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• Initial coatings improve the microstructure of surrogate fuel elements. • Initial coating thickness is crucial in tuning the microstructure. • Potential for fuel elements with greater than 60 vol.% fissile fuel exists. • Higher fuel fractions would result in improved efficiency and decreased weight. Nuclear thermal propulsion (NTP), which may utilize cermet fuels, shows promise in improving the feasibility of long-distance space travel. These cermet fuels are composed of a ceramic nuclear fuel phase, such as UO 2 or UN, and a protective refractory metal (W or Mo) phase. In this work, a material system consisting of tungsten-yttria stabilized zirconia (W-YSZ) surrogate fuel elements were fabricated via spark plasma sintering. Prior to consolidation, magnetron sputtering was utilized to provide conformal W coatings to the YSZ particles, such coatings were 80 to 550 nm in thickness. These coatings, when excess W powder was added, were found to reduce the ceramic-ceramic contacts as well as improve the densification of the cermet over powders that were not coated. Furthermore, when the coating thickness was at least 350 nm, and additional W powder added to yield a metallic fraction of 32 vol.%, the ceramic-ceramic contacts remained nearly identical to higher W fractions. This suggests that conformal coated ceramic fuel particles would reduce the necessary amount of refractory metal matrix, which in turn would reduce neutron poisoning, lower fuel element weight, and increase fissile fuel content from the 60 vol.% fuel in conventional NTP cermets. [ABSTRACT FROM AUTHOR]

• Ti 3 C 2 T X tracks were fabricated on PET-based sheets using aerosol jet printing. • The deposition is uniform whatever the thickness and the geometry of the pattern. • The resistivity of the printed patterns is 23 μΩ m. • The resistance of Ti 3 C 2 T X tracks is affected by temperature of 13% (−10 °C - 60 C). [Display omitted] Aerosol jet printing (AJP) is a promising printing technology for fabricating sensors and electronics, due to its high flexibility in ink and substrate selection. Indeed, inks suitable for AJP can differ in morphology (2D and 3D nanoparticle, nanoflake, nanosheet, etc.), in electrical properties (conductive, semiconductive, insulating, etc.), or in additional advanced features (biocompatibility, stretchability, etc.). Inks can be deposited on planar, or complex 3D surfaces, which can be made of a variety of materials. Ti 3 C 2 T x , a MXene, is a prominent 2D material, and is considered a promising material for energy storage electrodes and sensing elements due to its good stability and electrical conductivity. In this work, we propose a fabrication process based on AJP to print Ti 3 C 2 T X ink on PET-based sheets and we analyze the morphology (width and thickness) and the resistance by changing the number of overlaid printed layers (N layers) and the pattern. The results from the morphological analysis and resistance measurements indicate uniform deposition and good repeatability using AJP, regardless of N layers and the geometry of the printed pattern (thin lines, serpentine, long lines). Finally, for the first time, we estimate the temperature effects on the resistance of pure Ti 3 C 2 T X printed lines. For example, in the range − 10–60 °C and in the range 20–120 °C the resistance of Ti 3 C 2 T X printed on PET-based sheet increases by 13% and 20%, respectively. We also deposit different types of conformal coating to protect the printed layers from oxidation. [ABSTRACT FROM AUTHOR]

A mixture of polydopamine (PDA) and polyethyleneimine (PEI) are used as the adhesive, wetting, and reducing agent simultaneously to fabricate a conductive silver membrane. The conformal coating of PDA/PEI on individual polypropylene fibers of polypropylene micromembrane (PPMM) renders the latter to be hydrophilic for subsequent electroless silver deposition. The resulting conductive silver membrane demonstrates impressive electric conductivity in both X and Z directions. The thickness of conformal silver overcoat is 250 nm and the effective loading is 2.4 mg/cm2. The mechanical strength of conducive silver membrane is similar to that of pristine PPMM. Both cyclic voltammetry and impedance spectroscopy on the conductive silver membrane reveal a large electrochemical active surface area. To validate its usefulness as a robust soft electrode, the conductive silver membrane is evaluated for the detection of chlorine in aqueous solution in which a low detection limit of 0.07 ppm and a wide detection range of 0.1–20 ppm are validated. [Display omitted] • Surface functionalization of individual polypropylene fibers. • Polydopamine/polyethyleneimine as adhesive, wetting, and reducing agent. • Uniform electroless Ag coating for conductive Ag membrane. • Flexible and porous membrane for free chlorine determination. [ABSTRACT FROM AUTHOR]

A series of Fe2O3@LSF (La0.8Sr0.2FeO3−δ perovskite) core-shell materials (CSM) was prepared by infiltration of LSF precursors gel containing various complexants and their mixtures to nanocrystalline aggregates of hematite followed by thermal treatment. The content of LSF phase and amount of carboxyl groups in complexant determine the percent coverage of iron oxide core with the LSF shell. The most conformal coating core-shell material was prepared with citric acid as the complexant, contained 60 wt% LSF with 98% core coverage. The morphology of the CSM was studied by HRTEM-EELS combined with SEM-FIB for particles cross-sections. The reactivity of surface oxygen species and their amounts were determined by H2-TPR, TGA-DTG, the oxidation state of surface oxygen ions by XPS. It was found that at complete core coverage with perovskite shell, the distribution of surface oxygen species according to redox reactivity in CSM resemble pure LSF, but its lattice oxygen storage capacity is 2–2.5 times higher. At partial coverage, the distribution of surface oxygen species according to redox reactivity resembles that in iron oxide. [ABSTRACT FROM AUTHOR]

NaCl-type Ni-Co oxide solid solution is expected to be a promising alternative anode material for lithium-ion batteries. However, the synthesis of solid solutions with well-defined morphology and homogeneity is still challenging. Based on a novel Ni x Co 1−x (OH)(OCH 3)@polydopamine intermediate and its topotactic thermolysis, a unique synthetic route towards Ni x Co 1−x O solid solution (0

