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We present detailed studies on the covalent adsorption of molecular oxygen and atomic hydrogen on the hexagonal boron nitride (h-BN) nanomesh on Rh(111). The functionalization of this two-dimensional (2D) material was investigated under ultra-high vacuum conditions using synchrotron radiation-based in situ high-resolution X-ray photoelectron spectroscopy, temperature-programmed X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy. We are able to provide a deep insight into the adsorption behavior and thermal stability of oxygen and hydrogen on h-BN/Rh(111). Oxygen functionalization was achieved via a supersonic molecular beam while hydrogen functionalization was realized using an atomic hydrogen source. Adsorption of the respective species was observed to occur selectively in the pores of h-BN leading to spatially defined modification of the 2D layer. The adsorption of the observed molecular oxygen species was found to be an activated process that requires high-energy oxygen molecules. Upon heating to 700 K, oxygen functionalization was observed to be almost reversible except for small amounts of boron oxides evolving due to the reaction of oxygen with the 2D material. Hydrogen functionalization of h-BN/Rh(111) was fully reversed upon heating to about 640 K.

2D non-layered materials (2DNLMs) featuring massive undercoordinated surface atoms and obvious lattice distortion have shown great promise in catalytic/electrocatalytic applications, but their controllable synthesis remains challenging. Here, a new type of ultrathin carbon-wrapped titanium nitride nanomesh (TiN NM@C) is prepared using a rationally designed nano-confinement topochemical conversion strategy. The ultrathin 2D geometry with well-distributed pores offers TiN NM@C plentiful exposed active sites and rapid charge transfer, leading to outstanding electrocatalytic performance tackling the sluggish sulfur redox kinetics in lithium-sulfur batteries (LSBs). LSBs employing TiN NM@C electrocatalyst deliver excellent rate capabilities (e.g., 304 mAh g-1 at 10 C), greatly outperforming that of using TiN nanoparticles embedded in carbon nanosheets (TiN NPs@C) as a benchmark. More impressively, a free-standing electrode for LSBs with a high sulfur loading of 7.3 mg cm-2 is demonstrated, showing a high peak areal capacity of 5.6 mAh cm-2 at a high current density of 6.1 mA cm-2 . This work provides a new avenue for the facile and controllable fabrication of 2DNLMs with impressive electrocatalysis for LSBs as well as other energy conversion and storage technologies.

We report on the successful observation of a single electron phenomenon on a large area suspended graphene nanomesh (GNM) device patterned by the helium ion beam milling (HIBM) technique. The HIBM can be used to further regular the shape of the suspended graphene nanoribbon after the conventional RIE process, and also drill the periodic nanopores on suspended graphene to build potential barriers. It provides a more practical way to use graphene for quantum technology.

Nanomeshes having ultrathin thicknesses and penetrating nanopores promise fast diffusion and precise selectivity and are highly desired in diffusion-involved processes such as separation. Herein, we report a liquid-phase two-dimensional (2D) assembly strategy to synthesize phenolic and carbonaceous nanomeshes with sub-10 nm pores and thicknesses. The synthesis is enabled simply by introducing glycerol in the thermopolymerization of resol/polyether micelles dispersed in ethanol. Experimental and simulation results reveal that glycerol's strong ability to form hydrogen bonds constrain the motion of the micelles, directing them to pack and merge exclusively in the lateral direction. Upon removal of polyether, we obtain phenolic nanomeshes with lateral sizes up to hundreds of micrometers, which can be further converted to carbonaceous nanomeshes. As a proof of concept, we use stacked phenolic and carbonaceous nanomeshes as separation membranes. They show superior permselectivity to nanosized solutes with permeance ∼2-110 times higher than that of other membranes.

A one-step method for plasma synthesis of nitrogen-doped carbon nanomesh is presented. The method involves a molten polymer, which is a source of carbon, and inductively coupled nitrogen plasma, which is a source of highly reactive nitrogen species. The method enables the deposition of the nanocarbon layer at a rate of almost 0.1 µm/s. The deposited nanocarbon is in the form of randomly oriented multilayer graphene nanosheets or nanoflakes with a thickness of several nm and an area of the order of 1000 nm2. The concentration of chemically bonded nitrogen on the surface of the film increases with deposition time and saturates at approximately 15 at.%. Initially, the oxygen concentration is up to approximately 10 at.% but decreases with treatment time and finally saturates at approximately 2 at.%. Nitrogen is bonded in various configurations, including graphitic, pyridinic, and pyrrolic nitrogen.

Graphene nanostructures are attracting a great deal of interest because of newly emerging properties originating from quantum confinement effects. We report on using interferometric lithography to fabricate uniform, chip-scale, semiconducting graphene nanomesh (GNM) with sub-10 nm neck widths (smallest edge-to-edge distance between two nanoholes). This approach is based on fast, low-cost, and high-yield lithographic technologies and demonstrates the feasibility of cost-effective development of large-scale semiconducting graphene sheets and devices. The GNM is estimated to have a room temperature energy bandgap of ~30 meV. Raman studies showed that the G band of the GNM experiences a blue shift and broadening compared to pristine graphene, a change which was attributed to quantum confinement and localization effects. A single-layer GNM field effect transistor exhibited promising drive current of ~3.9 μA/μm and ON/OFF current ratios of ~35 at room temperature. The ON/OFF current ratio of the GNM-device displayed distinct temperature dependence with about 24-fold enhancement at 77 K.

