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Flexible transparent conductive electrodes (FTCEs) constitute an indispensable component in state‐of‐the‐art electronic devices, such as wearable flexible sensors, flexible displays, artificial skin, and biomedical devices, etc. This review paper offers a comprehensive overview of the fabrication techniques, growth modes, material dimensions, design, and their impacts on FTCEs fabrication. The growth modes, such as the "Stranski–Krastanov growth," "Frank–van der Merwe growth," and "Volmer–Weber growth" modes provide flexibility in fabricating FTCEs. Application of different materials including 0D, 1D, 2D, polymer composites, conductive oxides, and hybrid materials in FTCE fabrication, emphasizing their suitability in flexible devices are discussed. This review also delves into the design strategies of FTCEs, including microgrids, nanotroughs, nanomesh, nanowires network, and "kirigami"‐inspired patterns, etc. The pros and cons associated with these materials and designs are also addressed appropriately. Considerations such as trade‐offs between electrical conductivity and optical transparency or "figure of merit (FoM)," "strain engineering," "work function," and "haze" are also discussed briefly. Finally, this review outlines the challenges and opportunities in the current and future development of FTCEs for flexible electronics, including the improved trade‐offs between optoelectronic parameters, novel materials development, mechanical stability, reproducibility, scalability, and durability enhancement, safety, biocompatibility, etc. [ABSTRACT FROM AUTHOR]

In this study, we report the effects of various ceramic processing methods with different sintering aids on the relative density, crystallinity, microstructure, and electrical conductivity of proton conducting BaZr 0.85 Y 0.15 O 3− δ (BZY) pellets in details. First, the BZY ceramic pellets are fabricated by the solid-state reactive sintering by adding diverse sintering aids including CuO, NiO, ZnO, SnO, MgO, and Al 2 O 3 . Among these, CuO is found to be the most effective sintering aid in terms of the sintering temperature and total conductivity. However, transition metals as sintering aids have detrimental effects on the electrical conductivity of the BZY electrolytes. Second, the BZY electrolytes have been synthesized by four different methods: the solid-state, combustion, hydrothermal, and polymer gelation methods. The BZY pellets synthesized by the polymer gelation method exhibit dense microstructure with a high relative density of 95.3%. Moreover, the electrical conductivity of the BZY pellets synthesized by the polymer gelation method is higher than those prepared by the solid-state methods under the same test conditions: 1.28 × 10 −2 S cm −1 (by the polymer gelation method) vs. 0.53 × 10 −2 S cm −1 by the solid-state method at 600 °C in wet 5% H 2 in Ar. [ABSTRACT FROM AUTHOR]

Abstract: During continuous power operation for 2740 h, the major mechanisms and patterns of performance degradation in a polymer electrolyte membrane fuel cell (PEMFC) stack are investigated under low cathode humidification with simulated reformate fuel gases through the use of various physicochemical and electrochemical analysis tools. As operating time increases, the operating voltages and open-circuit voltages (OCVs) of the stack decrease with the large voltage distributions. In the post-mortem analysis of the stack, the delamination of the catalyst layer (CL) of unstable operating membrane electrode assemblies (MEAs) is significant near the cathode gas inlets. This observation is in agreement with the results of OCV, hydrogen crossover current, and anode off-gas measurements. This phenomenon may be due to the acceleration of carbon corrosion in the cathode during the frequent start-up and shut-down process, because the local cathode potential can reach more than 1.5 V in the air/fuel boundary. Additionally, the frequent membrane hydration and dehydration by the accumulation of excess water (through electrochemical reaction) and faster water evaporation (under dry-air cathode conditions and high operating temperatures) may accelerate the interface delamination between the membrane and cathode CL with a substantially uneven distribution of water. [Copyright &y& Elsevier]

Abstract: This paper is presented to investigate operational characteristics of a direct methanol fuel cell (DMFC) stack with regard to fuel and energy efficiency, including its performance and stability under various operating conditions. Fuel efficiency of the DMFC stack is strongly dependent on fuel concentration, working temperature, current density, and anode channel configuration in the bipolar plates and noticeably increases due to the reduced methanol crossover through the membrane, as the current density increases and the methanol concentration, anode channel depth, and temperature decreases. It is, however, revealed that the energy efficiency of the DMFC stack is not always improved with increased fuel efficiency, since the reduced methanol crossover does not always indicate an increase in the power of the DMFC stack. Further, a lower methanol concentration and temperature sacrifice the power and operational stability of the stack with the large difference of cell voltages, even though the stack shows more than 90% of fuel efficiency in this operating condition. The energy efficiency is therefore a more important characteristic to find optimal operating conditions in the DMFC stack than fuel efficiency based on the methanol utilization and crossover, since it considers both fuel efficiency and cell electrical power. These efforts may contribute to commercialization of the highly efficient DMFC system, through reduction of the loss of energy and fuel. [Copyright &y& Elsevier]

The piezoelectric quartz crystal resonator is a common electronic device used for a reference clock which has high Q-valued resonance. In this paper, a general description on the quartz crystal resonator based scanning probe microscopy is presented. Most well-known type of the quartz crystal resonator is the tuning fork which has been employed as a force sensor in many different types of the scanning probe microscopy. The most important advantage of the quartz crystal resonator based scanning probe microscopy is high resolution imaging. Furthermore, it has potential to be used at low temperature due to its low power dissipation, compactness, and non-optical detection. [ABSTRACT FROM AUTHOR]

We have investigated the effects of electron density discontinuity on the transports of edge currents of two-dimensional electron gas (2DEG). The electric field applied to a gate, which covers the 2DEG partially, gives rise to change in the carrier density and results in a density gradient, which deforms the edge currents. The transverse and longitudinal resistances were measured as functions of gate voltage VG in the quantum Hall regime. The deviations of the longitudinal resistances from the normal quantum Hall resistances are attributed to the reflections of the edge currents under the influence of the abrupt density discontinuity. A switching behavior of the transverse resistance by controlling the gate voltage was observed when VG=−2.2 and −2.0 V for magnetic field H=5 and 7.2 T, respectively. [Copyright &y& Elsevier]

