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Two-step hydrothermal deposition of zinc-oxide (ZnO) nanorods was used to functionalize carbon fiber textiles in order to produce increased hydrophilicity on fiber surface. On carbon fiber textiles, tightly packed ZnO nanorods developed after five seed cycles and 5 h of growth treatment in a 30 mM precursor salt based on the hydrothermal synthesis. Extensive characterizations have been performed on field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Energy-dispersive X-ray spectroscopy, High resolution transmission electron microscopy, Photoluminescence spectroscopy, and Raman spectroscopy to assess the different aspects such as structural, morphological, elemental, and wettability of the plain and ZnO-modified carbon fiber textiles. ZnO nanomaterial having hexagonal nanorods shape and wurtzite crystalline structure were uniformly deposited on the fabrics. Owing to the wettability study, ZnO prisms improved the hydrophilicity of virgin carbon fiber textiles to enable strong bonds with polymer matrix. The findings highlight the significant improvement in the static water contact angle as a result of the samples' ZnO coating's ability to reduce surface free energy. The improved hydrophilicity in carbon fiber may enhance the bonding between carbon fibers and matrix materials in composite materials. Hydrophilic carbon fibers are more easily wetted by the matrix materials, allowing for better penetration of the matrix into the fiber structure. [ABSTRACT FROM AUTHOR]

Metal-oxide nanocomposite materials provide a versatile platform with emerged novel phenomena for low-power optical, electronic and energy devices. In this work, heteroepitaxial La 0.7 Sr 0.3 MnO 3 :Ag (LSMO:Ag) nanocomposite thin films were deposited on flexible mica substrates and the optical-electrical response was comprehensively investigated under compositional engineering and mechanical bending. With the change in Ag volume ratio, the response time and intensity for the light-induced resistance change is greatly modified. This modulation behaviour is understood based on a proposed band diagram, where the Fermi level alignment between Ag and LSMO heteroepitaxial interfaces provide additional carrier hopping routes which facilitates the carrier and energy transfer. Additionally, the response properties remain stable, with neglectable degradation over 40 cycles of in-situ mechanical bending and 50,000 cycles of fatigue tests, thus showing superior endurability. The flexible LSMO:Ag nanocomposite films exhibit great potential for high-performance, highly tunable, mechanically endurable and multifunctional optical-electronic applications. This also meets the harsh criteria for devices servicing in special mechanical conditions that requires tunable functionality. [ABSTRACT FROM AUTHOR]

Quantifying methane emissions is essential for meeting near-term climate goals and is typically carried out using methane concentrations measured downwind of the source. One major source of methane that is important to observe and promptly remediate is fugitive emissions from oil and gas production sites but installing methane sensors at the thousands of sites within a production basin is expensive. In recent years, relatively inexpensive metal oxide sensors have been used to measure methane concentrations at production sites. Current methods used to calibrate metal oxide sensors have been shown to have significant shortcomings, resulting in limited confidence in methane concentrations generated by these sensors. To address this, we investigate using machine learning (ML) to generate a model that converts metal oxide sensor output to methane mixing ratios. To generate test data, two metal oxide sensors, TGS2600 and TGS2611, were collocated with a trace methane analyzer downwind of controlled methane releases. Over the duration of the measurements, the trace gas analyzer's average methane mixing ratio was 2.40 ppm with a maximum of 147.6 ppm. The average calculated methane mixing ratios for the TGS2600 and TGS2611 using the ML algorithm were 2.42 ppm and 2.40 ppm, with maximum values of 117.5 ppm and 106.3 ppm, respectively. A comparison of histograms generated using the analyzer and metal oxide sensors mixing ratios shows overlap coefficients of 0.95 and 0.94 for the TGS2600 and TGS2611, respectively. Overall, our results showed there was a good agreement between the ML-derived metal oxide sensors' mixing ratios and those generated using the more accurate trace gas analyzer. This suggests that the response of lower-cost sensors calibrated using ML could be used to generate mixing ratios with precision and accuracy comparable to higher priced trace methane analyzers. This would improve confidence in low-cost sensors' response, reduce the cost of sensor deployment, and allow for timely and accurate tracking of methane emissions. [ABSTRACT FROM AUTHOR]

Mist chemical vapor deposition (mist‐CVD) is expected to be a potentially low‐environment‐impact and low‐cost crystal growth technique. With mist‐CVD, soluble materials are usually selected as raw materials, and mist is usually generated from an aqueous solution including raw materials. However, any substances to be included in the mist can be potentially supplied as raw materials. Namely, there is no need for the substances to be dissolved in some solvent. Therefore, as a trial, it is demonstrated that mist including poorly soluble particles are used as raw materials for mist‐CVD crystal growth. [ABSTRACT FROM AUTHOR]