Metallic nanomesh, one of the emerging transparent conductive film (TCF) materials with both high electrical conductivity and optical transmittance, shows great potential to replace indium tin oxide (ITO) in optoelectronic devices. However, lithography-fabricated metallic nanomeshes suffer from an iridescence problem caused by the optical diffraction of periodic nanostructures, which has negative effects on display performance. In this work, we propose a novel approach to fabricate large-scale metallic nanomesh as TCFs on flexible polyethylene terephthalate (PET) sheets by maskless phase separation lithography of polymer blends in a low-cost and facile process. Polystyrene (PS)/polyphenylsilsequioxane (PPSQ) polymer blend was chosen as resist material for phase separation lithography due to their different etching selectivity under O2 reactive ion etching (RIE). The PS constituent was selectively removed by O2 RIE and the remained PPSQ nanopillars with varying sizes in random distribution were used as masks for further pattern transfer and metal deposition process. Gold (Au) nanomeshes with adjustable nanostructures were achieved after the lift-off step. Au nanomesh exhibited good optoelectronic properties (RS = 41 Ω/sq, T = 71.9%) and non-iridescence, without angle dependence owing to the aperiodic structures of disordered apertures. The results indicate that this Au nanomesh has high potential application in high-performance and broad-viewing-angle optoelectronic devices.

Recording the electrical potentials of bioengineered cardiac tissue after transplantation would help to monitor the maturation of the tissue and detect adverse events such as arrhythmia. However, a few studies have reported the measurement of myocardial tissue potentials in vivo under physiological conditions. In this study, human-induced pluripotent stem cell-derived cardiomyocyte (hiPSCM) sheets were stacked and ectopically transplanted into the subcutaneous tissue of rats for culture in vivo. Three months after transplantation, a flexible nanomesh sensor was implanted onto the hiPSCM tissue to record its surface electrical potentials under physiological conditions, i.e., without the need for anesthetic agents that might adversely affect cardiomyocyte function. The nanomesh sensor was able to record electrical potentials in non-sedated, ambulating animals for up to 48 h. When compared with recordings made with conventional needle electrodes in anesthetized animals, the waveforms obtained with the nanomesh sensor showed less dispersion of waveform interval and waveform duration. However, waveform amplitude tended to show greater dispersion for the nanomesh sensor than for the needle electrodes, possibly due to motion artifacts produced by movements of the animal or local tissue changes in response to surgical implantation of the sensor. The implantable nanomesh sensor utilized in this study potentially could be used for long-term monitoring of bioengineered myocardial tissue in vivo under physiological conditions.

Absence of functional groups on the basal plane of molybdenum disulfide (MoS2) significantly hinders the performance of MoS2 field-effect transistor-based biosensor (bio-FET). We present a novel method for creating nano-scale holes on a MoS2 channel using block copolymer lithography, where the edge areas on the nanoholes were used to form covalent linkage between the capture molecules of cortisol aptamer and the MoS2 channel. The comparative analysis of Raman and XPS spectra well supported the formation of the nanoholes on MoS2 together with the concomitant increase in the edge area. The performance of the nanomesh bio-FET was studied by comparing its detection behavior for cortisol with that of a bio-FET manufactured with pristine MoS2. The nanomesh MoS2 bio-FET detected cortisol 109 times as low as that by the pristine MoS2 bio-FET. The selectivity of the nanomesh bio-FET was validated by detection experiments with other steroid hormones and antigens. Additionally, clinical applicability was demonstrated by performing experiments in artificial saliva and human serum.

The designed arginine-rich surfactant-like peptide R3L12(arginine3-leucine12) is shown to form a remarkable diversity of self-assembled nanostructures in aqueous solution, depending on pH, including nanotubes, mesh-like tubular networks in three-dimensions and square planar arrays in two-dimensions. These structures are built from α-helical antiparallel coiled-coil peptide dimers arranged perpendicular to the nanotube axis, in a “cross-α” nanotube structure. The aggregation behavior is rationalized based on the effects of dimensionality, and the balance of hydrophobic and electrostatic interactions. The nanotube and nanomesh structures display arginine at high density on their surfaces, which may be valuable for future applications.

