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Complex hierarchical metamaterials are currently the focus of many cutting‐edge studies due to their potential to advance such critically important areas of technology as energy storage and transformation, sensing, photovoltaics, nano‐medicine, antibacterial and self‐regenerating materials. However, the deterministic design of novel hierarchical metamaterials remains problematic due to the lack of efficient, highly reliable methods for controlling the internal structure and architecture of materials. A comprehensive advanced model is proposed to simulate the formation of complex hierarchical metamaterials with a controllable structure. The control is achieved via selective deposition of noble metal nanoparticles (Au, Au, Pd, Pt). Moreover, the novel method for the nanofabrication is theoretically examined and experimentally verified. This approach allows for the sophisticated spatiotemporal control of growth conditions and, as a result, achieving the targeted internal structure of metamaterials. This opens a way to the deterministic design and formation of complex multi‐material metamaterials on the basis of metal oxides and noble metal nanoparticles. Moreover, a fundamental insight related to the longstanding question about the prevalence of bottom‐up versus top‐down growth for various materials and systemswhich is challenging to directly verify experimentally is presented. [ABSTRACT FROM AUTHOR]

Les récents progrès sur la compréhension des décharges produites dans les liquides diélectriques entre deux électrodes dont on choisit la composition, ouvrent des perspectives nouvelles dans la maîtrise de l'élaboration de nanoparticules. De telles décharges permettent de synthétiser des nanoparticules ayant des diamètres caractéristiques compris entre 2 et 10 nm. Surtout, elles permettent d'atteindre des rendements de production remarquablement élevés, de l'ordre de la centaine de grammes par heure. La difficulté principale consiste à maîtriser ce procédé qui est basé sur un phénomène stochastique : le claquage d'un diélectrique, qui permet la formation d'une décharge électrique. [ABSTRACT FROM AUTHOR]

Atmospheric pressure plasmas (APPs) have achieved great scientific and technological advances for a wide range of applications. The synthesis and treatment of materials by APPs have always attracted great attention due to potential economic benefits if compared to low-pressure plasma processes. Nonetheless, APPs present very distinctive features that suggest atmospheric pressure operation could bring other benefits for emerging new technologies. In particular, materials synthesized by APPs which are suitable candidates for third generation photovoltaics are reviewed here. [ABSTRACT FROM AUTHOR]

The purpose of the present investigation is to gain understanding of the mechanisms responsible for the cleaning properties of Ar–N2 post-discharges at room temperature. The evolution of the gas-phase composition is monitored by optical emission spectroscopy, and X-ray photoelectron spectroscopy is used to characterize the surface of iron samples initially covered by a contamination layer at various treatment times. Both techniques suggest that cleaning is at least a two-step process, beginning with the removal of aliphatic carbon from the surface. [Copyright &y& Elsevier]

Inside Front Cover: Atmospheric pressure plasmas offer unique capabilities for new emerging advanced materials, bringing together process versatility and nanoscale precision engineering at low costs. The unique features of atmospheric pressure plasmas may represent advantageous characteristics for many materials applications and more specifically for new emerging photovoltaic technologies, which require processing and synthesis of a vast range of materials with reduced costs. Further details can be found in the article by Davide Mariotti et al. on page 70. [ABSTRACT FROM AUTHOR]

Luminescent security labels are effective platforms for protection of consumer goods from counterfeiting. However, the lifetimes of such security approaches are limited due to narrow‐band photoluminescent features of the label elements, which can be used for the protection technology disclosure. In this paper, a novel concept for the application of non‐linear white‐light luminescence from hybrid metal–semiconductor structures fabricated by direct femtosecond laser writing for the creation of physically unclonable security labels is proposed. A close connection is demonstrated between the internal composition of hybrid structures, which is controlled at the fabrication stage, and their non‐linear optical signals. It is shown that the application of decorrelation procedure based on discrete cosine transform and polar codes for label coding can overcome the problem of the white‐light photoluminescent spectra correlation. The proposed fabrication approach and coding strategy allows reaching a high degree of device uniqueness (up to 99%), bit uniformity (close to 0.5), and encoding capacity up to 1.25 × 10437 in a single label element. The results demonstrate that the barriers for the application of white‐light luminescent nano‐objects for the creation of physically unclonable labels are removed. [ABSTRACT FROM AUTHOR]