Quantifying methane emissions is essential for meeting near-term climate goals and is typically carried out using methane concentrations measured downwind of the source. One major source of methane that is important to observe and promptly remediate is fugitive emissions from oil and gas production sites but installing methane sensors at the thousands of sites within a production basin is expensive. In recent years, relatively inexpensive metal oxide sensors have been used to measure methane concentrations at production sites. Current methods used to calibrate metal oxide sensors have been shown to have significant shortcomings, resulting in limited confidence in methane concentrations generated by these sensors. To address this, we investigate using machine learning (ML) to generate a model that converts metal oxide sensor output to methane mixing ratios. To generate test data, two metal oxide sensors, TGS2600 and TGS2611, were collocated with a trace methane analyzer downwind of controlled methane releases. Over the duration of the measurements, the trace gas analyzer’s average methane mixing ratio was 2.40 ppm with a maximum of 147.6 ppm. The average calculated methane mixing ratios for the TGS2600 and TGS2611 using the ML algorithm were 2.42 ppm and 2.40 ppm, with maximum values of 117.5 ppm and 106.3 ppm, respectively. A comparison of histograms generated using the analyzer and metal oxide sensors mixing ratios shows overlap coefficients of 0.95 and 0.94 for the TGS2600 and TGS2611, respectively. Overall, our results showed there was a good agreement between the ML-derived metal oxide sensors’ mixing ratios and those generated using the more accurate trace gas analyzer. This suggests that the response of lower-cost sensors calibrated using ML could be used to generate mixing ratios with precision and accuracy comparable to higher priced trace methane analyzers. This would improve confidence in low-cost sensors’ response, reduce the cost of sensor deployment, and allow for timely and accurate tracking of methane emissions.

Doped and alloyed transition metal-oxides (TMOs) attract vast attention owing to their tunable electronic properties (e.g., conductivity, band gap, and optical absorption), making them appealing for many (photo)-electronic, chromic, and green energy applications. Dual-functional materials combining electrochromic (EC) and energy storage (e.g., supercapacitor, SC) applications are of interest as they can store energy while shading the light transmission through a window or give off a visual signal of their current energy storage state by a color change. Pure tungsten-oxides exhibit distinctive EC properties but attain low energy density compared to other TMOs (e.g., MoO3 and V2O5). The coloration efficiency and energy density can be enhanced by controlling the morphology, size, and composition of the nanoscale TMOs that constitute the active EC film. Thus far, most EC-SC works showed a trade-off between increased areal capacitance and a decrease in the coloration efficiency or transmittance; the improved EC-SC properties for doped or alloyed metal-oxides were related mostly to the small grain size or to structural distortion caused by the added cation, exhibiting more active sites. Herein, we demonstrate a straightforward and facile synthesis of crystalline Mo/V-alloyed tungsten-oxide ultrathin nanowires (uNWs). We investigated the growth mechanism and succeeded in preserving the crystallinity up to 25% (atomic) alloying. The additional properties (compared to unmodified tungsten-oxide) of the alloyed uNWs, such as absorbance peaks, lead to improved specific capacitance while preserving the high coloration efficiency of uNW W–O, and in the case of W–Mo–O, a better coloration efficiency is measured. [ABSTRACT FROM AUTHOR]

Nowadays, with the expanded radar (Radio Detection and Ranging) systems, the investigation of various materials with the capability to reduce or block reflected electromagnetic radiation has developed sharply. In this study, graphene quantum dots-decorated metal-oxide magnetic composites were fabricated as electromagnetic absorber materials because of their light weight, and good electric and magnetic properties. Furthermore, to investigate morphology engineering, a hydrothermal route was applied to fabricate nanostructures. Nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and elemental mapping (EDS-mapping). Also, the magnetic moment and electromagnetic interference shielding were tested by Vibrating-sample magnetometer (VSM) and reflection loss (RL), respectively. [ABSTRACT FROM AUTHOR]

Highly porous metal oxide–polymer nanocomposites are attracting considerable interest due to their unique structural and functional features. A porous polymer matrix brings properties such as high porosity and permeability, while the metal oxide phase adds functionality. For the metal oxide phase to perform its function, it must be fully accessible, and this is possible only at the pore surface, but functioning surfaces require controlled engineering, which remains a challenge. Here, highly porous nanocomposite beads based on thin metal oxide nanocoatings and polymerized high internal phase emulsions (polyHIPEs) are demonstrated. By leveraging the unique properties of polyHIPEs, i.e., a three-dimensional (3D) interconnected network of macropores, and high-precision of the atomic-layer-deposition technique (ALD), we were able to homogeneously coat the entire surface of the pores in polyHIPE beads with TiO2-, ZnO-, and Al2O3-based nanocoatings. Parameters such as nanocoating thickness, growth per cycle (GPC), and metal oxide (MO) composition were systematically controlled by varying the number of deposition cycles and dosing time under specific process conditions. The combination of polyHIPE structure and ALD technique proved advantageous, as MO-nanocoatings with thicknesses between 11 ± 3 and 40 ± 9 nm for TiO2 or 31 ± 6 and 74 ± 28 nm for ZnO and Al2O3, respectively, were successfully fabricated. It has been shown that the number of ALD cycles affects both the thickness and crystallinity of the MO nanocoatings. Finally, the potential of ALD-derived TiO2-polyHIPE beads in photocatalytic oxidation of an aqueous bisphenol A (BPA) solution was demonstrated. The beads exhibited about five times higher activity than nanocomposite beads prepared by the conventional (Pickering) method. Such ALD-derived polyHIPE nanocomposites could find wide application in nanotechnology, sensor development, or catalysis. [ABSTRACT FROM AUTHOR]