A thin, soft nanomesh strain gauge enables natural skin motion monitoring with minimum mechanical constraints., Ultraconformable strain gauge can be applied directly to human skin for continuous motion activity monitoring, which has seen widespread application in interactive robotics, human motion detection, personal health monitoring, and therapeutics. However, the development of an on-skin strain gauge that can detect human body motions over a long period of time without disturbing the natural skin movements remains a challenge. Here, we present an ultrathin and durable nanomesh strain gauge for continuous motion activity monitoring that minimizes mechanical constraints on natural skin motions. The device is made from reinforced polyurethane-polydimethylsiloxane (PU-PDMS) nanomeshes and exhibits excellent sustainability, linearity, and durability with low hysteresis. Its thinness geometry and softness provide minimum mechanical interference on natural skin deformations. During speech, the nanomesh-attached face exhibits skin strain mapping comparable to that of a face without nanomeshes. We demonstrate long-term facial stain mapping during speech and the capability for real-time stable full-range body movement detection.

The importance of continuous monitoring of skin hydration in daily life, to aid in the diagnosis of skin diseases, is rising. Electrodes that can be worn directly on the skin are attracting attention as an effective means. However, they should not inhibit natural water evaporation from the skin and should not cause inflammation or irritation even if they are attached to the body for long periods of time. In this study, nanomesh electrodes that have previously been reported to exhibit high biocompatibility are also found to exhibit high water vapor permeability, resulting in properties that prevent skin dampness. Furthermore, the skin impedance measured using nanomesh electrodes is found to correlate with the hydration level of skin measured using existing medical equipment. This study provides a new approach to measure skin hydration in conditions close to bare skin.

We report on successful fabrication of large-area suspended graphene nanomesh (GNM) by using the helium ion beam milling (HIBM) technique. By positioning the meshed area on the suspended graphene, a heterostructure composed of graphene nanoribbon and GNM is demonstrated. Increased driving current with a wider transport gap is observed for the heterostructure devices in contrast to a fully meshed devices.

This paper is devoted to the in silico study of the electronic properties and electrical conductivity of hydrogenated graphene nanomesh (GNM). It is found that the conductivity of GNM can be controlled by varying the type of hydrogenation. Due to the hydrogenation of the nanohole edges by one or two hydrogen atoms, the energy gap can be changed, the anisotropy of the electrical conductivity can be enhanced, and the electron work function can be controlled. By varying the type of hydrogenation, it is possible to form conductive and insulating paths on 2D GNM. Thus, a certain combination of the sp2- and sp3-topologies of the GNM edge atoms allows one to fully &ldquo, turn off&rdquo, the electronic conductivity in all directions or, conversely, &ldquo, turn on&rdquo, the desired direction for current transfer.

Nitrogen-doped graphene quantum dots (N-GQDs) were synthesized by direct electrolysis of a carbon cloth electrode coated with nitrogen-doped nanomesh graphene (NG) in high yield (~ 25%). The N-GQDs emit intense blue fluorescence with a quantum yield (QY) of 10% ± 3%. Meanwhile, the N-GQDs are rich in hydroxyl, carboxyl, basic pyridinic nitrogen, and nitro groups, which are conducive to strengthen the interaction between N-GQDs and Fe3+ for highly sensitive determination of Fe3+ ions. Specifically, the determination for Fe3+ was conducted at different concentrations of N-GQD solution with a wide linear range of 10–1000 μM (150 μg·mL−1) and a low detection limit of 0.19 μM (10 μg·mL−1). Moreover, the fluorescence quenching mechanism illustrated that the functional groups generated by electrochemical oxidation enhanced the interaction of N-GQDs and Fe3+, and the narrow band gap (2.83 eV) of N-GQDs accomplished electron transfer from N-GQDs to Fe3+ easily.

In this work, we present a fabrication procedure of metal nanomesh arrays with the newly developed nanoimprint resist mr-NIL212FC used in a bi-layer resist system for a lift-off process. We comparatively analyzed and evaluated nanomeshes fabricated with a freshly prepared h-PDMS/PDMS stamp and a stamp used 501 times. Therefore, we first performed a step&repeat imprint test run in a self-built low cost step&repeat UV-NIL setup. We inspected the imprint behavior of the stamp, the UV-transmission through the stamp as well as stamp lifetime and stamp degradation with regard to the possible changes of its surface roughness. The nanomesh fabrication process is characterized by a good lift-off performance, leading to a low defect density of

This paper demonstrates that the electrical properties of suspended graphene nanomesh (GNM) can be tuned by systematically changing the porosity with helium ion beam milling (HIBM). The porosity of the GNM is well-controlled by defining the pitch of the periodic nanopores. The defective region surrounding the individual nanopores after HIBM, which limits the minimum pitch achievable between nanopores for a certain dose, is investigated and reported. The exponential relationship between the thermal activation energy (EA) and the porosity is found in the GNM devices. Good EA tuneability observed from the GNMs provides a new approach to the transport gap engineering beyond the conventional nanoribbon method.

Silver nanowire (AgNW) has been studied as an important material for next-generation wearable devices due to its high flexibility, high electrical conductivity and high optical transmittance. However, the inherently high surface roughness of AgNWs and low adhesion to the substrate still need to be resolved for various device applications. In this study, an embedded two-dimensional (2D) Ag nanomesh was fabricated by mechanical press welding of AgNW networks with a three-dimensional (3D) fabric shape into a nanomesh shape, and by embedding the Ag nanomesh in a flexible substrate. The effect of the embedded AgNWs on the physical and electrical properties of a flexible transparent electrode was investigated. By forming embedded nanomesh-type AgNWs from AgNW networks, improvements in physical and electrical properties, such as a 43% decrease in haziness, 63% decrease in sheet resistance, and 26% increase in flexibility, as well as improved adhesion to the substrate and low surface roughness, were observed.

