F-doped SnO2 thin films grown on flexible substrates at low temperatures by pulsed laser deposition

Fluorine-doped tin oxide (SnO₂:F) films were deposited on polyethersulfone plastic substrates by pulsed laser deposition. The electrical and optical properties of the SnO₂:F films were investigated as a function of deposition conditions such as substrate temperature and oxygen partial pressure during deposition. High quality SnO₂:F films were achieved under an optimum oxygen pressure range (7.4-8 Pa) at relatively low growth temperatures (25-150 °C). As-deposited films exhibited low electrical resistivities of 1-7 mΩ-cm, high optical transmittance of 80-90% in the visible range, and optical band-gap energies of 3.87-3.96 eV. Atomic force microscopy measurements revealed a reduced root mean square surface roughness of the SnO₂:F films compared to that of the bare substrates indicating planarization of the underlying substrate.     

Spherical indentation and scratch durability studies of transparent conducting layers on polymer substrates

The effect of moderate normal and tangential spherical loading on the durability of brittle ceramic films sputtered on polymer substrates is investigated. Indium tin oxide films with various thicknesses are deposited by sputtering on polyethylene terephthalate substrates and their mechanical durability is assessed using a spherical nanoindenter and scratch tester with built-in optical microscopy capability.It is observed that crack initiation occurs at 40 mN normal applied load. As loading increases, formation of brittle ring cracking and of secondary radial cracks is evident. It is also shown that ring crack spacing is thickness dependent. During scratch testing two main coating failure modes are observed. The first is through thickness cracking and the second is buckling spallation of the coating. Both failure mechanisms exhibit thickness dependence.     

Durability study on sputtered indium tin oxide thin film on Poly Ethylene Terephthalate substrate

This paper discusses the durability of the DC-Magnetron sputtered Indium Tin Oxide (ITO) thin films on 127-μm Poly Ethylene Terephthalate substrate under harsh environmental conditions and high cyclic bending fatigue. Two sets of experiments were conducted on a 60 Ω per square ITO sheet. The first set of experiments was conducted on samples with different temperature and humidity combinations while being subjected to cyclic bending fatigue loadings. The other set of experiments was conducted on samples with the same combinations of temperature and humidity but without bending fatigue loading. Design of experiments tool was used to study the effect of temperature, humidity, bending fatigue and the interaction among them on the percent change in electrical resistance of the ITO film. It was found that bending fatigue is the dominant factor to the electrical failure of ITO thin film. The failure was also influenced by temperature and humidity, especially combined high temperature and high humidity. Therefore, it is suggested that controlling the environmental factors during the roll to roll manufacturing process is crucial on quality of the products.     

Preparation and character of textured ZnO:Al thin films deposited on flexible substrates by RF magnetron sputtering

ZnO:Al thin films deposited on transparent TPT substrates by magnetron sputtering were etched in acetic acid solution. The effects of etching solution concentration and etching time on the structure and properties of ZnO:Al films were investigated. The obtained films had a hexagonal structure and a highly preferred orientation with the c-axis perpendicular to the substrate. The ZAO film etched in 1% acetic acid solution for 10 s had a pyramidal structure and an enhanced light scattering ability, the average transmittance and reflectance in the visible region were 72% and 26% respectively, the sheet resistance was 260 Ω/□. Both transmittance and reflectance of the films decreased as the etching solution concentration and etching time increasing. Etching had a negative effect on the conductive properties of ZAO films. The lowest sheet resistance was 120 Ω/□ for the ZAO film without etching.     

Graphene-based conducting inks for direct inkjet printing of flexible conductive patterns and their applications in electric circuits and chemical sensors

A series of inkjet printing processes have been studied using graphene-based inks. Under optimized conditions, using water-soluble single-layered graphene oxide (GO) and few-layered graphene oxide (FGO), various high image quality patterns could be printed on diverse flexible substrates, including paper, poly(ethylene terephthalate) (PET) and polyimide (PI), with a simple and low-cost inkjet printing technique. The graphene-based patterns printed on plastic substrates demonstrated a high electrical conductivity after thermal reduction, and more importantly, they retained the same conductivity over severe bending cycles. Accordingly, flexible electric circuits and a hydrogen peroxide chemical sensor were fabricated and showed excellent performances, demonstrating the applications of this simple and practical inkjet printing technique using graphene inks. The results show that graphene materials-which can be easily produced on a large scale and possess outstanding electronic properties-have great potential for the convenient fabrication of flexible and low-cost graphene-based electronic devices, by using a simple inkjet printing technique.      