Chemoresistive nanostructured gas sensors are employed in many diverse applications in the medical, industrial, environmental, etc. fields; therefore, it is crucial to have a device that is able to quickly calibrate and characterize them. To this aim, a portable, user-friendly device designed to easily calibrate a sensor in laboratory and/or on field is introduced here. The device comprises a small hermetically sealed chamber (containing the sensor socket and a temperature/humidity sensor), a pneumatic system, and a custom electronics controlled by a Raspberry Pi 4 developing board, running a custom software (Version 1.0) whose user interface is accessed via a multitouch-screen. This device automatically characterizes the sensor heater in order to precisely set the desired working temperature, it acquires and plots the sensor current-to-voltage and Arrhenius relationships on the touch screen, and it can record the sensor responses to different gases and environments. These tests were performed in dry air on two representative sensors based on widely used SnO2 material. The device demonstrated the independence of the Arrhenius plot from the film applied voltage and the linearity of the I–Vs, which resulted from the voltage step length (1–30 min) and temperature (200–550 °C). [ABSTRACT FROM AUTHOR]

Nanoengineered nanoparticles have a significant impact on the morphological, physiology, biochemical, cytogenetic, and reproductive yields of agricultural crops. Metal and metal oxide nanoparticles like Ag, Au, Cu, Zn, Ti, Mg, Mn, Fe, Mo, etc. and ZnO, TiO2, CuO, SiO2, MgO, MnO, Fe2O3 or Fe3O4, etc. that found entry into agricultural land, alter the morphological, biochemical and physiological system of crop plants. And the impacts on these parameters vary based on the type of crop and nanoparticles, doses of nanoparticles and its exposure situation or duration, etc. These nanoparticles have application in agriculture as nanofertilizers, nanopesticides, nanoremediator, nanobiosensor, nanoformulation, phytostress-mediator, etc. The challenges of engineered metal and metal oxide nanoparticles pertaining to soil pollution, phytotoxicity, and safety issue for food chains (human and animal safety) need to be understood in detail. This review provides a general overview of the applications of nanoparticles, their potentials and challenges in agriculture for sustainable crop production. [ABSTRACT FROM AUTHOR]

Metal-oxide semiconducting materials are promising for building high-performance field-effect transistor (FET) based biochemical sensors. The existence of well-established top-down scalable manufacturing processes enables the reliable production of cost-effective yet high-performance sensors, two key considerations toward the translation of such devices in real-life applications. Metal-oxide semiconductor FET biochemical sensors are especially well-suited to the development of Point-of-Care testing (PoCT) devices, as illustrated by the rapidly growing body of reports in the field. Yet, metal-oxide semiconductor FET sensors remain confined to date, mainly in academia. Toward accelerating the real-life translation of this exciting technology, we review the current literature and discuss the critical features underpinning the successful development of metal-oxide semiconductor FET-based PoCT devices that meet the stringent performance, manufacturing, and regulatory requirements of PoCT. [ABSTRACT FROM AUTHOR]

Presently described is a sliding-kernel computation-in-memory (SKCIM) architecture conceptually involving two overlapping layers of functional arrays, one containing memory elements and artificial synapses for neuromorphic computation, the other is used for storing and sliding convolutional kernel matrices. A low-temperature metal-oxide thin-film transistor (TFT) technology capable of monolithically integrating single-gate TFTs, dual-gate TFTs, and memory capacitors is deployed for the construction of a physical SKCIM system. Exhibiting an 88% reduction in memory access operations compared to state-of-the-art systems, a 32 × 32 SKCIM system is applied to execute common convolution tasks. A more involved demonstration is the application of a 5-layer, SKCIM-based convolutional neural network to the classification of the modified national institute of standards and technology (MNIST) dataset of handwritten numerals, achieving an accuracy rate of over 95%., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Chemoresistive nanostructured gas sensors are employed in many diverse applications in the medical, industrial, environmental, etc. fields; therefore, it is crucial to have a device that is able to quickly calibrate and characterize them. To this aim, a portable, user-friendly device designed to easily calibrate a sensor in laboratory and/or on field is introduced here. The device comprises a small hermetically sealed chamber (containing the sensor socket and a temperature/humidity sensor), a pneumatic system, and a custom electronics controlled by a Raspberry Pi 4 developing board, running a custom software (Version 1.0) whose user interface is accessed via a multitouch-screen. This device automatically characterizes the sensor heater in order to precisely set the desired working temperature, it acquires and plots the sensor current-to-voltage and Arrhenius relationships on the touch screen, and it can record the sensor responses to different gases and environments. These tests were performed in dry air on two representative sensors based on widely used SnO2 material. The device demonstrated the independence of the Arrhenius plot from the film applied voltage and the linearity of the I–Vs, which resulted from the voltage step length (1–30 min) and temperature (200–550 °C).