The fabrication of van der Waals heterostructures (vdWHs) has drawn considerable interest because of their wide range of functionalities. Herein, a novel PdSe2/ReSe2 vdWHs with gate‐tunable rectification behavior and excellent broadband photodetection characteristics is presented. The application of the gate bias substantially enhances the rectification behavior, with the highest rectification ratio (≈3.13 × 103) observed at gate voltage Vg = −60 V. The density functional theory calculations demonstrate the direct and indirect bandgap behavior of PdSe2 and ReSe2 in the monolayer structure, respectively. Additionally, the PdSe2/ReSe2 heterojunction displays a strong photo‐response in the near‐infrared region and achieves a high photoresponsivity, an excellent external quantum efficiency, and rapid rise and decay times of 1.7 × 103 A W−1, 4.05 × 103, and 5 and 20 ms, respectively. Furthermore, the device exhibits a remarkable detectivity of ≈3.5 × 1012 Jones. The findings hold great potential for advancing the fabrication of multifunctional vdW heterostructure devices. [ABSTRACT FROM AUTHOR]

The real-time atomic force microscope for biological sample is a challenging research field. We have demonstrated a real-time atomic force microscope by implementing a mechanical resonator type scanner called by “microscanner” The microscanner was designed to have a resonance frequency in the range of 5–10 kHz and an amplitude of 1–3 μm. The resonant vibration of the microscanner was served as a fast-scan directional motion, and an image acquisition rate of 30 frames/s with 256×256 pixels per frame was achieved. Time-varying sequential images of a poly(ethylene-oxide) sample were taken as a demonstration of potential for excellence in real-time imaging a moving nano-object. [ABSTRACT FROM AUTHOR]

We have built a high-speed, tapping mode scanning force microscope using a high frequency quartz crystal resonator. In our design, a cantilever tip was attached to the end of an optical fiber which was glued to a thickness shear mode, AT-cut quartz crystal resonator so as to vibrate in the longitudinal direction. This design allows the microscope to be operated in tapping mode with the flexibility of shear mode operation, which leads to an expected improvement of image quality. Furthermore, combining this geometry with an optical microscope leads to the possibility of commercial applications. [ABSTRACT FROM AUTHOR]

We demonstrate an electrostatic force microscopy based on a quartz tuning fork with 50 nm spatial resolution and 1 pN force sensitivity. We use a tuning fork with a spring constant of 1300 N/m and a Q factor of 3000. A sharpened nickel tip is attached to a prong of the tuning fork as well as electrically connected to the electrode of the prong. By applying a dc bias to the tip, ferroelectric domain patterns are recorded and read out on piezoelectric thin film. [ABSTRACT FROM AUTHOR]

We demonstrate high-speed near-field scanning optical microscopy using a tapered fiber tip that is inserted in a perforated quartz-crystal resonator. With this high-frequency dithering probe, we have obtained near-field optical images at the scanning speed of 1.3 mm/s and it takes only 0.5 s to image the surface area of 100 µm² for 64 × 64 pixels without any compromise of spatial lateral resolution. As an application, we have obtained sequential scanning images of the diffusing microspheres in water, which shows slow change of the sample configuration in the time scale of several minutes. [ABSTRACT FROM AUTHOR]

We utilize an “inductive pulse” quartz crystal microbalance method to study N2 adsorption on quartz, silver, and a single wall carbon nanotube at 77 K. This method is based on radio frequency electric pulse excitation and ring-down signal measurements of quartz crystal resonators located in an induction coil. The surface areas and adsorption strength c are estimated by the Brunauer-Emmett-Teller (BET) model. The estimated c for quartz and silver surface are about 1/5 times smaller than that measured by the conventional method. This is explained as suppression of the self-heating effect, by using our inductive pulse method. We suggest a simple theoretical estimation of self-heating effects on conventional and inductive pulse methods. For the intermediate adsorption range, we analyze our data using the generalized Frenkel-Hasley-Hill (FHH) model with fractal dimension. While the quartz and silver have fractal dimensions of about 2.2±0.1, single wall carbon nanotube has 1.2±0.1, which are explained by its strong adsorptive force. [ABSTRACT FROM AUTHOR]

Abstract Adding boron and phosphorus compounds substantially improved the thermal stability of carbon nanotubes (CNTs), increasing their oxidation temperature by 37–173 °C. Analysis of the B1s and P2p X-ray photoelectron spectral peaks suggested that the boron and phosphorus compounds chemically poisoned active sites of CNTs by forming C–O–B, C–O–P and C–P–O bonds. These interactions drove away oxygen from the active sites and delayed their oxidative reactions. Incorporation of these compounds in CNT pastes followed by high-temperature heat treatment in a vacuum considerably enhanced their field emission characteristics, evaluated by measuring current–voltage (I–V) curves and long-term stability, for an X-ray tube application. Graphical abstract Functionalization of CNTs with B- and P-compounds protects their surface from oxidation. Image 1 [ABSTRACT FROM AUTHOR]

This study investigated the effect of graphite nanoplatelet (GNP) size and dispersion on the thermal conductivities and tensile strengths of epoxy-based composites. GNPs of four different platelet sizes, ranging from 1.6 to 3 µm, were derived by mechanically exfoliating and breaking expanded graphite (EG) particles using high-energy bead milling and sonication. The GNPs were used as fillers at loadings of 0–10 wt%. As the GNP size and loading amount increased, the thermal conductivities of the GNP/epoxy composites increased, but their tensile strengths decreased. However, interestingly, the tensile strength reached a maximum value at the low GNP content of 0.3% and thereafter decreased, irrespective of the GNP size. Our observations of the morphologies and dispersions of the GNPs in the composites indicated that the thermal conductivity was more likely related to the size and loading number of fillers, whereas the tensile strength was more influenced by the dispersion of fillers in the matrix. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenide (TMDC) materials are attractive candidates for 2D solar cell devices thanks to their straightforward integration with various substrates and traditional semiconductor technologies, wide band gap ranges over the visible light spectrum, and high absorption coefficient values. Although there are several previous reports on the fabrication of 2D material-based solar cells, difficult and complex processes in the fabrication are highly required to be modified for wider use in daily life applications. Photolithography, the most commonly used manufacturing process for TMDC-based solar cells, is complicated. In this study, we demonstrate that the fabrication of 2D tungsten diselenide (WSe2) by adopting a wet transfer process with thermal release tape simplifies the manufacturing steps for TMDC-based solar cell devices. This simplification not only reduces the production cost by excluding several factors such as transmittance, thermal expansion, surface flatness, and durability but also improves the yield. Furthermore, a proof-of-concept demonstration of creating a WSe2/Si junction with an aluminum oxide (Al2O3) antireflective coating provided a power conversion efficiency of 6.39%, which is a significant improvement over that of a WSe2/Si solar cell without the antireflective coating layer (1.08%). [ABSTRACT FROM AUTHOR]

