Search Results (295)

The emergence of advanced low-dimensional materials of the graphene family opens up unique opportunities for energy-efficient and fast processing of electrical and optical signals in a wide spectral range from ultraviolet to infrared. Non-volatile resistive states in memristors based on two-dimensional (2D) crystals, 1D nanoribbons, and 0D quantum dots are accessible for control by light and an electric field due to polarization and rearrangement of sp²-sp³ hybridization of carbon atoms, as well as due to photoinduced phase transitions. Two-dimensional materials possess unique structural and electronic properties required for the development of highly efficient nanoenergy memristor devices for low-energy information technology. This article discusses memristors and photomemristors based on graphene, graphene oxide, diamane, and chalcogenide semiconductors such as MoS₂, WSe₂, MoS_2−xO_x, which are structurally similar to graphene and have a 2D layered structure. Memristors based on graphene and graphene oxide, bigraphene, and diamane, fabricated using localized electron irradiation, exhibit nonlinear behavior and well-controlled memristive states associated with sp²-sp³ transitions of carbon atoms under low-power conditions. The review highlights the dual role of graphene as an active material and electrode, as well as the redox control mechanism. Due to a well-controlled redox process, graphene-based devices exhibit the dynamic behavior required for neuromorphic computing directly in the sensor, reducing the energy and time costs associated with data processing. Neuromorphic computing in a photomemristor-based sensor enables the creation of a compact nano-energy system for real-time information recognition in a wide spectral range, similar to biological vision, for use in self-driving cars, personalized medicine, and other applications. Full article

The development of hybrid organic coatings for corrosion protection remains a key research priority. This study focuses on synthesising Layered Double Hydroxide (ZnGa-LDHs) intercalated with environmentally friendly disodium sebacate (SB) corrosion inhibitor, forming ZnGa-SB. To overcome the challenge of limited dispersibility in organic coatings, ZnGa-SB was combined with Graphene Nanoribbons (GNR), produced through the oxidative unzipping of multi-walled carbon nanotubes (MWCNT). The resulting composite, ZnGa-SB/GNR, was synthesised using an in situ hydrothermal method and incorporated into polyurethane (PU) enamel. The synergy between high-barrier GNRs and active ZnGa-SB creates a “labyrinth effect” that effectively inhibits the diffusion of corrosive species. Microstructural analysis, including XRD, FT-IR, Raman, TGA, FE-SEM, and EDS, confirmed the nanofiller structure. The nanofillers were embedded into acrylic resin (AC) for short-term anticorrosive testing in a 0.1 M NaCl solution and then into PU for long-term evaluation in a 3.5 wt% NaCl solution, using electrochemical impedance spectroscopy (EIS). The PU/ZnGa-SB/GNR coating exhibited a high impedance modulus of 5.90 × 10⁷ Ω cm² at |Z|_0.01 Hz, even after 2688 hours of immersion, indicating enhanced corrosion resistance. This coating demonstrated superior performance in cross-cut and pencil hardness tests and sustained less damage in salt spray analysis compared to other coatings. The synergistic effect offers a promising approach for developing next-generation hybrid anti-corrosive coatings. Full article

Valley-dependent topological physics offers a promising avenue for designing nanoscale devices based on gapless single-layer graphene. To demonstrate this potential, we investigate an electrical bias-controlled topological discontinuity in valley polarization within a two-segment armchair nanoribbon of gapless single-layer graphene. This discontinuity is created at the interface by applying opposite in-plane, transverse electrical biases to the two segments. An efficient tight-binding theoretical formulation is developed to calculate electron states in the structure. In a reference configuration, we obtain energy eigenvalues and probability distributions that feature interface-confined electron eigenstates induced by the topological discontinuity. Moreover, to elucidate the implications of interface confinement for electron transport, a modified configuration is introduced to transform the eigenstates into transport-active, quasi-localized ones. We show that such states result in Fano “anti-resonances” in transmission spectra. The resilience of these quasi-localized states and their associated Fano fingerprints is examined with respect to fluctuations. Finally, a proof-of-concept band-stop electron energy filter is presented, highlighting the potential of this confinement mechanism and, more broadly, valley-dependent topological physics in designing nanoscale devices in gapless single-layer graphene. Full article