Removal of toxic metals is essential to achieving sustainability in wastewater purification. The achievement of efficient treatment at a low cost can be seriously challenging. Adsorption methods have been successfully demonstrated for possession of capability in the achievement of the desirable sustainable wastewater treatment. This review provides insights into important conventional and unconventional materials for toxic metal removal from wastewater through the adsorption process. The importance of the role due to the application of nanomaterials such as metal oxides nanoparticle, carbon nanomaterials, and associated nanocomposite were presented. Besides, the principles of adsorption, classes of the adsorbent materials, as well as the mechanisms involved in the adsorption phenomena were discussed. [ABSTRACT FROM AUTHOR]

Direct current (DC) and radio frequency (RF) magnetron sputtering methods were selected for conducting the deposition of structural materials, namely ceramic and metallic co-depositions. A total of six configurations were deposited: single thin layers of oxides (Cr2O3, SiO2) and co-deposition configurations (50:50 wt.%) as structural materials (W, Be)—(Cr2O3, SiO2), all deposited on 304L stainless steel (SS). A comprehensive evaluation such as surface topology, thermal desorption outgassing, and structural/chemical state was performed. Moreover, mechanical characterization evaluating properties such as adherence, nano indentation hardness, indentation modulus, and deformation relative to yielding, was performed. Experimental results show that, contrary to SiO2 matrix, the composite layers of Cr2O3 with Be and W exhibit surface smoothing with mitigation of artifacts, thus presenting a uniform and compact state with the best microstructure. These results are relevant in order to develop future dense coatings to be used in the fusion domain. [ABSTRACT FROM AUTHOR]

Cross‐point arrays of analog synaptic devices are expected to realize neuromorphic computing hardware for neural network computations with compelling speed boost and superior energy efficiency, as opposed to the conventional hardware based on the von Neumann architecture. To achieve desired characteristics of analog synaptic devices for fully parallel vector–matrix multiplication and vector–vector outer‐product updates, metal‐oxide based electrochemical random‐access memory (ECRAM) is proposed as a promising synaptic device due to its complementary metal‐oxide‐semiconductor‐compatibility and outstanding synaptic characteristics over other non‐volatile memory candidates. In this work, ECRAM devices with 3D vertical structure is fabricated to demonstrate a minimal 4F2 cell size, highly scalable channel volume and low programming energy, providing optimized synaptic device performance and characteristics as well as high integrity as a cross‐point array. Various weight‐update profiles of the vertical ECRAM devices are obtained by adjusting programming voltage pulses, exhibiting trade‐offs among dynamic range, linearity, symmetry, and update deviation. Based on simulation with advanced algorithms for analog cross‐point array and neural network designs, the potential of vertical ECRAM for high‐density array is evaluated. Simulation studies suggest that the neuromorphic computing performance can be improved further by balancing the weight update characteristics of vertical ECRAM. [ABSTRACT FROM AUTHOR]

Metal-oxides hold promise as superior plasmonic materials in the mid-infrared compared to metals, although their integration over established material technologies still remains challenging. We demonstrate localized surface plasmons in self-assembled, hemispherical CdZnO metal-oxide nanoparticles on GaAs, as a route to enhance the absorption in mid-infrared photodetectors. In this system, two localized surface plasmon modes are identified at 5.3 and 2.7 μm, which yield an enhancement of the light intensity in the underlying GaAs. In the case of the long-wavelength mode the enhancement is as large as 100 near the interface, and persists at depths down to 50 nm. We show numerically that both modes can be coupled to infrared intersubband transitions in GaAs-based multiple quantum wells, yielding an absorbed power gain as high as 5.5, and allowing light absorption at normal incidence. Experimentally, we demonstrate this coupling in a nanoparticle/multiple quantum well structure, where under p-polarization the intersubband absorption is enhanced by a factor of 2.5 and is still observed under s-polarization, forbidden by the usual absorption selection rules. Thus, the integration of CdZnO on GaAs can help improve the figures of merit of quantum well infrared photodetectors, concept that can be extended to other midinfrared detector technologies.

E-beam evaporated metal-oxide thin films have been studied with different stoichiometries as carrier transport materials for large-scale perovskite solar cell devices. The thin films are deposited through a reactive evaporation of pure metals in various oxygen atmosphere pressures. The measured optical and electrical properties were used in numerical modelling using SCAPS-1D software to demonstrate a power conversion efficiency in excess of 26%. X-ray photoelectron spectroscopy and optical characterization confirmed the variation of the oxygen concentration into these films with respect to the deposition pressures. The electrical measurements using hall probes complies with the reasonable data range. The field emission scanning electron microscopy demonstrated the deposition of dense, homogeneous and pin-hole-free uniform films throughout the substrate's surface. Hydrophobic surface was found for the films grown with nano-porous structure. In particular, large-scale vapour deposition of perovskite solar cells becomes feasible due to such fabrication technique without breaking the vacuum. [ABSTRACT FROM AUTHOR]