The efficiency of thin-film chalcogenide solar cells is dependent on their window layer thickness. However, the application of an ultrathin window layer is difficult because of the limited capability of the deposition process. This paper reports the use of atomic layer deposition (ALD) processes for fabrication of thin window layers for Cu(Inx,Ga1−x)Se2 (CIGS) thin-film solar cells, replacing conventional sputtering techniques. We fabricated a viable ultrathin 12 nm window layer on a CdS buffer layer from the uniform conformal coating provided by ALD. CIGS solar cells with an ALD ZnO window layer exhibited superior photovoltaic performances to those of cells with a sputtered intrinsic ZnO (i-ZnO) window layer. The short-circuit current of the former solar cells improved with the reduction in light loss caused by using a thinner ZnO window layer with a wider band gap. Ultrathin uniform A-ZnO window layers also proved more effective than sputtered i-ZnO layers at improving the open-circuit voltage of the CIGS solar cells, because of the additional buffering effect caused by their semiconducting nature. In addition, because of the precise control of the material structure provided by ALD, CIGS solar cells with A-ZnO window layers exhibited a narrow deviation of photovoltaic properties, advantageous for large-scale mass production purposes. [ABSTRACT FROM AUTHOR]

Silicon is an attractive anode material for all-solid-state batteries due to its high theoretical capacity and low working potential. However, the poor cycle stability caused by electrical and ionic contact loss resulting from the severe volume change of the Si associated with Li should be addressed. Here, we report Si nanoparticles embedded in carbon nanofiber (CNF) sheathed with Li 6 PS 5 Cl (LPSCl) (Si/CNF@LPSCl) as anode material to achieve high energy density and stable cyclability for all-solid-state batteries. By embedding Si in the CNF, more favorable strain release and robust electronic pathways are available. The conformal coating of solid electrolyte on the surface of Si/CNF composite enhances the interfacial stability between the active material and the solid electrolyte, which leads to the improvement in electrochemical properties by suppressing the contact loss. The Si/CNF@LPSCl composite electrode exhibits a reversible capacity of 1172 mAh g−1 at 0.1C and stable cyclability of 84.3% at 0.5C after 50 cycles. Especially, the concentration of active material (Si/CNF@LPSCl) in the electrode is significantly increased without noticeable performance degradation due to the improved interfacial stability, which enables the increase of the energy density and reduction of the fabrication cost. • The Si/carbon nanofiber composite was prepared by an electro-spinning method. • By embedding the Si in the carbon nanofiber, strain release is available. • The solid electrolyte coating could preserve the charge conducting path. • The ratio of active material in the electrode could be significantly increased. [ABSTRACT FROM AUTHOR]

Controllable construction of self-supporting electrodes with efficient charge migration on the whole electrode and abundant electrocatalytic active sites is still challenging in oxygen evolution reaction (OER). Here, an intentionally designed self-supporting electrode consisting of NiCoP nanowire arrays embedded in 3D integrated N-doped carbon network (NiCoP@NC-NCNTs) is fabricated for high-performance electrocatalytic OER. The NiCoP@NC-NCNTs has been prepared via in-situ growth of N-doped carbon nanotubes (NCNTs) and N-doped carbon (NC) layer on NiCo arrays and subsequent phosphating reaction. Due to the intertwined network structure of NCNTs and the conformal coating of NC layer on the surface of NiCoP arrays, the NiCoP@NC-NCNTs catalyst not only realizes effective charge migration on the whole electrode, but also offers abundant catalytic active sites. Compared to NiCoP nanowire arrays without embedding in 3D carbon network, the NiCoP@NC-NCNTs exhibits a remarkable performance for electrocatalytic OER, in terms of an ultralow overpotential of 227 mV at 10 mA cm−2, and 317 mV even at 100 mA cm−2. Meanwhile, a negligible current degradation can be found in the chronoamperometric (i-t) curve after the long-term stability test. This work proves that it is a promising strategy to develop electrocatalysts by embedding the bimetallic phosphides in 3D carbon networks. [Display omitted] • NiCoP nanowire arrays imbedded in 3D integrated carbon network has been designed and prepared. • The 3D integrated structure is achieved by the combining template method with physical-chemical vapor deposition. • The 3D integrated N-doped carbon network provides continues electron transfer pathway throughout the whole electrode. • The 3D integrated structure with several synergistic effects exhibits remarkable OER activity. [ABSTRACT FROM AUTHOR]

Conformal coatings with higher adhesion strength is crucial for mitigating the growth of whiskers from the pure tin (Sn) or Sn-rich surfaces of the Pb-free electronics. Silane coupling agents have the ability to form a durable bond between polymeric coatings and metallic materials. The main goal of this paper is to investigate the effect of silane agents on the adhesion behavior of polyurethane (PU), polyurethane acrylate (PUA) and both coatings filled with silicone rubber (SR) nanoparticles on the tin solder pads. It was found that an isocyanate-based silane provided excellent adhesion for PU and PU + SR coatings and an acrylic-based silane for PUA and PUA + SR coatings on the tin surface. This was due to the reaction bond formation between the silane coupling agent and the coating. Hence, the selection of silane coupling agents with the organofunctional group similar to the coating material is crucial to improve the adhesion properties of the coating. [ABSTRACT FROM AUTHOR]

A flexible, smooth, and low profile conformal coating was developed to accomplish the encapsulation of a microelectromechanical system (MEMS) device that will be applied to sense the static pressure on aircraft during real flight testing. The encapsulant should be able to protect the MEMS device and the multichip module (MCM) from adverse environmental conditions, i.e., mechanical shock, temperature fluctuation, engine fuel and oil contamination, and moisture/mobile ion permeation. Presently, conventional packaging schemes for electronics cannot satisfy this specific outdoor application, and a new encapsulation combination has been designed in accord with the requirement of reliability without hermeticity (RWOH). A bi-layer structure was selected because of property limitations of a single material. Pliable elastomeric silicones are typically flexible, water repellent, and abrasion resistant. The silicone encapsulant will be first applied to planarize the MEMS surface and function as durable dielectric insulation, stress-relief, and shock/vibration absorbers over a wide humidity/temperature range. To compensate for the deficiency of silicone on engine fuel/oil contamination, Parylene C is to be deposited afterward. This bi-layer coating can achieve excellent bulk properties, such as moisture and mobile ion barrier resistance, chemical compatibility, and electrical insulation characteristics. However, the poor adhesion of Parylene C to silicone greatly restricts its application. To address this problem, silane coupling agents were used as an adhesion promoter. Significant adhesion improvement was achieved by placing an interlayer silane coupling agent to provide interfacial bonding to the silicone elastomeric surface and the Parylene C film. Furthermore, a possible mechanism of adhesion enhancement will also be presented in this study [ABSTRACT FROM PUBLISHER]