To enhance the sensitivity of graphene-DNA sensors for Hg²⁺ detection, a novel graphene nanoribbon-DNA sensor was fabricated using a template-assisted approach. Silicon nanowires served as templates to decorate the graphene device, followed by plasma etching to delineate graphene nanoribbons. After template removal, the resulting sensors based on silicon nanowire templates were successfully constructed. DNA sequences containing four guanine bases were conjugated with graphene sensors prepared using the templates. The carboxyl groups on the edges of the graphene nanoribbons were activated with EDC/NHS chemistry to facilitate covalent bonding with amino-modified DNA. The kinetic response and Hg²⁺ detection capability of the fabricated sensors were characterized using a semiconductor parameter analyzer. Results indicated that the silicon nanowire-templated graphene nanoribbon sensor exhibited high sensitivity, with a detection limit of 3.62 pM. This innovative approach further improved the sensitivity of graphene-DNA sensors for Hg²⁺ detection. Full article

Graphitic nanomaterials have emerged as foundational components in nanoscience owing to their exceptional electrical, mechanical, and chemical properties, which can be tuned by controlling dimensionality and structural order. From zero-dimensional (0D) quantum dots, carbon nano-onions, and nanodiamonds to one-dimensional (1D) nanoribbons, two-dimensional (2D) nanowalls, and three-dimensional (3D) graphene foams, these architectures underpin advancements in catalysis, energy storage, sensing, and electronic technologies. Among various synthesis routes, chemical vapor deposition (CVD) provides unmatched versatility, enabling atomic-level control over carbon supply, substrate interactions, and plasma activation to produce well defined graphitic structures directly on functional supports. This review presents a comprehensive, dimension-resolved overview of CVD-derived graphitic nanomaterials, examining how process parameters such as precursor chemistry, temperature, hydrogen etching, and template design govern nucleation, crystallinity, and morphological evolution across 0D to 3D hierarchies. Comparative analyses of Raman, XPS, and XRD data are integrated to relate structural features with growth mechanisms and functional performance. By connecting mechanistic principles across dimensional scales, this review establishes a unified framework for understanding and optimizing CVD synthesis of graphitic nanostructures. It concludes by outlining a path forward for improving how CVD-grown carbon nanomaterials are made, monitored, and integrated into real devices so these can move from lab-scale experiments to practical, scalable technologies. Full article

This paper presents a compact and high-performance 2-to-4 optical decoder based on a plasmonic well structure incorporating suspended graphene nanoribbons. By exploiting the tunable graphene’s chemical potential, the propagation and confinement of surface plasmon polaritons are dynamically controlled, enabling efficient routing of optical signals toward the output ports. Finite-difference time-domain simulations are employed to analyze the influence of channel geometry and graphene chemical potential on surface plasmon polariton propagation, refractive index, and transmission loss. The designed structure, featuring a 30 nm wide and 10 nm high plasmonic well, achieves a low propagation loss of 0.188 dB/µm and a high figure of merit of 1950 at 40 THz. The designed decoder exhibits a contrast ratio of 36.93 dB and crosstalk suppression of −36.93 dB, while occupying a remarkably small area (0.05 µm²), demonstrating superior optical performance and compactness compared to previously reported designs. These results confirm the potential of the proposed plasmonic well-based decoder as a fundamental component for next-generation nanoscale optical and plasmonic computing systems. Full article

We present a comprehensive first-principles study of nanoribbons made from the α-borophene sheet. This study looks at how edge shape, ribbon width, and magnetic ordering affect their structural, electronic, and transport properties. Ribbons cut along armchair (ac) and zigzag (zz) directions with various edge designs—armchair (a), single (s), and double (d) chains—are all stable. The double chain “dd” edges have the highest binding energies and the lowest edge energies, which aligns with near-bulk coordination. Our analysis of electronic structure and ballistic transport shows strong metallic characteristics in almost all configurations. Only the narrowest “3-ad” ribbon shows a small energy gap that disappears as the width increases. Zigzag ribbons (“zz”) display edge magnetism that depends on width, changing from non-magnetic to antiferromagnetic and finally to ferromagnetic states. Their spin-resolved transmission demonstrates clear spin filtering with polarization exceeding about 40%. Edge passivation affects these properties: hydrogen and fluorine reduce the “zz” edge magnetic moments and spin transport, while oxygen maintains finite magnetism. Near the Fermi level, many ribbons allow for multiple conducting channels. This feature supports low-resistance charge flow even for widths below 10 nm, while higher-energy transmission shows greater dependence on width. These findings position α-borophene nanoribbons as promising one-dimensional components for nanoelectronic connections and spintronic devices, combining high stability, adjustable edge magnetism, and strong metallic conduction. Full article

