. Since the introduction of aluminum hydroxide, it facilitates the capture of F− bringing the interface layer from oxide to more stable fluoride during the cycling. Combining with the first principles calculation results, the aluminum coating surface suppresses the evolution of surfacial oxygen confirmed by oxygen release energy, and the optimized models infer that the fluorinated layer can obviously stabilize the interface structure of LiCoO2. This study provides a direct coating method which confers a notable improvement on cycling stability of LiCoO2 under high voltage and enables the implementation of high energy storage applications.

Antimony selenide (Sb2Se3) is a promising light absorber material for solar cells because of its superior photovoltaic properties. However, the current performance of the Sb2Se3 solar cell is much lower than its theoretical value (∼32%) due to its low open-circuit voltage (VOC). In this paper, we have demonstrated inorganic vanadium oxides (VOx) as a hole transport layer (HTL) for Sb2Se3 solar cells to enhance efficiency through the VOC improvement. Here, a solution-processed VOx through the decomposition of the triisopropoxyvanadium (V) oxide is deposited on the Sb2Se3 absorber layer prepared by close-spaced sublimation (CSS). With VOx HTL, the built-in voltage (Vbi) is significantly increased, leading to improved VOC for the Sb2Se3 solar cell devices. As a result, the efficiency of the device increases from an average efficiency of 5.5% to 6.3% with the VOx.

The open-circuit voltage (V $_\text{oc}$ ) of CdTe-based photovoltaics may be limited by carrier recombination at interfaces (front or back) or in the absorber layer. Reduction in recombination of a given dominant mechanisms can lead to improved device performance if the remaining mechanisms turn on in a narrow bias range just below the open circuit voltage. In this article, we demonstrate enhanced performance by incorporating solution-processed Cu $_\text{x}$ AlO $_\text{y}$ to form a back-buffer layer in CdSe/CdTe devices. Outstanding minority carrier lifetimes of 656 and 4.2 ns were measured with glass side and film side illumination for device stacks processed with Cu $_\text{x}$ AlO $_\text{y}$ . Devices demonstrated efficiencies of up to 17.4% with V $_\text{oc}$ of 859 mV, FF of 75.6% and J $_\text{sc}$ of 26.9 mAcm−2 while the efficiency of the reference device without the back-buffer layer was 16.5% with V $_\text{oc}$ of 839 mV, FF of 70.6%, and J $_\text{sc}$ of 27.9 mAcm−2.

Solid oxide fuel cells are promising renewable energy devices due to their high efficiency and fuel flexibility. As they operate at a higher temperature than other fuel cells, ceramic materials, such as perovskite-based La0.6Sr0.4CoO3 and La0.6Sr0.4Co0.2Fe0.8O3, can be used as electrodes to replace expensive noble metals. However, when the corresponding electrode and yttria-stabilized zirconia electrolyte are sintered together, SrZrO3 produced from a side reaction acts as an insulator and deteriorates the performance of the fuel cell. Thus, the dense functional layer of a ceria-based material should be introduced between the electrode and the electrolyte to suppress the formation of secondary phases. However, in the conventional cell manufacturing process, it is challenging to manufacture a dense functional layer under constrained sintering conditions. In this study, we develop a method for fabricating a dense gadolinia-doped ceria (GDC) functional layer, even under constrained sintering conditions, by using a sacrificial bismuth oxide, Bi2O3, sintering aid layer above the GDC layer. As thermal sintering progresses at 1000–1200 °C, the Bi2O3 sintering aid layer is sublimated, leaving only the pure GDC functional layer. The fabricated dense GDC functional layer characterized by various analysis methods shows improved solid oxide fuel cell performance.

Perovskite solar cells (PSC) capable of open-circuit voltage (VOC) over 1.5 V was fabricated based on a formamidinium lead-bromide (FAPbBr3) perovskite absorber film prepared by sequential deposition procedure using dimethylsulfoxide (DMSO) and tetramethylenesulfoxide (TMSO) mixed solvent. A PbBr2 film formed from a precursor PbBr2 solution with the DMSO–TMSO mixed solvent was reacted with FABr to convert into FAPbBr3 film. The mixed solvent-based PbBr2 film exhibits as an amorphous-like phase containing a PbBr2–TMSO complex, which led to formation of an FAPbBr3 film possessing high crystallinity and uniform thick absorber layer compared with the pristine PbBr2 film prepared by pure DMSO solvent. With a bandgap of 2.1 eV, FAPbBr3-based PSCs prepared by the solution process with PbBr2–TMSO complex exhibited high VOC up to 1.55 V and power conversion efficiency of 7.8% on the device fabrication using a Li-treated mesoporous TiO2 as electron transport layer with 5 x 5 mm2 cell active area.