Adsorption properties of azobenzene, the prototypical molecular switch, were investigated on a hexagonal boron nitride (h-BN) monolayer (“nanomesh”) prepared on Rh(111). The h-BN layer was produced by decomposing borazine (B3N3H6) at 1000–1050 K. Temperature-programmed desorption (TPD) studies revealed that azobenzene molecules adsorbed on the “wire” and “pore” regions desorb at slightly different temperatures. Angle-resolved high-resolution electron energy loss spectroscopy (HREELS) measurements demonstrated that the first molecular layer is characterized predominantly by an adsorption geometry with the molecular plane parallel to the surface. Scanning tunneling microscopy (STM) indicated a clear preference for adsorption in the pores, manifesting a templating effect, but in some cases one-dimensional molecular stripes also form, implying attractive molecule–molecule interaction. Density functional theory (DFT) calculations provided further details regarding the adsorption energetics and bonding and confirmed the experimental findings that the molecules adsorb with the phenyl rings parallel to the surface, preferentially in the pores, and indicated also the presence of an attractive molecule–molecule interaction.

Spin engineering provides a powerful strategy for manipulating the interaction between electrons in the d orbital and oxygen-containing adsorbates, while a little endeavor was performed to understand whether such a strategy can make a prosperous enhancement for fuel electrooxidations. Herein, we demonstrate that spin engineering of trimetallic Pd-Fe-Pt nanomeshes (NMs) can achieve superior enhancement for fuel electrooxidations. Magnetization characterizations reveal that Pd59Fe27Pt14 NMs own the highest number of polarized spins (μb = 0.85 μB/f.u.), playing an important role on facilitating the adsorption of OHads to promote the oxidation of COads, as confirmed by theoretical results. Consequently, the optimized Pd59Fe27Pt14 NMs exhibit excellent methanol oxidation reaction activity and stability with a mass activity of 1.61 A mgPt-1, 2.6-fold and 7.3-fold larger than those of PtRu/C and Pt/C. Such catalysts also present exceptional performances in ethanol oxidation and formic acid oxidation reactions. Our work highlights a new strategy for designing efficient electrocatalysts for fuel electrooxidations and beyond.

This chapter demonstrates the dimensional scalability of LEIT and TEIT fabrication strategies by applying them for making nano-EMTEs. EBL and photolithography with UV stepper are used for nanomesh patterning in LEIT method for making nano-EMTEs. For demonstration, copper nano-EMTEs are fabricated on flexible COC films, exhibiting excellent optical and electrical performances. Similarly in TEIT process, NWL has employed for making the silica template with nano features, which are further used in fabrication of nickel nano-EMTEs on flexible epoxy/COC substrates. The silica templates demonstrated favorable mechanical robustness, and its potential as promising candidate material for reusable electrodeposition templates for production of flexible nano-EMTEs.

CoSe2 has been as one of promising electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) due to its earth-abundant resource, and tunable electronic structure. However, enhancing electrocatalytic activity of CoSe2 to meet the large-scale practical applications is desirable. Herein, we report a facile plasma nitridation strategy to generate N-doped CoSe2 nanomesh arrays on commercial carbon paper (N-CoSe2@CP). The obtained N-CoSe2@CP electrodes combined advantages of abundant electrochemical active sites and beneficial electronic structures, thus exhibiting a low overpotential of 106 mV and 237 mV to drive 10 mA cm−2 towards HER and OER in alkaline medium, respectively. Moreover, it can be employed as bifunctional electrocatalyst for overall water splitting, where a small potential of 1.57 V was required to reach 10 mA cm−2, and long-term stability was also realized. This work develops a promising strategy to explore highly-efficient nanocatalysts towards new energy conversion.

Filtering capacitors with high energy densities are of critical importance in stabilizing the pulse signal of circuits that require the conversion of alternating current to direct current, which is however far from satisfactory at current stage due to lack of a reasonable design. Here, we report an ultrafast aqueous electrochemical capacitor based on highly conductive and continuously cross-linked poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) nanomesh films fabricated using a rational morphology engineering strategy. The interpenetrating polymer network promoted an efficient electron transfer and provided smooth channels for ion transport while exposing a significant number of accessible interfacial area to electrolyte. In addition to the large phase angle of − 84° at 120 Hz, this polymer-based electrochemical capacitor exhibited an extremely high areal specific capacitance of 1087 μF cm−2 and areal specific energy density of 544 μF V2 cm−2, far superior to those of most reported aqueous filtering capacitors. Furthermore, it can efficiently smoothen the ripples generated when arbitrary alternating current waveforms were converted into straight signals over a wide frequency range of 1–10,000 Hz. Moreover, it was conveniently integrated with a rotating disk triboelectric nanogenerator for ripple filtering and pulse energy smoothing. This work brings a view for aqueous filtering capacitors with high performance.

