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The next generation of advanced materials is tending toward increasingly complex compositions. Synthesizing precise composition is time-consuming and becomes exponentially demanding with increasing compositional complexity. An experienced human operator does significantly better than a novice but still struggles to consistently achieve precision when synthesis parameters are coupled. The time to optimize synthesis becomes a barrier to exploring scientifically and technologically exciting compositionally complex materials. This investigation demonstrates an active learning (AL) approach for optimizing physical vapor deposition synthesis of thin-film alloys with up to five principal elements. We compared AL-based on Gaussian process (GP) and random forest (RF) models. The best performing models were able to discover synthesis parameters for a target quinary alloy in 14 iterations. We also demonstrate the capability of these models to be used in transfer learning tasks. RF and GP models trained on lower dimensional systems (i.e., ternary, quarternary) show an immediate improvement in prediction accuracy compared to models trained only on quinary samples. Furthermore, samples that only share a few elements in common with the target composition can be used for model pre-training. We believe that such AL approaches can be widely adapted to significantly accelerate the exploration of compositionally complex materials. [ABSTRACT FROM AUTHOR]

Solution‐based methods for fabricating all‐inorganic perovskite film arrays often suffer from limited control over nucleation and crystallization, resulting in poor homogeneity and coverage. To improve film quality, advanced vapor deposition techniques are employed for continuous film. Here, the vapor deposition strategy to the all‐inorganic perovskite films array, enabling area‐selective deposition of perovskite through substrate modulation is expanded. It can yield a high‐quality perovskite film array with different pixel shapes, various perovskite compositions, and a high resolution of 423 dpi. The resulting photodetector arrays exhibit remarkable optoelectronic performance with an on/off ratio of 13 887 and responsivity of 47.5 A W−1. The device also displays long‐term stability in a damp condition for up to 12 h. Moreover, a pulse monitoring sensor based on the perovskite films array demonstrates stable monitoring for pulse signals after being worn for 12 h and with a low illumination of 0.055 mW cm−2, highlighting the potential application in wearable optoelectronic devices. [ABSTRACT FROM AUTHOR]

The study of lubricating oil is paramount for the optimal functioning of modern engines, and it has generated intensive research in the automotive industry. The aim is to improve the tribological properties of lubricants by including nanomaterials as additives in base oils. This article presents an exhaustive bibliographic review of the experiments carried out to optimize the tribological properties of nano-lubricants in order to identify the nanoparticles and experimental processes used and analyze the results obtained. The methodology adopted combines inductive and deductive elements. It begins with the formulation of a general theory on the application of nanoparticles in lubricants, followed by the collection of specific data on the conceptualization and preparation of nano-lubricants. A total of 176 articles focused on the application of nanoparticles in lubricants, especially to reduce the coefficient of friction, are reviewed. These works, with impact levels Q1 and Q2, delve into the application and are analyzed to review the obtained results. Most researchers worked with a nanoparticle concentration range of 0% to 1% by volume. [ABSTRACT FROM AUTHOR]

Abstract Solution‐based methods for fabricating all‐inorganic perovskite film arrays often suffer from limited control over nucleation and crystallization, resulting in poor homogeneity and coverage. To improve film quality, advanced vapor deposition techniques are employed for continuous film. Here, the vapor deposition strategy to the all‐inorganic perovskite films array, enabling area‐selective deposition of perovskite through substrate modulation is expanded. It can yield a high‐quality perovskite film array with different pixel shapes, various perovskite compositions, and a high resolution of 423 dpi. The resulting photodetector arrays exhibit remarkable optoelectronic performance with an on/off ratio of 13 887 and responsivity of 47.5 A W−1. The device also displays long‐term stability in a damp condition for up to 12 h. Moreover, a pulse monitoring sensor based on the perovskite films array demonstrates stable monitoring for pulse signals after being worn for 12 h and with a low illumination of 0.055 mW cm−2, highlighting the potential application in wearable optoelectronic devices.

The next generation of advanced materials is tending toward increasingly complex compositions. Synthesizing precise composition is time-consuming and becomes exponentially demanding with increasing compositional complexity. An experienced human operator does significantly better than a novice but still struggles to consistently achieve precision when synthesis parameters are coupled. The time to optimize synthesis becomes a barrier to exploring scientifically and technologically exciting compositionally complex materials. This investigation demonstrates an active learning (AL) approach for optimizing physical vapor deposition synthesis of thin-film alloys with up to five principal elements. We compared AL-based on Gaussian process (GP) and random forest (RF) models. The best performing models were able to discover synthesis parameters for a target quinary alloy in 14 iterations. We also demonstrate the capability of these models to be used in transfer learning tasks. RF and GP models trained on lower dimensional systems (i.e., ternary, quarternary) show an immediate improvement in prediction accuracy compared to models trained only on quinary samples. Furthermore, samples that only share a few elements in common with the target composition can be used for model pre-training. We believe that such AL approaches can be widely adapted to significantly accelerate the exploration of compositionally complex materials.

Using gas-phase deposition (Physical Vapor Deposition (PVD) and Metal Organic Chemical Vapor Deposition (MOCVD)) methods, modern implant samples (Ti alloy and CFR-PEEK polymer, 30% carbon fiber) were functionalized with film heterostructures consisting of an iridium or gold sublayer, on the surface of which an antibacterial component (silver) was deposited: Ag/Ir(Au)/Ti(CFR-PEEK). The biocidal effect of the heterostructures was investigated, the effect of the surface relief of the carrier and the metal sublayer on antibacterial activity was established, and the dynamics of silver dissolution was evaluated. It has been shown that the activity of Ag/Ir heterostructures was due to high Ag+ release rates, which led to rapid (2–4 h) inhibition of P. aeruginosa growth. In the case of Ag/Au type heterostructures, the inhibition of the growth of P. aeruginosa and S. aureus occurred more slowly (from 6 h), and the antibacterial activity appeared to be due to the contribution of two agents (Ag+ and Au+ ions). It was found, according to the in vitro cytotoxicity study, that heterostructures did not exhibit toxic effects (cell viability > 95–98%). An in vivo biocompatibility assessment based on the results of a morphohistological study showed that after implantation for a period of 30 days, the samples were characterized by the presence of a thin fibrous capsule without volume thickening and signs of inflammation. [ABSTRACT FROM AUTHOR]

