Paper/Carbon Nanotube-Based Wearable Pressure Sensor for Physiological Signal Acquisition and Soft Robotic Skin

A wearable and flexible pressure sensor is essential to the realization of personalized medicine through continuously monitoring an individual’s state of health and also the development of a highly intelligent robot. A flexible, wearable pressure sensor is fabricated based on novel single-wall carbon nanotube /tissue paper through a low-cost and scalable approach. The flexible, wearable sensor showed superior performance with concurrence of several merits, including high sensitivity for a broad pressure range and an ultralow energy consumption level of 10^–6 W. Benefited from the excellent performance and the ultraconformal contact of the sensor with an uneven surface, vital human physiological signals (such as radial arterial pulse and muscle activity at various positions) can be monitored in real time and in situ. In addition, the pressure sensors could also be integrated onto robots as the artificial skin that could sense the force/pressure and also the distribution of force/pressure on the artificial skin

All-Graphene-Based Highly Flexible Noncontact Electronic Skin

Noncontact electronic skin (e-skin), which possesses superior long-range and high-spatial-resolution sensory properties, is becoming indispensable in fulfilling the emulation of human sensation via prosthetics. Here, we present an advanced design and fabrication of all-graphene-based highly flexible noncontact e-skins by virtue of femtosecond laser direct writing (FsLDW). The photoreduced graphene oxide patterns function as the conductive electrodes, whereas the pristine graphene oxide thin film serves as the sensing layer. The as-fabricated e-skins exhibit high sensitivity, fast response–recovery behavior, good long-term stability, and excellent mechanical robustness. In-depth analysis reveals that the sensing mechanism is attributed to proton and ionic conductivity in the low and high humidity conditions, respectively. By taking the merits of the FsLDW, a 4 × 4 sensing matrix is facilely integrated in a single-step, eco-friendly, and green process. The light-weight and in-plane matrix shows high-spatial-resolution sensing capabilities over a long detection range in a noncontact mode. This study will open up an avenue to innovations in the noncontact e-skins and hold a promise for applications in wearable human–machine interfaces, robotics, and bioelectronics

All-Graphene-Based Highly Flexible Noncontact Electronic Skin

Noncontact electronic skin (e-skin), which possesses superior long-range and high-spatial-resolution sensory properties, is becoming indispensable in fulfilling the emulation of human sensation via prosthetics. Here, we present an advanced design and fabrication of all-graphene-based highly flexible noncontact e-skins by virtue of femtosecond laser direct writing (FsLDW). The photoreduced graphene oxide patterns function as the conductive electrodes, whereas the pristine graphene oxide thin film serves as the sensing layer. The as-fabricated e-skins exhibit high sensitivity, fast response–recovery behavior, good long-term stability, and excellent mechanical robustness. In-depth analysis reveals that the sensing mechanism is attributed to proton and ionic conductivity in the low and high humidity conditions, respectively. By taking the merits of the FsLDW, a 4 × 4 sensing matrix is facilely integrated in a single-step, eco-friendly, and green process. The light-weight and in-plane matrix shows high-spatial-resolution sensing capabilities over a long detection range in a noncontact mode. This study will open up an avenue to innovations in the noncontact e-skins and hold a promise for applications in wearable human–machine interfaces, robotics, and bioelectronics

Catalyst-Free, Selective Growth of ZnO Nanowires on SiO₂ by Chemical Vapor Deposition for Transfer-Free Fabrication of UV Photodetectors

Catalyst-free, selective growth of ZnO nanowires directly on the commonly used dielectric SiO₂ layer is of both scientific significance and application importance, yet it is still a challenge. Here, we report a facile method to grow single-crystal ZnO nanowires on a large scale directly on SiO₂/Si substrate through vapor–solid mechanism without using any predeposited metal catalyst or seed layer. We found that a rough SiO₂/Si substrate surface created by the reactive ion etching is critical for ZnO growth without using catalyst. ZnO nanowire array exclusively grows in area etched by the reactive ion etching method. The advantages of this method include facile and safe roughness-assisted catalyst-free growth of ZnO nanowires on SiO₂/Si substrate and the subsequent transfer-free fabrication of electronic or optoelectronic devices. The ZnO nanowire UV photodetector fabricated by a transfer-free process presented high performance in responsivity, quantum efficiency and response speed, even without any post-treatments. The strategy shown here would greatly reduce the complexity in nanodevice fabrication and give an impetus to the application of ZnO nanowires in nanoelectronics and optoelectronics