Solution-Processed Two-Dimensional Metal Oxide Anticorrosion Nanocoating.

Molecularly thin two-dimensional (2D) nanomaterials are attractive building blocks for constructing anticorrosion nanocoatings as an ultimate pursuit in the metal-related industry. However, the nanocoating of prefocused graphene is far from industrial demands due to its high cost, low scalability, and insufficient quality. We propose all requirements to realize rational anticorrosion nanocoating of metal oxide nanosheets. The proof-of-concept study with Ti0.87O2 and Ca2Nb3O10 nanosheets demonstrates that the 10 and 20 nm thick coatings fabricated by a facile layer-by-layer (LbL) self-assembly on stainless steel (SUS) give perfect inhibition efficiency (IE) values of 99.92% and 99.89%, respectively. A driving test with a nanosheet-coated car-baffle demonstrated suitable corrosion resistance and mechanical and thermal robustness for industrial applications. The revealed and controlled thermal oxidation mechanisms are critical toward high-temperature application of the 2D oxide anticorrosion nanocoating. The advantages of nanosheet coating and extensible materials design will open a solid but exciting route to anticorrosion nanotechnology.

Preparation of SnO2 nanotubes via a template-free electrospinning process.

A facile and environmentally friendly template-free method is developed for the fabrication of SnO2 nanotubes via electrospinning and precisely controlled heat treatment method. It is revealed that the as-spun solid SnO2 precursor fibers gradually transformed into hollow-structured nanotubes when the temperature was controlled precisely from 200 °C to 600 °C. It was confirmed, that this remarkable structural evolution corporate the respective thermal decomposition of polyvinyl butyral (PVB) at the surface and inside of the fibers. The formation mechanism of the nanotubes has been clarified by systematically investigating the morphology, phase structure, chemical state, and decomposition of the organic compounds during the heat treatment. The as-prepared SnO2 nanotubes exhibit a high specific surface area of 32.91 m2 g-1 and a porous structure with pore sizes of 2 nm and 10-25 nm. The SnO2 nanotubes were assembled as a photosensor, which demonstrates a fast response upon UV light illumination at 254 nm. From this discovery, it is expected that a new method for fabricating nanotubes will be established and the development of materials with a higher functionality will be promoted.

High photosensitivity and external quantum efficiency photosensors achieved by a cable like nanoarchitecture.

The poor intrinsic flexibility of semiconducting ceramic materials hinders their applications in wearable electronics. Here, we present a highly efficient photosensor with extreme levels of bending and repeatable resilience based on cable-like structure. The ZnO@TiO2 cable-like photosensor demonstrates an ultra-high external quantum efficiency (2.82 × 106%) and photosensitivity (1.27 × 105) upon UV light illumination at 254 nm, and a stability of 85% at the small curvature radius of 0.5 mm. Moreover, the ZnO@TiO2 photodetector demonstrates extremely stable flexibility over 1000 bending cycles. This specific nanoscale architecture has future potential applications for soft integrated electronics.

Stabilizing Nanocrystalline Oxide Nanofibers at Elevated Temperatures by Coating Nanoscale Surface Amorphous Films.

Nanocrystalline materials often exhibit extraordinary mechanical and physical properties but their applications at elevated temperatures are impaired by the rapid grain growth. Moreover, the grain growth in nanocrystalline oxide nanofibers at high temperatures can occur at hundreds of degrees lower than that would occur in corresponding bulk nanocrystalline materials, which would eventually break the fibers. Herein, by characterizing a model system of scandia-stabilized zirconia using hot-stage in situ scanning transmission electron microscopy, we discover that the enhanced grain growth in nanofibers is initiated at the surface. Subsequently, we demonstrate that coating the fibers with nanometer-thick amorphous alumina layer can enhance their temperature stability by nearly 400 °C via suppressing the surface-initiated grain growth. Such a strategy can be effectively applied to other oxide nanofibers, such as samarium-doped ceria, yttrium-stabilized zirconia, and lanthanum molybdate. The nanocoatings also increase the flexibility of the oxide nanofibers and stabilize the high-temperature phases that have 10 times higher ionic conductivity. This study provides new insights into the surface-initiated grain growth in nanocrystalline oxide nanofibers and develops a facile yet innovative strategy to improve the high-temperature stability of nanofibers for a broad range of applications.

Stretchable Platinum Network-Based Transparent Electrodes for Highly Sensitive Wearable Electronics.

A platinum network-based transparent electrode has been fabricated by electrospinning. The unique nanobelt structured electrode demonstrates low sheet resistance (about 16 Ω sq-1 ) and high transparency of 80% and excellent flexibility. One of the most interesting demonstrations of this Pt nanobelt electrode is its excellent reversibly resilient characteristic. The electric conductivity of the flexible Pt electrode can recover to its initial value after 160% extending and this performance is repeatable and stable. The good linear relationship between the resistance and strain of the unique structured Pt electrode makes it possible to assemble a wearable high sensitive strain sensor. Present reported Pt nanobelt electrode also reveals potential applications in electrode for flexible fuel cells and highly transparent ultraviolet (UV) sensors.

Electrospun assembly: a nondestructive nanofabrication for transparent photosensors.

Transparent electrodes based on a metal nanotrough network show superior electrical and optical properties. However, most metal networks fabricated by electrospinning are formed as film electrodes and are hard to pattern for the geometry shape of the device without any loss. Herein, we fabricate a highly transparent and flexible photodetector (PD) via a simple controlled electrospinning method. Owing to the trough- and belt-like geometry of Pt network electrodes, up to 83% transmittance can be obtained when the sheet resistances is 16 Ω sq-1, which may be the best performance for Pt-based transparent electrodes at present. The benefit of this advantage, is that a wearable UV PD could be obtained by a facile electrospun assembly. This all-transparent device achieves an extraordinary transparency of 90% at 550 nm and an even superior response sensitivity compared with that of a Pt film-based sensor (14 Ω sq-1 at 50% transparency). More importantly, this assembly approach has the versatility to enable us to fabricate highly transparent and flexible electronics in wearable applications, especially for the integration of oxide semiconductors and adhesive photoelectric hybrids.

Enhanced conductivity of (110)-textured ScSZ films tuned by an amorphous alumina interlayer.

Herein a novel strategy to tune the crystallite orientation and the ionic conductivity of solid electrolyte films through interfacial control has been reported. 10 mol% Sc2O3-doped ZrO2 (10ScSZ) thin films were prepared with an amorphous alumina (AO) interlayer (AO/10ScSZ) using magnetron sputtering. It has been found that a (110)-preferred orientation develops in AO/10ScSZ films annealed at 1000 °C due to a strong interfacial interaction, while 10ScSZ films deposited without the AO interlayer are (111)-textured. The (110)-oriented AO/10ScSZ films show an ionic conductivity nearly 4 times higher than that of the (111)-oriented 10ScSZ films. This is explained by the fact that the (110)-texture provides faster migration pathways with lower energy barrier for oxygen vacancies. These results reveal the relationship between the crystal structure and the conductivity of AO/ScSZ heterostructured films, which can facilitate the development of high-performance multilayered electrolytes and enable the miniaturization of solid-state electrochemical devices operable at temperatures below 600 °C.