(3-Aminopropyl)triethoxysilane (APTES) silane possesses one terminal amine group and three ethoxy groups extending from each silicon atom, acting as a crucial interface between organic and inorganic materials. In this study, after APTES was deposited on the aluminum alloy AA2024-T3 as a primer for an optional top coating with polystyrene (PS), its role with regard to stability as a protection layer and interaction with the topcoat were studied via combinatorial experimentation. The aluminum alloy samples primed with APTES under various durations of concentrated vapor deposition (20, 40, or 60 min) with an optional post heat treatment and/or PS topcoat were comparatively characterized via electrochemical impedance spectroscopy (EIS) and surface energy. The samples top-coated with PS on an APTES layer primed for 40 min with a post heat treatment revealed excellent performance regarding corrosion impedance. A primed APTES surface with higher surface energy accounted for this higher corrosion impedance. Based on the SEM images and the surface energy calculated from the measured contact angles on the APTES-primed surfaces, four mechanisms are suggested to explain that the good protection performance of the APTES/PS coating system can be attributed to the enhanced wettability of PS on the cured APTES primer with higher surface energy. The results also suggest that, in the early stages of exposure to the corrosion solution, a thinner APTES primer (deposited for 20 min) enhances protection against corrosion, which can be attributed to the hydrolytic stability and hydrolyzation/condensation of the soaked APTES and the dissolution of the naturally formed aluminum oxide pre-existing in the bare samples. An APTES primer subjected to additional heat treatment will increase the impedance of the coating system significantly. APTES, and silanes, in general, used as adherent agents or surface modifiers, have a wide range of potential applications in micro devices, as projected in the Discussion section. [ABSTRACT FROM AUTHOR]

The study of lubricating oil is paramount for the optimal functioning of modern engines, and it has generated intensive research in the automotive industry. The aim is to improve the tribological properties of lubricants by including nanomaterials as additives in base oils. This article presents an exhaustive bibliographic review of the experiments carried out to optimize the tribological properties of nano-lubricants in order to identify the nanoparticles and experimental processes used and analyze the results obtained. The methodology adopted combines inductive and deductive elements. It begins with the formulation of a general theory on the application of nanoparticles in lubricants, followed by the collection of specific data on the conceptualization and preparation of nano-lubricants. A total of 176 articles focused on the application of nanoparticles in lubricants, especially to reduce the coefficient of friction, are reviewed. These works, with impact levels Q1 and Q2, delve into the application and are analyzed to review the obtained results. Most researchers worked with a nanoparticle concentration range of 0% to 1% by volume.

ObjectivesThe wetting gradient surface has potential application value in such fields as ship anti-fouling and submarine drag reduction, requiring further research on low-cost and low-complexity wetting gradient surface preparation technology.MethodsThe preparation and static wetting characteristics of a silica-based wetting gradient surface are analyzed using vapor deposition, alkali corrosion and a combination of both.ResultsThe contact angle using vapor deposition reaches 104.9°, with a largest range of about 23°; that using alkali corrosion reaches 80.2°, with a largest range of about 60°; and that using both methods reaches 102.1°, with a largest range of about 40°.ConclusionsThe results of this study can provide references for the preparation of functional surfaces for marine equipment.

Abstract Vapor deposition of polymers is known to result in densified thin films, and recent developments have advanced these polymers with interesting fabrication techniques to a variety of controlled structures other than thin films. With the advantages of chemical modification and functionalization of these polymers, advancements have combined both the physical and chemical properties of these vapor-deposited polymers to obtain controlled anisotropic polymers, including layer-by-layer, gradient, hierarchical, porosity, and the combination of the above, meaning that the produced polymers are functional and are addressed in devised physical configurations and chemical compositions. The main purpose of using polymer coatings as a tool for surface modification is to provide additional properties that decouple the natural properties of the underlying materials (including metals, polymers, oxides/ceramics, glass, silicon, etc.), and recent advancements have rendered novel insights into combined physical and chemical properties to fulfill the increasing needs of sophisticated requirements of materials for users. The review herein intends to deliver messages of recent progress of the advancements of vapor-deposited polymers, with discussions of the variations of the physical structures and chemical functionalities, and how these two aspects are integrated with novel fabrication techniques. The advanced vapor polymers now have the capability of controlled anisotropy in the physical structure and chemical composition and are expected to pave the way for interface engineering toward prospective material designs. Table of content: 1. Introduction 2. Fabrication and Materials 3. Controls of Anisotropy 4. Applications 5. Conclusions and Outlook

This work reports the formation of silver nanoparticles (AgNPs) by sputter deposition in thin films of three different ionic liquids (ILs) with the same anion (bis(trifluoromethylsulfonyl)imide) and cation (imidazolium), but with different alkyl chain lengths and symmetries in the cationic moiety ([C4C1im][NTf2], [C2C2im][NTf2], and [C5C5im][NTf2]). Ionic liquid (IL) films in the form of microdroplets with different thicknesses (200 to 800 monolayers) were obtained through vacuum thermal evaporation onto glass substrates coated with indium tin oxide (ITO). The sputtering process of the Ag onto the ILs when conducted simultaneously with argon plasma promoted the coalescence of the ILs' droplets and the formation, incorporation, and stabilization of the metallic nanoparticles in the coalesced IL films. The formation/stabilization of the AgNPs in the IL films was confirmed using high-resolution scanning electron microscopy (SEM) and UV-Vis spectroscopy. It was found that the IL films with larger thicknesses (600 and 800 monolayers) were better media for the formation of AgNPs. Among the ILs used, [C5C5im][NTf2] was found to be particularly promising for the stabilization of AgNPs. The use of larger IL droplets as capture media was found to promote a better stabilization of the AgNPs, thereby reducing their tendency to aggregate. [ABSTRACT FROM AUTHOR]