Exploiting emerging artificial photosystems with regulated vectorial charge transfer pathways is retarded by the difficulties in precise interface modulation at the nanoscale level, deficiency of suitable assembly methodologies, and ultra‐short charge lifetime. Herein, it is first conceptually demonstrated the general design of transition metal chalcogenides quantum dots (TMCs QDs)‐insulating polymer‐metal oxides (MOs) electron‐tunneling photosystems, wherein TMCs QDs are controllably layer‐by‐layer self‐assembled on the MOs substrates assisted by an ultrathin insulating polymer interim layer. It is ascertained that electrons photoexcited over TMCs QDs in spatially highly ordered MOs/(TMCs QDs/polymer)n multilayered heterostructures can be unidirectionally extracted and tunneled to the MOs substrates across the intermediate insulating polymer layer by engendering the tandem charge transfer to accelerate the interfacial charge migration kinetics, thereby triggering the significantly boosted net efficiency of solar‐driven photoelectrochemical water oxidation. This study would spark new inspirations for designing novel electron‐tunneling photosystems for fine carrier modulation towards solar energy harvesting and conversion. [ABSTRACT FROM AUTHOR]

Metal oxide semiconductor has attracted so much attention due to its high carrier mobility. Herein, thermoelectric study of nanocrystalline SnO2 through a simple co-precipitation method is conducted to enhance the Seebeck coefficient (S). X-ray diffraction, thermogravimetric analysis (TGA), resistivity (r), Seebeck coefficient (S), and power factor (PF) measurements are conducted to analyze the thermoelectric properties of the material. The measurements show that there are two interesting results, which are the unusual resistivity behavior and the high value of the S. Resistivity behavior shows a non-reflective intermediate semiconductor-metals behavior where the turning point occurs at 250 o C. This behavior is strongly correlated to the surface oxide reaction due to annealing temperature. The maximum S likely occurs at 250 ºC, since the curve shows a slight thermopower peak at 250 ºC. The value of the S is quite high with around twenty times higher than other publications about SnO2 thermoelectric material, this happens due to the bandgap broadening. The energy gap of SnO2 calculated using density functional theory (DFT), which was performed by Quantum Espresso 6.6. The result shows that there is a broadening energy gap at different momentum or wave factor. Nanocrystalline semiconductors material is giving an impact to increase the width of bandgap due to quantum confinement and could enhance the thermopower especially in SnO2 nanocrystalline

Metal-oxide semiconducting materials are promising for building high-performance field-effect transistor (FET) based biochemical sensors. The existence of well-established top-down scalable manufacturing processes enables the reliable production of cost-effective yet high-performance sensors, two key considerations toward the translation of such devices in real-life applications. Metal-oxide semiconductor FET biochemical sensors are especially well-suited to the development of Point-of-Care testing (PoCT) devices, as illustrated by the rapidly growing body of reports in the field. Yet, metal-oxide semiconductor FET sensors remain confined to date, mainly in academia. Toward accelerating the real-life translation of this exciting technology, we review the current literature and discuss the critical features underpinning the successful development of metal-oxide semiconductor FET-based PoCT devices that meet the stringent performance, manufacturing, and regulatory requirements of PoCT.

Cross‐point arrays of synaptic devices have been investigated as a core platform for neuromorphic computing architectures. To achieve a significant speed boost in deep neural network computations compared to the von Neumann architecture, it is essential to develop synaptic devices with optimal performance for fully parallel vector‐matrix‐multiplication. Among various non‐volatile memory candidates, metal‐oxide based electrochemical random‐access memory (ECRAM) is considered as a promising analog synapse due to its superior switching characteristics and CMOS‐compatibility. However, the switching mechanisms of metal‐oxide ECRAM remain to be understood, impeding improvements of the synaptic characteristics and device performance. Here, ionic programming dynamics based on oxygen ion migration and associated redox‐reactions are investigated in metal‐oxide ECRAMs by considering ion transport via the electrolyte and diffusion in the channel. Additionally, the origins of update asymmetry and long‐term retention found in voltage‐pulse programming measurements are explained by non‐uniform distribution of the off‐stoichiometry in the channel layer. By exploiting the programming mechanism, ECRAMs can achieve desirable synaptic characteristics under voltage‐pulse mode. Finally, experimental and simulation studies consistently suggest that channel and electrolyte with high ionic transport properties can improve the performance of metal‐oxide ECRAMs, opening a path toward optimized synaptic device characteristics for the maximum computation performance. [ABSTRACT FROM AUTHOR]

Direct current (DC) and radio frequency (RF) magnetron sputtering methods were selected for conducting the deposition of structural materials, namely ceramic and metallic co-depositions. A total of six configurations were deposited: single thin layers of oxides (Cr2O3, SiO2) and co-deposition configurations (50:50 wt.%) as structural materials (W, Be)—(Cr2O3, SiO2), all deposited on 304L stainless steel (SS). A comprehensive evaluation such as surface topology, thermal desorption outgassing, and structural/chemical state was performed. Moreover, mechanical characterization evaluating properties such as adherence, nano indentation hardness, indentation modulus, and deformation relative to yielding, was performed. Experimental results show that, contrary to SiO2 matrix, the composite layers of Cr2O3 with Be and W exhibit surface smoothing with mitigation of artifacts, thus presenting a uniform and compact state with the best microstructure. These results are relevant in order to develop future dense coatings to be used in the fusion domain.

