Search Results (57)

With the increasing demand for alternatives to traditional indium tin oxide (ITO), copper nanowires (Cu NWs) have gained significant attention due to their excellent conductivity, cost-effectiveness, and ease of synthesis. However, challenges such as wire–wire contact resistance and oxidation susceptibility hinder their practical applications. This review discusses the development and challenges associated with Cu NW-based flexible transparent conductors (FTCs). Cu NWs are considered a promising alternative to traditional materials like ITO, thanks to their high electrical conductivity and low cost. This paper explores various synthesis methods for Cu NWs, including template-assisted synthesis, hydrazine reduction, and hydrothermal processes, while highlighting the advantages and limitations of each approach. The key challenges, such as contact resistance, oxidation, and the need for protective coatings, are also addressed. Several strategies to enhance the conductivity and stability of Cu NW-based FTCs are proposed, including thermal sintering, laser sintering, acid treatment, and photonic sintering. Additionally, protective coatings like noble metal core–shell layers, electroplated layers, and conductive polymers like PEDOT:PSS are discussed as effective solutions. The integration of graphene with Cu NWs is explored as a promising method to improve oxidation resistance and overall performance. The review concludes with an outlook on the future of Cu NWs in flexible electronics, emphasizing the need for scalable, cost-effective solutions to overcome current challenges and improve the practical application of Cu NW-based FTCs in advanced technologies such as displays, solar cells, and flexible electronics. Full article

The collector ring/carbon brush assembly of a hydrogenerator set is a critical component for transmitting excitation current into the self-exciting winding. Its operating environment necessitates excellent corrosion resistance and current-carrying frictional properties. The surface condition and material composition of the collector ring are key factors influencing the performance of the brush/ring interface. Coatings have proven effective in enhancing both tribological and corrosion-resistant characteristics. In this study, copper/graphene composite coatings were fabricated via electroplating, and the effects of graphene deposition rate on current-carrying friction characteristics were systematically investigated to optimize electroplating parameters. The results showed that the composite coating reduced contact resistance by 32.58% and friction coefficient by 37.59%. Electrochemical and immersion tests were conducted to evaluate the corrosion behavior under varying pressure and current density conditions. The results revealed that the optimal corrosion resistance was achieved under 1 N pressure and 12 A/cm² current density. The copper/graphene composite coating demonstrated superior corrosion resistance compared to uncoated samples. In summary, the electroplated copper/graphene composite coatings exhibit excellent current-carrying frictional performance and corrosion resistance, offering a promising solution for enhancing the durability and efficiency of hydrogenerator collector rings. Full article

This paper presents a non-enzymatic sensor for glucose detection in an environment where glucose and insulin coexist. The sensor is based on a three-electrode chip fabricated by etching the copper foil of a printed circuit board. The working electrode is coated with a graphene oxide-polyvinyl alcohol composite film, followed by the electroplating of a nickel–cobalt layer and an additional surface treatment using O₂ plasma. The experimental results indicate that within a glucose concentration of 2 mM to 10 mM and an insulin concentration of 0.1 mM to 1 mM, the measured current exhibits a linear relationship with the concentration of glucose or insulin, regardless of whether cyclic voltammetry or linear sweep voltammetry is used. However, the detection limit for insulin is 0.01 mM, ensuring that glucose detection remains unaffected by insulin interference. In this sensor, nickel–cobalt serves as a catalyst for glucose and insulin detection, while the graphene oxide-polyvinyl alcohol composite enhances sensing performance. Full article

The design and implementation of two-dimensional materials into a metal matrix have been the focus of considerable research interest for achieving enhanced properties. Nevertheless, conventional and modern manufacturing techniques often struggle to fabricate bulk 2D metal matrix composites (2DMMCs) while preserving the desired distribution and preventing thermomechanical damage to the constituent phases. Cold spray technology is a solid-state manufacturing method known for maintaining the composition of the original feedstock without causing significant detrimental changes during the deposition process. This study investigates the influence of cold spray process parameters on the microstructure, porosity, and microhardness of copper composites reinforced with 1 wt.% graphene platelets. The copper–graphene composite powder was synthesized via high-energy ball milling and subsequently deposited using two distinct sets of cold spray parameters employing medium- and high-pressure systems. Scanning electron microscopy, dispersive X-ray spectroscopy, porosity measurements, microhardness testing, and Raman spectroscopy were used to comprehensively evaluate the deposits. The findings demonstrate the preservation of the 2D phase and show how cold spray parameters influence porosity, hardness, and the incorporation of graphene within the copper matrix. Full article