• Tin whisker growth can be effectively mitigated by the parylene C coating. • Tin surface coated with the parylene was exposed to 85°C/85% RH for up to 5000 h. • Chemical and mechanical stability of parylene affected its whisker penetration. • Adhesion of parylene coating to tin influenced corrosion and tin whisker activities. • Whisker mitigation strategies are presented for the application of parylene coating. Usage of pure tin (Sn) or Sn-rich alloy in electronics industry is growing, which makes them more susceptible to the spontaneous growth of tin whiskers. The risk of having these whiskers can be dramatically mitigated by applying a conformal coating such as parylene C. The purpose of this paper is to investigate the degradation of parylene C coating (with two thicknesses, 12.5 μm and 25 μm) during thermal aging in high humidity environment (85 °C/85% relative humidity for up to 5000 h) and its effect on the tin whisker mitigation property. It was observed that under the high temperature and high humidity (HTHH) environment, the oxidation occurs at early times, followed by bond scission, resulting in the loss in strength and modulus of the parylene coating. After 2500 h of aging, due to the degradation of the silane agent at the tin/parylene interface, the adhesion of the parylene coating on the tin surface was significantly weakened, which resulted in extensive corrosion of the tin solderpads. The loss of adhesion of the coating, along with the corrosion of the tin surface facilitated tin whisker nucleation at the interface while the loss of mechanical strength and the brittleness made the growing whiskers penetrate easily through the coating. Tin whiskers with a smaller diameter were buckled and grew along the delaminated interfacial region while those with a larger diameter penetrated and continued to grow through the coating. Although the thicker parylene coating helped delay the complete penetration and increase the critical diameter of whiskers for complete penetration, it showed more tin whisker activities and easy penetration by large diameter whiskers due to poorer adhesion. Hence, the effectiveness of the parylene coating on tin whisker mitigation will depend on its degradation kinetics of mechanical properties and adhesion under such harsh conditions. [ABSTRACT FROM AUTHOR]

• Inexpensive MnO 2 was used to synthesis micro/nano spherical precursor of LiMn 0.8 Fe 0.2 PO 4 /C by efficient reduction reactions. • The uniform conductive carbon network connecting LMFP nanoparticle provides rapid lithium ion and electron transport. • The LiMn 0.8 Fe 0.2 PO 4 /C material has a low carbon content, high tap density and good processability. • The LiMn 0.8 Fe 0.2 PO 4 /C cathode exhibits good rate performance and cyclability with high voltage platform. • The facile synthesis route is promising for scale-up production without introducing impurity ion and waste liquid. A green strategy is designed for synthesizing LiMn 0.8 Fe 0.2 PO 4 /C composites bases on mechano-chemical liquid-phase activation technique. The micro-nano spherical precursor is prepared by the effective redox reaction between MnO 2 and H 2 O 2 in H 3 PO 4 aqueous solution with subsequent addition FeC 2 O 4 •2H 2 O and Li 2 CO 3 , which is followed by spray drying. The dense LiMn 0.8 Fe 0.2 PO 4 /C microspheres are formed from conformal carbon coating connected with primary nano-sized particles, which provides rapid electron and ion transport pathways during the electrode reaction. The obtained LiMn 0.8 Fe 0.2 PO 4 /C cathode exhibits reduced electrochemical polarization with high voltage platform and high discharge capacity of 159 mAh g −1 at 0.1 C. Even at high rate of 10 C, the composite shows an impressing discharge capacity of 130 mAh g −1 with obviously stable plateau. Besides, uniformly conductive carbon network distributed all over the primary nano-sized particles effectively inhibits the occurrence of interfacial side reactions during electrode cycling, and the electrode exhibits good cycling stability with capacity retention rate of 95% after 500 cycles at 1 C. This work provides a scalable route to fabricate high energy density LiMn 0.8 Fe 0.2 PO 4 /C cathode with excellent rate performance for Li-ion battery. [Display omitted] [ABSTRACT FROM AUTHOR]

Ni-rich cathode material is considered to be a promising cathode for commercial applications in lithium-ion batteries because of its low cost and high capacity. However, its chemical, electrochemical, and mechanical instability at the cathode-electrolyte interface cause a series of problems, such as inferior electrochemical performance and serious safety concerns. To construct a stable interface, we develop a simple and reproducible method to encapsulate LiNi 0.8 Co 0.1 Mn 0.1 O 2 within ionic and electronic conductive half-cyclized polyacrylonitrile. The images of scanning electron microscopy and transmission electron microscopy prove that a continuous polymer layer formed on the surface of the cathode material. The organic coating layer is composed of both cyano groups that provide lithium-ion transport channels and cycled cyano groups that conduct electrons. At the same time, the elasticity of the coating polymer layer can maintain the mechanical stability of the cathode material during charge/discharge. Electrochemical studies demonstrate that the cycle and rate performances of LiNi 0.8 Co 0.1 Mn 0.1 O 2 are obviously improved. After 100 cycles at a current density of 200 mA•g−1, the capacity retention is increased from 83.93 to 96.24%. The design of this real conformal coating strategy provides a possible solution for the modification of other cathode materials. [ABSTRACT FROM AUTHOR]