Multi-walled carbon nanotubes (MWCNTs) grown by chemical vapor deposition (CVD), which are commercially available in large quantities, commonly show poor field emission characteristics due to their low crystallinity. In this study, we fabricated highly crystalline MWCNTs using arc discharge (AD) via a mixture of N 2 and O 2 gases. The AD-MWCNTs showed a high oxidation temperature and lower threshold (V th) and turn-on (V to) voltages in repeated field emission measurements compared to CVD-MWCNTs. In a lifetime evaluation performed at an anode current of 3 mA for 20 and 120 h in diode and triode configurations, respectively, AD-MWCNTs showed better long-term stability than the CVD-MWCNTs. Thus, our findings demonstrate that AD-MWCNTs are promising for use in high-performance field emitters. [ABSTRACT FROM AUTHOR]

We have demonstrated high-speed scanning shear-force microscopy using a fiber tip attached to quartz crystal vibrating at 2.0 MHz resonance frequency. With a high-frequency dithering probe, we have obtained clear images at the scanning speed of 1.2 mm/s and it takes only 0.5 s to image the surface area of 55 μm2 for 64x64 pixels without any compromise of spatial lateral resolution. This speed is more than five times faster than that obtained by other topographic imaging methods and can be further improved to realize real-time shear-force probe microscopy. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT) pastes for field emitters were fabricated by varying the milling speed, CNT amount and glass frit (GF) powder size. The CNTs remained agglomerated at lower milling speeds while they were damaged and shortened at higher speeds. Increasing the amount of CNTs improved the field emission properties, but excessive CNTs led to increased removal of the CNT paste with surface activation because of lower cohesion strength. Small GF particles were incorporated to provide a flat surface to the CNT paste, which improved its field emission uniformity and lifespan. The dispersion, density and milling damage characteristics of CNTs in the pastes were assessed by their sheet resistances under the assumption of equal printed thicknesses. Tape activation reduced the thickness of the CNT pastes by different amounts that depended on the cohesion strength of the paste. This reduction caused the sheet resistance to increase. For all cases in this study, the field emission properties of the CNT pastes were closely related to their sheet resistances, suggesting that sheet resistance could be used as a figure-of-merit for the evaluation of CNT pastes for field emission applications. [ABSTRACT FROM AUTHOR]

We demonstrate, for the first time, high-efficiency supercapacitors by utilizing chemical vapor deposition ( CVD)-grown graphenes hybridized with multiwalled carbon nanotubes ( CNTs). A single-layer graphene was grown by simple CVD growth method, and transferred to polyethylene terephthalate substrates. The bare graphenes were further hybridized with multiwalled CNTs by drop-coating CNTs on graphenes. The supercapacitors using bare graphenes and graphenes with CNTs revealed that graphenes with CNTs resulted in enhanced supercapacitor performances of 2.2- (the mass-specific capacitance) and 4.4-fold (the area-specific capacitance) of those of bare graphenes. Our strategy to improve electrochemical performance of CVD-grown graphenes is advantageous for large-scale graphene electrodes due to high electrical conductivity of CVD-grown graphenes and cost-effectiveness of using multiwalled CNTs as compared to conventional employment of single-walled CNTs. [ABSTRACT FROM AUTHOR]

Ti 3 C 2 T x MXene, a recently discovered 2D material, possesses unique properties; however, its lack of stability against oxidation poses a significant challenge to its application. This study leverages the auto-oxidation of Ti 3 C 2 T x MXene to synthesize TiO 2 (termed as m-TiO 2) nanoparticles, addressing MXene susceptibility to oxidation as an advantage. This study enhances the utilization of remaining MXenes, minimizing waste and maximizing resource efficiency. The Ti 3 C 2 T x MXene was allowed to oxidize in deionized water under ambient conditions for an extended period of one year, resulting in a transformation from dark black Ti 3 C 2 T x MXene to milky white m-TiO 2 , indicating Ti 3 C 2 T x MXene degradation. The size of the Ti 3 C 2 T x MXene nanoflakes under investigation is ∼500 nm, while the resulting high surface area porous m-TiO 2 nanoparticles have an average size of ∼40 nm. The transformation of Ti 3 C 2 T x MXene into m-TiO 2 nanoparticles was assessed through a combination of analytical techniques, including X-ray diffraction analysis (XRD), UV-Vis absorbance analysis, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analysis. The specific surface areas (SSA) of 7.2 m2/g and 39.1 m2/g for Ti 3 C 2 T x MXene and m-TiO 2 nanoparticles, respectively, signify the presence of micro/nanopores in the latter. The m-TiO 2 nanoparticles exhibit promising photocatalytic properties, efficiently degrading methylene blue (MB) dye under UV light. • Auto-oxidation of Ti 3 C 2 T x MXene to m-TiO 2 nanoparticles in ambient conditions. • Ti 3 C 2 T x MXene yielded m-TiO 2 nanoparticles with a higher rutile phase. • m-TiO 2 nanoparticles exhibit a surface area > 5 times that of the parent MXene. • m-TiO 2 nanoparticles exhibited ∼40% photocatalytic efficiency after 60 min. • m-TiO 2 usage from residual MXenes maximizes resource use and minimizes waste. [ABSTRACT FROM AUTHOR]

Abstract: We have studied frictional force between SiN tip and Si surface by using lateral force microscopy. The cantilever we have used has very low stiffness of 0.006N/m, and the normal force acting on the surface was much lower than the attractive force such as van der Waals force. In this low normal force limit, it was found that the frictional force did not depend on the normal force. We suggest a calibration method to estimate the attractive force from the lateral force data in this limit. The estimated attractive force between Si sample and SiN tip with radius of 10nm was 0.4nN in flat region and 0.65nN at the corner of a rectangular hole. [Copyright &y& Elsevier]

