Force touch sensors have received a great deal of attention for various applications owing to their versatile ability to detect touch and pressure. To demonstrate high‐performance force touch sensors, numerous studies have been performed, focusing on high sensitivity, transparency, and mechanical durability against bending. However, it is still challenging to apply force touch sensors in flexible applications, because their sensing performance is subject to change and degraded by induced mechanical stress and deformation when the device is bent. Here, a high‐performance and transparent nanoforce touch sensor with bending‐insensitivity is reported. This is achieved by developing a thin, flexible, and transparent hierarchical nanocomposite film, which is composed of a nanostructured plastic base, coplanar electrodes, and a dielectric polymer layer with silver nanoparticles. The fabrication process is simple that high manufacturing repeatability, uniformity, and reliability are achieved on a large‐area (8 in.) scale. The fabricated device shows a pressure sensitivity of 0.036 kPa−1 with high transparency (83%) in a pressure range up to 3 kPa. In particular, its thin thickness (45 µm) and the coplanar electrode enable to achieve excellent insensitivity to the bending with a radius of curvature of 4 mm more than 10 000 times.
Automatic dispensing of reagents into autoclave blocks followed by synthesis, isolation, and automated structure analysis with X-ray diffractometry represents an efficient methodology for the combinatorial synthesis of microporous materials. The figure shows a typical diffractogram of as-synthesized AFI-type molecular sieves taken with a CCD camera.
Nanowire (NW) transfer technology has provided promising strategies to realize future flexible materials and electronics. Using this technology, geometrically controlled, high-quality NW arrays can now be obtained easily on various flexible substrates with high throughput. However, it is still challenging to extend this technology to a wide range of high-performance device applications because its limited temperature tolerance precludes the use of high-temperature annealing, which is essential for NW crystallization and functionalization. A pulsed laser technique has been developed to anneal NWs in the presence of a flexible substrate; however, the induced temperature is not high enough to improve the properties of materials such as ceramics and semiconductors. Here, we present a versatile nanotransfer method that is applicable to NWs that require high-temperature annealing. To successfully anneal NWs during their transfer, the developed fabrication method involves sequential removal of a nanoscale sacrificial layer. Using this method, we first produce an ultralong, perfectly aligned polycrystalline barium titanate (BaTiO) NW array that is heat treated at 700 °C on a flexible polyethylene terephthalate (PET) substrate. This high-quality piezoelectric NW array on a flexible substrate is used as a flexible nanogenerator that generates current and voltage 37 and 10 times higher, respectively, than those of a nanogenerator made of noncrystallized BaTiO NWs.
We describe a very simple breathing rate-sensing method that detects a significant electric current change between two metal electrodes on an oxidized surface. The current change is caused by the formation of a water layer from exhaled breath. We discovered that breathing onto the oxidized surface causes instant water condensation, and it generates 20 times increased current than that measured in the inhalation period. The condensed water quickly evaporates, enabling us to detect dynamic human breathing in real time. We also investigated the breathing rate sensor by varying the relative humidity, temperature, and breathing frequency and confirmed its potential for practical applications.
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