Industrial Graphene Coating of Low-Voltage Copper Wires for Power Distribution

Copper (Cu) is the electrical conductor of choice in many categories of electrical wiring, with household and building installation being the major market of this metal. This work demonstrates the coating of Cu wires-with diameters relevant for low-voltage (LV) applications-with graphene. The chemical vapor deposition (CVD) coating process is rapid, safe, scalable, and industrially compatible. Graphene-coated Cu wires display good oxidation resistance and increased electrical conductivity (up to 1% immediately after coating and up to 3% after 24 months), allowing for wire diameter reduction and thus significant savings in wire production costs. Combined spectroscopic and diffraction analysis indicates that the conductivity increase is due to a change in Cu crystallinity induced by the coating process conditions, while electrical testing of aged wires shows that graphene plays a major role in maintaining improved electrical performances over long periods of time. Finally, graphene coating of Cu wires using an ambient-pressure roll-to-roll (R2R) CVD reactor is demonstrated. This enables the in-line production of graphene-coated metallic wires as required for industrial scale-up.

Ultrasensitive Boron-Nitrogen-Codoped CVD Graphene-Derived NO2 Gas Sensor

Recent trends in 2D materials like graphene are focused on heteroatom doping in a hexagonal honeycomb lattice to tailor the desired properties for various lightweight atomic thin-layer derived portable devices, particularly in the field of gas sensors. To design such gas sensors, it is important to either discover new materials with enhanced properties or tailor the properties of existing materials via doping. Herein, we exploit the concept of codoping of heteroatoms in graphene for more improvements in gas sensing properties and demonstrate a boron- and nitrogen-codoped bilayer graphene-derived gas sensor for enhanced nitrogen dioxide (NO₂) gas sensing applications, which may possibly be another alternative for an efficient sensing device. A well-known method of low-pressure chemical vapor deposition (LPCVD) is employed for synthesizing the boron- and nitrogen-codoped bilayer graphene (BNGr). To validate the successful synthesis of BNGr, the Raman, XPS, and FESEM characterization techniques were performed. The Raman spectroscopy results validate the synthesis of graphene nanosheets, and moreover, the FESEM and XPS characterization confirms the codoping of nitrogen and boron in the graphene matrix. The gas sensing device was fabricated on a Si/SiO₂ substrate with prepatterned gold electrodes. The proposed BNGr sensor unveils an ultrasensitive nature for NO₂ at room temperature. A plausible NO₂ gas sensing mechanism is explored via a comparative study of the experimental results through the density functional theory (DFT) calculations of the adsorbed gas molecules on doped heteroatom sites. Henceforth, the obtained results of NO₂ sensing with the BNGr gas sensor offer new prospects for designing next-generation lightweight and ultrasensitive gas sensing devices.