Hydrogen generation during wastewater treatment has remained a long-standing challenge for the environment preservation welfare. In the present work, we have fabricated a promising bifunctional thin film-based catalyst for hydrogen generation with concurrent wastewater treatment. The prepared catalyst film is a vertically oriented thin SnS (tin monosulfide) nanosheet array on a Ni-foam (SnS/NF) obtained via a solution process, demonstrating a promising electrocatalytic activity towards the generation of green H2 fuel at the cathodic side and the decomposition of urea waste at the anodic side. Notably, while assembling two identical electrodes as cathode and anode together with a reference electrode (i.e., SnS/NF∥SnS/NF vs. RHE assembly) in 1 M KOH aqueous electrolyte containing 0.33 M urea, the electrolyzer electrolyzed urea at a lower cell potential of 1.37 and 1.43 V (vs. RHE) to deliver a current density of 10 mA cm−2 and 50 mA cm−2, respectively, for the decomposition of urea at the anodic SnS/NF electrode and green hydrogen fuel generation at the cathodic SnS/NF electrode. This activity on electrocatalytic urea decomposition lies within the best performance to those of the previously reported sulfide-based and other catalytic materials. The promising catalytic activities of the SnS catalyst film are attributed to its combined effect of self-standing nanosheet array morphology and high crystallinity, which provides abundant active sites and a facile charge transfer path between the nanosheet arrays and the electrolyte. Thus, the present work offers a green avenue to the waste-urea treatment in water and sustainable hydrogen energy production. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) heterostructure with atomically sharp interface holds promise for future electronics and optoelectronics because of their multi-functionalities. Here we demonstrate gate-tunable rectifying behavior and self-powered photovoltaic characteristics of novel p-GeSe/n-MoSe2 van der waal heterojunction (vdW HJ). A substantial increase in rectification behavior was observed when the devices were subjected to gate bias. The highest rectification of ~ 1 × 104 was obtained at Vg = − 40 V. Remarkable rectification behavior of the p-n diode is solely attributed to the sharp interface between metal and GeSe/MoSe2. The device exhibits a high photoresponse towards NIR (850 nm). A high photoresponsivity of 465 mAW−1, an excellent EQE of 670%, a fast rise time of 180 ms, and a decay time of 360 ms were obtained. Furthermore, the diode exhibits detectivity (D) of 7.3 × 109 Jones, the normalized photocurrent to the dark current ratio (NPDR) of 1.9 × 1010 W−1, and the noise equivalent power (NEP) of 1.22 × 10–13 WHz−1/2. The strong light-matter interaction stipulates that the GeSe/MoSe2 diode may open new realms in multi-functional electronics and optoelectronics applications. [ABSTRACT FROM AUTHOR]

This study investigates the structural and optical properties of doped CuI nanocrystals synthesized using a facile chemical method. Cadmium (Cd) and iron (Fe) were used as dopants, resulting in CuI–Cd and CuI–Fe samples. X-ray diffraction (XRD) was employed to characterize the crystal structure and phase purity. Rietveld refinement of the XRD data provided significant refinement parameters. The Williamson-Hall and Size-strain methods were applied for further analysis, yielding consistent size and strain values. X-ray photoelectron spectroscopy (XPS) was utilized to investigate the electronic states and dopant incorporation in CuI nanocrystals. The undoped and doped CuI samples exhibited distinctive morphologies, with pure CuI displaying an irregular shape, CuI–Cd showcasing a hexagonal morphology, and CuI–Fe featuring a triangular morphology. The average crystallite sizes of the nanocrystals were determined to be 96.67 nm, 70.57 nm, and 54.10 nm for pure CuI, CuI–Cd, and CuI–Fe, respectively. Energy-dispersive X-ray (EDX) analysis confirmed the presence of Cd and Fe in the doped samples. Optical bandgap energies estimated using Tauc's plot were 4.1 eV (CuI), 4.0 eV (CuI–Cd), and 4.0 eV (CuI–Fe). • CuI nanocrystals were doped with Cd and Fe using a simple chemical method. • Rietveld refinement of the XRD data provided significant refinement parameters. • EDX and XPS analysis confirmed the presence of dopants. • Optical bandgap energies estimated using Tauc's plot were 4.1 eV (CuI), 4.0 eV (CuI–Cd), and 4.0 eV (CuI–Fe). [ABSTRACT FROM AUTHOR]

The energy storage capacity of MXenes can be significantly augmented by increasing their specific surface area, which can additionally amplify the number of active sites available for electrochemical reactions. Herein, we have presented a method to enhance the energy storage capacity of Ti 3 C 2 T x MXenes by growing the TiO 2 nanogrooves on the surface of Ti 3 C 2 T x (termed as Ti 3 C 2 T x -NG) without drying the exfoliated MXene layers using hydrothermal treatment. The Ti 3 C 2 T x MXene flakes dimensions ranged from 500 to 1000 nm, whereas the decorated TiO 2 nanogrooves have a size of ∼10 nm. The Ti 3 C 2 T x MXene demonstrates a specific surface area (SSA) of ∼ 11 m2/g, while the Ti 3 C 2 T x -NG exhibits an enhanced SSA of ∼40 m2/g. The Ti 3 C 2 T x -NG utilized in the fabrication of symmetric supercapacitors exhibited a significantly higher specific capacitance (∼81 F/g) compared to Ti 3 C 2 T x MXene (∼62 F/s) at a scan rate of 100 mV/s. Reversible oxidation and reduction reactions between TiO 2 and Ti 3 C 2 T x , accompanied by the adsorption or release of hydroxide ions (OH-) contribute to charge transport in the supercapacitors. Additionally, due to the layered structure of Ti 3 C 2 T x MXene, a smaller number of ions can exist between two adjacent MXene layers due to the small spacing, whereas more ions can exist between two adjacent Ti 3 C 2 T x -NG layers as interlayer spacing between adjacent layers is relatively broader due to the nanosized TiO 2 nanogrooves, facilitating in the higher charge storage. • TiO 2 growth at MXene without converting the exfoliated MXene to powder. • Dispersed MXene flakes enable more TiO 2 growth. • TiO 2 boosts energy storage via improved surface area and charge transport. • Proposed charge storage mechanism in TiO 2 and Ti 3 C 2 Tx for charge storage. [ABSTRACT FROM AUTHOR]