With the aim of improving UV light trapping capability in monolayer graphene, a nanomesh metamaterial absorber is proposed, which exhibits the polarization-insensitive feature due to the geometrical symmetry. Through the functional combination of magnetic resonance and UV mirror, the absorption of unpolarized UV light in monolayer graphene can reach 99.5% under normal incidence. The absorption enhancement is induced by the magnetic resonance mode between the dielectric silica nanomesh and the calcium fluoride base layer. The effects of geometric parameters on the absorption spectra are systematically investigated. The proposed structure shows insensitive to manufacturing deviations, which can maintain at a high UV absorption rate of more than 99% within the nanomesh width ranging from 50 nm to 90 nm. Furthermore, after delicate optimization of the geometric parameters, two sharp resonances with absorbance more than 90% can be excited simultaneously inside the absorber. Our work provides an important theoretical guide for the design of optoelectronic devices based on two-dimensional materials in the UV range.

Improving the energy density of MXene micro-supercapacitors (MSCs) is still a challenge because the MXene nanosheets will easily agglomerate, leading to irreversible reduction of capacity. We present SiC/MXene heterostructure by ionization-bombardment assisted deposition synthesis. Under high voltage, C–C bond and Si-O bond are broken by electron bombardment. After arc sintering, C atom and Si atom form stable Si-C bond with lower bond energy, and then form SiC nanocrystals. Furthermore, SiC nanocrystals were patterned into mesoporous SiC nanonesh to enhance the specific surface area. The surface of SiC framework is full of charge, which makes the MXene nanosheets uniformly deposited and self-assembled to form heterostructure. SiC/MXene heterostructure has low barrier, strong bonding force and fast electron migration rate. SiC nanomesh provide a conductive network, and also serve as a framework to support the MXene film, increasing ion storage space, creating an interconnected path for the conduction of Na ions. The specific capacity of the MXene/SiC MSC is up to 97.8 mF cm−2 at a current density of 1 A cm−2. The fabrication of high-performance nanostructures leads to large-scale production and micro-energy storage devices.

In biointegrated electronics, the facile control of mechanical properties such as softness and stretchability in electronic devices is necessary to minimize the perturbation of motions inherent in biological systems1–5. For in vitro studies, multielectrode-embedded dishes6–8 and other rigid devices9–12 have been widely used. Soft or flexible electronics on plastic or elastomeric substrates13–15 offer promising new advantages such as decreasing physical stress16–18 and/or applying mechanical stimuli19,20. Recently, owing to the introduction of macroporous plastic substrates with nanofibre scaffolds21,22, three-dimensional electrophysiological mapping of cardiomyocytes has been demonstrated. However, quantitatively monitoring cells that exhibit significant dynamical motions via electric probes over a long period without affecting their natural motion remains a challenge. Here, we present ultrasoft electronics with nanomeshes that monitor the field potential of human induced pluripotent stem cell-derived cardiomyocytes on a hydrogel, while enabling them to move dynamically without interference. Owing to the extraordinary softness of the nanomeshes, nanomesh-attached cardiomyocytes exhibit contraction and relaxation motions comparable to that of cardiomyocytes without attached nanomeshes. Our multilayered nanomesh devices maintain reliable operations in a liquid environment, enabling the recording of field potentials of the cardiomyocytes over a period of 96 h without significant degradation of the nanomesh devices or damage of the cardiomyocytes. Ultrasoft nanomesh electronics enable monitoring of the field potential of cardiomyocytes without interference with their natural motion.

Molybdenum disulfide (MoS2) presents a promising catalyst to replace state-of the-art platinum (Pt) for hydrogen evolution reaction (HER), but it still lacks an effective way due to the catalytically inert basal plane. Herein, we report a rational design of MoS2 nanomesh that possesses evenly distributed holes and defects to make full use of the 2H-MoS2 basal planes by combining ball-milling with ultrasonic methods. The exfoliation of muti-layer MoS2 to fewer layer or enven monolayer is proceed in pure water without using any chemicals or surfactants. The great advantage of the catalyst is the monolayer, holey and defective structure, which maximizing the synergistic activity for both electrocatalytic and photocatalytic HER performances. Impressively, the MoS2 nanomesh renders outstanding electrocatalytic HER activity with an overpotential of 160 mV at a current density of 10 mV cm−2, and a small Tafel slope of 46 mV decade−1. The photocatalytic H2 evolution rate is about 4.84 mmol h−1 when working with Eosin Y as an organic photosensitizer. Additionally, this catalyst shows excellent cycle stability in the electrochemical and photocatalytic reactions. This present work put a new insight into the large-scale production of chemically active 2H MoS2-based catalysts for HER.