Current collectors are key components of lithium-ion batteries, providing conductive pathways and maintaining interfacial stability with the electrode materials. Conventional metal-based current collectors, such as aluminum and copper, exhibit excellent conductivity and mechanical strength. However, they have considerable limitations, including electrochemical corrosion, interfacial resistance caused by the formation of passive layers, and mechanical degradation due to repeated cycling. To overcome these challenges, various carbon-based coatings, including amorphous carbon, graphene, and carbon nanotubes, have been developed. These coatings enhance the current collector performance by improving the collector conductivity, chemical stability, and interfacial adhesion. Vertically aligned graphene-like structures known as carbon nanowalls (CNWs) have garnered attention owing to their unique architecture, resulting in high surface area, exceptional conductivity, and excellent thermal and mechanical properties. In this mini-review, the recent advancements in carbon-based coating technologies and their role in enhancing the performance of current collectors were summarized, focusing on the innovative applications of CNWs in next-generation energy storage systems. Full article

Copper, though highly conductive, requires improved wear resistance and thermal dissipation in applications that involve continuous movement and current-induced vibrations, such as power breakers. Conventional solutions, such as copper–tungsten alloys or lubricant use, face limitations in durability, friction, or environmental impact. This study explores the development of copper–graphene (Cu-GNPs) composite coatings using pulsed electrodeposition to enhance the tribological, thermal, and mechanical properties of circuit breaker components by adopting an industrially scalable technique. The influence of deposition bath temperature, duty cycle, and frequency on coating morphology, hardness, wear resistance, and heat dissipation was systematically evaluated using a 2³ full factorial design and an Analysis of Variance (ANOVA). The results revealed that optimized pulsed electrodeposition significantly improved coating performance: hardness increased by 76%, wear volume decreased by more than 99%, and friction coefficient stabilized at 0.2, reflecting effective graphene integration. The addition of graphene further improved thermal diffusivity by 19.5%, supporting superior heat dissipation. These findings suggest that pulsed copper–graphene composite coatings offer a promising alternative to traditional copper alloys, enhancing the lifespan and reliability of electronic components through improved wear resistance, lower friction, and superior heat transfer. Full article

Recent clinical outbreaks of infectious diseases caused by pathogenic microorganisms, such as viruses, bacteria, and fungi, along with the emergence of unwanted microorganisms in industrial settings, have significantly reduced efficiency. Graphene has recently attracted significant attention as a potential antimicrobial agent because of its low toxicity, ease of production and functionalization, and high solubility in water. The presence of oxygen functional groups allows the interaction of the compound with bacteria and other biomolecules, making it an interesting candidate for antimicrobial therapy. Moreover, integrating graphene into copper coatings has been shown to enhance their antimicrobial properties. However, the implementation of copper–graphene composite coatings is currently limited by the difficulty of uniformly distributing graphene within the copper matrix. Copper (Cu)-doped graphitic nanoplatelets (CuGnPs), one option to overcome this challenge, are made via a mechanochemical reaction between solid graphite and Cu powder. The configuration of C–Cu bonds within CuGnPs can be identified using a range of analytical techniques, including transmission electron microscopy, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and time-of-flight secondary ion mass spectrometry. To evaluate the antibacterial activity of the Cu-GnPs, we employed Escherichia coli or Staphylococcus aureus. Various amounts (250, 500, 750, and 1000 μg/mL) of prepared CuGnP samples were incubated in a bacterial suspension for 3 or 6 h at 150 rpm and 37 °C for a colony-forming unit assay. Three hours and six hours of treatment of the bacteria with CuGnPs led to a significant difference in bacterial survival compared with that of the control. It was observed that CuGnPs, with copper bound to graphene oxide, more effectively inhibited the proliferation of E. coli compared with nanoplatelets containing graphene oxide alone. These findings suggest that the unique properties of CuGnPs, such as C–Cu bonds, high surface area, and the coexistence of micropores and mesopores, are valuable for exerting strong antimicrobial effects making CuGnPs effective at preventing bacterial colonization on industrial surfaces. Full article