The wetting behavior of ionic liquids (ILs) on the mesoscopic scale considerably impacts a wide range of scientific fields and technologies. Particularly under vacuum conditions, these materials exhibit unique characteristics. This work explores the effect of the deposition rate and substrate temperature on the nucleation, droplet formation, and droplet spreading of ILs films obtained by thermal evaporation. Four ILs were studied, encompassing an alkylimidazolium cation (CnC1im) and either bis(trifluoromethylsulfonyl)imide (NTf2) or the triflate (OTf) as the anion. Each IL sample was simultaneously deposited on surfaces of indium tin oxide (ITO) and silver (Ag). The mass flow rate was reproducibly controlled using a Knudsen cell as an evaporation source, and the film morphology (micro- and nanodroplets) was evaluated by scanning electron microscopy (SEM). The wettability of the substrates by the ILs was notably affected by changes in mass flow rate and substrate temperature. Specifically, the results indicated that an increase in the deposition rate and/or substrate temperature intensified the droplet coalescence of [C2C1im][NTf2] and [C2C1im][OTf] on ITO surfaces. Conversely, a smaller impact was observed on the Ag surface due to the strong adhesion between the ILs and the metallic film. Furthermore, modifying the deposition parameters resulted in a noticeable differentiation in the droplet morphology obtained for [C8C1im][NTf2] and [C8C1im][OTf]. Nevertheless, droplets from long-chain ILs deposited on ITO surfaces showed intensified coalescence, regardless of the deposition rate or substrate temperature. [ABSTRACT FROM AUTHOR]

(3-Aminopropyl)triethoxysilane (APTES) silane possesses one terminal amine group and three ethoxy groups extending from each silicon atom, acting as a crucial interface between organic and inorganic materials. In this study, after APTES was deposited on the aluminum alloy AA2024-T3 as a primer for an optional top coating with polystyrene (PS), its role with regard to stability as a protection layer and interaction with the topcoat were studied via combinatorial experimentation. The aluminum alloy samples primed with APTES under various durations of concentrated vapor deposition (20, 40, or 60 min) with an optional post heat treatment and/or PS topcoat were comparatively characterized via electrochemical impedance spectroscopy (EIS) and surface energy. The samples top-coated with PS on an APTES layer primed for 40 min with a post heat treatment revealed excellent performance regarding corrosion impedance. A primed APTES surface with higher surface energy accounted for this higher corrosion impedance. Based on the SEM images and the surface energy calculated from the measured contact angles on the APTES-primed surfaces, four mechanisms are suggested to explain that the good protection performance of the APTES/PS coating system can be attributed to the enhanced wettability of PS on the cured APTES primer with higher surface energy. The results also suggest that, in the early stages of exposure to the corrosion solution, a thinner APTES primer (deposited for 20 min) enhances protection against corrosion, which can be attributed to the hydrolytic stability and hydrolyzation/condensation of the soaked APTES and the dissolution of the naturally formed aluminum oxide pre-existing in the bare samples. An APTES primer subjected to additional heat treatment will increase the impedance of the coating system significantly. APTES, and silanes, in general, used as adherent agents or surface modifiers, have a wide range of potential applications in micro devices, as projected in the Discussion section.

This study investigates the electronic, optical, and thermo electronic properties executed by First Principles and experimental examination on undoped HfO2 and Copper (Cu) based transition metal oxides (HfO2) nanostructured thin films. Thermoelectric properties of undoped HfO2 by semi-classical Boltzmann transport theory were carried out using the BotlzTraP code. Copper (Cu) based transition metal oxides (HfO2) nanostructured thin films have been designed on properly cleaned micro slides of CORNING glass substrate with dimensions of 70 × 50 mm and thickness 0.96–1.06 mm using electron beam evaporation. During deposition, the substrate temperature has been varied from 30 to 150 ℃ maintaining the overall thickness at ~ 25 nm through crystal quartz monitor. Surface morphology, optical properties, including optical parameters, have been measured precisely with high resolution. Atomic Force Microscopy (AFM) has been employed for films morphology, grain sizes, and roughness. Using Gwyddion software, for all the samples at 30 ℃ (namely AZ-I), 100 ℃ (AZ-II), and 150 ℃ (AZ-III) substrate temperature, the root mean square (RMS) roughness calculated as 2.56 nm, 5.04 nm, and 4.32 nm, respectively. Whereas, the grain size was verified as 17.42 nm, 21.49 nm, and 24.87 nm respectively along with other surface parameters proved that the film's surface density and crystallinity were improved by increasing substrate temperature. Optical properties transmittance and reflectance were measured Dual beam Perkin-Elmer spectrophotometer-950 ranging from 250 to 2500 nm (UV–VIS-NIR). The overall changes in transmittance showed the maximum value (above 70%) in the visible region whereas minimum (below 10%) for NIR and IR regions of the light spectrum for all the samples AZ-I, AZ-II, and AZ-III. Other concerned optical constants like refractive indices, molar reflectivity, and extinction coefficients were also calculated. Their variations and performances have been proved that the deposited D/M/D nanostructured films were favorable as optically active films and energy efficient windows. The simulations and experimental results show association in electronic and optical parameters. Created with "BioRender.com", as a premium member. [ABSTRACT FROM AUTHOR]

The three processes of preparing boron powder were described through boron trifluoride as raw materials using metal thermal reduction, molten salt electrolysis and vapor deposition, respectively. The purity, yield, advantages and disadvantages of boron powder prepared by each processe were analyzed and compared. A boron powder preparation process that was prepared from borane using boron trifluoride as raw materials by fluid bed-chemical vapor deposition method was proposed with high efficiency, low energy and easy industrialization.