The adsorption of molecules on surfaces affects the surface dipole and thus changes in the work function may be expected. The effect in change of work function is particularly strong if charge between substrate and adsorbate is involved. Here we report the deposition of a strong electron acceptor molecule, tetrafluorotetracyanoquinodimethane C$_{12}$F$_4$N$_4$ (F$_{4}$TCNQ) on a monolayer of hexagonal boron nitride nanomesh ($h$-BN on Rh(111)). The work function of the F$_{4}$TCNQ/$h$-BN/Rh system increases upon increasing molecular coverage. The magnitude of the effect indicates electron transfer from the substrate to the F$_{4}$TCNQ molecules. Density functional theory calculations confirm the work function shift and predict doubly charged F$_{4}$TCNQ$^{2-}$ in the nanomesh pores, where the $h$-BN is closest to the Rh substrate, and to have the largest binding energy there. The preferred adsorption in the pores is conjectured from a series of ultraviolet photoelectron spectroscopy data, where the $\sigma$ bands in the pores are first attenuated. Scanning tunneling microscopy measurements indicate that F$_{4}$TCNQ molecules on the nanomesh are mobile at room temperature, as "hopping" between neighboring pores is observed.

Developing a novel electrode material with better electrochemical behavior and extended cyclability is a major issue in the field of hybrid capacitors. In this work, we propose a novel strategy for...

Herein, abundant and uniform nanopores with sub-3-nm sizes are introduced to 1.5 nm-thick nickel-iron layered double hydroxide (NiFe LDH) ultrathin nanosheets via an etching-aging process, realizing remarkable enhancement in oxygen evolution reaction (OER) performance. Detailed analyses revealed that the NiFe LDH phase around the nanopores can be preferentially oxidized into electroactive Fe:NiOOH phase. In addition, the buffering space provided by the nanopores can effectively avoid structural deformation during repeated redox cycling, leading to better electrochemical stability, which synergistically make the catalyst a promising candidate for commercial water splitting. This work highlights the positive role of porous structure in accelerating the formation of active phases beyond just increment of surface area, which can provide insight in designing advanced catalysts.

It is well known that introducing periodic holes into graphene can be used to obtain semiconducting graphene nanomeshes (GNM). Using Molecular Dynamics (MD) simulations as well as semi-empirical Extended Huckel (EH) method, the mechanical and electronic properties of GNM heterojunction are studied. In this study the mechanical and electronic properties of graphene nanoribbons with different hole sizes and different hole shapes (circular, square and equilateral triangle) were studied. Midgap states were observed near the Fermi level, which are also affected by the geometries of the holes. Dependence of the properties on the density (ρ) was also investigated for each geometry. It has been found that GNM is significantly brittle compared to pristine graphene nanoribbons. It is observed that the relationship between the hole shape and size and the band gap is different for armchair and zigzag chirality.

Facile yet rational design of efficient electrocatalyst toward triiodide reduction reaction is a persistent challenge for the practical application of dye-sensitized solar cell (DSSC). Here we propose a protocol for fabricating atomic N-coordinated cobalt sites (Co-Nx-C) within nanomesh graphene frameworks (Co-NMG). The as-synthesized Co-NMG combines the features of atomically dispersed active sites and interconnected mesoporous structure with high porosity, which makes these active sites fully exposed and accessible while facilitating the mass transport of reactants. As a result, the Co-NMG electrocatalysts with substantial active sites and desired porous architectures exhibit high electrocatalytic activity and long-term electrochemical stability. Electrochemical measurements and DFT calculations reveal that the catalytic sites toward the reduction of triiodide mainly derive from the abundant topological defects, nitrogen dopants, and especially the atomic Co-Nx-C moieties. Furthermore, with Co-NMG as counter electrodes (CEs), the DSSCs display a power conversion efficiency of 9.06%, which is higher than that of Pt CEs (7.71%). This work not only provides a promising CE material for DSSC to address the issues associated with Pt catalyst, but also opens up new avenues for developing nanocarbon based catalysts with desired features for other energy-related applications.

In this article, 3D pillared carbon nanotube (CNT)-porous graphene (PG) nanomesh architectures are computationally investigated as methane storage nanocontainer. The purpose of this article is to screen the configurations of 3D pillared CNT-PG materials and to select the optimal one for maximizing the methane storage capacity. Molecular mechanics (MM) calculations and MD simulations are executed to depict the structural characteristics and methane adsorption properties. The calculated structural parameters coincide well with the empirical conclusions. The methane adsorption simulations are systematic investigated as a function of geometry variables such as PG interlayer spacing, distance of CNTs, and the number of PG sheets in a wide range of pressure. The average adsorption energy of methane in different configurations is concentrated between 2 and 4 kcal mol−1. The results revealed that the applications of 3D CNT-PG models can significantly enhance methane adsorption performance in comparison to pillared graphene: the maximum amount of adsorbed methane of 3D CNT-PG displays 21.3 mmol/gr (interlayer spacing of 1.2 nm and bilayer PG), which is about 25% higher than that of pillared graphene. Meanwhile, the deformation of (6, 6) carbon nanotubes can significantly improve the methane storage capacity. This provides a viable structure modification method, which is suitable for enhancement of methane storage.