Bacterial adhesion and biofilm maturation is significantly influenced by surface properties, encompassing both bare surfaces and single or multi-layered coatings. Hence, there is an utmost interest in exploring the intricacies of gene regulation in sulfate-reducing bacteria (SRB) on copper and graphene-coated copper surfaces. In this study, Oleidesulfovibrio alaskensis G20 was used as the model SRB to elucidate the pathways that govern pivotal roles during biofilm formation on the graphene layers. Employing a potent reporter green fluorescent protein (GFP) tagged to O. alaskensis G20, the spatial structure of O. alaskensis G20 biofilm on copper foil (CuF), single-layer graphene-coated copper (Cu-GrI), and double-layer graphene-coated copper (Cu-GrII) surfaces was investigated. Biofilm formation on CuF, Cu-GrI, and Cu-GrII surfaces was quantified using CLSM z-stack images within COMSTAT v2 software. The results revealed that CuF, Cu-GrI, and Cu-GrII did not affect the formation of the GFP-tagged O. alaskensis G20 biofilm architecture. qPCR expression showed insignificant fold changes for outer membrane components regulating the quorum-sensing system, and global regulatory proteins between the uncoated and coated surfaces. Notably, a significant expression was observed within the sulfate reduction pathway confined to dissimilatory sulfite reductases on the Cu-GrII surface compared to the CuF and Cu-GrI surfaces. Full article

With the rapid development of industrial automation and power electronics, the requirements for electrical contact materials are increasing. However, traditional electrical contact materials encountered significant bottlenecks in terms of performance enhancement and production environmental friendliness. Therefore, this paper proposes a new material design idea that utilizes π-π interactions between graphene and compounds with conjugated structures in order to achieve uniform dispersion of graphene in the metal matrix and thus enhance the performance of composites. Based on this design idea, we used nicotinic acid, which has a conjugated structure and is safe, as the complexing agent, and successfully prepared high-quality silver-graphene (Ag-G) composite coatings with graphene uniformly dispersed in the metal matrix on copper substrates by composite electrodeposition technique. Subsequently, the mechanical properties of composite coatings were investigated by hardness test and X-ray diffractometer, and the tribological properties of the composite coatings and the comprehensive performance under the current carrying conditions were systematically evaluated by using friction and wear tester and load key life tester. The results show that the Ag-G composite coatings have significant advantages in mechanical, tribological, and current carrying conditions. This result not only verifies the feasibility of the design idea of the material, but also provides a new direction for the research and development of electrical contact materials. Full article

The condensation of water vapor plays a crucial role in various applications, including combating water scarcity. In this study, by employing molecular dynamics simulations, we delved into the impact of graphene coatings on water vapor condensation on copper surfaces. Unique to this work was the exploration of various levels of graphene coverage and distribution, a facet largely unexplored in prior investigations. The findings demonstrated a notable increase in the rate of water vapor condensation and heat transfer performance as the graphene coverage was reduced. Using graphene coverages of 84%, 68%, and 52%, the numbers of condensed water molecules were 664, 735, and 880 molecules/ns, respectively. One of the most important findings was that when using the same graphene coverage of 68%, the rate of water vapor condensation and heat transfer performance increased as the graphene coating became more distributed. The overall performance of the water condensation correlated well with the energy and vibrational interaction between the graphene and the copper. This phenomenon suggests how a hybrid surface can enhance the nucleation and growth of a droplet, which might be beneficial for tailoring graphene-coated copper surfaces for applications demanding efficient water vapor condensation. Full article

Advanced thermal interface materials with high thermal conductivity are crucial for addressing the heat dissipation issue in high-power, highly integrated electronic devices. One great potential way in this field is to take advantage of cooling copper foil (Cu) materials based on graphene (G). However, the current manufacturing of these cooling copper foil materials is accompanied by high cost, process complexity, and environmental problems, which limit their development and application. In this work, a simple, low-cost, environmentally friendly graphene-copper foil composite film (rGO/G-Cu) with high thermal conductivity was successfully prepared using graphene oxide directly as a dispersant and binder of graphene coating. The microstructure characterization, thermal conductivity and thermal management performance tests were carried out on the composite films. The results demonstrate that compared to pure copper foil (342.47 W·m⁻¹·K⁻¹) and 10% PVA/G-Cu (367.98 W·m⁻¹·K⁻¹) with polyvinyl alcohol as a binder, 10% rGO/G-Cu exhibits better thermal conductivity (414.56 W·m⁻¹·K⁻¹). The introduction of two-dimensional graphene oxide effectively enhances the adhesion between the coating and the copper foil while greatly improving its thermal conductivity. Furthermore, experimental results indicate that rGO/G-Cu exhibits excellent heat transfer performance and flexibility. This work is highly relevant to the development of economical and environmentally friendly materials with high thermal conductivity to meet the increasing demand for heat dissipation. Full article