As the improvement of power conversion efficient (PCE) of perovskite solar cell slows down, considering the future development of perovskite from the perspective of industrialization is critical. Vapor deposition has been demonstrated as a realizable industrial-scale fabrication method, however, the development of vapor deposited perovskite solar cells lags far behind that of the solution method. In-depth researches on this issue have gradually increased in recent years in order to raise the PCE. In this review, we will focus on the fabrication of high-quality perovskite thin film through component engineering. The fundamental processes of perovskite vapor deposition were discussed and the understanding and control over these processes are firstly reviewed. Then, advance by component engineering for high-quality thin film and bandgap tunning for application in solar cell are summarized. Finally, future challenges and strategy for development were discussed. We highlight the importance of the understanding of the fundamental processes in vapor deposition for the future development of solar cells.

Accurate non-invasive monitoring of blood glucose (BG) is a challenging issue in the therapy of diabetes. Here near-infrared (NIR) photoplethysmography (PPG) sensor based on a vapor-deposited mixed tin-lead hybrid perovskite photodetector is developed. The device shows a high detectivity of 5.32 × 10 12 Jones and a large linear dynamic range (LDR) of 204 dB under NIR light, guaranteeing accurate extraction of eleven features from the PPG signal. By a combination of machine learning, accurate prediction of blood glucose level with mean absolute relative difference (MARD) as small as 2.48% is realized. The self-powered PPG sensor also works for real-time outdoor healthcare monitors using sunlight as a light source. The potential for early diabetes diagnoses by the perovskite PPG sensor is demonstrated., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Abstract Threshold switching in chalcogenides has attracted considerable attention because of their potential application to high-density and three-dimensional stackable cross-point array structures. However, despite their excellent threshold switching characteristics, the selectivity and endurance characteristics of such selectors should be improved for practical application. In this study, the effect of Ag on the threshold switching behavior of a Ga2Te3 selector was investigated in terms of selectivity and endurance. The Ag-Ga2Te3 selector exhibited a high selectivity of 108 with low off-state current of

The results of direct synthesis of composite powder based on boron nitride (BN) are considered. Concentrated light heating of the initial boron powder was carried out in a xenon high-flux optical furnace in a nitrogen flow. Formation of particles of the desired sizes and architecture highly dependent of the synthesis conditions. The flow of nitrogen separates the particles depending on their architecture and size. An increase in the distance from the reaction zone leads to the formation of powder with a wider bandgap, increases the amount of amorphous phase, and decreases the amount of oxide in the collected composite powder. However, the close distance to the reaction zone and high temperatures provide a denser packing of the structure on the particle surface and the disappearance of the BN transition phases. Incorporation of the nickel sulfate hexahydrate to initial boron contributes to the formation of graphene-like structures. [ABSTRACT FROM AUTHOR]

This review has systematically summarized and organized researches from both academic articles and industrial patents in the direction of dry-method preparation It also introduces advantages, history, categories, details, and applications of solvent-free dry-film technology. Based on the obtained insights, powder spray and binder fibrillation processes are found to be suitable for mass production of batteries, especially all solid-state batteries (ASSBs). [Display omitted] Solvent-free dry-film technology has attracted wide attention due to its ability to avoid pollution/waste caused by poisonous organic solvents, as well as its advantage for energy density enhancement, electrochemical performance improvement and electrode–electrolyte interface compatibility. However, a summary of the research advancements and technology development in this field is still missing. To fill this gap, a complete overview of the technical advantages, development process, principal mechanisms and application fields of solvent-free dry film technology is presented here. Firstly, the history of solvent-free dry-film technology is introduced, followed by detailed discussions on different types of dry-film making methods. Moreover, powder spray and binder fibrillation are emphasized as key methods due to their low-cost mass-production capability, with an elaboration on the associated preparation process including principle, procedure, and parameters. Both patents from the industry and research papers from the academy of the aforementioned two methods are analyzed/summarized for complete information, whose technical advantages are found to be suitable for all solid-state batteries (ASSBs). Based on the insights obtained above, perspectives are given for promoting future development of solvent-free dry-film technology. [ABSTRACT FROM AUTHOR]

Aluminum nitride (AlN) is a wide band gap semiconductor with interesting piezoelectric properties for many applications, including micromechanical systems (MEMS), acoustic wave sensors or energy harvesting devices. The influence of DC reactive magnetron sputtering (DCRMS) deposition parameters on the structural, crystalline, and piezoelectric properties of AlN thin films are presented. The systematic approach of Design of Experiments (DoE) has been used to evaluate the role of magnetron power, nitrogen and argon flows on the deposition process and the film properties. Magnetron power and argon flow have resulted to be the parameters causing the most significant effects on the deposition rate. AlN films have been deposited with a high crystal quality, showing low values of FWHM (0.28) and c-axis orientation parallel oriented respect to the growth direction, as evidenced by X-ray diffraction (XRD) analysis and high-resolution transmission electron microscopy (HRTEM). These samples also showed a high piezoelectric coefficient (d 33) of 5 pC/N for AlN thin films. This work highlights the importance of deposition parameters on the properties of the film and the important role that DoE play for its optimization with a minimum number of depositions. [Display omitted] • Systematic methodology to reduce the number of samples needed to optimize a film. • Study of how each parameter and its interactions affect the film properties. • New analysis of the AlN elemental composition through an atomic percentage profile. • Connection between crystallinity, microstructure and piezoelectricity is evidenced. [ABSTRACT FROM AUTHOR]

In this study, we report on the fabrication of polycrystalline thin film Bi 2 SiO 5 , a notable non-perovskite ferroelectric material. The thin films were deposited on Pt-covered Si substrates by pulsed laser deposition (PLD) at room temperature, followed by a post-annealing process in air. The as-deposited thin film was of an amorphous phase of Bi-Si-O, and turned to a polycrystalline phase of Bi 2 SiO 5 by the post-annealing above 550°C. The influences of the post-annealing temperature on the phase preference, surface morphology, and dielectric properties of the thin films were investigated by Raman spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), and dielectric measurements. As a result, the optimal post-annealing temperature was determined to be 600°C, yielding a good ferroelectric polycrystalline Bi 2 SiO 5 thin film with a relative dielectric constant of 143 and a remanent polarization (2 P r) of 7.2 μC cm−2. • Polycrystalline Bi 2 SiO 5 thin films fabricated by PLD with post-annealing. • As-deposited amorphous Bi-Si-O thin films crystalized by post-annealing above 550 °C. • Post-annealing temperature affects crystallization, roughness, and dielectric properties. • Remanent polarization (2 P r) of 7.2 μC cm−2 was obtained by post-annealing at 600 °C. [ABSTRACT FROM AUTHOR]