It is possible to assemble hydrogenated amorphous carbon (HAC) nanoparticles into fibres by a two-step process based on discharges in heptane. In a first step, HAC nanoparticles are synthesized by successive discharges between two platinum pin-electrodes separated by a gap-distance set to 100 µm. Next, the gap-distance is increased to 2 mm. New discharges create non-conductive HAC fibres by assembly of nanoparticles dispersed in the liquid. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) in a thin film (TF) form have appeared recently as multifunctional elements for micro- and opto-electronic devices. However, achieving the roughness of MOF TF less than 10 nm is still a challenge, which limits their further integration with the corresponding devices. Here, we report on plasma etching (PE) approach allowing one to improve the quality of MOF TF surfaces. We demonstrate that PE of a spin-coated HKUST-1 TFs with a varied thickness (1.9 to 3 μ m) and roughness (more than 200 nm) decreases the film roughness by 100 times (up to 2 nm), while the chemical composition and the structure remain. As a result, an optical quality for the TF surface can be achieved resulting to a mirror like reflectivity as well as an optical sensitivity of water through the interference effect. The obtained results, thereby, pave the way to a universal post-processing of MOF TFs for diverse applications where their roughness plays a key role. • Plasma etching of MOF films results in decrease the roughness by 100 times up to 2 nm. • An optical quality for MOF film surface corresponds to a mirror-like reflectivity. • An optical sensitivity of water via interference effect is demonstrated. [ABSTRACT FROM AUTHOR]

Producing alloy nanoparticles by discharge‐assisted erosion of electrodes immersed in liquid nitrogen is possible in the cobalt–nickel system. Several electrode configurations are tested. When one nickel electrode faces one cobalt electrode, CoxNi1−x alloy nanoparticles are produced with nickel cubic nanoparticles and cobalt round‐shaped faceted nanoparticles. The possibility of forming alloys is attributed to a sufficiently long residence time of both parent clusters within the discharge and to their total miscibility. It is also possible to form submicrometric CoxNi1−x alloy particles when discharges between cobalt electrodes are run in liquid nitrogen loaded with nickel nanoparticles produced in a former step. Starting by discharges between Co electrodes before Ni electrodes do not produce any alloy. The two mechanisms responsible for alloy synthesis are discussed. [ABSTRACT FROM AUTHOR]

Nanosecond‐pulsed spark discharge between two lead electrodes in liquid nitrogen has been used to synthesize hexagonal lead nanosheets. These original nanostructures are collected on a substrate located under the electrodes. After the full evaporation of the liquid nitrogen, the nanosheets are oxidized in air and transform into a lead dioxide. The resulting hexagonal sheets have typical widths of around 1 µm and typical thicknesses of around 10 nm. Investigations by energy dispersive spectroscopy microanalysis, transmission electron microscopy, high‐angle annular dark‐field scanning transmission electron microscopy and electron microdiffraction were performed in order to identify the crystal structure in which these hexagonal nanosheets crystallize. An analysis of the chemical composition pointed to a stoichiometric lead dioxide, PbO2. This PbO2 lead dioxide crystallizes in the hexagonal system (a = 0.912 nm and c = 1.265 nm) and belongs to the space group P6/m2/m2/m. On the basis of group theory (symmetry analysis), the nanosheets develop a hexagonal‐prismatic shape in liquid nitrogen, assumed to be an isotropic medium. From the energetic point of view, this shape, dictated by the 6/m2/m2/m point group, corresponds to an absolute extremum, an indicator of the stability of this lead dioxide. A mechanism similar to that of the ledge mechanism explaining the formation of thin plates in a metallic matrix has been adapted and proposed for the formation of the lead nanosheets in the liquid nitrogen. When the liquid nitrogen is removed, the lead nanosheet is oxidized, leading to a lead dioxide, inheriting the nanosheet morphology. As far as the authors are aware, this is the first time that such a lead dioxide has been synthesized by spark discharge in liquid nitrogen followed by oxidation in air. The crystallographic structure is determined and the morphology is explained. A mechanism for the development of the lead nanosheets and their oxidation is proposed. This hexagonal phase, designated γ‐PbO2, is thought to be the third polymorph after the α‐PbO2 and β‐PbO2 phases of lead dioxide, the former being orthorhombic and the latter being tetragonal. The crystal structure of a novel phase of lead dioxide, γ‐PbO2, forming nanosheets, is identified by energy dispersive spectroscopy microanalysis, transmission electron microscopy and electron microdiffraction. On the basis of the symmetry analysis, the hexagonal‐prismatic shape is explained and a mechanism of formation is proposed. [ABSTRACT FROM AUTHOR]