Due to the direct contact between the probe and sample, the contact of the four-probe method is important for the structural integrity of the sample and the accuracy of electrical resistivity measurements, especially for surface-coated metal foils with multilayered structures. Here, we analyzed the accuracy and stability of four-probe method probing on different sides of copper (Cu) foils covered with graphene (Gr). Theoretical simulations showed similar potential distributions on the probe tip when probing on the Cu and Gr sides. The resistivity of the Gr/Cu foil was 2.31 ± 0.02 μΩ·cm when measured by probing on the Cu side, and 2.30 ± 0.10 μΩ·cm when measured by probing on the Gr side. The major difference in the mean deviation is attributed to surface damage. In addition, the method of probing on the Cu side was sensitive to the resistivity changes of Gr induced by polymers with a dielectric constant range of 2~12, which is consistent with the calculations based on the random phase approximation theory. Our results demonstrated that the probing position on the metal side in the four-probe method can effectively protect the structural integrity of the functional surface-coated layer and maintain the high sensitivity of the measurement, providing guidance for the resistivity measurements of other similarly heterogeneous materials. Full article

The deposition of thin uniform dielectric layers on graphene is important for its successful integration into electronic devices. We report on the atomic layer deposition (ALD) of Al₂O₃ nanofilms onto graphene grown by chemical vapor deposition onto copper foil. A pretreatment with deionized water (DI H₂O) for graphene functionalization was carried out, and, subsequently, trimethylaluminum and DI H₂O were used as precursors for the Al₂O₃ deposition process. The proper temperature regime for this process was adjusted by means of the ALD temperature window for Al₂O₃ deposition onto a Si substrate. The obtained Al₂O₃/graphene heterostructures were characterized by Raman and X-ray photoelectron spectroscopy, ellipsometry and atomic force and scanning electron microscopy. Samples of these heterostructures were transferred onto glass substrates by standard methods, with the Al₂O₃ coating serving as a protective layer during the transfer. Raman monitoring at every stage of the sample preparation and after the transfer enabled us to characterize the influence of the Al₂O₃ coating on the graphene film. Full article

Designing minimally invasive, defect-free coatings based on conformal graphene layers to shield metals from both abiotic and biotic forms of corrosion is a persistent challenge. Single-layer graphene (SLG) grown on polycrystalline copper (PC-Cu) surfaces often have inherent defects, particularly at Cu grain boundaries, which weaken their barrier properties and worsen corrosion through grain-dependent mechanisms. Here, we report that an SLG grown via chemical vapor deposition (CVD) on Cu (111) single crystal serves as a high-performance coating to lower corrosion by nearly 4–6 times (lower than bare Cu (111)) in abiotic (sulfuric acid) and microbiologically influenced corrosion (MIC) environments. For example, the charge transfer resistance for SLG/Cu (111) (3.95 kΩ cm²) was 2.5-fold higher than for bare Cu (111) (1.71 kΩ cm²). Tafel analysis corroborated a reduced corrosion current (42 ± 3 µA cm⁻²) for SLG/Cu (111) compared to bare Cu (111) (115 ± 7 µA cm⁻²). These findings are consistent with the results based on biofilm measurements. The SLG/Cu (111) reduced biofilm formation by 3-fold compared to bare Cu (111), increasing corrosion resistance, and effectively mitigating pitting corrosion. The average depths of the pits (3.4 ± 0.6 µm) for SLG/Cu (111) were notably shallower than those of bare Cu (111) (6.5 ± 1.2 µm). Surface analysis of the corrosion products corroborated these findings, with copper sulfide identified as a major component across both surfaces. The absence of grain boundaries in Cu (111) resulted in high-quality SLG manifesting higher barrier properties compared to SLG on PC-Cu. Our findings show promise for using the presented strategy for developing durable graphene coatings against diverse forms of corrosion. Full article