• T2SL photodetectors with deep and vertical sidewalls were prepared. • High-performance ALD-Al 2 O 3 with TMA and H 2 plasma combined pretreatment was achieved. • Surface leakage was effectively suppressed by TMA and H 2 plasma combined pretreatment. • The surface pretreatment effects and dark current mechanisms were studied in detail. For type-II InAs/GaSb superlattice (T2SL) photodetectors with deep and vertical mesa sidewalls, passivation for suppression of surface leakage currents is facing two key challenges that in the conformal coating of sharp sidewalls and increasing dominance of surface leakage currents as device dimensions shrink. In this work, atomic layer deposited (ALD)-Al 2 O 3 and SiO 2 method was employed as conformal passivation for deep and vertical mesa sidewalls. And a stable and high-quality interface between the ALD-Al 2 O 3 and T2SL mesa sidewalls was obtained by the combined pretreatment of trimethylaluminum (TMA) and H 2 plasma exposure (Al 2 O 3 TH), and thus a significant improvement in electrical performances has been achieved. The electrical performances before and after baking were compared among the Al 2 O 3 TH, conventional sulfur plus SiO 2 passivated photodiodes. The dark current density of Al 2 O 3 TH passivated photodiodes were improved by 81% at 77 K under 0.1 V reverse bias and exhibited no deterioration after 90 °C-4 days baking treatment. Investigation on the effects of TMA and/or H 2 plasma pretreatments demonstrates that combined pretreatment of TMA and H 2 plasma, rather than TMA or H 2 plasma alone, prior to the deposition of ALD-Al 2 O 3 leads to a more thorough elimination of interface native oxides and surface states introduced in mesa process. The innovative application of this effective surface pretreatment technique is very encouraging for the passivation of deep and vertical sidewalls in III-V compound-based devices, such as large-format T2SL infrared detectors. [ABSTRACT FROM AUTHOR]

As an important biomaterial, lactic acid (LA) widely exists in human blood and sweat. The development of enzyme-free LA sensors with high-sensitivity and low-cost remains a challenge. We present here a structure of Co-doped porous carbon film derived from zeolitic imidazolate framework-67 (ZIF-67) on 3D carbon frameworks through a pyrolysis process. The conformal coating of ZIF-67 film is realized by a combination of gas-phase and liquid phase growths with the assistance of an induction step from atomic layer deposited-ZnO nanomembrane. In the resultant hierarchical structure with large surface area, Co-doped porous carbon film is closely stacked and firmly attached to carbon skeleton to form Co-doped N-containing carbon framework (Co-NCF). Therein, the Co-doped porous carbon provides catalytic Co nanoparticle, while the carbon skeleton bridges the individual carbon nanoparticle to form a conductive pathway. When adopted as an enzyme-free LA sensor, the Co-NCF composite exhibits excellent electrochemical sensing property in terms of an ultrahigh sensitivity of 1108 μA mM-1cm−2 at a liner range from 0.1 to 1 mM with a limit of detection of 13.7 μM. This work, therefore, presents an efficient strategy to prepare porous carbon structures toward new electrode materials in promising biomedicine systems. • A new strategy to induce the 3D assembly of MOFs on organic substrates. • Combination of gas phase and liquid phase growths leads to firm attaching. • Hierarchical 3D structure with vast active sites for high sensitivity. [ABSTRACT FROM AUTHOR]

This work presents an embedding process for ultrathin silicon chips in mechanically flexible solder mask resist and their electrical contacting by inkjet printing. Photosensitive solder mask resist is applied by conformal spray coating onto epoxy bonded ultrathin chips with a daisy chain layout. The contact pads are opened by photolithography using UV direct light exposure. Circular and rectangular openings of 90 µm and 130 µm diameter, respectively, edge length are realized. Commercial inks containing nanoparticular silver and gold are inkjet printed to form conductive tracks between daisy chain structures. Different numbers of ink layers are applied. The track resistances are characterized by needle probing. Silver ink shows low resistances only for multiple layers and 90 µm openings, while gold ink exhibits low resistances in the single-digit Ω-range for minimum two printed layers. [ABSTRACT FROM AUTHOR]

Polymer/semiconductor nanostructure array based solar cells (SCs) exhibit extremely low optical losses, excellent light-harvesting, improved carrier lifetime, increased defect tolerance etc. and can be a new pathway for low-cost high efficiency SCs. In order to fabricate efficient heterojunction SCs, it is extremely necessary to evaluate their optimal geometric configuration theoretically. In this article, using 3D-finite difference time domain (FDTD) method, we have optimized the geometric configuration of poly (3, 4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS) coated vertically aligned GaAs Nano pyramid (NP) array heterojunction SCs to obtain high average optical absorption and J sc of 92.2% and 41.1 mA/cm2, respectively. The optimized structure simulated in Lumerical Charge Solver DEVICE module, exhibit power conversion efficiency (PCE) of 15.9% despite low carrier mobility and lifetime of 1000 cm2v−1s−1 and 2ns respectively. • Role of GaAs nanopyramids (NPs) in efficient light harvesting is studied. • Optimization of geometrical dimensions of the NPs is performed in terms of optical J sc. • Conformal coating of PEDOT:PSS results in absorption enhancement. • GaAs NPs/PEDOT PSS based solar cells exhibits PCE of ~13%. [ABSTRACT FROM AUTHOR]

Ceramic implants have superior performance due to the excellent wear resistance and biocompatibility. However, the poor machinability limits their applications. Plasma sprayed ceramic coating on the additively manufactured metal substrate not only provides a 3-dimensional conformal implant coating and but also forms a highly wear-resistant surface layer. In this paper, three types of ceramic coatings of Al 2 O 3, ZrO 2 , and Al 2 O 3 –ZrO 2 composite have been fabricated by atmosphere plasma spray on the CoCrMo alloy substrate prepared by selective laser melting (SLM). It has been found that the Al 2 O 3 –ZrO 2 composite coating has better corrosion and wear resistance compared with the ceramic coating (Al 2 O 3, ZrO 2) and the CoCrMo substrate. The adhesion strength between the Al 2 O 3 –ZrO 2 composite coating and the substrate reaches 238 MPa. In addition, the wear and corrosion resistance increase with wear progression for all the fabricated ceramic coatings. The highly dense microstructure, fewer microcracks, and the amorphous phases are deterministic factors responsible for the superior tribological and corrosion performance of the Al 2 O 3 –ZrO 2 composite coating. The fabrication route has been proved very promising to manufacture high-performance implants with ceramic coating. [ABSTRACT FROM AUTHOR]

In this study, the protection of Cu 2 O nanowire (NW) against photocorrosion using reduced graphene oxide (rGO) through annealing has proven challenging. The rGO was incapable of forming conformal passivation around Cu 2 O NW strands, exposing Cu 2 O NW to a dramatic photocorrosion. The result validated the hypothesis, which underlines the possibility of carbon decomposition from rGO into CO or CO 2 gases, distorting the integrity of rGO sheets as a protective coating. Therefore, the current study proposes the carbon coating using the sputtering technique to produce a conformal coating around the NW strand, which should be the ideal protection strategy. [Display omitted] • Complete protection of Cu 2 O NW with rGO through annealing is challenging. • The rGO sheets were incapable of coating a single strand of NW for protection. • Passivation around Cu 2 O NW strand using rGO should be the ideal coating strategy. • Carbon sputtering on Cu 2 O NW via sputtering is proposed for a conformal coating. [ABSTRACT FROM AUTHOR]