This focused review aims to reveal and illustrate some unique features of processes triggered by high-density energy applied to liquids and gas-liquid interfaces and to highlight a wide spectrum of their technological applications capable of producing various advantageous effects, ranging from nanosynthesis to biological and medical applications. Plasma, electric discharges, laser, and ultrasound power effects were selected as representative examples of high-density energy and liquid interactions, yet the available possibilities are not limited by these quite different types of power and thus the reader could extrapolate the outlined features and effects to other kinds of powerful impacts. The basic physical mechanisms are briefly reviewed with the aim to familiarize the readers with the potential capabilities of high-density energy processes in liquids. These will be of direct interest to researchers tasked with the development, optimization, and characterization of processes and highly reactive environments for highly controlled transformation of matter in abiotic and biological systems. It could also be highly useful for under- and post-graduate students specializing in the related fields and general physical audience involved in various plasma, materials, energy conversion, and other concurrent research activities. [ABSTRACT FROM AUTHOR]

From results of in situ FTIR absorption and optical emission spectroscopy, the interaction of (3-aminopropyl)triethoxysilane (APTES) with late ArN2 afterglow is shown to occur mainly with N atoms. They react preferentially with carbon from CH x groups in the precursor, leading to the synthesis of CN bonds. No production of NH radical is observed, demonstrating the lack of direct reaction between active nitrogen and APTES. The NH2 group is not affected by the afterglow. One of the CC bonds of the propylamine group in the APTES is likely broken. These nanoparticles present secondary amides due to reactions with active nitrogen. They are amorphous and react in air to produce a salt. [ABSTRACT FROM AUTHOR]

Controlling microdischarges in plasma electrolytic oxidation is of great importance in order to optimize coating quality. The present study highlights the relationship between the polarity at which breakdown occurs and the electrolyte pH as compared with the isoelectric point (IEP). It is found that working at a pH higher than the IEP of the grown oxide prevents the buildup of detrimental cathodic discharges. The addition of phosphates results in a shift in the IEP to a lower value and therefore promotes anodic discharges at the expense of cathodic ones. [ABSTRACT FROM AUTHOR]

Glycine and proline have been treated in Ar-O2 afterglows at low temperature to study their modification in highly reactive non-equilibrium media. These two amino-acids can be efficiently etched in suited conditions. In the case of glycine, O(3P) is the main reactive species responsible for the etching mechanism. It reacts preferentially with the -CH2- group instead of the amine group-NH2. Further oxidation processes are observed but they are not rate-limiting. Etching of proline is a multi-step process, probably initiated by O(3P) and then followed by reactions which control the etch-rate, the opening of the non-aromatic ring of proline being a probable route. [ABSTRACT FROM AUTHOR]

Non-vulcanized styrene-butadiene rubber thin films were exposed to Radio-Frequency low-pressure air plasma. Two different configurations corresponding to direct and downstream RF plasmas were compared. Optical emission spectroscopy provided information about plasma composition and temperature. The plasma treated SBR surfaces were characterized by contact angles and XPS spectroscopy. Two different phenomenological mechanisms are proposed to describe the observed differences according to the plasma configuration used and account for the impact of the activated gas phase on the structure of plasma-treated non-vulcanized SBR surface.. [ABSTRACT FROM AUTHOR]