This work reports the formation of silver nanoparticles (AgNPs) by sputter deposition in thin films of three different ionic liquids (ILs) with the same anion (bis(trifluoromethylsulfonyl)imide) and cation (imidazolium), but with different alkyl chain lengths and symmetries in the cationic moiety ([C4C1im][NTf2], [C2C2im][NTf2], and [C5C5im][NTf2]). Ionic liquid (IL) films in the form of microdroplets with different thicknesses (200 to 800 monolayers) were obtained through vacuum thermal evaporation onto glass substrates coated with indium tin oxide (ITO). The sputtering process of the Ag onto the ILs when conducted simultaneously with argon plasma promoted the coalescence of the ILs’ droplets and the formation, incorporation, and stabilization of the metallic nanoparticles in the coalesced IL films. The formation/stabilization of the AgNPs in the IL films was confirmed using high-resolution scanning electron microscopy (SEM) and UV-Vis spectroscopy. It was found that the IL films with larger thicknesses (600 and 800 monolayers) were better media for the formation of AgNPs. Among the ILs used, [C5C5im][NTf2] was found to be particularly promising for the stabilization of AgNPs. The use of larger IL droplets as capture media was found to promote a better stabilization of the AgNPs, thereby reducing their tendency to aggregate.

The wetting behavior of ionic liquids (ILs) on the mesoscopic scale considerably impacts a wide range of scientific fields and technologies. Particularly under vacuum conditions, these materials exhibit unique characteristics. This work explores the effect of the deposition rate and substrate temperature on the nucleation, droplet formation, and droplet spreading of ILs films obtained by thermal evaporation. Four ILs were studied, encompassing an alkylimidazolium cation (CnC1im) and either bis(trifluoromethylsulfonyl)imide (NTf2) or the triflate (OTf) as the anion. Each IL sample was simultaneously deposited on surfaces of indium tin oxide (ITO) and silver (Ag). The mass flow rate was reproducibly controlled using a Knudsen cell as an evaporation source, and the film morphology (micro- and nanodroplets) was evaluated by scanning electron microscopy (SEM). The wettability of the substrates by the ILs was notably affected by changes in mass flow rate and substrate temperature. Specifically, the results indicated that an increase in the deposition rate and/or substrate temperature intensified the droplet coalescence of [C2C1im][NTf2] and [C2C1im][OTf] on ITO surfaces. Conversely, a smaller impact was observed on the Ag surface due to the strong adhesion between the ILs and the metallic film. Furthermore, modifying the deposition parameters resulted in a noticeable differentiation in the droplet morphology obtained for [C8C1im][NTf2] and [C8C1im][OTf]. Nevertheless, droplets from long-chain ILs deposited on ITO surfaces showed intensified coalescence, regardless of the deposition rate or substrate temperature.

The performance of silver/tin oxide (Ag/SnO2) nanocomposites as coating materials with high antibacterial capability is evaluated in this study. Scanning electron microscopy (SEM) and density functional theory (DFT) analyses were used to characterize the nanocomposite structures and confirm that Ag (1 1 1) and SnO2 (1 1 0) form nanorods of Ag/SnO2. The antibacterial properties of these materials were investigated by using an Alamar Blue Assay (ABA) absorbance method. The results indicated that toxicity to E. coli and S. aureus increased with respect to the proportion of Ag within the composite, with the highest antibacterial activity being observed at a 4:1 ratio of Ag:SnO2. Additionally, the antimicrobial properties of the composites were enhanced when particle sizes were reduced from the micro- to nanometer range. Our study demonstrates that nano-Ag/SnO2 composites are highly suitable for antibacterial coatings of glass-based materials.

Soft biomaterials are a crucial component in several application fields. They are used, for example, in biomedical implants, biosensors, drug delivery systems as well as in tissue engineering. In parallel to extensive ongoing efforts to synthesize new materials, the development of means to tailor the materials’ surface properties and thus their interaction with the environment is an important field of research. This has led to the emergence of several surface modification techniques that enable the exploitation of biomaterials in a broader range of technologies. In particular, the use of functional thin films can enable a plethora of biomedical applications by combining advantageous bulk properties of the substrate (e.g. flexibility, lightweight, structural strength) with tailored surface properties of the thin film (e.g. enhancing/prevention of cell proliferation, controlled drug release). For some biomedical applications, thin films can also be the main functional components, e.g. in biosensors. The present review focuses on recent developments in the applications of soft biomaterials based on thin films deposited from the vapor phase. In the field of soft biomaterials, the possibility of depositing from the vapor phase—without the need for any solvents—offers the unprecedented benefit that no toxic leachables are included in the biomaterial. Further, due to the complete lack of solvents and chemicals overall being used in small quantities only, depositing thin films from the vapor phase can be a more sustainable choice than other techniques that are commonly used.