Conducting Polymer Nanowire Arrays for High Performance Supercapacitors

This Review provides a brief summary of the most recent research developments in the fabrication and application of one‐dimensional ordered conducting polymers nanostructure (especially nanowire arrays) and their composites as electrodes for supercapacitors. By controlling the nucleation and growth process of polymerization, aligned conducting polymer nanowire arrays and their composites with nano‐carbon materials can be prepared by employing in situ chemical polymerization or electrochemical polymerization without a template. This kind of nanostructure (such as polypyrrole and polyaniline nanowire arrays) possesses high capacitance, superior rate capability ascribed to large electrochemical surface, and an optimal ion diffusion path in the ordered nanowire structure, which is proved to be an ideal electrode material for high performance supercapacitors. Furthermore, flexible, micro‐scale, threadlike, and multifunctional supercapacitors are introduced based on conducting polyaniline nanowire arrays and their composites. These prototypes of supercapacitors utilize the high flexibility, good processability, and large capacitance of conducting polymers, which efficiently extend the usage of supercapacitors in various situations, and even for a complicated integration system of different electronic devices.     

柔性快递包装盒的分拣机械手结构设计

为了满足目前抓取分拣快递包装盒需要,提出一种绳牵引驱动结构的单铰链柔性机械手,通过在机械手的内侧安装扭弹簧和矩形橡胶垫使得机械手能够贴合包装盒抓取,减少包装盒的受压变形,介绍了该手爪结构的驱动原理,通过全局优化的方式得出扭弹簧的刚度系数与预紧角和机械手的关节尺寸,计算结果表明,抓取最大最小包装盒压力相同,结构的柔顺自适应更好,而且还计算得出了关节角位移和指尖开度随气压变化的曲线图,为气缸驱动减少空行时间提高抓取效率提供理论参考。     

Test method for measuring non-visible set-off from inks and lacquers on the food-contact surface of printed packaging materials

The main objective was to develop a technique to expose spots of invisible set-off of inks and lacquers on the food-contact surface of food-packaging materials. Set-off is the unintentional transfer of components of printing inks from the outer printed surface onto the food-contact surfaces. The target sensitivity was 20 µg cm^-2 and the technique should be capable of examining large areas of printed substrate for no more than 4% coverage by set-off. These requirements equate to an ability to detect a worst-case migration potential of less than 50 µg kg^-1. Other objectives were the industrial requirements that the equipment should be inexpensive, should be easy to use by existing personnel and should preferably be non-destructive with a clear criterion for pass or fail. The approaches investigated included chemical analysis of solvent extracts, Fourier-transform infrared spectroscopy and microbeam analytical techniques, but these were found to be cumbersome and had only limited success. The objectives were achieved using an optical approach to excite and observe luminescence from invisible set-off. In model experiments, resins were applied to different substrates (plastic, paper and cartonboard). For a given resin on a given material, the key to success was to maximize the discrimination between the luminescence from the resin and that from the substrate by selecting the optimal combination of exciting wavelength and viewing goggles with selective wavelength filters. The required level of detection (20 µg cm^-2) was achieved or exceeded for all ten resins tested on three different plastics. It was also achieved for two different papers and in all but four cases of the resins on three different cartonboards. Quantitation was achieved by the use of a calibration palette prepared using different quantities of resin spotted onto the relevant blank packaging material.     

Highly flexible supercapacitors with manganese oxide nanosheet/carbon cloth electrode

We report a simple and cost-effective synthesis of hierarchically porous structure composed of Birnessite-type manganese dioxide (MnO₂) nanosheets on flexible carbon cloth (CC) via anodic electrodeposition technique. Petal-shaped MnO₂, having sheet thickness of a few nm and typical width of 100 nm, with a strong adhesion on CC is observed. This hierarchically porous MnO₂–CC hybrid structure dose exhibit not only excellent capacitance properties, such as up to 425 F g⁻¹ in specific capacitance, but also high crack resistance owing to its efficient release of bending stress, as observed by cyclic voltammetry and galvanostatic charge/discharge measurements under different curvature of bending configurations. Furthermore, flexible supercapacitors based on this kind of MnO₂ nanosheet/CC electrode showed significantly improved stability in capacitive performance over 3000 cycles under the bending test, which is highly promising for future applications in flexible energy storage device.     

Ultra-flexible Al2O3 fibers: A novel catalyst support material for sustainable catalysis

Flexible aluminum oxide (Al₂O₃) fibers were prepared by the blow spinning method and their potential as a high-temperature catalyst support was investigated. The synthesized Al₂O₃ fibers exhibited remarkable flexibility in both mechanical compression and recovery tests, which remained intact in a wide temperature range from −196 °C to 1200 °C. Moreover, their low thermal conductivity of 0.030 W K⁻¹∙m⁻¹, demonstrated an outstanding thermal insulation. Subsequently, nickel nanoparticles were uniformly distributed on the surface of the Al₂O₃ fibers as a self-supporting catalyst using a conventional impregnation method. The resulting self-supporting Ni/Al₂O₃ catalyst demonstrated remarkable thermo-catalytic performance and re-activation capability at high temperatures for thermocatalytic reaction of dry reforming of methane (DRM). Our findings highlight the potential of pure Al₂O₃ flexible fibers as a versatile material for various industrial applications, including high-temperature catalysis.