[Display omitted] • Water, oxygen, and impurities were removed from the heterostructure interface using shielding gas. • The theoretical model was analyzed for pick-up graphene with a high yield rate of up to ∼100%. • Ultra large-scale hBN encapsulated graphene was fabricated (area ∼12 637 μm2). • Adhesion force of the PMMA/hBN interface was calculated using steered molecular dynamic simulation. • The field-effect mobility of encapsulated graphene exceeds 600 000 cm2V−1s−1 at room temperature. 2D materials based on van der Waals heterostructures have remarkable applications in electronic devices. However, trapped contaminations between the interface heterostructure layers during fabrication processes degrade the device performance. Here, we report a novel fabrication method to prevent contamination of the device from air impurities to obtain atomically clean interfaces using an Argon shielding gas environment. Large-area graphene encapsulated with hexagonal boron nitride, approximately ∼12,637 μm2, has been fabricated. Using the proposed methodology, high graphene mobility up to 600 000 cm2V−1s−1 at room temperature has been achieved. The theoretical analysis combined with a molecular dynamic simulation model was utilized to improve the dry transfer technique for large-scale fabrication of 2D materials. [ABSTRACT FROM AUTHOR]

An ultrahigh capacity supercapacitor is fabricated using a nano-layered MXene as an active electrode material, and Ni-foil is used as a current collector. The high-quality Ti3C2Tx obtained from supernatant during etching and washing processes improves the specific capacitance significantly. As another strategy, the surface of Ni-foil is engineered by coating chemical vapor deposition-grown graphene. The graphene grown directly on the Ni-foil is used as a current collector, forming the electrode structure of Ti3C2Tx/graphene/Ni. The surface passivation of the current collectors has a high impact on charge-transfer, which in turn increases the capacitance of the supercapacitors. It is found that the capacitance of the graphene-based supercapacitors is more than 1.5 times of the capacitance without graphene. A high specific capacitance, ~ 542 F/g, is achieved at 5 mV/s scan rate based on cyclic voltammetry analysis. Also, the graphene-based supercapacitor exhibits a quasi-rectangular form in cyclic voltammetry curves and a symmetric behavior in charge/discharge curves. Furthermore, cyclic stability up to 5000 cycles is confirmed with high capacitance retention at high scan rate 1000 mV/s. A reduced series resistance with a high limit capacitance is revealed by equivalent circuit analysis with the Nyquist plot. [ABSTRACT FROM AUTHOR]

We demonstrate a solar cell application based on vertical graphene nano hills (VGNH) directly grown without using a catalyst. The photovoltaic device based on VGNH grown on top of interfacial layer Al 2 O 3 is compared with that on top of bare silicon by critically analyzing its electrical properties. The role of the interfacial layer is to minimize surface recombination and enhance its built-in potential. Our key process is simple to fabricate large-area devices, avoiding an unreliable transfer process. In addition, the thickness of VGNH is optimized and the surface texturing of silicon is performed to overcome the crucial problem of the high reflectivity of silicon. A low reflectivity of thick layers of VGNH is achieved with low series resistance despite of the vertical structure, which is beneficial for high photocurrent. A higher work function of VGNH ∼4.7 eV is measured by KPFM. The conversion efficiency of 10.97% is achieved with an active area of 0.9 cm2 by co-doping with PEDOT: PSS and inorganic acid HNO 3. Moreover, the photo-responsivity of the VGNH-based device is estimated as 1.196 AW-1 under deep ultraviolet light. Image [ABSTRACT FROM AUTHOR]

2D layered germanium selenide (GeSe) with p-type conductivity is incorporated with asymmetric contact electrode of chromium/Gold (Cr/Au) and Palladium/Gold (Pd/Au) to design a self-biased, high speed and an efficient photodetector. The photoresponse under photovoltaic effect is investigated for the wavelengths of light (i.e. ~220, ~530 and ~850 nm). The device exhibited promising figures of merit required for efficient photodetection, specifically the Schottky barrier diode is highly sensitive to NIR light irradiation at zero voltage with good reproducibility, which is promising for the emergency application of fire detection and night vision. The high responsivity, detectivity, normalized photocurrent to dark current ratio (NPDR), noise equivalent power (NEP) and response time for illumination of light (~850 nm) are calculated to be 280 mA/W, 4.1 × 109 Jones, 3 × 107 W−1, 9.1 × 10−12 WHz−1/2 and 69 ms respectively. The obtained results suggested that p-GeSe is a novel candidate for SBD optoelectronics-based technologies. [ABSTRACT FROM AUTHOR]

We have developed a novel way to fabricate few layers graphene by controlling the uniformity of graphene using 'tape-peeling' method to solve the problem in the direct growth method based on the polymer carbon source. This method increases uniformity of the directly grown graphene by removing large amounts of residues during graphene direct growth using tape-peeling, and it can help in controlling the thickness of graphene. For the direct growth of graphene, nickel (Ni) was deposited on the silicon dioxide (SiO 2) substrate, and poly (methylmethacrylate) was used as a carbon source. During the annealing process in the chemical vapor deposition (CVD) technique, a few layer graphene is grown between the Ni and the SiO 2 substrate. The Ni is removed by etching using iron (III) chloride (FeCl 3), but thick carbon residues are left on the substrate. These residues are removed, and the overall thickness of graphene, to some extent, is controlled by the tape-peeling method. It has been found that the tape-peeling method is effective in removing the residues on the sample surface. The directly grown graphene processed by tape-peeling was used in fabricating the photoelectric devices and the corresponding studies have been performed. Image 1 [ABSTRACT FROM AUTHOR]

This paper reports the local conductivity mapping of graphene films prepared by chemical vapor deposition and mechanical exfoliation with the help of atomic force microscope where a conducting tip scanned the graphene surface with bias voltage. The surface morphology measured by field emission scanning electron microscopy confirmed that domains and wrinkles were formed on graphene samples grown by chemical vapor deposition, and the difference in the amount of current is observed on these domain boundaries and wrinkles. The percolation current path observed in current map explains that graphene grown by the chemical vapor deposition has low conductivity compared with one mechanically exfoliated. On the other hand, exfoliated graphene layer showed sign of conductivity differences on step edges and wrinkles in comparison to flat region. The resulting observations can be explained with the help of existing theories regarding graphene and by considering the effect of sample preparation conditions. [ABSTRACT FROM AUTHOR]