The exceptional sensing properties of hydrogen-saturated zigzag phosphorene nanoribbons (ZPNRs-H) for sulfur-containing gases, namely SO₃, SO₂, and H₂S, were investigated using first-principles calculations based on density functional theory. The total energy, adsorption energy, and Mulliken charge transfer were assessed to evaluate the adsorption properties of the ZPNRs-H towards these gases. Notably, the ZPNRs-H exhibits physical adsorption for SO₂ and H₂S gas molecules, while demonstrating chemical adsorption for SO₃, characterized by a substantial adsorption energy and pronounced charge transfer. Furthermore, the adsorption of SO₃ significantly modulates the electronic density of states near the Fermi level of ZPNRs-H. The current–voltage (I–V) characteristics unveil a remarkable enhancement in conductivity post-SO₃ adsorption, underscoring the high sensitivity of ZPNRs-H towards SO₃. Our findings provide profound theoretical insights, heralding the potential of ZPNRs-H as a cutting-edge sensor for SO₃ detection. Full article

With the continuous exploration and advancement of communication frequency bands, terahertz and mid-to-far-infrared communication systems have attracted significant attention in recent years. Modulators are essential components in these systems, making the enhancement of modulator performance in the infrared and terahertz bands a prominent research focus. In this study, we propose a high-performance infrared transmission-type modulator based on the plasmon resonance effect of graphene nanoribbons. This design synergistically exploits near-field enhancement from metal slits and defect states in one-dimensional photonic crystals to strengthen light–graphene interactions. The modulator achieves a modulation depth exceeding 80% and an operating bandwidth greater than 4 THz in the mid-infrared range, enabling efficient signal modulation for free-space optical communication. Importantly, the proposed design alleviates experimental challenges typically associated with the need for high graphene mobility and a wide Fermi energy tuning range in conventional approaches, thereby improving its practical feasibility. Moreover, the approach is scalable to far-infrared and terahertz bands, offering valuable insights for advancing signal modulation technologies across these spectral regions. Full article

Efficient detection of toxic and flammable vapors remains a major technological challenge, especially for environmental and industrial applications. This paper reports on the fabrication technology and gas-sensing properties of nanostructured Ga₂O₃/GaS_0.98Se_0.02. The β-Ga₂O₃ nanowires/nanoribbons with inclusions of Ga₂S₃ and Ga₂Se₃ microcrystallites were obtained by thermal treatment of GaS_0.98Se_0.02 slabs in air enriched with water vapors. The microstructure, crystalline quality, and elemental composition of the obtained samples were investigated using electron microscopy, X-ray diffraction, and Raman spectroscopy. The obtained structures show promising results as active elements in gas sensor applications. Vapors of methanol (CH₃OH), ethanol (C₂H₅OH), and acetone (CH₃-CO-CH₃) were successfully detected using the nanostructured samples. The electrical signal for gas detection was enhanced under UV light irradiation. The saturation time of the sensor depends on the intensity of the UV radiation beam. Full article

A fluorescent sandwich assay was devised to quantify CK-MB. In a typical immunoassay, antibodies bind to the target, and the detected signal is quantified according to the target’s concentration. We innovated a unique fluorescence assay known as the “enzyme-linked aptamer assay” (ELAA) by substituting antibodies with a pair of high-affinity aptamers labelled with biotin, namely apt. A1 and apt. A2. Avidin-labelled ALP binds to biotin-labelled aptamers, hydrolyzing its substrate, 2-phosphoascorbic acid trisodium salt, resulting in the formation of ascorbic acid. The catalytic hydrolysate functions as a reducing agent, causing the deterioration of MoS₂ nanosheets. This results in the transformation of MoS₂ nanosheets into nanoribbons, leading to the release of quenched AGQDs. The reestablishment of fluorescence is triggered by Förster Resonance Energy Transfer (FRET) between the MoS₂ nanoribbons and AGQDs, enhancing the sensitivity of disease biomarker detection. The working range for detection falls between 2.5 nM and 160 nM, and the limit of detection (LOD) for CK-MB is verified at 0.20 nM. Full article

The catalytic activity of monolayer and bilayer boron-doped edge black phosphorene nanoribbons (BPNRs) as electrocatalysts for the nitrogen reduction reaction (NRR) was investigated using first-principles calculations based on density functional theory (DFT). The results indicate that boron incorporation facilitates effective N₂ adsorption at specific BPNR edges, thereby achieving superior NRR electrocatalytic performance. Through NRR screening criteria, six candidate edges (B@ZZ₃-1, B@ZZ₄-1, B@AC₀-1, B@ZZ₀^AA-1, B@ZZ₁^AB-3, and B@ZZ₄^AA-3) were identified. Electronic property analysis revealed that boron doping significantly reduces the bandgap of BPNRs and enhances catalytic activity by promoting electron accumulation at boron sites. Free energy pathway calculations demonstrated that B@AC₀-1, B@ZZ₀^AA-1, and B@ZZ₁^AB-3 exhibit overpotentials of 0.19 V, 0.28 V, and 0.15 V, respectively, during the NRR process, outperforming other phosphorus-based catalysts in activity. Full article