In the past decade, the perovskite solar cell (PSC) has attracted tremendous attention thanks to the substantial efforts in improving the power conversion efficiency from 3.8% to 25.5% for single‐junction devices and even perovskite‐silicon tandems have reached 29.15%. This is a result of improvement in composition, solvent, interface, and dimensionality engineering. Furthermore, the long‐term stability of PSCs has also been significantly improved. Such rapid developments have made PSCs a competitive candidate for next‐generation photovoltaics. The electron transport layer (ETL) is one of the most important functional layers in PSCs, due to its crucial role in contributing to the overall performance of devices. This review provides an up‐to‐date summary of the developments in inorganic electron transport materials (ETMs) for PSCs. The three most prevalent inorganic ETMs (TiO2, SnO2, and ZnO) are examined with a focus on the effects of synthesis and preparation methods, as well as an introduction to their application in tandem devices. The emerging trends in inorganic ETMs used for PSC research are also reviewed. Finally, strategies to optimize the performance of ETL in PSCs, effects the ETL has on J–V hysteresis phenomenon and long‐term stability with an outlook on current challenges and further development are discussed. [ABSTRACT FROM AUTHOR]

Herein, dielectric/semiconductor interfacial p‐doping is used to develop a high‐carrier‐mobility and balanced ambipolar tin oxide (SnO2) thin‐film transistor (TFT). To introduce this interfacial doping, TFTs are fabricated by using two different ion‐conducting oxide dielectrics containing trivalent atoms. These ion‐conducting dielectrics are LiInO2 and LiGaO2 containing a mobile Li+ ion that reduces the operating voltage of these TFTs to ≤2.0 V. During SnO2 thin film deposition, the interfacial SnO2 layer is p‐doped by an In or Ga atom of the gate dielectric and therefore, hole conduction is facilitated in the channel of the TFT. To realize this interfacial doping phenomenon, a reference TFT is fabricated with a Li2ZnO2 dielectric that contains a divalent zinc atom. Comparative electrical data indicate that TFTs with LiInO2 and LiGaO2 dielectrics are ambipolar in nature, whereas the TFT with a Li2ZnO2 dielectric is a unipolar n‐channel transistor, corroborating the interfacial doping of SnO2. Most interestingly, using a LiInO2 dielectric, a 1.0 V balanced ambipolar TFT with high electron and hole mobility values of 7 and 8 cm2 V−1 s−1, respectively, can be fabricated, with an on/off ratio > 102 for both operations. The TFT with a LiInO2 dielectric is utilized successfully to fabricate a low‐voltage complementary metal–oxide–semiconductor (CMOS) inverter. [ABSTRACT FROM AUTHOR]

We evaluated solid-state sensors (MOS) manufactured using nanostructured tin oxide (SnO2) obtained by different synthesis methods for selectivity, response and repeatability at different operating temperatures and methane concentrations. In addition, Zeolite 13X pellets were placed in front of the sensors to improve CH4 selectivity in the presence of CO2. The palladium doped sensor (1.4% w/w) showed the highest sensitivity at 80 ºC (83%) and shorter response times (16 s), whereas non-doped sensors exhibited the best sensitivity (78%) and response times (14 s) for those with smaller particle size (8 nm). Zeolite 13X pellets proved to be efficient at making the sensor more selective for CH4 in the presence of CO2.

Pure, mixed and doped metal oxides (MOX) have attracted great interest for the development of electrical and electrochemical sensors since they are cheaper, faster, easier to operate and capable of online analysis and real-time identification. This review focuses on highly sensitive chemoresistive type sensors based on doped-SnO2, RhO, ZnO-Ca, Smx-CoFe2−xO4 semiconductors used to detect toxic gases (H2, CO, NO2) and volatile organic compounds (VOCs) (e.g., acetone, ethanol) in monitoring of gaseous markers in the breath of patients with specific pathologies and for environmental pollution control. Interesting results about the monitoring of biochemical substances as dopamine, epinephrine, serotonin and glucose have been also reported using electrochemical sensors based on hybrid MOX nanocomposite modified glassy carbon and screen-printed carbon electrodes. The fundamental sensing mechanisms and commercial limitations of the MOX-based electrical and electrochemical sensors are discussed providing research directions to bridge the existing gap between new sensing concepts and real-world analytical applications.

