Rapid advances in functional sensing electronics place tremendous demands on innovation toward creative uses of versatile advanced materials and effective designs of device structures. Here, we first report a feasible and effective fabrication strategy to integrate commercial abrasive papers with microcracked gold (Au) nanofilms to construct cuttable and self-waterproof crack-based resistive bending strain sensors. Via introducing surface microstructures, the sensitivities of the bending strain sensors are greatly enhanced by 27 times than that of the sensors without surface microstructures, putting forward an alternative suggestion for other flexible electronics to improve their performances. Besides, the bending strain sensors also endow rapid response and relaxation time of 20 ms and ultrahigh stability of >18 000 strain loading–unloading cycles in conjunction with flexibility and robustness. In addition, the concepts of cuttability and self-waterproofness (attain and even surpass IPX-7) of the bending strain sensors have been demonstrated. Because of the distinctive sensing properties, flexibility, cuttability, and self-waterproofness, the bending strain sensors are attractive and promising for wearable electronic devices and smart health monitoring system.Keywords: flexible devices; gold nanoparticles; paper-based electronics; self-waterproof sensors; surface microstructures;

A cobaltosic-oxide-nanosheets/reduced-graphene-oxide composite (CoNSs@RGO) was successfully prepared as a light-weight broadband electromagnetic wave absorber. The effects of the sample thickness and amount of composite added to paraffin samples on the absorption properties were thoroughly investigated. Due to the nanosheet-like structure of Co3O4, the surface-to-volume ratio of the wave absorption material was very high, resulting in a large enhancement in the absorption properties. The maximum refection loss of the CoNSs@RGO composite was–45.15 dB for a thickness of 3.6 mm, and the best absorption bandwidth with a reflection loss below–10 dB was 7.14 GHz with a thickness of 2.9 mm. In addition, the peaks of microwave absorption shifted towards the low frequency region with increasing thickness of the absorbing coatings. The mechanism of electromagnetic wave absorption was attributed to impedance matching of CoNSs@RGO as well as the dielectric relaxation and polarization of RGO. Compared to previously reported absorbing materials, CoNSs@RGO showed better performance as a lightweight and highly efficient absorbing material for application in the high frequency band.

Advanced wearable sensors for human motion detection are receiving growing attention and have great potential for future electronics. Herein, we demonstrate microcrack-assisted strain sensors using silver nanowires@patterned polydimethylsiloxane. Through designed percolating network microstructures, the strain sensors have significant inherent advantages, including simple fabrication processes and ultrahigh sensitivity far surpassing other stretchable sensing devices. Noteworthily, the strain sensors possess a tremendous gauge factor (GF) of 150 000 within a large stretchability of 60% strain range. The sensing mechanism depends on the change in electrical resistance, which is dramatically affected by a percolating-microcrack surface microstructure in the case of strain concentration of mechanical deformation. The superior sensing performance in conjunction with an appealing stretchability, reversibility, low creep and ultrahigh stability enables the strain sensors to act as wearable monitors and electronic skins for diverse applications, including but not limited to full-range detection of human body motions, as well as visual control of a light-emitting diode indicator, etc.

•The hybrid nanogenerator can obtain both mechanical and heat energy from the same energy source.•It realizes advantage complementary by combining high voltage of TENG and high current of TEG.•The hybridized nanogenerator can act as sustainable power source to drive commercial electronics.•The system exhibits high removal efficiency of 92.1% for PM2.5 and implements real-time gas quality monitoring.Rapid urbanization and industrialization causes huge energy consumption, bringing about a variety of air pollution issue due to the massive exhaust gas emitted from factories, power plants, traffic, etc. While normal supply of fossil fuels is ensured, the task of achieving energy saving and emission reduction is very taxing. It's an optimal option to further control exhaust gas through effectively recycling industrial exhaust gas energy. Here, a hybrid nanogenerator composed of a triboelectric nanogenerator (TENG) and thermoelectric generator (TEG) has been proposed for gas energy recycle and purification. Both mechanical and heat energy of exhaust gas can be recycled by combining the merits of TENG and TEG which achieves advantage complementary. It delivers an regulated power of 147.6 W m−3, which is capable of powering electronic devices and being stored up. Moreover, exhaust gas purification is implemented through reclaiming exhaust gas energy with no external power. It obtains high removal efficiency of 92.1% for PM2.5 and realizes real-time gas quality monitoring. This work has potential application prospect to serve for large-scale industrial exhuast gas recycle and treatment equipments which help reduce resource consumption and relax environmental problems.Download high-res image (207KB)Download full-size image

Triboelectric nanogenerators (TENGs) or TENG-based self-charging systems harvesting energy from ambient environment are promising power solution for electronics. The stable running remains a key consideration in view of potential complex application environment. In this work, a textile-based tailorable multifunctional TENG (T-TENG) is developed. The T-TENG is used as self-powered human body motion sensor, water energy harvester, and formed all textile-based flexible self-charging system by integrating with textile-based supercapacitors. The service behavior and the mechanism of performance retention are also studied when the T-TENG is damaged. As a self-powered human body motion sensor, the T-TENG maintains the stable properties when it is cut. As a water energy harvester, the T-TENG is capable of scavenging mechanical energy from water efficiently even if it is damaged partly. Besides, the charge properties of the self-charging system are systematically investigated when the T-TENG is cut. The investigation on service behavior of T-TENG and TENG-based self-charging system pushes forward the development of highly reliable electronics and is a guide for other nanodevices and nanosystems.