First principles calculation based on density functional theory has been applied to systematically study the electronic structure, especially band gap of recently synthesized periodic porous structure, graphene nanomesh, as well as its analogous system BN nanomesh. These porous structures possess various band gaps due to two parameters: neck length and width. The modulation of these parameters can be achieved through different etching templates in experiments. Two mechanisms, plane and nanoribbon, are proposed to understand the band gap variation with respect to neck length and width, qualitatively. We also examine electronic frontier states around Fermi level. Especially, armchair necked BN nanomesh has separated highest occupied and lowest unoccupied states in real space, which also makes it be reactive at different site. The hydrogen storage potentials based on transition metal atoms such as Sc trapped in anionic decorated pores are also been explored. No clustering problem is found and one Sc can adsorb four H 2 molecules with binding energy per H 2 of 0.13 eV.

Two-dimensional transition-metal dichalcogenides (TMDCs) are very promising for photovoltaic (PV) applications due to their excellent light absorption properties and appropriate bandgap energy, Although multifunctional applications of TMDCs in photovoltaic devices have been achieved, the photovoltaic conversion efficiency under 1 sun is still very low with small active area because of their inexpedient high sheet resistance and limitation of synthesis techniques. In this study, we demonstrate uniform synthesis of 4-in. wafer-scale MoS2 thin films by thermal decomposition of solution precursors. The solar cells are fabricated by transferring n-MoS2 thin films on p-Si substrates to form p-n heterojunctions and then transferring Au nanomeshes prepared in a novel surface treatment as transparent top electrodes onto MoS2. The circular n-MoS2/p-Si heterojunction solar cell exhibited a power conversion efficiency of 5.96% at a diameter of 0.3 in. and proved to be easily scalable to 1-in. diameter with 5.18% efficiency. To the best of our knowledge, the solar cells of this study are the most efficient and the largest in all types of solar cells based on TMDC reported so far. Finally, based on finite difference time-domain simulation, we proposed a strategy for implementing n-MoS2/p-Si heterojunction solar cell with efficiency higher than 15% by introducing optimal doping control of n-MoS2 and efficient anti-reflection layers.

The commercialized aluminum electrolytic capacitors (AECs) currently used for alternating current (AC) line-filtering have low specific capacitances, making them usually the largest components in electronic circuits. Herein, an ultrathin free-standing graphene nanomesh film (GMF) with uniform and dense nanoholes has been successfully fabricated by an in-situ carbothermal reduction strategy on the basis of spontaneously assembled graphene hybrid film. Due to the carbothermal reduction reaction between carbon atoms of graphene and the metal oxide nanoparticles in-situ generated during assembly process, in-plane nanopores are generated within graphene film. The pore size and density of GMF can be conveniently tuned by annealing temperature. With large ion-accessible surface area, efficient ion diffusion and electron transport pathways, the typical GMF-based electrochemical capacitor (EC) exhibits a high volumetric capacitance of up to 7.6 F cm−3 at 120 Hz, unprecedented power density of up to 3000 W cm−3, ultrafast frequency response with a phase angle of −82.3°, and a short resistor-capacitor time constant of 0.32 ms at 120 Hz, as well as long-term cycling stability. The performances of these ECs are superior to those of the state-of-the-art carbon-based ECs for this purpose; thus, it is promising to replace commercialized AECs for AC line-filtering in future electronics.

Conductive hydrogels are promising materials for soft electronic devices. To satisfy the diverse requirement of bioelectronic devices, especially those for human–machine interfaces, hydrogels are required to be transparent, conductive, highly stretchable, and skin-adhesive. However, fabrication of a conductive-polymer-incorporated hydrogel with high performance is a challenge because of the hydrophobic nature of conductive polymers making processing difficult. Here, we report a transparent, conductive, stretchable, and self-adhesive hydrogel by in situ formation of polydopamine (PDA)-doped polypyrrole (PPy) nanofibrils in the polymer network. The in situ formed nanofibrils with good hydrophilicity were well-integrated with the hydrophilic polymer phase and interwoven into a nanomesh, which created a complete conductive path and allowed visible light to pass through for transparency. Catechol groups from the PDA–PPy nanofibrils imparted the hydrogel with self-adhesiveness. Reinforcement by the nanofibrils ...

Biomimetic surfaces with various extents of liquid adhesion intensely appeal to many researchers due to their academic significance and potential industry applications. The present work aims to discuss the relationship between bouncing dynamics of impact droplets and static liquid adhesion driven by micro/-nanostructure features. Here, we fabricated three types of nanostructure (nanotube, nanomesh, and nanowire) superhydrophobic surfaces based on the TiO2 nanomaterials, and all of these resultant surfaces were endowed with the robust superhydrophobicity, and showed the low liquid adhesion with the sliding angles from 7.5° to 3°. Subsequently, the bouncing dynamics of impact droplets on these surfaces were evaluated and showed remarkable distinctions with different capacity to rebound off. This is explained in that the impact droplet has induced a higher capillary-induced adhesion force interaction as compared to the static droplet on the nanotube structure surface due to the existence of dynamic pressure during the moving process. The produced high capillary-induced adhesion force interaction finally caused the impact droplet to not bounce off the surface. On the contrary, the impact droplet can successfully bounce off the nanowire structure surface, which is mainly due to the almost no capillary adhesion force interaction induced by the open structure system on the superhydrophobic surface. Accepted version