Curcumin is known as a biologically active compound and a possible antimicrobial agent. Here, we combine it with TiO2 and ZnO semiconductors, known for their photocatalytic properties, with an eye towards synergistic photo-harvesting and/or antimicrobial effects. We deposit different nanoscale multi-layer structures of curcumin, TiO2 and ZnO, by combining the solution-based spin-coating (S-C) technique and the gas-phase atomic layer deposition (ALD) and molecular layer deposition (MLD) thin-film techniques. As one of the highlights, we demonstrate for these multi-layer structures a red-shift in the absorbance maximum and an expansion of the absorbance edge as far as the longest visible wavelength region, which activates them for the visible light harvesting. The novel fabrication approaches introduced here should be compatible with, e.g., textile substrates, opening up new horizons for novel applications such as new types of protective masks with thin conformal antimicrobial coatings. [ABSTRACT FROM AUTHOR]

Nanostructured-silicon with a conformal carbon coating (Si@C) is a promising anode-material for the next-generation lithium-ion battery (LIB). However, silicon nanostructure and the carbon nanocoating usually are formed in the separated processing steps, making the entire synthesis process costly, complicated and time-consuming. Herein, we propose a process in which silica nanomaterials (i.e. , diatomite and stöber sphere) are firstly converted into Mg 2 Si. After the converted Mg 2 Si further reacts with CaCO 3 , a conformal carbon nanolayer (1–5 nm) spontaneously grows on the newly formed Si nanostructures to obtain Si@C. Especially, diatomite-derived Si@C delivers a reversible capacity of 1359.7 mA h g−1 at 4 A g−1, and retains 764.6 mA h g−1 even after 500 cycles. The process reported in this study can provide a scalable way to synthesize high-performance Si@C anode materials for LIBs. • Conformal carbon-coated silicon composite is synthesized synchronously in one step. • The composite possesses porous structure, making it stable in cycling. • Both carbon layer and porous structure are beneficial to electrochemical performance. [ABSTRACT FROM AUTHOR]

Keywords: biomedical devices; cell encapsulation; hydrogel coatings; immune isolation; tissue engineering EN biomedical devices cell encapsulation hydrogel coatings immune isolation tissue engineering 1 1 1 05/26/21 20210521 NES 210521 In article number 2010169, Simmyung Yook, Jee-Heon Jeong, and co-workers develop a simple and facile method for conformal hydrogel coating of living cells, mini-organs, and biomedical devices. Biomedical devices, cell encapsulation, hydrogel coatings, immune isolation, tissue engineering This method overcomes inevitable challenges in cell encapsulation and enables the engineering of 3D hydrogels for tissue engineering or delivery of therapeutic cells and drugs. [Extracted from the article]

Conformal coating is typically composed of polymeric film and is used to protect delicate electronic components such as printed-circuit boards. Without removing conformal coating, it would be difficult to repair these complicated electronics. Methylene chloride, also called dichloromethane (DCM), has a widespread usage in conformal coating stripper products. The high toxicity of DCM increases human health risk when workers are exposed to DCM during the conformal coating removal processes. Therefore, the replacement of DCM would be beneficial to greatly improve the overall safety profile for workers in the electronics and coating industries. This research identified and evaluated alternative chemicals for replacing DCM used in acrylic conformal coating stripping operations. The solubility of an acrylic conformal coating was measured and characterized using Hansen solubility parameters (HSP) theory. Coating dwell time tests using various solvent blends verified the accuracy of the created HSP solubility sphere. A data processing method was also developed to identify and screen potential alternative solvent blends in terms of safety, toxicity, and cost-effectiveness. The identified safer solvent blends were demonstrated to provide equivalent stripping performance as compared to DCM based coating strippers within an acceptable cost range. The results of this research will be of value to other types of conformal coatings, such as silicone and polyurethane, where DCM is commonly used in similar coating stripping operations. By safely removing conformal coating, delicate electronics would be available for re-manufacturing, enabling a circular economy. [ABSTRACT FROM AUTHOR]

An effective strategy for improving the charge transport efficiency of p-type Cu2O photocathodes is the use of counter n-type semiconductors with a proper band alignment, preferably using Al-doped ZnO (AZO). Atomic layer deposition (ALD)-prepared AZO films show an increase in the built-in potential at the Cu2O/AZO interface as well as an excellent conformal coating with a thin thickness on irregular Cu2O. Considering the thin thickness of the AZO overlayers, it is expected that the composition of the Al and the layer stacking sequence in the ALD process will significantly influence the charge transport behavior and the photoelectrochemical (PEC) performance. We designed various stacking orders of AZO overlayers where the stacking layers consisted of Al2O3 (or Al) and ZnO using the atomically controlled ALD process. Al doping in ZnO results in a wide bandgap and does not degrade the absorption efficiency of Cu2O. The best PEC performance was obtained for the sample with an AZO overlayer containing conductive Al layers in the bottom and top regions. The Cu2O/AZO/TiO2/Pt photoelectrode with this overlayer exhibits an open circuit potential of 0.63 V and maintains a high cathodic photocurrent value of approximately −3.2 mA cm−2 at 0 VRHE for over 100 min. [ABSTRACT FROM AUTHOR]

• Development of plasma enhanced chemical vapor deposition system. • Forward directed ions aid conformal filling of B x C into high aspect ratio trench. • 94.25% fill factor and 88.25% conformal coverage ratio at 3:7 ar/he flow ratio. • Promising for fabrication of high efficiency neutron detector. A single-step process has been developed for the conformal deposition of boron carbide in high aspect ratio trenches fabricated in an n-type (111) silicon substrate. Plasma enhanced chemical vapor deposition was used to deposit boron carbide from ortho-carborane (O C 2 B 10 H 12) precursor mixed with helium and argon gas. The depositions were carried out under substrate self-bias conditions to achieve a high fill factor using forward-directed ions. Nearly complete filling of 25 µm deep trenches with high-aspect ratio (> 6:1) via conformal coating of side walls has been confirmed from cross-sectional scanning electron microscopy studies. The results presented in this article establish that the process technology developed for achieving conformal deposition of the neutron stopping layer is suitable for the fabrication of Silicon p-i-n based three-dimensional thermal neutron detectors with high neutron detection efficiency. [ABSTRACT FROM AUTHOR]