• Reactivity of supported PdCu nanoparticles in aldol-condensation reaction was tested. • Particles stability was identified by X-ray tomography measurements. • Catalyst deactivation was caused by oxide deformation and nanoparticles aggregation. • TiO 2 -supported PdCu nanoparticles showed improved reactivity and stability. The impact of tandem dehydrogenation-aldol condensation reactions on the structure of oxide-supported PdCu catalysts was studied by a combination of X-ray tomography measurements, ensemble-averaging spectroscopy techniques and reactivity measurements. X-ray tomography measurements generated 3D images at submicron resolution of the packed catalyst in the flow reactor following its exposure to various reaction conditions. Quantitative analysis of the tomography data revealed that exposure of the catalyst to reaction conditions induced structural deformation of the mixed Mg-Al oxide supports, accompanied by sintering of the PdCu nanoparticles into micron-sized aggregates. Improved stability was achieved once the PdCu particles were supported on an oxide, such as anatase TiO 2 , which does not undergo restructuring or phase transition under reaction conditions. This study demonstrates that structural information extracted by X-ray tomography measurements may uncover important structure-reactivity correlations and identify the reasons for catalysts deactivation. [ABSTRACT FROM AUTHOR]

Abstract Cu 2 ZnSnS(e) 4 deposited using solution processes has potential for terrawatt-scale deployment. The champion highest efficiency Cu 2 ZnSn(S, Se) 4 cell published in literature is spin-coated using the highly dangerous hydrazine which is an impractically scalable solvent and deposition combination. As an alternative solvent amine-thiol mixtures have shown to complex with a wide range of binary chalcogenides with much lower health risks than hydrazine. Herein we present two further toxicity reductions, first by employing a less harmful amine-thiol pairing and second by using water as a diluting solvent. We exclude extraneous elements from the precursor solution such as halogens and with a sub-micron thickness crystalline absorber achieve an efficiency of 6.8%. With the modified solution deposited by ultrasonic spray pyrolysis, this solution process is scalable, abundant, and relatively non-toxic. Highlights • 6.8% Efficient kesterite solar cell. • Metal oxides dissolved in a water-based solution process. • Deposited by ultrasonic spray pyrolysis. [ABSTRACT FROM AUTHOR]

Accurate and selective detection of target gas/volatile organic compounds (VOCs) is of utmost importance. The chemiresistive gas sensors have been a desirable candidate due to their compact footprint and ease of fabrication, but they show poor selectivity. This work presents a combination of nanomaterials-based chemiresistive gas sensors with machine learning (ML) techniques to achieve sensitive, selective, and quantified detection of tested VOCs. The sensor array consists of four separate sensing layers over interdigitated electrodes-based platform. The sensing materials were comprised of silver, gold, palladium, and platinum nanoparticles decorated on tin oxide hollow-sphere structures which were successfully synthesized through chemical routes and characterized accordingly. Surface decoration of different metal nanoparticles has produced sensitive and diverse sensing patterns among the tested VOCs. The sensing mechanism and related gas sensing kinetics were then analyzed to explain high sensitivity and diverse sensing phenomena. The subsequent incorporation of ML models has resulted in qualitative and quantitative detection of VOCs. A comparative analysis was carried out among different types of applied features and ML models with reasoning. Particularly, a deep neural network (DNN) model with time series (TS) response sequence as input information, delivered the best performance. The DNN_TS model presented an average classification accuracy of 98.33 %, in conjunction with excellent concentration prediction. The DNN_TS model showed a very fast prediction time of 2.74 µs with adaptive learning while utilizing minimum computing resources, which favors the real-time sensing capability. The reported results promote the development of an autonomous, smart, and selective gas sensor system for real-time applications. [Display omitted] • Metal nanoparticles decorated SnO 2 hollow-spheres based gas sensor array was employed. • Excellent and diverse sensing response pattern was observed for the tested VOCs. • The issue of selectivity was addressed using soft computing tools. • Applied deep learning model effectively classify and quantify among the tested VOCs. • Comparative analysis was done among different input features engaged with ML models. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3) production via electrochemical nitrogen reduction is gaining popularity as a clean and sustainable alternative to the Haber−Bosch process (HBP). Here we report ZnMn 2 O 4 derived from spent primary Zn-C battery as an efficient electrocatalyst for nitrogen reduction reaction (NRR). This catalysts needs only water apart from N 2 as reactant. The catalyst exhibits high activity and selectivity with an NH 3 yield rate of 143 ± 3 μg h−1 mg cat −1 and a faradaic efficiency of 49 ± 2 % at − 0.5 V vs. RHE. Mechanistic modeling of the experimental data was carried out to gain insight into the kinetic parameters. DFT calculations were also employed to corroborate the mechanism hypothesized for NRR in this work. [Display omitted] • Electrochemical ammonia production via nitrogen reduction reaction. • Spinel ZnMn 2 O 4 is recovered from spent Zn/C batteries. • Kinetic parameters were studied using mechanistic modeling. • The highest efficiency and yield rate were attained using ZnMn 2 O 4 as an electrocatalyst. [ABSTRACT FROM AUTHOR]

In this paper, a detailed reliability analysis of metal-oxide conductive bridge memories (CBRAM) is presented. This paper mostly focuses on electrical characterization of metal-oxide CBRAM devices endurance, using optimized program/erase conditions, and data retention at high temperature. The addition of a thin metal-oxide layer (0.5 nm-thick Al2O3) in the bottom of the GdOx memory stack significantly increases the ROFF and the memory window (more than one decade), with improved endurance performance (up to 105 cycles) with respect to the monolayer CBRAM device. Meanwhile, high thermal stability was also achieved (two decades of window margin are constantly maintained beyond 24 h at 250 °C). The bilayer oxide GdOX/Al2O3 CBRAM is a promising technology for potential future high density memory applications.