By combining density functional theory with the non-equilibrium Green’s function method, we conducted a first-principles investigation of spin-dependent transport properties in a molecular device featuring a dynamic covalent chemical bridge connected to zigzag graphene nanoribbon electrodes. The effects of spin-filtering and spin-rectifying on the I–V characteristics are revealed and explained for the proposed molecular device. Interestingly, our results demonstrate that all three devices exhibit significant single-spin-filtering behavior in parallel (P) magnetization and dual-spin-filtering effects in antiparallel (AP) configurations, achieving nearly 100% spin-filtering efficiency. At the same time, from the I–V curves, we find that there is a weak negative differential resistance effect. Moreover, a high rectifying ratio is found for spin-up electron transport in AP magnetization, which is explained by the transmission spectrum and local density of state. The fundamental mechanisms governing these phenomena have been elucidated through a systematic analysis of spin-resolved transmission spectra and spin-polarized electron transport pathways. These results extend the design principles of spin-controlled molecular electronics beyond graphene-based systems, offering a universal strategy for manipulating spin-polarized currents through dynamic covalent interfaces. The nearly ideal spin-filtering efficiency and tunable rectification suggest potential applications in energy-efficient spintronic logic gates and non-volatile memory devices, while the methodology provides a framework for optimizing spin-dependent transport in hybrid organic–inorganic nanoarchitectures. Our findings suggest that such systems are promising candidates for future spintronic applications. Full article

We propose a DNA nucleobase sequencing device composed of zigzag graphene nanoribbon electrodes connected with a porphyrin molecule via carbon chains (GEPM). The connecting geometry between the nanoribbons with an even width number and the carbon chains is laterally symmetric to filter out electrons of specific modes. Various properties of the GEPM and of the GEPM + nucleobase systems, such as interaction energies, charge density differences, spin-differential electronic densities, and electric currents, are investigated using the density functional theory (DFT) combined with the non-equilibrium Green’s function (NEGF) method. The results show that the GEPM device holds promise for DNA sequencing with the measurement of the electric signals through it. The four nucleobases—adenine (A), cytosine (C), guanine (G), and thymine (T)—can be efficiently distinguished based on the conductance and current sensitivity when they are located on the porphyrin molecule of the GEPM device. The symmetry of the connecting geometry between the carbon chains and the nanoribbons selects Bloch states with specific symmetry to pass through the device and results in broad transmission valleys or gaps. In addition, the edge magnetism of graphene nanoribbons can further manipulate the transmission and then the sequencing effects. The device exhibits extremely high conductance sensitivity in the parallel magnetic configuration. This study explores the possible advantage of this technology compared with conventional nanopore sequencing devices and potentially expands the variety of available sequencing structures. Full article

Using the Bridgman technique, GaSe single crystals were obtained which were mechanically split into plane-parallel plates with a wide range of thicknesses. By heat treatment in air at 820 °C and 900 °C, for 30 min and 6 h, micro- and nanocomposite layers of Ga₂Se₃–Ga₂O₃ and β–Ga₂O₃ (native oxide) with surfaces made of nanowires/nanoribbons were obtained. The obtained composite Ga₂Se₃–Ga₂O₃ and nanostructured β–Ga₂O₃ are semiconductor materials with band gaps of 2.21 eV and 4.60 eV (gallium oxide) and photosensitivity bands in the green–red and ultraviolet-C regions that peaked at 590 nm and 262 nm. For an applied voltage of 50 V, the dark current in the photodetector based on the nanostructured β–Ga₂O₃ layer was of 8.0 × 10⁻¹³ A and increased to 9.5 × 10⁻⁸ A upon 200 s excitation with 254 nm-wavelength radiation with a power density of 15 mW/cm². The increase and decrease in the photocurrent are described by an exponential function with time constants of τ_1r = 0.92 s, τ_2r = 14.0 s, τ_1d = 2.18 s, τ_2d = 24 s, τ_1r = 0.88 s, τ_2r = 12.2 s, τ_1d = 1.69 s, and τ_2d = 16.3 s, respectively, for the photodetector based on the Ga₂Se₃–Ga₂S₃–GaSe composite. Photoresistors based on the obtained Ga₂Se₃–Ga₂O₃ composite and nanostructured β–Ga₂O₃ layers show photosensitivity bands in the spectral range of electronic absorption bands of ozone in the same green–red and ultraviolet-C regions, and can serve as ozone sensors (detectors). Full article