Silicon nanostructures are synthesized with a DC atmospheric pressure microplasma jet usingan Ar/SiH4/H2 gas mixture. The plasma is characterized by OES and imaged using an EMCCD camera. The effect of hydrogen admixture to the formed structures is studied by transmission electron microscopy. Under specific conditions, crystalline silicon nanoparticles grow in an amorphous matrix investigated by electron energy loss spectroscopy. As-grown silicon nanoparticles are collected in ethanol for dynamic light scattering and photoluminescence measurements. The size distribution peaks at 4 nm. The silicon nanocrystals exhibit roomtemperature photoluminescence that peaks at ~415 and ~465 nm. [ABSTRACT FROM AUTHOR]

On-line atmospheric pressure plasma treatment of cylindrical substrates is of great interest in tire industry in view of developing a cheaper and cleaner process than electrolytic plating ones that are applied on metallic tire reinforcing materials. Here we assess the feasibility of such a continuous treatment by depositing organo-chlorinated thin films from dichloromethane on zinc-plated steel wires crossing a tubular dielectric barrier discharge. We show that working conditions highly influence layers growth and have to be carefully adjusted for obtaining homogeneous and defect-free coatings. Thin films chemistry is strongly dependent on the energy injected in the discharge. Layers become more inorganic when power increases, resembling carbon black or graphite and no longer hydrocarbon. [ABSTRACT FROM AUTHOR]

Photoluminescence of (0001) epitaxial ZnO films with thicknesses of 10, 30 and 100 nm on C-sapphire substrates have been studied at room temperature and after exposure to Ar, Ar-O2, Ar-N2 and Ar-H by remote microwave and radiofrequency plasmas. The photoluminescence are not modified by remote plasma treatments where only neutral species were involved. On the contrary, the photoluminescence signal is enhanced or quenched after radiofrequency plasma treatments when energetic ion species are involved in the surface treatment processes. Little changes of electric properties are observed, however, the optical transmission indicates that the absorption edge and probably also the index of refraction are affected. Photoluminescence peak shifts, widths and intensities changes show very strong similarities with polarized emission of ZnO single crystal where it exists a strong dichroism. The photoluminescence emission properties may then result from this optical modification. However, the plasma treatments on the different samples show very low stability in time, except, for the treatment in argon plasma alone. In this later case, in-situ monitoring of photoluminescence as a function of temperature revealed a partial recovery of the photoluminescence properties after a heat treatment at 400 °C for few minutes. These results indicate that photoluminescence of (0001) ZnO thin film, related to σ-emission polarized emission from c-axis polar surfaces, is highly affected by surface and implanted charged species. [ABSTRACT FROM AUTHOR]

Highlights: [•] A blown arc discharge fed with TIPO and N2 is studied for the deposition of TiO2 thin films. [•] Fine control of the deposition parameters allows to limit homogeneous gas-phase reactions. [•] Highly photocatalytic coatings have been grown at a substrate temperature below 490K. [ABSTRACT FROM AUTHOR]

Abstract: Thin film deposition of TiOx is performed with an atmospheric pressure plasma afterglow from a nitrogen-fed blown arc discharge. Titanium tetraisopropoxide is used as titanium precursor molecule and injected in the afterglow by an ultrasonic nebuliser. The coatings are made of a homogenous thin film and agglomerates, whose mean size and number depend on the deposition time and on the reactivity of the afterglow. These agglomerates are created by aggregation of nanoparticles synthesised in the gas phase. The latter are crystalline and responsible for the photocatalytic activity of the coating. The presence of a crystalline phase with a high specific surface area induces a photodegradation of the stearic acid with kinetics close to that obtained with an anatase sample deposited by magnetron sputtering at 523K. The substrate temperature is always lower than 523K. Significant photocatalytic activity has even been achieved with a substrate temperature as low as 460K. [Copyright &y& Elsevier]