Threshold switching in chalcogenides has attracted considerable attention because of their potential application to high-density and three-dimensional stackable cross-point array structures. However, despite their excellent threshold switching characteristics, the selectivity and endurance characteristics of such selectors should be improved for practical application. In this study, the effect of Ag on the threshold switching behavior of a Ga2Te3 selector was investigated in terms of selectivity and endurance. The Ag-Ga2Te3 selector exhibited a high selectivity of 108 with low off-state current of < 100 fA, steep turn-on slope of 0.19 mV/dec, and high endurance of 109 cycles. The transient response was verified to depend on the pulse input voltage and measurement temperature. Considering its excellent threshold switching characteristics, the Ag-Ga2Te3 selector is a promising candidate for applications in cross-point array structures. [ABSTRACT FROM AUTHOR]

• The non-vacuum deposited PEDOT film without external oxidant. • The dense and smooth PEDOT film using BEDOT as monomer. • The PEDOT film with high electrical conductivity and hole mobility. • The PEDOT-based PSC with enhanced performance and stability. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is a well-known hole transport material, and widely used in inverted perovskite solar cells (PSCs). However, its high acidity and hydrophilicity from PSS can corrode the adjacent electrode and perovskite layer, seriously reducing the device performance and durability. Herein, a PEDOT film is fabricated by reactive vapor deposition method, where 5-bromo-2,3-dihydro-thieno[3,4-b][1,4]dioxine as monomer is evaporated and self-polymerized on a substrate at ambient pressure and low temperatures without external oxidants. The resulting PEDOT film is uniform and smooth with high conductivity, and the corresponding inverted CH 3 NH 3 PbI 3 (MAPbI 3) PSC exhibits superior device performance with a PCE of 21.34 %, which is one of the best efficiencies reported for the inverted PSCs with PEDOT:PSS as HTMs. Moreover, a general issue related to the acidic nature of PSS is successfully resolved, and the target device without encapsulation retained more than 80 % of the initial efficiency after 1000 h at ∼ 30 °C and 50 % RH, and kept about 80 % of the initial efficiency after 100 h in N 2 atmosphere at 80 °C. This report may provide a facile and effective method for the PEDOT fabrication applied for perovskite solar cells and other optoelectronic devices with high performance and stability. [ABSTRACT FROM AUTHOR]

The results of direct synthesis of composite powder based on boron nitride (BN) are considered. Concentrated light heating of the initial boron powder was carried out in a xenon high-flux optical furnace in a nitrogen flow. Formation of particles of the desired sizes and architecture highly dependent of the synthesis conditions. The flow of nitrogen separates the particles depending on their architecture and size. An increase in the distance from the reaction zone leads to the formation of powder with a wider bandgap, increases the amount of amorphous phase, and decreases the amount of oxide in the collected composite powder. However, the close distance to the reaction zone and high temperatures provide a denser packing of the structure on the particle surface and the disappearance of the BN transition phases. Incorporation of the nickel sulfate hexahydrate to initial boron contributes to the formation of graphene-like structures.

Nitrogen-doped mesoporous carbon microspheres have been successfully synthesized via a spray drying-vapor deposition method for the first time, using commercial Ludox silica nanoparticles as hard templates. Compared to freeze-drying and air-drying methods, mesoporous carbon with a higher packing density can be achieved through the spray drying method. Vapor deposition of polypyrrole followed by carbonization and etching is beneficial for the generation of ultra-thin carbon network. The mesoporous carbon microspheres possess a mesopore-dominate (95%) high surface area of 1528 m2 g−1, a wall thickness of 1.8 nm, and a nitrogen content of 8 at% in the framework. Benefiting from the increased apparent density, high mesopore surface area, and considerable nitrogen doping, the resultant mesoporous carbon microspheres show superior gravimetric/volumetric capacitance of 533.6 F g−1 and 208.1 F cm−3, good rate performance and excellent cycling stability in electric double-layer capacitors.

The objective of this article is to provide an overview on the current development of microand nanoporous fiber processing and manufacturing technologies. Various methods for making microand nanoporous fibers including co-electrospinning, melt spinning, dry jet-wet quenching spinning, vapor deposition, template assisted deposition, electrochemical oxidization, and hydrothermal oxidization are presented. Comparison is made in terms of advantages and disadvantages of different routes for porous fiber processing. Characterization of the pore size, porosity, and specific area is introduced as well. Applications of porous fibers in various fields are discussed. The emphasis is put on their uses for energy storage components and devices including rechargeable batteries and supercapacitors. [ABSTRACT FROM AUTHOR]

High purity Mg was successfully coated on polyetheretherketone (PEEK) by vapor deposition method in order to improve the bioactivity including antibacterial property of PEEK implant. The morphology and elemental composition of the coating were characterized by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), showing that the coating was mainly composed of Mg at deposition temperature of 175 °C, 185 °C, 200 °C and 230 °C. The higher the substrate temperature was, the larger the Mg particle size was. The coating degraded and gradually peeled off from the surface of PEEK after up to 21 days' immersion. It was found that the degradation of Mg coating could strongly kill Staphylococcus aureus with antibacterial rate reaching to 99%. Mg can be expected to be coated on those bio-inert biomaterials to offer specific bioactivities.

Boron nitride (BN) is primarily a synthetically produced advanced ceramic material. It is isoelectronic to carbon and, like carbon, can exist as several polymorphic modifications. Microwave plasma chemical vapor deposition (MPCVD) of metastable wurtzite boron nitride is reported for the first time and found to be facilitated by the application of direct current (DC) bias to the substrate. The applied negative DC bias was found to yield a higher content of sp3 bonded BN in both cubic and metastable wurtzite structural forms. This is confirmed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Nano-indentation measurements reveal an average coating hardness of 25 GPa with some measurements as high as 31 GPa, consistent with a substantial fraction of sp3 bonding mixed with the hexagonal sp2 bonded BN phase.

Organic thin films with smooth surfaces are mandated for high-performance organic electronic devices. Abrupt nucleation and aggregation during film formation are two main factors that forbid smooth surfaces. Here, we report a simple fast cooling (FC) adapted physical vapor deposition (FCPVD) method to produce ultrasmooth organic thin films through effectively suppressing the aggregation of adsorbed molecules. We have found that thermal energy control is essential for the spread of molecules on a substrate by diffusion and it prohibits the unwanted nucleation of adsorbed molecules. FCPVD is employed for cooling the horizontal tube-type organic vapor deposition setup to effectively remove thermal energy applied to adsorbed molecules on a substrate. The organic thin films prepared using the FCPVD method have remarkably ultrasmooth surfaces with less than 0.4 nm root mean square (RMS) roughness on various substrates, even in a low vacuum, which is highly comparable to the ones prepared using conventional high-vacuum deposition methods. Our results provide a deeper understanding of the role of thermal energy employed to substrates during organic film growth using the PVD process and pave the way for cost-effective and high-performance organic devices.