Although transparent conductive oxides (TCOs) including indium tin oxide (ITO), fluorine tin oxide (FTO) and Aluminum-doped Zinc oxide (AZO) have been commercialized, and they can be found in many consumer electronics, TCOs are mechanically brittle and this issue actually limits them to the application of future flexible solar cell devices. Therefore, one-dimensional (1D) metallic materials such as nanowires (NWs) have widely studied as transparent conductors because they exhibit excellent electrical and optical properties due to the quantum confinement effect that occurs in such structural one-dimensionality. More importantly, they are ductile as compared to traditional TCOs. Since demand for modern electronic devices have been escalating, a great variety of 1D materials such as bimetallic or core–shell metallic NWs, metal–oxide, metal–CNTs/Graphene and metal–polymer composite 1-D nanomaterials have been developing owing to the fact that their electrical, optical, and mechanical performance becomes several order of magnitude higher than the pure metal NWs, especially under extreme mechanical and chemical conditions. Derived from those metal NW researches, advanced two-dimensional (2D) metallic materials such as nanomesh and nanogrid are designed as potential alternative to replace either conventional TCO films or random metal NW-based films due to their ample carriers (electrons) can transport consistently through this solid metallic network and are collected by the contact terminals without significantly compromising the optical transmittance. Moreover, metal nanomesh and nanogrid architectures possesses excellent flexibility, which can withstand even more harsh mechanical conditions. Therefore, they can provide a great potential for the emerging super-flexible and stretchable devices. Despite the aforementioned advantages, scalable fabrication of 1D and 2D nanomaterials is still a challenging research topic, in terms of the yield and quality. To integrate nanoscale building blocks into high-performance devices further requires more sophisticated designs. In this review, we emphasize on the current development of 1D and 2D nanomaterials in the application of transparent conductors in renewable energy devices. Computational simulation methods for property prediction and device design will also be reviewed. Additionally, we also discuss the promising fabrication methods for those nanomaterials that are considered to be scalable, applicable, and budget-wise to this solar industry.

It is of practical and theoretical significance to realize full spectrum-active photocatalytic hydrogen (H2) evolution using a single-component photocatalyst. The bottleneck is the utilization of near infrared (NIR) light with 52% of the energy in solar spectrum due to the mismatch between its low single photon energy and the large bandgaps of many photocatalysts. In fact, except for the intrinsic inter-band transition, charge-transfer transition is another strategy to produce hot electrons as a result of light excitation. Herein, charge-transfer transition is achieved in hydrogen-interstitial CuWO4 nanomesh (H-CuWO4) by introducing low-valence Cu+ and W5+. The resulting polaron absorption produces abundant free electrons upon NIR irradiation. Meanwhile, the intrinsic inter-band transition supplies more electrons upon ultraviolet and visible (UV and Vis) irradiations. The mesh structure induced by the self-assembled orientated attachment facilitates the electron transport in the photocatalytic process. Further, the lattice stress resulting from the H intercalation raises the conduction band (CB) above the H+/H2 potential level. CuWO4, incapable of realizing photocatalytic H2 evolution, is therefore activated to be a single-component full spectrum-active photocatalyst based on the dual-channel mechanism without any assistance of cocatalysts. It exhibits an excellent H2 evolution rate and high stability. This advance may have great potential in the future environmental and energy engineering applications.

The exploration of various porous nanocarbon materials with an extraordinary electrochemical capacitive performance in ionic liquid (IL) electrolytes is urgently needed for development of the next-generation energy storage devices. Significant improvements in energy density have been achieved, however, supercapacitors with IL electrolytes usually suffer from issues related to low power density and large IR drop. Herein, we report an unprecedented carbon nanomesh that is made up of interconnected densely-packed carbon nanocages with ultrathin partially graphitic shells. The large specific surface area and well-developed mesopores combined with its unique structural features, make it a very competitive material for high-performance supercapacitor in IL electrolyte. Notably, this unique nanosheets morphology with lots of in-plane nanopores on their surface can provide fast cross-plane ion diffusion pathways, and meanwhile, the carbon nanocages with partially graphitic shells ensure the rapid electron transfer. The supercapacitor assembled with the optimized sample can deliver a high specific capacitance (up to 194 F/g at 1 A/g), superior rate capability (68% capacitance retention at 70 A/g), low IR drop (0.685 V at 70 A/g). Moreover, benefiting from the wide working voltage and high-rate capability, the energy densities can maintain at 56.1 Wh/kg even at an ultrahigh power density of 61.250 kW/kg. Strikingly, the as-assembled supercapacitor can successfully power a light-emitting diodes (LED, 2.2 V) module with 53 red LED lights demonstrating its great potential for practical applications in energy storage devices.