Owing to their tunable properties, 2D materials including MXenes are widely used in different optoelectronic devices due to their inherent conductivity and transparency. MXenes are a class of 2D materials that can be synthesized in the form of a colloidal solution, and these are hydrophilic in nature. Due to their hydrophilicity, MXenes can be easily coated on different substrates, making them suitable in applications like solar cells. Like other materials, MXenes-based solar cell fabrication doesn't require a growth process or a transfer process, hence, solar cells fabrication using MXenes is comparatively a simplified process. In this study, a facile technique was adopted to fabricate the metal-semiconductor (MXenes-Si) junction simply by spin-coating Ti 3 C 2 Tx-MXenes on an n-type Si substrate. The electrical properties of the coated MXenes films were investigated at different MXenes to DI water ratios to obtain the optimized concentration for the highest solar cell efficiency. To stabilize the interface between MXenes and Si, Al 2 O 3 was deposited, and the thickness-dependent tunneling effect was also optimized at a 2 nm thick Al 2 O 3 layer. To improve the solar cell efficiency, AuCl 3 doping, and texturing of silicon substrate were performed. With these two additional treatments, the efficiency of the solar cell was increased from 2.87% to 3.36%, exhibiting an increase of ∼17% as compared to that without treatment. • As a replacement to Si based solar cell, 2D material MXene-based solar cell has studied. • Spin-coating was adopted to deposit Ti 3 C 2 Tx-MXenes on n-type Si substrate. • MXenes can be easily coated on different substrates, making them suitable in solar applications. • Al 2 O 3 was deposited to stabilize the interface between MXenes and Si. • The thickness-dependent tunneling effect was optimized at a 2 nm thick Al 2 O 3 layer. [ABSTRACT FROM AUTHOR]

Gas-phase treatments using chloroform (CHCl 3) and water vapor were used to remove metal impurities (MIs) from as-prepared multi-walled carbon nanotubes (AP-MWCNTs), which is a non-destructive way to produce highly pure CNTs with extremely low MI content and with retention of CNT properties. After purification using CHCl 3 , the MIs in the AP-MWCNTs had significantly decreased to 12 ppm, representing a purification efficiency of 99.8%. This purification method, applicable to various AP-MWCNTs with high contents and different compositions of MIs, is more effective than liquid-phase purification using acids and does not damage the CNT structure and morphology. This moderate purification is due to a combination of factors. Chlorine radicals and hydrochloric acid from the thermal decomposition of CHCl 3 react with MIs encased by graphitic carbon layers to form metal chlorides that sublime at high temperature. Hydrogen, oxygen, and water vapor generated during the formation of the metal chlorides etch graphitic carbon layers and lead to the formation of new pores and cracks, which provide fast reaction and diffusion paths. During metal purification, the MWCNT surface becomes lightly coated with chlorine or chlorinated carbon, which are eliminated from the surface post-treatment using water vapor. Image 1 [ABSTRACT FROM AUTHOR]

It is of immense interest to improve the power conversion efficiency of graphene/silicon Schottky junction solar cells. The ultrathin graphene has essential properties, such as tunable work function to increase Schottky barrier height and built-in potential for efficient charge transport in photovoltaic devices. Here, we use plasma-enhanced CVD to grow graphene directly on planar n-type silicon to fabricate solar cells compatible for industrial-level applications. A key component to our accomplishment is the optimization of directly grown, continuous layers of graphene to achieve superior performance. Thus, by controlling the graphene thickness, the work function is significantly improved, the open circuit voltage is increased, and the energy conversion efficiency is enhanced. While the transfer of CVD grown graphene has limitations due to cracks and impurities during the complex process, our direct growth method demonstrates an efficiency of 5.51 % on bare planar silicon with a large device area. Furthermore, the efficiency is remarkably increased to 9.18 % by adding and doping a polymer layer. Interestingly, with the addition of a doped polymer layer, the cell exhibits excellent stability for at least one month. Our result suggests a promising simple path to fabricate high efficiency solar cells at low temperature and low cost. Image 1 [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Three-dimensional (3D) imaging of nanostructures with high aspect ratio features is a challenging problem of broad relevance to nanoscience and nanotechnology. Though a wide variety of experimental strategies to improve 3D imaging capabilities have been proposed, current measurement capabilities are mainly limited to imaging deep trenches, in large part due to the lack of truly 3D scanning algorithms and limited dynamic control of the tilt angle. Herein, we report a non-contact atomic force microscope (AFM) strategy that overcomes these challenges by employing an intelligent 3D scanning algorithm that combines sidewall detection and real-time adjustment of the probe's direction. To test this approach, we measured the depth and sidewall topography of porous anodic aluminum oxide (trench), via holes and silicon nanopillar (protrusion) with precision tracing. Using a carbon nanotube-based AFM probe, it was possible to measure the depth of holes with an aspect ratio of 5.9. In addition to this, we have successfully achieved the 3D image of via holes with an aspect ratio of 4.3 and a resolution of 2 nm, which enables realistic profiling of the sidewall and bottom edge of holes. Taken together, our findings demonstrate how the intelligent scanning algorithm based on detection-and-decision with a high-aspect-ratio probe can be utilized as a broadly applicable nanoscience measurement tool to characterize 3D topographical features of nanostructures. [ABSTRACT FROM AUTHOR]

The efficiency of a heterojunction with intrinsic thin‐layer (HIT) solar cell with an insulator/ITO structure was discussed in this paper. First, the efficiency was analyzed by OPAL 2 simulations. Second, an insulator/ITO structure was experimentally applied to a HIT solar cell. The OPAL 2 simulations using an insulator/ITO/Si structure and a TCO/ITO/Si structure showed that the generation current density in the Si substrate increased when the insulator or TCO layer had a proper thickness. Experimentally, HfO2, a type of insulator, was deposited on a HIT solar cell with a thickness varying from 3 to 15 nm. The average efficiency of the HIT solar cell improved from 18.21% to 20.75% after HfO2 deposition. The highest efficiency was achieved for the 3‐nm‐thick HfO2/HIT solar cell structure, which exhibited the best improvement in the current density of approximately 1.5 mA/cm2. For the external quantum efficiency of the HfO2/HIT solar cell, the total absorption was improved by HfO2 deposition. The results suggest that the HfO2 layer improves the solar cell efficiency of the HIT solar cell by increasing light absorption. The simulations using an insulator or TCO/ITO/Si structures showed that the generation current density increased when the insulator or TCO layer had a proper thickness. Experimentally, the average efficiency of the HIT solar cell improved from 18.21% to 20.75% after HfO2 deposition, a type of insulator. The highest efficiency was achieved for the 3‐nm‐thick HfO2/HIT solar cell structure, which exhibited the best improvement in the current density of approximately 1.5 mA/cm2. [ABSTRACT FROM AUTHOR]

