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Solution‐processable organic semiconductors can serve as the basis for new products including rollable displays, tattoo‐like smart bandages for real‐time health monitoring, and conformable electronics integrated into clothing or even implanted in the human body. For such exciting commercial applications to become a reality, good device performance and uniformity over large areas are necessary. The design of new materials has progressed at an astonishing pace, but accessing their intrinsic, efficient electrical properties in large‐area flexible device arrays is difficult. The development of protocols that allow integration with industrial‐scale processing for high‐throughput manufacturing, without the need to compromise on performance, is the key for transitioning these materials to real‐life applications. In this work, large‐area arrays of organic thin‐film transistors obtained by spray‐coating the high‐mobility polymer indacenodithiophene‐co‐benzothiadiazole (IDTBT) are demonstrated. A maximum charge carrier mobility of 2.3 cm2 V−1 s−1, with a very narrow performance distribution, is obtained over surface areas of 10 cm × 10 cm. The devices retain their electrical properties when bent multiple times and at different curvatures. In addition, large arrays of highly sensitive (0.25% change in mobility for 1% humidity variation), reusable, near‐identical humidity sensors are produced in a one‐step fabrication and calibrated from 0% to 94% relative humidity. [ABSTRACT FROM AUTHOR]

Capability of high-speed and low-cost manufacturing makes the printing techniques a very promising approach for large-area flexible electronics mass manufacturing. Due to fast and intensive technology development, the lack of knowledge about the reliability and lifetime of printed electronics is obvious, requiring further investigation. Especially, the effect of torsional bending on lifetime is a mostly unexplored field of reliability testing. In this article, a torsional bending test of parallel printed silver conductors (0.3-, 0.5-mm pitch) on polymer substrate (polyethylene terephthalate, 125-μm thickness) was conducted and analyzed. According to the experimental results, torsional bending causes wear-out type failures in conductors and the length-to-width (LTW) ratio of the sample’s substrate was observed to have a significant impact on reliability. If the LTW ratio is smaller than 3, the lifetime of printed conductor seems to collapse and samples lasted for approximately only 17 bending cycles on average. Lifetime was improved by increasing the LTW ratio and samples withstood over hundreds of cycles with LTW ratio of higher than 15. However, the distance of a conductor from the edge of the substrate was not observed to have any significant influence on the reliability under torsional bending. [ABSTRACT FROM AUTHOR]

This paper presents the design and experimental characterization of large-area active matrixes on foil for pressure-sensing applications. Front-end circuits based on organic thin-film transistors on a flexible substrate are laminated with a foil hosting screen-printed PDVF-TrFE piezo sensors to create the complete flexible sensing systems with $6 \times 10$ sensing elements on a $16.5~\text {cm} \times 27.5$ cm area. After defining the specifications based on the application scenarios, and designing two different front-end matrixes (A and B), the performance of the sensing surface B has been investigated in simulation. Numerical results show a readout speed of 5 kframe/s and 78.6 dB maximum signal-to-noise ratio with impact forces up to 50 kN. Experiments made with a prototype based on front end A confirm that the system can correctly reconstruct the impact profile of forces up to 50 kN obtained in a drop tower setup. Measurements of the front end circuit B show an input equivalent noise of 451 $\mu \text{V}_{\mathrm {rms}}$ and a 5% settling time of 13.8 $\mu \text{s}$ , both adequate for the specified applications. [ABSTRACT FROM AUTHOR]

Transparent flexible n-ZnO:Al (100 nm)/ n-ZnO (40 nm)/ p-CuAlO:Ca (100 nm, 200 nm, 300 nm) diodes were fabricated on polyethylene terephthalate substrates at room temperature using a sputtering technique. No additional heat treatment was performed on the fabricated devices. Increase of the diode layer thickness reduced the on-current and leakage-current levels simultaneously, which led the rectification ratio to first increase and then decrease as the p-layer thickness increased. The ultraviolet (UV) response of the diode was also investigated under irradiation at 365 nm. The n-ZnO:Al (100 nm)/ n-ZnO (40 nm)/ p-CuAlO:Ca (200 nm) diode exhibited photocurrent/leakage current ratio of 1.03 × 10 and responsivity of 0.64 A/W at reverse bias of −6 V when measured in flat status. The corresponding photocurrent/leakage current ratio and responsivity were 7.99 × 10 and 0.65 A/W, respectively, for an outwardly bent diode with 5.5 cm radius of curvature. The increases of current levels under bending are attributed to the decreases of series resistance for the diode under tensile strain. [ABSTRACT FROM AUTHOR]

The recent efforts in exploiting semiconductor nanowires (NWs) for high-performance macroelectronics are reviewed. In brief, a new concept of NW thin-film transistors (NW-TFTs) has been proposed and demonstrated from oriented semiconductor NW thin films. In NW-TFTs, the source and drain electrodes are bridged by multiple single-crystal NWs in parallel. Therefore, charges travel from source to drain within single crystals, ensuring high carrier mobility. Recent studies have shown that high-performance NW-TFTs and high-frequency circuits can be produced from silicon NWs on a variety of substrates, including glass and plastics, using a solution assembly process. The device performance of these NW-TFTs not only greatly surpasses that of solution-processed organic TFTs but is also significantly better than that of conventional amorphous or polycrystalline silicon TFTs, approaching single-crystal silicon-based devices. Further- more, with a similar framework, group III-V or II-VI NW or nanoribbon materials of high intrinsic carrier mobility or optical functionality can be assembled into thin films on flexible substrates to enable new multifunctional electronics/optoelectronics that are not possible with traditional macroelectronics. This approach thus opens a new avenue to high-performance flexible macroelectronics and will not only impact existing applications but also enable a whole new generation of flexible, wearable, or disposable electronics for computing, storage, and wireless communication. [ABSTRACT FROM AUTHOR]

This Letter presents a technique for implementing circuits with multiple subthreshold swings. Such circuits are of particular interest to large‐area and flexible electronics, including active matrix displays and sensors. In these circuits, devices with large swings may be used for high‐precision analogue driving, whereas steep subthreshold devices may be used for fast and low‐power switching. This Letter demonstrates that large swings may be obtained by the series connection of diode structures to the source terminals of steep subthreshold devices. In principle, this technique is applicable to a wide range of thin‐film transistors, but it is particularly well suited for heterojunction field‐effect transistors where the gate heterojunctions may be readily utilised as diodes without altering the fabrication process or increasing the number of mask steps. Implementation of multiple subthreshold swings is demonstrated experimentally and described by a first‐order model. [ABSTRACT FROM AUTHOR]