Today, it is necessary to better understand the role of reactive species in plasmas on biological objects in order to use plasma processes for biomedical applications. Even when well-known plasma set-ups producing one main reactive species in a controlled environment are used, it is still difficult to understand reactive species interaction processes with biological systems. In this study, nanoimaging with the most sensitive mass spectrometry technology, and the use of isotopic 15N2 or/and 18O2 containing-Ar gas mixtures to produce the plasma is proposed in order to obtain isotopic and elemental data on microwave late afterglow treated Escherichia coli bacteria. By this way, new data dealing with reactive species binding processes on plasma treated bacteria by using NanoSIMS50 mass spectrometer are obtained. [ABSTRACT FROM AUTHOR]

Silicon oxide nanowires are synthesised below 523 K by a non-VLS mechanism on different substrates: Fe-0.5 wt.-%Si and Fe-1.5 wt.-%Si alloys and silicon wafers coated or not by 30-nm thick coatings of iron. An Ar-O2 micro-afterglow is used to feed the substrate with oxidising species over an area of ≈2 mm2. In this area, circular bundles of nanowires appear after 15 min and are randomly distributed. Each bundle diameter increases with time and reaches 50 µm. After several hours, bundles overlap and give a continuous carpet of nanowires. TEM analyses show that no iron is found in the nanowires, whatever the substrate. A growth mechanism, based on the emergence of a surface defect is proposed. [ABSTRACT FROM AUTHOR]

Abstract: Surface effects during plasma activation of poly(p-phenilene sulphide)—PPS have been studied. Samples that were exposed to weakly ionized highly dissociated oxygen plasma created an inductively coupled radiofrequency discharge with the power of 100W. The electron density and temperature were measured with a double Langmuir probe and were 4×1015 m−3 and 3eV, respectively, while the neutral atom density was measured with a fiber optics catalytic probe and was 4×1021 m−3. The surface tension was determined by measuring the contact angle of deionized water, while the appearance of surface functional groups was detected by XPS. The surface tension of untreated PPS was 7×10−3 N/m or/and increased to 7×10−2 N/m in few seconds of plasma treatment. It remained fairly constant for longer plasma treatments. The XPS survey spectrum showed little oxygen on untreated samples, but its concentration increased to about 20at.% in few seconds. Detailed high resolution XPS C 1s peak showed that the carbon was left fairly stable during plasma treatment. The main functional groups formed were rather sulphate in sulphite groups, as determined from high resolution S 2p peak. Namely, a strong transition from sulphide to sulphate state of sulfur was observed. The spontaneous deactivation of the polymer surface was measured as well. The deactivation was fairly logarithmic with the characteristic decay time of several hours. [Copyright &y& Elsevier]

Time-resolved optical emission spectroscopy of nanosecond-pulsed discharges ignited in liquid nitrogen between two bismuth electrodes is used to determine the main discharge parameters (electron temperature, electron density and optical thickness). Nineteen lines belonging to the Bi I system and seven to the Bi II system could be recorded by directly plunging the optical fibre into the liquid in close vicinity to the discharge. The lack of data for the Stark parameters to evaluate the broadening of the Bi I lines was solved by taking advantage of the time-resolved information supported by each line to determine them. The electron density was found to decrease exponentially from 6.5 ± 1.5 × 1016 cm−3 200 ns after ignition to 1.0 ± 0.5 × 1016 cm−3 after 1050 ns. The electron temperature was found to be 0.35 eV, close to the value given by Saha's equation. [ABSTRACT FROM AUTHOR]

Reform of methane was produced in a quartz tube by microwave plasma at atmospheric pressure. A flux of 10 l/min and 5 l/min of pure argon was inserted in the plasma and then a small amount of methane (from 0.5 to 5 sccm) was added to the argon. The species present in the plasma at discharge and post-discharge were monitored by optical emission spectroscopy (OES) diagnostic during the process. The efficiency of dissociation was evaluated by both the density of species H α (656.6 nm) and CH (431.4 nm). [ABSTRACT FROM AUTHOR]