The evolutionary system of mineralogy relies on varied physical and chemical attributes, including trace elements, isotopes, solid and fluid inclusions, and other information-rich characteristics, to understand processes of mineral formation and to place natural condensed phases in the deep-time context of planetary evolution. Part I of this system reviewed the earliest refractory phases that condense at T > 1000 K within the turbulent expanding and cooling atmospheres of highly evolved stars. Part II considers the subsequent formation of primary crystalline and amorphous phases by condensation in three distinct mineral-forming environments, each of which increased mineralogical diversity and distribution prior to the accretion of planetesimals >4.5 billion years ago. (1) Interstellar molecular solids: Varied crystalline and amorphous molecular solids containing primarily H, C, O, and N are observed to condense in cold, dense molecular clouds in the interstellar medium (10 < T < 20 K; P < 10-13 atm). With the possible exception of some nanoscale organic condensates preserved in carbonaceous meteorites, the existence of these phases is documented primarily by telescopic observations of absorption and emission spectra of interstellar molecules in radio, microwave, or infrared wavelengths. (2) Nebular and circumstellar ice : Evidence from infrared observations and laboratory experiments suggest that cubic H2O ("cubic ice") condenses as thin crystalline mantles on oxide and silicate dust grains in cool, distant nebular and circumstellar regions where T ~100 K. (3) Primary condensed phases ofthe inner solar nebula: The earliest phase of nebular mineralogy saw the formation of primary refractory minerals that solidified through high-temperature condensation (1100 < T< 1800 K; 10-6 < P < 10-2 atm) in the solar nebula more than 4.565 billion years ago. These earliest mineral phases originating in our solar system formed prior to the accretion of planetesimals and are preserved in calcium-aluminum-rich inclusions, ultra-refractory inclusions, and amoeboid olivine aggregates. [ABSTRACT FROM AUTHOR]

The performance of silver/tin oxide (Ag/SnO 2) nanocomposites as coating materials with high antibacterial capability is evaluated in this study. Scanning electron microscopy (SEM) and density functional theory (DFT) analyses were used to characterize the nanocomposite structures and confirm that Ag (1 1 1) and SnO 2 (1 1 0) form nanorods of Ag/SnO 2. The antibacterial properties of these materials were investigated by using an Alamar Blue Assay (ABA) absorbance method. The results indicated that toxicity to E. coli and S. aureus increased with respect to the proportion of Ag within the composite, with the highest antibacterial activity being observed at a 4:1 ratio of Ag:SnO 2. Additionally, the antimicrobial properties of the composites were enhanced when particle sizes were reduced from the micro- to nanometer range. Our study demonstrates that nano-Ag/SnO 2 composites are highly suitable for antibacterial coatings of glass-based materials. [ABSTRACT FROM AUTHOR]

Minerals preserve records of the physical, chemical, and biological histories of their origins and subsequent alteration, and thus provide a vivid narrative of the evolution of Earth and other worlds through billions of years of cosmic history. Mineral properties, including trace and minor elements, ratios of isotopes, solid and fluid inclusions, external morphologies, and other idiosyncratic attributes, represent information that points to specific modes of formation and subsequent environmental histories--information essential to understanding the co-evolving geosphere and biosphere. This perspective suggests an opportunity to amplify the existing system of mineral classification, by which minerals are defined solely on idealized end-member chemical compositions and crystal structures. Here we present the first in a series of contributions to explore a complementary evolutionary system of mineralogy--a classification scheme that links mineral species to their paragenetic modes. The earliest stage of mineral evolution commenced with the appearance of the first crystals in the universe at >13 Ga and continues today in the expanding, cooling atmospheres of countless evolved stars, which host the high-temperature (T > 1000 K), low-pressure (P < 10-2 atm) condensation of refractory minerals and amorphous phases. Most stardust is thought to originate in three distinct processes in carbon- and/or oxygen-rich mineral-forming stars: (1) condensation in the cooling, expanding atmospheres of asymptotic giant branch stars; (2) during the catastrophic explosions of supernovae, most commonly core collapse (Type II) supernovae; and (3) classical novae explosions, the consequence of runaway fusion reactions at the surface of a binary white dwarf star. Each stellar environment imparts distinctive isotopic and trace element signatures to the micro- and nanoscale stardust grains that are recovered from meteorites and micrometeorites collected on Earth's surface, by atmospheric sampling, and from asteroids and comets. Although our understanding of the diverse mineral-forming environments of stars is as yet incomplete, we present a preliminary catalog of 41 distinct natural kinds of stellar minerals, representing 22 official International Mineralogical Association (IMA) mineral species, as well as 2 as yet unapproved crystalline phases and 3 kinds of non-crystalline condensed phases not codified by the IMA. [ABSTRACT FROM AUTHOR]

In this study, the deposition and characteristics of Si- and Ti-series multilayer coatings with respective glass/Si 3 N 4 /NiCr/Ag/NiCr/Si 3 N 4 and glass/TiO 2 /ZnSnO 3 /ZnO/Ag/NiCrO x /ZnSnO 3 /Si 3 N 4 structures were investigated. Experimental analyses were performed, and the optical performance and thermal stability of the coatings were assessed. The as-deposited Si- and the Ti-series samples exhibited optimal shading coefficient of 0.49 and 0.57, respectively. Thermal annealing in air was performed to analyze the thermal stability and oxidation resistance of the samples. The Si- and Ti-series samples prevented the failure of low-emissivity properties at 700 and 600 °C, respectively. In addition to high transparency, the Si-series samples exhibited improved low-emissivity properties, reduced light pollution, and superior thermal stability compared to the Ti-series samples. The use of Si 3 N 4 and NiCr layers effectively prevented the oxidation and cracking of the Ag layer upon heat treatment. This study presents the characteristics of Si- and Ti-series samples for energy-saving building applications. [ABSTRACT FROM AUTHOR]