Diamond is highly desirable as a conformal thin-film coating for three-dimensional (3D) devices due to its extreme hardness, durability and biocompatibility, especially in the case of implantable medical devices and prosthetics. Recent advances in microwave plasma chemical vapour deposition (CVD) have enabled conformal coating of such 3D structures with nanodiamond films. However, these techniques have not been extended to micro-crystalline diamond, due to interactions between the 3D substrates and resonant microwave cavity. Here we demonstrate more uniform growth of CVD polycrystalline diamond (PCD) coatings on complex-shaped structures, with the use of in-cavity Faraday cages, to isolate the 3D sample from the microwave cavity. While this does disrupt the distribution of the microwave plasma, which surrounds the 3D structure, we show that growth of relatively uniform micro-crystalline and faceted PCD films is possible over the entirety of the exposed 3D sample surface. The resultant technique opens possibilities for the coating of complex 3D geometries with a wider range of diamond materials than has been possible to date. Unlabelled Image • Three-dimensional structures can be coated uniformly with a Faraday cage. • The Faraday cage helps to prevent shape-dependent plasma enhancement. • The use of a Faraday cage will enable the coating of complex structures with high quality. [ABSTRACT FROM AUTHOR]

• Demonstration of voltage-controlled liquid flow through a macroporous silicon membrane. • Three-dimensional fluidic channel array based on a macroporous silicon membrane. • Dynamic liquid flow control using polypyrrole-based electrochemical wetting change. In this paper, we demonstrate the voltage-controlled flow of organic liquid through a macroporous silicon structure. The demonstrated flow control structure consists of a silicon-based macropore membrane and flow control units formed on polypyrrole (PPy)-coated pores, which are actuated by its electrochemical wetting change. Conformal coating of a PPy layer along macropore silicon walls is achieved with the help of spray-deposited tin-oxide (SnO 2) layer on the pores. The transport of organic liquid through the developed membrane is successfully controlled by low-voltage external bias on the PPy layer. Cyclic deliveries of organic liquid were demonstrated using the proposed concept. Considering the highly-ordered fluidic channel structure formed in silicon, which can have multiple separated electrodes, the proposed concept has the potential to achieve an actuated fluidic dispenser in an arrayed form. [ABSTRACT FROM AUTHOR]

We report a spray deposition technique for patterning liquid metal alloys to form stretchable conductors, which can then be encapsulated in silicone elastomers via the same spraying procedure. While spraying has been used previously to deposit many materials, including liquid metals, this work focuses on quantifying the spraying process and combining it with silicones. Spraying generates liquid metal microparticles (~5 μm diameter) that pass through openings in a stencil to produce traces with high resolution (~300 µm resolution using stencils from a craft cutter) on a substrate. The spraying produces sufficient kinetic energy (~14 m/s) to distort the particles on impact, which allows them to merge together. This merging process depends on both particle size and velocity. Particles of similar size do not merge when cast as a film. Likewise, smaller particles (<1 µm) moving at the same speed do not rupture on impact either, though calculations suggest that such particles could rupture at higher velocities. The liquid metal features can be encased by spraying uncured silicone elastomer from a volatile solvent to form a conformal coating that does not disrupt the liquid metal features during spraying. Alternating layers of liquid metal and elastomer may be patterned sequentially to build multilayer devices, such as soft and stretchable sensors. [ABSTRACT FROM AUTHOR]

This work focuses on the development of nanoparticle-based layer-by-layer (LbL) coatings for enhancing the detection sensitivity and selectivity of volatile organic compounds (VOCs) using on-chip mid-infrared (MIR) waveguides (WGs). First, we demonstrate construction of conformal coatings of polymer/mesoporous silica nanoparticles (MSNs) on the surface of Si-based WGs using the LbL technique and evaluate the coating deposition conditions, such as pH and substrate withdrawal speed, on the thickness and homogeneity of the assemblies. We then use the modified WGs to achieve enhanced sensitivity and selectivity of polar organic compounds, such as ethanol, versus non-polar ones, such as methane, in the MIR region. In addition, using density functional theory calculations, we show that such an improvement in sensing performance is achieved due to preferential adsorption of ethanol molecules within MSNs in the vicinity of the WG evanescent field. [ABSTRACT FROM AUTHOR]

• Confined ablation plume studied with nanosecond holographic phase contrast imaging. • Densification and plume widening due to confined geometry. • More than 80% longer plasma lifetime of a confined plume. • Dominant role of particle fragmentation, not vapour condensation during deposition. Laser-induced reverse transfer (LIRT) is a direct-write technique for patterning materials onto transparent substrates. A laser pulse transmits through the transparent material and a small air gap to ablate a donor target surface, the vaporised target species then transfer to the transparent material. There is not yet a detailed understanding of the material ejection and deposition processes, and reports show high-resistivity films and only limited demonstration of conductive linear tracks. Here we use a recently developed capability of holographic phase contrast imaging at nanosecond temporal resolution to report the morphology of the confined ablation plume. This reveals previously unobserved phenomena such as the influence of the rebounding pressure wave and a >80% longer plasma lifetime of a confined plume, showing the importance of plume shielding and incubation effects for applications. Focusing on silver, graphite and copper, static and scanned beam experiments show the dominant role of sputtering of fragmented particles rather than vapour condensation. The results highlight the challenges in using LIRT for conformal coating without surface damage but will excite further study of this rarely explored technique, with potential for facile, reliable fabrication of conductive patterns and digitally controlled customisation of glass products for applications such as embedded sensors and electronics. [ABSTRACT FROM AUTHOR]