In graphene/silicon (Gr/Si) solar cell antireflection (ARCs) coatings remarkably enhance the power conversion efficiency. Traditionally titanium dioxide and polymethyl methacrylate used an ARC in Gr/Si solar cells. In such cases controlling film thicknesses and smoothness required a lot of efforts. Here we introduced Vanadium Pentoxide (V 2 O 5 ) as an ARC in Gr/Si solar cells deposited using thermal evaporator. A well smooth controlled thin-film of V 2 O 5 was achieved. It can easily be thermal evaporated because of its low melting temperature. It was observed after V 2 O 5 coating current density of Gr/Si solar cell remarkably increased from 14 mA/cm 2 to 28 mA/cm 2 without losing the fill factor. It also helps to improve the V oc from 0.41 to 0.44 V. Different layer thickness shows different colors, results show that a 70 nm layer thickness of V 2 O 5 shows the best ARC for single layer Gr/Si solar cell. [ABSTRACT FROM AUTHOR]

Graphene/Si Schottky junction solar cells are widely studied in relation to the harvesting of solar energy, but high efficiency is limited due to surface recombination at the interface. Moreover, surface defects, wrinkles, and impurities may arise during the wet transfer process of graphene. We propose an easy approach to fabricate high efficiency solar cells by using directly grown graphene on a textured substrate with a large active area. In our novel technique, we directly grow a few layers of graphene on top of Al 2 O 3 /Si by using plasma enhanced chemical vapor deposition. The high-k dielectric layer of Al 2 O 3 acts as an electron blocking layer which minimizes the surface recombination at the interface. Furthermore, the barrier width is optimized by controlling the thickness of the Al 2 O 3 interlayer to achieve the highest efficiency of 8.4%. The devices were not intentionally doped, and no aging effect was found in 9 months. We believe that our stable solar cell results indicate a new route for the production of metal-insulator-semiconductor Schottky junction solar cells with high efficiency without need of chemical doping of the emitter layer. [ABSTRACT FROM AUTHOR]

Two-dimensional materials based vertical field-effect transistors have been widely studied due to their useful applications in industry. In the present study, we fabricate graphene/MoS2/(Cr/Au) vertical transistor based on the mechanical exfoliation and dry transfer method. Since the bottom electrode was made of monolayer graphene (Gr), the electrical transport in our Gr/MoS2/(Cr/Au) vertical transistors can be significantly modified by using back-gate voltage. Schottky barrier height at the interface between Gr and MoS2 can be modified by back-gate voltage and the current bias. Vertical resistance (Rvert) of a Gr/MoS2/(Cr/Au) transistor is compared with planar resistance (Rplanar) of a conventional lateral MoS2 field-effect transistor. We have also studied electrical properties for various thicknesses of MoS2 channels in both vertical and lateral transistors. As the thickness of MoS2 increases, Rvert increases, but Rplanar decreases. The increase of Rvert in the thicker MoS2 film is attributed to the interlayer resistance in the vertical direction. However, Rplanar shows a lower value for a thicker MoS2 film because of an excess of charge carriers available in upper layers connected directly to source/drain contacts that limits the conduction through layers closed to source/drain electrodes. Hence, interlayer resistance associated with these layers contributes to planer resistance in contrast to vertical devices in which all layers contribute interlayer resistance. [ABSTRACT FROM AUTHOR]

In recent years, graphene (Gr) based solar cells have attracted extensive interest because of their ability to produce low cost and highly efficient solar cells. Conventional Gr/Si Schottky junction based solar cells are mostly fabricated by transfer of graphene on silicon substrate. In current work the direct growth of graphene by using the Plasma Enhanced Chemical Vapor Deposition (PECVD) technique was demonstrated to make fabrication more practical on a large scale. Firstly Gr/Si Schottky junction based solar cells were fabricated, and by optimizing the growth process, power conversion efficiency (PCE) of about 3.5% was achieved. Additionally, we demonstrated a metal insulator semiconductor (MIS) structure by introducing hafnium oxide (HfO 2 ), and an enriched efficiency of 6.68% was reached. Furthermore, the chemical doping of Gr grown on top of HfO 2 passivated Si was done and the efficiency was further enhanced by 8.5%. This study also suggests that the V oc of the Gr/HfO 2 /Si solar cells strongly depends on the thickness of the HfO 2 interfacial layer. These solar cells proved reliable as their efficiency was still consistent even after four months. The current study envisions the use of graphene based solar cells for commercial application. [ABSTRACT FROM AUTHOR]

In recent times, 2D materials-based heterostructures are extensively studied for fabricating different nanodevices. Among these materials, transition metal dichalcogenides (TMDC), hexagonal boron nitride (hBN), and graphene (Gr) are widely used in these devices. Optoelectronic memory devices based on 2D materials are among the recently studied devices for structural flexibility and device size miniaturization. In this study, a non-volatile optoelectronic memory device has been fabricated using tungsten diselenide (WSe 2), and hBN-encapsulated Gr-based heterostructures. This device can be easily controlled with UV light and an electric field. Two points were focused on in this study; first, the doping state was changed partially i.e., by illuminating a part of the WSe 2 layer by UV light and a p-n homo-junction was created. This phenomenon occurs due to the unique structure of Wse 2 /hBN and the p-n junction could be created in one layer. Secondly, Gr has been used as a floating gate to increase the retention time as Gr is acting as a charge trapping layer. The retention time is further increased due to the thickness of hBN because the defect states keep increasing the charges together. [Display omitted] • Fabrication of an optoelectronic memory device using WSe 2 , and hBN encapsulated Gr-based heterostructures • Memory device can be easily controlled with UV light and an electric field. • Graphene used as a floating gate to increase the retention time as Gr is acting as a charge trapping layer. • The retention time improvement with the thickness of hBN because the defect states keep increasing the charges together. [ABSTRACT FROM AUTHOR]

To reduce the operating temperature of solid oxide fuel cells (SOFCs), we develop a highly conductive, bimodal-shape Nd 0.2 Ce 0.8 O 2−δ (NDC) materials at an intermediate temperature (IT) with excellent sinterability for the anode-supported cell design. The advanced bimodal NDC composite materials consist of powders synthesized by both the glycine-nitrate process and coprecipitation methods. The bimodal NDC electrolyte shows 2–3 fold higher conductivity than that of singly processed NDC electrolytes in the IT range. Further, this doubly processed highly conductive NDC material for the electrolyte and composite cathode significantly improves the performance of the anode-supported configuration of IT-SOFCs. This is due to the rapid transport of oxygen-ions in the electrolyte, small grain sizes of the bimodal cathode with a high porosity, and the improved interfacial property between the electrolyte and cathode, which results in decreased ohmic and polarization resistance of bimodal-based cells at 550–650 °C. [ABSTRACT FROM AUTHOR]