We report the preparation of nanocomposites of reduced graphene oxide with embedded Fe3O4/Fe nanorings (FeNR@rGO) by chemical hydrothermal growth. We illustrate the use of these nanocomposites as novel electromagnetic wave absorbing materials. The electromagnetic wave absorption properties of the nanocomposites with different compositions were investigated. The preparation procedure and nanocomposite composition were optimized to achieve the best electromagnetic wave absorption properties. Nanocomposites with a GO:α-Fe2O3 mass ratio of 1:1 prepared by annealing in H2/Ar for 3 h exhibited the best properties. This nanocomposite sample (thickness = 4.0 mm) showed a minimum reflectivity of–23.09 dB at 9.16 GHz. The band range was 7.4–11.3 GHz when the reflectivity was less than–10 dB and the spectrum width was up to 3.9 GHz. These figures of merit are typically of the same order of magnitude when compared to the values shown by traditional ferric oxide materials. However, FeNR@rGO can be readily applied as a microwave absorbing material because the production method we propose is highly compatible with mass production standards.

During the investigation of mechanical properties of nanomaterials by atomic force microscope (AFM), a non-normal stress state with large scanning angles is a universal phenomenon. The mechanical service behaviors of ZnO nanowires (NWs) with diameters ranging from 177 to 386 nm under non-normal stress state were studied by AFM at a scanning rate of 14.8 μm s−1. We expanded the application scope of the threshold force equation determining the fracture threshold forces of ZnO NWs which was established in our previous work. The criterion equation for security service of ZnO NWs was established by the threshold force equation and force calibration equation. The criterion equation was used to predict the security service range of ZnO NWs successfully. The modulus and fracture strength of the ZnO NWs were also calculated through the fracture threshold force obtained from the threshold force equation. The results have important and meaningful consequences for security practical applications of ZnO NWs under non-normal stress state.

A novel microwave absorption composite was fabricated by mixing reduced graphene oxide (RGO) and tetrapod-like ZnO (T-ZnO). The microwave absorption properties of the fabricated composites with different components were investigated. The effects of RGO mass fractions and thickness of composites on microwave absorption properties were studied in the range from 2 to 18 GHz. The electromagnetic parameters showed that the RGO/T-ZnO composites were mainly dependent on dielectric loss. The composites with 5 wt% RGO and 10 wt% T-ZnO had the optimum microwave absorption properties at the thickness of 2.9 mm, and the corresponding minimum reflection loss was −59.50 dB at 14.43 GHz. The bandwidth corresponding to the reflection loss below −20 dB was 8.9 GHz (from 9.1 GHz to 18.0 GHz) when the thickness was in the range of 2.5–4.0 mm. Thus, the composite has a low reflection loss value and wide effective absorption bandwidth in X-band (8–12 GHz) and Ku-band (12–18 GHz), which has great potential for military stealth. The excellent microwave absorption properties were mainly attributed to dielectric relaxation and polarization of RGO, electronic polarization from the needle-like tips of T-ZnO, electrical conduction loss and multiple scattering.

•The presentation of a self-powered e-skin with combination of PDMS and carbon fiber.•It provides a simple route to achieve high-resolution pressure sensing by using micro-size conductive fibers.•With excellent flexibility, the device can be adhered on most curved surfaces for pressure sensing purposes.•The unique construction of the e-skin brings about a significant reduction in the number of test channels.Electronic skin (e-skin) comprises a network of tactile sensors, which has broad application prospects in prosthetics, advanced robotics and continuous health monitoring. Here, a self-powered artificial e-skin is fabricated in a simple and cost-effective method for high resolution pressure sensing. No external power supply is needed for the e-skin owing to the triboelectric mechanism. The response time of pressure sensing is approximately 68 ms and the sensitivity is 0.055 nA K Pa−1. With excellent flexibility, the device can be adhered on most curved surfaces for pressure sensing purposes. The fabricated e-skin with resolution as high as 127×127 dpi is capable of mapping the 2D tactile trajectory of a tip. The resolution can proceed to be improved with the enhancement of the pixel density. Furthermore, the unique construction brings about a significant reduction in the number of the test channels from N×N to 2×N, which greatly decreases the measurement costs. This work offers an effective step for e-skin, with superiorities of self-powered, high resolution, simple fabrication and low-cost.