Flexible thin-film solar cells are important for their advantages in many aspects, and aluminum antimonide (AlSb) can be used as an absorbent layer in thin-film solar cells. However, its deliquescence limits its practical use. In this work, AlSb films were prepared by radio frequency (RF) magnetron sputtering on stainless steel flexible substrates. A flexible conformal coating membrane using acrylic resin was deposited on the AlSb films and its deliquescence prevention effect was verified. It was found that after conformal coating treatment, the deliquescence of the AlSb film was effectively stopped. The bare AlSb films and the Ni/AlSb/acrylic resin/Ni multilayer films were exposed to ambient air at the same time under the same conditions for lengths of time ranging from 1 min to 60 days. After 60 days, the bare AlSb film experienced significant deliquescence, such that the film was completely destroyed. However, the Ni/AlSb/acrylic resin/Ni multilayer films did not exhibit deliquescence. [ABSTRACT FROM AUTHOR]

In recent years major advances in surface chemistry and surface functionalization have been performed through the development, most often inspired by living organisms, of versatile methodologies. Among those, the contact of substrates with aminomalononitrile (AMN) containing solutions at pH = 8.5 allows a conformal coating to be deposited on the surface of all known classes of material. Since AMN is a molecule probably formed in the early atmosphere of our planet and since HCN-based compounds have been detected on many comets and Titan (Saturn's largest moon) it is likely that such molecules will open a large avenue in surface functionalization mostly for bio-applications. This mini review describes the state of the art of AMN-based coatings from their deposition kinetics, composition, chemical reactivity, hypothetical structure to their first applications as biomaterials. Finally, the AMN-based versatile coatings are compared to other kinds of versatile coating based on catecholamines and polyphenols. [ABSTRACT FROM AUTHOR]

The experimental analysis of the response of nanocoated tapered long-period gratings to surrounding refractive index (SRI) changes is presented. The modal transition is demonstrated to be an effective method to improve their SRI sensitivity over a broad SRI range. The dip-coating method is shown to be a reliable technique for the deposition of conformal coatings with the necessary thickness control to tune the transition region in the desired SRI range. [ABSTRACT FROM PUBLISHER]

• Al 2 O 3 , ZrO 2 , HfO 2 , and TiO 2 films were coated on Ag nanoparticles by ALD at 100 °C. • Coated Ag NPs were characterized by TEM, XPS, particle sizes, and UV–Vis spectra. • Al 2 O 3 , ZrO 2 , and HfO 2 protected Ag NPs from corrosion in neutral and acid solutions. The goal of this work is to explore atomic layer deposition (ALD) as a thin film coating technique to inhibit corrosion of metal nanoparticles, given the technique's ability to form a conformal coating on high aspect ratio substrates. Various coating materials, including Al 2 O 3 , ZrO 2 , HfO 2 , and TiO 2 of different thicknesses were coated on Ag nanoparticles (NPs) in a fluidized bed ALD reactor. To avoid sintering of Ag NPs during the ALD process, the reaction temperature was set to 100 °C, lower than typical ALD reaction temperatures for these metal oxides. The ultrathin coatings (up to ~10 nm thick) were conformally deposited on the surface of Ag NPs. During the corrosion tests in a neutral 3.5 wt% NaCl solution, the corrosion current density was lowered by more than one order of magnitude; in an acid 0.5 M H 2 SO 4 solution, the stabilities of different thin coatings were compared. Ultraviolet–visible spectra of coated Ag NPs showed retention of surface plasmonic resonance. [ABSTRACT FROM AUTHOR]

III-V nanostructure-based solar cells (SCs), with remarkable performance improvement in recent years, are considered as promising candidates for next-generation photovoltaics. In this paper, we present a simulation study of a new structure of PEDOT:PSS/InP truncated nanopyramid (TNP) Hybrid Solar Cell (HSC) using a finite difference time domain (FDTD) method. In the TNP-HSC, the nanopyramids (NPs) are flattened from the top to increase the photon capturing capability and then the TNPs are coated with PEDOT:PSS to enhance the light absorption in the long-wavelength region of solar spectral irradiance. Besides, to delineate the mechanism of photo-absorption enhancement in the proposed structure, a rigorous analysis of the electric field and photo-generation rate profiles at different wavelengths is performed. The simulation results show that the PEDOT:PSS coated of InP TNP exhibits better performance than uncoated InP NP SCs or planar counterpart. In addition, the optimization of the geometrical parameters of InP TNPs, including period, lattice constant, top surface flatness, and coating thickness, leads to the power conversion efficiency of 24.73%, which is 1.8 times greater than its planar counterpart. • Role of nanopyramids in PEDOT:PSS/InP solar cells studied using FDTD method. • Optimization of nanostructure done in terms of optical Jsc. • Truncated nanopyramids exhibit better absorption than pointed nanopyramids. • Electrical Jsc of 27 mA/cm2 is obtained with ITO/InP TNP/Al Solar cell structure. • Photo Conversion Efficiency (PCE) of 24.73% is achieved with our optimized. [ABSTRACT FROM AUTHOR]

We report on the growing of metal-organic frameworks that are isoreticular and isostructural to UiO-66, onto cotton fabrics via a solvothermal method. Four different metal-organic frameworks (MOFs) (UiO-66, UiO-66-NH2, UiO-66-NDC, and UiO-67) were chosen as a case study. The presence of the UiO-based MOFs was confirmed through X-ray diffraction and Scanning Electron Microscopy. We used thermogravimetric analysis to quantify the amount of the MOF loading, which ranged from 0.8% to 2.6% m/m. We also explored the role of ligand size, growth time, and reaction temperature on the conformal coating of cotton fibers with these Zr-based MOFs. Cotton fabrics coated with Zr-based MOFs can find applications as selective filters in aggressive environments due to their enhanced chemical and thermal stabilities. [ABSTRACT FROM AUTHOR]

In recent years, atomic layer deposition (ALD) is widely used for surface modification of materials to improve the catalytic performance for removing pollutants, e.g., CO, hydrocarbons, heavy metal ions, and organic pollutants, and much progress has been achieved. In this review, we summarize the recent development of ALD applications in environmental remediation from the perspective of surface modification approaches, including conformal coating, uniform particle deposition, and area-selective deposition. Through the ALD conformal coating, the activity of photocatalysts improved. Uniform particle deposition is used to prepare nanostructured catalysts via ALD for removal of air pollutions and dyes. Area-selective deposition is adopted to cover the specific defects on the surface of materials and synthesize bimetallic catalysts to remove CO and other contaminations. In addition, the design strategy of catalysts and shortcomings of current studies are discussed in each section. At last, this review points out some potential research trends and comes up with a few routes to further improve the performance of catalysts via ALD surface modification and deeper investigate the ALD reaction mechanisms. [ABSTRACT FROM AUTHOR]