Combined structure of anodic TiO 2 nanotubes and TiO 2 nanoparticles (TiNTs-TiNPs) has been synthesized by a facile combination of hydrothermal and chemical vapor deposition methods. Ordered TiO 2 nanotubes with smooth walls were fabricated by two step anodization method in ethylene glycol containing NH 4 F at 50 V. This nanotubular array after annealing at 450 °C was subjected to the hydrothermally produced gaseous environment in an autoclave with diluted TiCl 4 solution at its bottom. Vapors of TiCl 4 were allowed to react chemically with water vapors for predefined time durations at 180 °C that resulted in the deposition of TiO 2 nanoparticles on tubes' surface and side walls. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed that for one hour reaction duration, nanoparticles were evenly coated on the walls of nanotubes, whereas, longer durations tend to deteriorate the tubular structure. Consequently, the ordered TiNTs-TiNPs array produced after one hour coating has shown better performance for dye-sensitized solar cell DSSC) in back illumination mode with 130% increase in efficiency as compared to the device based on bare TiO 2 nanotubes. The same photoanode has higher reflective properties with higher scattering ability. The solar cell based on this photoanode exhibits higher external quantum efficiency and effective charge transport properties. This study shows that porous ordered 1D structures based on TiO 2 are of crucial importance for the high performance of DSSCs. [ABSTRACT FROM AUTHOR]

BaSi 2 , an earth-abundant photovoltaic material with a limiting efficiency of 32 %, has the interesting property that grain boundaries do not significantly degrade the film properties. In this study, we investigated the microstructure and its effect on the electrical and optoelectronic properties of the BaSi 2 films grown by close-spaced evaporation. Microstructural analysis confirmed the (100)-oriented epitaxial growth on both Si(100) and Si(111) substrates. In addition to conventional epitaxial relationships, lattice matching with the BaSi 2 (0 1 ¯ 3) plane parallel to Si(110) was observed on Si(100) substrates. The density of the epitaxial domain boundary was found to decrease with increasing film thickness, increasing growth temperature, and using Si(100) substrates instead of Si(111). Hall effect measurements revealed the conductivity type transition at a temperature between 900 and 1000 ∘C and a decreasing tendency of carrier density with film thickness. There was no obvious correlation between mobility and grain boundary density, consistent with previous reports. Carrier recombination kinetics were evaluated by the microwave-detected photoconductivity decay method and the photoconductivity measurement under constant optical irradiation. Both analyses revealed weak negative correlations between excess carrier lifetime and grain boundary density, which clarified the superiority of large-grained BaSi 2 films for photovoltaic applications. • BaSi 2 epitaxial films on Si substrates grown by close-spaced evaporation. • Grain size increases with film thickness and growth temperature. • Carrier lifetime analyzed by photoconductivity with pulsed and constant irradiation. • Carrier lifetime tends to decrease with increasing grain boundary density. [ABSTRACT FROM AUTHOR]

Vapor-deposition processes and the resulting thin polymer films provide consistent coatings that decouple the underlying substrate surface properties and can be applied for surface modification regardless of the substrate material and geometry. Here, various ways to structure these vapor-deposited polymer thin films are described. Well-established and available photolithography and soft lithography techniques are widely performed for the creation of surface patterns and microstructures on coated substrates. However, because of the requirements for applying a photomask or an elastomeric stamp, these techniques are mostly limited to flat substrates. Attempts are also conducted to produce patterned structures on non-flat surfaces with various maskless methods such as light-directed patterning and direct-writing approaches. The limitations for patterning on non-flat surfaces are resolution and cost. With the requirement of chemical control and/or precise accessibility to the linkage with functional molecules, chemically and topographically defined interfaces have recently attracted considerable attention. The multifunctional, gradient, and/or synergistic activities of using such interfaces are also discussed. Finally, an emerging discovery of selective deposition of polymer coatings and the bottom-up patterning approach by using the selective deposition technology is demonstrated.

Vapor phase syntheses, including parylene chemical vapor deposition (CVD) and initiated CVD, enable the deposition of conformal polymer thin films to benefit a diverse array of applications. This short review for nanotechnologists, including those new to vapor deposition methods, covers the basic theory in designing a conformal polymer film vapor deposition, sample preparation and imaging techniques to assess film conformality, and several applications that have benefited from vapor deposited, conformal polymer thin films.

(3-Aminopropyl)triethoxysilane (APTES) silane possesses one terminal amine group and three ethoxy groups extending from each silicon atom, acting as a crucial interface between organic and inorganic materials. In this study, after APTES was deposited on the aluminum alloy AA2024-T3 as a primer for an optional top coating with polystyrene (PS), its role with regard to stability as a protection layer and interaction with the topcoat were studied via combinatorial experimentation. The aluminum alloy samples primed with APTES under various durations of concentrated vapor deposition (20, 40, or 60 min) with an optional post heat treatment and/or PS topcoat were comparatively characterized via electrochemical impedance spectroscopy (EIS) and surface energy. The samples top-coated with PS on an APTES layer primed for 40 min with a post heat treatment revealed excellent performance regarding corrosion impedance. A primed APTES surface with higher surface energy accounted for this higher corrosion impedance. Based on the SEM images and the surface energy calculated from the measured contact angles on the APTES-primed surfaces, four mechanisms are suggested to explain that the good protection performance of the APTES/PS coating system can be attributed to the enhanced wettability of PS on the cured APTES primer with higher surface energy. The results also suggest that, in the early stages of exposure to the corrosion solution, a thinner APTES primer (deposited for 20 min) enhances protection against corrosion, which can be attributed to the hydrolytic stability and hydrolyzation/condensation of the soaked APTES and the dissolution of the naturally formed aluminum oxide pre-existing in the bare samples. An APTES primer subjected to additional heat treatment will increase the impedance of the coating system significantly. APTES, and silanes, in general, used as adherent agents or surface modifiers, have a wide range of potential applications in micro devices, as projected in the Discussion section.