The conversion of metal–organic frameworks (MOFs) into derivatives with a well‐defined shape and composition is considered a reliable way to produce efficient catalysts and energy capacitors at the nanometer scale. Yet, approaches based on conventional melting of MOFs provide the derivatives such as amorphous carbon, metal oxides, or metallic nanoclusters with an appropriate morphology. Here ultrafast melting of MOFs is utilized by femtosecond laser pulses to produce a new generation of derivatives with complex morphology and enhanced nonlinear optical response. It is revealed that such a nonequilibrium process allows conversion of interpenetrated 3D MOFs comprising flexible ligands into well‐organized spheres with a metal oxide dendrite core and amorphous organic shell. The ability to produce such derivatives with a complex morphology is directly dependent on the electronic structure, crystal density, ligand flexibility, and morphology of initial MOFs. An enhanced second harmonic generation and three‐photon luminescence are also demonstrated due to the resonant interaction of 100–1000 nm spherical derivatives with light. The results obtained are in the favor of new approaches for melting special types of MOFs for nonlinear nanophotonics. [ABSTRACT FROM AUTHOR]

This article reports the use of pulsed remote Ar‐O2 microwave plasma assisted chemical vapor deposition with an −NH2 containing organosilicon precursor ((3‐Aminopropyl)triethoxysilane: APTES). It is shown that modifying the plasma pulses duration (ton) and the plasma off duration (toff) allows to finely tune the deposited layer composition. In addition, the results of this work demonstrate that an important film growth occurs during toff, which results in an increased −NH2 density. Besides, high resolution MALDI‐ORBITRAP Mass spectrometry analysis clearly points out that APTES oligomers up to eight base units, including silsesquioxanes (cages), and cyclosiloxanes (rings) molecules with intact −NH2 groups are embedded into the as grown pp‐APTES thin film. [ABSTRACT FROM AUTHOR]

This white paper considers the future of plasma science and technology related to the manufacturing and modifications of plastics and textiles, summarizing existing efforts and the current state‐of‐art for major topics related to plasma processing techniques. It draws on the frontier of plasma technologies in order to see beyond and identify the grand challenges which we face in the following 5–10 years. To progress and move the frontier forward, the paper highlights the major enabling technologies and topics related to the design of surfaces, coatings and materials with non‐equilibrium plasmas. The aim is to progress the field of plastics and textile production using advanced plasma processing as the key enabling technology which is environmentally friendly, cost‐efficient, and offers high‐speed processing. This white papers tries to outline the future of plasma science and technology related to plastics and textiles with the current state‐of‐the‐art and grand challenges, which needs to be addressed to move the frontier of this field. Readers will learn where we stand today, and where do we want to go in the future. It is a "navigation chart" for plasma in plastics and textiles for everyone who is interested in the field! [ABSTRACT FROM AUTHOR]

Ignition of a discharge in liquid heptane is studied by a nanosecond time-resolved imaging using microgap conditions. Using an optical filter at 656 nm, we could enhance the spatial distribution of electrons within the interelectrode gap. Intense and multiple space charges are evidenced. [ABSTRACT FROM PUBLISHER]

Back Cover: Organo‐chlorinated thin films are produced from dichloromethane on zinc‐plated steel wires in a continuous‐flow AP‐DBD plasma process. High quality layers can be deposited at high deposition rates. A wide range of chlorinated species are created in the Ar discharge, ranging from small volatile gaseous molecules to large‐sized PAH. An increase in the injected energy induces a decrease in hydrogen concentration in the coating that becomes closer to a graphite structure. Further details can be found in the article by Simon Bulou et. al. on page 1089. [ABSTRACT FROM AUTHOR]

Cover: Superposed NanoSIMS‐AFM images showing enrichment in 18O, as indicated by orange‐red spots, coming directly from the discharge on the plasma treated bacteria deposited on a polycarbonate filter. 18O fixation on bacteria is high and not homogeneous in Ar‐N2‐O2 microwave afterglow. Further details can be found in the article by David Duday et. al. on page 864. [ABSTRACT FROM AUTHOR]