Alloy material is one of the most promising high-capacity anodic categories in Li-ion batteries, but suffers from huge volume expansion for practical applications. Hybridizing alloys with nanostructured carbon matrices is desirable to improve the overall electrochemical performances, however, alloys always distribute sparsely on nanostructured carbon matrices by physical connections, and easily detach from carbon matrices and aggregate to big congeries upon cycling. Here, we develop a facile and general hyrdogel-reduction approach for chemically binding and conformally coating alloys on nanostructured carbon matrices. As a typical illustration, carbon black (CB) is first immobilized within cyano-bridged Sn–Ni coordination polymer gel (Sn–Ni cyanogel), and after reduction, sub-10 nm Sn–Ni alloy layer is conformally coated on CB surface via Sn O C bonds, yielding the final CB@Sn–Ni hybrid framework. The sub-10 nm alloy layer and conformal coating nanostructure together with strong chemical bonding enable the CB@"Sn–Ni hybrid anode to exhibit long cycle life (400 mA h g−1 after 350 cycles at 0.2 A g−1) and high rate performance (294 and 190 mA h g−1 at 5 and 10 A g−1, respectively). This work provides an alternative insight into conformally coating and chemical combining electrode materials with nanostructured carbon matrices for boosting electrochemical properties. Unlabelled Image • Facile and general hyrdogel-reduction approach • Chemically binding and conformally coating alloys on nano‑carbon matrices • The structural and compositional merits enable stable and fast lithium storage. [ABSTRACT FROM AUTHOR]

Electrospun membranes have shown promise for use in membrane distillation (MD) as they exhibit exceptionally low vapor transport. Their high porosity coupled with the occasional large pore can make them prone to wetting. In this work, initiated chemical vapor deposition (iCVD) is used to modify for electrospun membranes with increased hydrophobicity of the fiber network. To demonstrate conformal coating, we demonstrate the approach on intrinsically hydrophilic electrospun fibers and render the fibers suitable for MD. We enable conformal coating using a unique coating procedure, which provides convective flow of deposited polymers during iCVD. This is made possible by using a 3D printed scaffold, which changed the orientation of the membrane during the coating process. The new coating orientation allows both sides as well as the interior of the membrane to be coated simultaneously and reduced the coating time by a factor of 10 compared to conventional CVD approaches. MD testing confirmed the hydrophobicity of the material as 100% salt rejections were obtained. [ABSTRACT FROM AUTHOR]

Encapsulation of pharmaceutical powders within thin functional polymer films is a powerful and versatile method to modify drug release properties. Conformal coating over the complete surface of the particle via chemical vapor deposition techniques is a challenging task due to the compromised gas–solid contact. In this study, an initiated chemical vapor deposition reactor was adapted with speakers and vibration of particles was achieved by playing AC/DC's song "Thunderstruck" to overcome the above-mentioned problem. To show the possibilities of this method, two types of powder of very different particle sizes were chosen, magnesium citrate (3–10 µm, cohesive powder) and aspirin (100–500 µm, good flowability), and coated with poly-ethylene-glycol-di-methacrylate. The release curve of coated magnesium citrate powder was retarded compared to uncoated powder. However, neither changing the thickness coating nor vibrating the powder during the deposition had influence on the release parameters, indicating, that cohesive powders cannot be coated conformally. The release of coated aspirin was as well retarded as compared to uncoated aspirin, especially in the case of the powder that vibrated during deposition. We attribute the enhancement of the retarded release to the formation of a conformal coating on the aspirin powder. [ABSTRACT FROM AUTHOR]

Li 2 TiSiO 5 (LTSO) fibers coated by an in-situ grown Li-Ti-O layer are synthesized through ALD and post thermal treatment. Due to the ALD coating technique, precise thickness control and conformal coating layer can be realized. Through post-heating treatment, the ALD-coated TiO x layer can react with lithium residues in the host materials, forming the Li-Ti-O coating layer. Benefiting from the Li-ion conductive feature of the Li-Ti-O phase, Li-Ti-O coated LTSO fibers exhibit a high reversible capacity of 229 mA h g−1 at a current density of 0.5 A g−1 after 400 cycles in the potential range of 0.1–3 V (vs. Li+/Li). Even at a high current density of 5 A g−1, a reversible capacity of 154 mA h g−1 can be achieved. Electrochemical impedance spectra (EIS) demonstrate that the Li-Ti-O coated LTSO fibers have an apparent chemical Li-ion diffusion coefficient of 1.43 × 10−15 cm2 s−1 and decreased charge transfer resistance compared to that of pristine LTSO fibers, leading to faster Li-ion transfer kinetics and improved electrochemical performances. • Li 2 TiSiO 5 fibers coated by an in-situ grown Li-Ti-O layer are realized through ALD and post-heating treatment. • The thickness of the Li-Ti-O coating layer can be precisely controlled by tuning the deposition cycles. • The Li-Ti-O coating layer improves the Li-ion diffusion kinetics and decreases the interfacial charge transfer resistance. • The Li 2 TiSiO 5 @Li-Ti-O (ALD-300) electrode delivers enhanced specific capacity and rate capability. [ABSTRACT FROM AUTHOR]

Conformal coatings provide environmental protection for sensitive military electronics. Preliminary MCNP6® modeling of metal oxide impregnated acrylic conformal coatings indicates a factor of 300 reduction in gammas below 10 keV and up to a 225% reduction in neutron displacement damage to Si-based electronics across the Watt spectrum. This work provides data which can allow an optimal overall shielding worth per total mass to be evaluated. • Inclusion of metal oxides in low-Z conformal coats improves 10 keV photon shielding. • High metal oxide %mass compositions reduce neutron displacement damage by 200%. • Gd 2 O 3 was the most promising shielding per unit mass and cost studied. [ABSTRACT FROM AUTHOR]