Since it was discovered, synthesizing large area graphene sheets by chemical or epitaxial methods is the conventional method for the application of graphene's outstanding properties. Unfortunately, CVD grown graphene is polycrystalline in nature with grain boundaries (GBs) unlike exfoliated single crystal graphene flakes. These GBs are known as the main source of degrading mechanical, chemical and electrical properties of CVD graphene. Nematic liquid crystal was employed to visualize grains and boundaries and to calculate the atomic orientation of adjacent grains. Electrical performance of various GB devices was observed, and the role of grain boundaries on the ultimate electrical performance was investigated. The same work was carried out at low temperature (∼7 K) to minimize the perturbation of two-dimensional electron which originated from the graphene lattice vibration. Interestingly, it was observed that there was no significant effect of the grain boundaries on the overall electrical performance of devices even at low temperature. These results lead to the conclusion that the grain boundaries in polycrystalline graphene sheets are not the cause for degradation in the electrical performance, if the grains were stitched well at the boundary in the growth process. [ABSTRACT FROM AUTHOR]

A controllable transparent device using an inorganic glass gel-dispersed liquid crystal (GDLC) was fabricated using the sol-gel method to overcome the limitations of conventional polymer-dispersed liquid crystals, such as haziness and yellowing. In this study, silica gel and titanium dioxide acted as a matrix holding the liquid crystal droplets, and the optical properties of the proposed GDLC were then studied in a silica solution by mixing tetra ethyl ortho-silicate, methyltriethoxysilane, isopropyl alcohol, and nitric acid in an aqueous solution. A titanium solution with titanium isopropoxide and acetylacetone was also mixed with the silica solution, with the further addition of a nematic liquid crystal. A parameter study was carried out by varying the concentration to obtain the best sample, with fast response times of ~0.5 and 3 ms, respectively for the on and off processes, high contrast, and low haziness when compared with previously reported results. The GDLC samples exhibited low scattering, a clear colorless state, and a low driving voltage, which are all very important advantages for applications. For demonstration, our glass-based smart window was also applied as a rear-view mirror in a vehicle for anti-dazzling purposes at night, which has not been reported by others. [ABSTRACT FROM AUTHOR]

The microstructure and compressive mechanical properties of squeeze casted Mg 15Li xAl (x = 0, 1, 3 and 5 wt%) alloys have been investigated. With addition of Aluminum (Al) in Mg 15Li alloy, the compressive yield strength is continuously increased and density is slightly decreased. This improved mechanical property is mainly attributed to the precipitation of Al Li intermetallic compounds into the β-phase and grain size refinement of β-phase. Accordingly, lightweight and high specific strength Mg Li Al alloys were developed successfully via proper addition of Al contents, resulted from favorable microstructural evolution. [ABSTRACT FROM AUTHOR]

A flexible polymer-dispersed liquid crystal (PDLC) film with graphene layers as transparent electrodes was fabricated by combining a UV curable polymer and a nematic liquid crystal. The PDLC film with a dimension of 5 × 10 cm 2 was flexible and operated normally with no damage when it was bent with a radius of 2 mm. Instead of using conventional transparent conducting film, the single-layer-graphene transferred on PET film was used as transparent electrodes. The thickness of the graphene-PDLC was about 210–220 μm. The single-layer-graphene grown by thermal chemical vapor deposition was transferred onto the PET film, and its sheet resistance was about 1.2 kΩ/□. The controllable transmission range between the on and off states was about 60% in the visible range. The response time for the turn-on and off processes were estimated to be 0.3 and 32 ms, respectively. This successful fabrication of graphene based PDLC is a crucial step toward paving the way for the commercialization of the emerging material, graphene. [ABSTRACT FROM AUTHOR]

We report a scalable growth of mono to few-layer molybdenum disulfide (MoS 2 ) atomic layers on different substrates by chemical vapor deposition (CVD). The effects of the source material (sulfur and MoO 3 powder) and the growth temperature were systematically optimized for the growth of both highly crystalline and large area MoS 2 . The deposited film thickness could be precisely controlled by varying the growth temperatures, and this was confirmed by Raman and AFM results. The monolayer, bilayer, and multilayer MoS 2 could be obtained at 650 °C, 700 °C, and 750–800 °C, respectively. The mobility value of ∼0.89 cm 2 /V s and current on/off ratio in the order of ∼10 4 was estimated for monolayer MoS 2 . The mobility value increased to ∼7.6 cm 2 /V s for the bilayer MoS 2 . Our results pave the way for the controlled synthesis of high-quality transition metal dichalcogenide materials, which are an attractive option for applications in electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

In the present study, the microstructural evolution and improving the mechanical properties have been achieved in Fe–Nb binary eutectic alloy via controlling the amount of boron (B) content. The addition of B leads to evolution of a unique microstructure with different length-scale heterogeneities, i.e., formation of bimodal structure, spherical colonies containing length-scale heterogeneity and precipitation of primary NbFeB phase. Following the evolution of microstructure, the mechanical properties including yield strength and plastic strain were significantly enhanced from 1100 MPa to 1660 MPa and from ∼4% to ∼20%, respectively. To elucidate deformation mechanism fracture topography and lateral surface morphology analyses are performed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). From these observations two distinct plastic deformation mechanisms can be suggested by following ways: (1) deformation-induced rotation motion of dendrites/eutectic colonies and (2) deformation-induced interface migration of lamellar structure. [ABSTRACT FROM AUTHOR]

Porous metallic glass compact (PMGC) using electro-discharge sintering (EDS) process of gas atomized Zr 41.2 Ti 13.8 Cu 12.5 Ni 10 Be 22.5 metallic glass powder was developed. The formation of uniform PMGC can only be achieved when low electrical input energy was applied. Functional iron-oxides were formed on the surface of PMGCs by hydrothermal technique. This finding suggests that PMGC can be applied in the new area such as catalyst via hydrothermal technique and offer a promising guideline for using the metallic glasses as a potential functional application. [ABSTRACT FROM AUTHOR]