A simple approach for growing porous electrochemically reduced graphene oxide (pErGO) networks on copper wire, modified with galvanostatically deposited copper foam is demonstrated. The as-prepared pErGO networks on the copper wire are directly used to fabricate solid-state supercapacitor. The pErGO-based supercapacitor can deliver a specific capacitance (Csp) as high as 81±3 F g−1 at 0.5 A g−1 with polyvinyl alcohol/H3PO4 gel electrolyte. The Csp per unit length and area are calculated as 40.5 mF cm−1 and 283.5 mF cm−2, respectively. The shape of the voltammogram retained up to high scan rate of 100 V s−1. The pErGO-based supercapacitor device exhibits noticeably high charge-discharge cycling stability, with 94.5% Csp retained even after 5000 cycles at 5 A g−1. Nominal change in the specific capacitance, as well as the shape of the voltammogram, is observed at different bending angles of the device even after 5000 cycles. The highest energy density of 11.25 W h kg−1 and the highest power density of 5 kW kg−1 are also achieved with this device. The wire-based supercapacitor is scalable and highly flexible, which can be assembled with/without a flexible substrate in different geometries and bending angles for illustrating promising use in smart textile and wearable device.

Carbonaceous materials with high surface area and a sheet-like structure promote fast ion-transport kinetics, making them an ideal choice to be used in supercapacitors. Few-layer graphene (FLG)-like nanosheets with abundance of micro as well as mesopores are achieved via mechanical exfoliation method from an agricultural waste biomass: peanut shell (PS). A well-known elementary method of probe-sonication, for the achievement of FLG sheets from renewable sources, is introduced in this study for the very first time. The Peanut shell-derived FLG (PS-FLG) possesses remarkably high specific surface area (2070 m2 g−1) with a sufficiently large pore volume of 1.33 cm3 g−1. For the fabrication of a binder-free supercapacitor, the PS-FLG-based electrodes exhibited a high specific capacity of 186 F g−1 without the use of any binder in 1 M H2SO4 as supporting electrolyte. The highest energy density of 58.125 W h Kg−1 and highest power density of 37.5 W Kg−1 was achieved by the material. Surprisingly, the working potential increased to 2.5 V in an organic electrolyte leading to an obvious increase in the energy density to 68 W h Kg−1. Solid-state-supercapacitor was fabricated with this material for the possible use of low-cost, high energy promising energy storage device.

Few-layer black phosphorous (BP) has emerged as a promising candidate for next-generation nanophotonic and nanoelectronic devices. However, rapid ambient degradation of mechanically exfoliated BP poses challenges in its practical deployment in scalable devices. To date, the strategies employed to protect BP have relied upon preventing its exposure to atmospheric conditions. Here, an approach that allows this sensitive material to remain stable without requiring its isolation from the ambient environment is reported. The method draws inspiration from the unique ability of biological systems to avoid photo-oxidative damage caused by reactive oxygen species. Since BP undergoes similar photo-oxidative degradation, imidazolium-based ionic liquids are employed as quenchers of these damaging species on the BP surface. This chemical sequestration strategy allows BP to remain stable for over 13 weeks, while retaining its key electronic characteristics. This study opens opportunities to practically implement BP and other environmentally sensitive 2D materials for electronic applications.

Layered black phosphorous has recently emerged as a promising candidate for next generation nanoelectronic devices. However, the rapid ambient degradation of mechanically exfoliated black phosphorous poses challenges in its practical implementation in scalable devices. As photo-oxidation has been identified as the main cause of degradation, to-date, the strategies employed to protect black phosphorous have relied upon preventing its exposure to atmospheric oxygen. These strategies inhibit access to the material limiting its use. An understanding of the effect of individual wavelengths of the light spectrum can lead to alternatives that do not require the complete isolation of black phosphorous from ambient environment. Here, we determine the influence of discrete wavelengths ranging from ultraviolet to infrared on the degradation of black phosphorous. It is shown that the ultraviolet component of the spectrum is primarily responsible for the deterioration of black phosphorous in ambient conditions. Based on these results, new insights into the degradation mechanism have been generated which will enable the handling and operating of black phosphorous in standard fabrication laboratory environments.

The rapid emergence of antibiotic-resistant bacterial strains warrants new strategies for infection control. NanoZymes are emerging as a new class of catalytic nanomaterials that mimic the biological action of natural enzymes. The development of photoactive NanoZymes offers a promising avenue to use light as a “trigger” to modulate the bacterial activity. Visible light activity is particularly desirable because it contributes to 44% of the total solar energy. Here we show that the favorable band structure of a CuO-nanorod-based NanoZyme catalyst (band gap of 1.44 eV) allows visible light to control the antibacterial activity. Photomodulation of the peroxidase-mimic activity of CuO nanorods enhances its affinity to H2O2, thereby remarkably accelerating the production of reactive oxygen species (ROS) by 20 times. This photoinduced NanoZyme-mediated ROS production catalyzes physical damage to the bacterial cells, thereby enhancing the antibacterial performance against Gram-negative-indicator bacteria Escherichia coli.