Among the diverse and ever-expanding list of candidate technologies to serve the Internet of Everything, the rise of thin-film transistors on plastic as active components for ubiquitous ICs has been nothing short of meteoric. The stage for this explosion of interest was set by a pivotal advantage of the low manufacturing cost and ultrathin form factor, as demonstrated in recent prototypes of thin-film radio frequency identification (RFID) tags. Most RFID tags use inductive antennas, whereas, in this paper, capacitively coupled antenna is presented. Advantages of capacitive-coupled tags are the monolithic integrated antenna, the compact size, the additional security due to very short range of operation, and the localization and orientation abilities. The main circuit block of the tag, a 12-bit code generator, is demonstrated achieving only 160 nW of power dissipation at 0.3 V power supply transmitting data at 810 b/s on a 18 $\mu \text{m}$ -thick plastic substrate. The footprint of the monolithic integrated antenna is 1 cm2 and essentially defines the size of the full tag. [ABSTRACT FROM AUTHOR]

The 3D N-doped graphene supported metal oxide has been synthesized as the sulfur host of Lithium-sulfur battery. A simple method of nanoparticles in-situ grown in aqueous solution is introduced. The SEM images and XRD spectra confirmed that nanoparticles with few tens of nanometers distributed on the surface of graphene sheet. The compound electrode showed an initial specific capacity of 1518 mA h g −1 at 0.2 C with a sulfur utilization of 90%. During 700 cycles, the capacity decay was only 0.03% per cycle. Even at a high rate of 2 C, the specific capacity can still be achieved 595 mA h g −1 . The visual charge-discharge test showed that the composite electrode had strong adsorption effect on polysulfide vividly. [ABSTRACT FROM AUTHOR]

CuO thin film/TiO 2 nanotubes heterostructures were fabricated to investigate the effect of p-n heterojunction on sensing properties. TiO 2 nanotubes were synthesized via anodization of Ti foil. Then, CuO thin film was covered on the nanotubes by oxidation of thermally evaporated Cu layer. For comparison, sensor devices those are composed of only CuO thin film and composed of TiO 2 nanotubes have been also fabricated. The heterostructure was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy. Fabricated sensor devices were exposed to H 2 , ethanol, acetone, chloroform and NO 2 gases at different operation temperatures. Experimental results showed that the heterostructure sensor has better performance toward H 2 in sensing with low operation temperature, low detection limit and high sensor response compared to TiO 2 nanotubes and CuO thin film. Moreover, the formation of heterostructure not only increased response toward H 2 but also dramatically decreased response toward VOCs and NO 2 . These improved sensing properties are attributed to the heterojunction between CuO thin film and TiO 2 nanotubes. [ABSTRACT FROM AUTHOR]

In this paper, we fabricated p-Co3O4/n-TiO2 heterostructures and investigated their gas sensing properties. The structural and morphological characterization were performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy analysis (XPS). The electrical properties of the heterostructure were studied within the temperature range from 293 K to 423 K. Changes in electrical properties and sensing behavior against reducing and oxidizing gases were attributed to the formation of p-n heterojunctions at the Co3O4 and TiO2 interface. In comparison with sensing performed with pristine TiO2 nanotubes (NTs), a significant improvement in H2 sensing at 200 °C was observed, while the sensing response against NO2 decreased for the heterostructures. Additionally, a response against toluene gas, in contrast to pristine TiO2 NTs, appeared in the Co3O4/TiO2 heterostructure samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A uniform ultrathin ZrO2 layer is developed on a corrugated copper substrate. • A detailed mechanistic analysis of the polymer brush deposition process and the creation of nano-metal oxide layers is carried out. • The polymer brush was removed using the H 2 plasma method, reducing numerous steps to a single step. We demonstrate a polymer brush assisted approach for the fabrication of continuous zirconium oxide (ZrO 2) films over large areas with high uniformity (pin-hole free) on copper (Cu) substrates. This approach involves the use of a thiol-terminated polymethyl methacrylate brush (PMMA-SH) as the template layer for the selective infiltration of zirconium oxynitrate (ZrN 2 O 7). The preparation of a highly uniform covalently grafted polymer monolayer on the Cu substrate is the critical factor in fabricating a metal oxide film of uniform thickness across the surface. Infiltration is reliant on the chemical interactions between the polymer functional group and the metal precursor. A following reductive H 2 plasma treatment process results in ZrO 2 film formation whilst the surface Cu 2 O passive oxide layer was reduced to a Cu/Cu 2 O interface. Fundamental analysis of the infiltration process and the resulting ZrO 2 film was determined by XPS, and GA-FTIR. Results derived from these techniques confirm the inclusion of the ZrN 2 O 7 into the polymer films. Cross-sectional transmission electron microscopy and energy dispersive X-ray mapping analysis corroborate the formation of ZrO 2 layer at Cu substrate. We believe that this quick and facile methodology to prepare ZrO 2 films is potentially scalable to other high-κ dielectric materials of high interest in microelectronic applications. [ABSTRACT FROM AUTHOR]