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Roll-to-roll (R2R) printing technologies have been widely adopted in a variety of engineering fields, e.g., organic photovoltaics and flexible electronics, owing to the advantages of cost and throughput. Although a minimum feature size of 100 nm has been demonstrated on R2R systems, the layer to layer registration accuracy (i.e., overlay accuracy) still remains as low as tens of microns, which prevents the fabrication of common electronic and functional devices, such as transistors. To realize the full potential of R2R technologies, the registration accuracy must be improved to match the printing resolution, i.e., 100s nm. To address the issue, we have developed a multi-layer R2R system with multiple-input multiple-output (MIMO) closed-loop control that achieves submicron level alignment precision for large-scale continuous printing processes. The enabling elements in the multi-layer R2R system include: (1) new vision-based alignment algorithm/method, which provides 100s nm position detection capability based on low-cost cameras; and (2) custom-built five-axis compliant roller positioner. Experimental results show that the compliant roller positioner has a ±1 mm range with 100s nm precision in X, Y, and Z axes respectively. For correcting in-plane web errors, the roller positioner can achieve a range of 1 mm with < 1 μm precision, realizing multi-layer R2R printing with submicron overlay accuracy. Based on the new methods, a gate/source-drain multi-layer electrode structure for field-effect transistors (FETs) has been designed and fabricated on a 4-inch PET web, demonstrating better than 1 μm overlay precision in fabricating flexible electronics on a R2R platform for the first time. • The first demonstration of a multi-layer R2R printing system that achieves better than 1 μm overlay accuracy. • The five-axis roller positioner actively corrects position errors with a precision of ±200 nm and ±2 μrad. • The new alignment solution achieves a large detection range (> 1 mm) with high-resolution (10s nm) based on low-cost cameras. • R2R printing of a multi-layer structure, i.e., FETs, was demonstrated on a 4-inch PET web with < 1 μm overlay precision. [ABSTRACT FROM AUTHOR]

Abstract: A diode-pumped passively Q-switched Nd:YAG/SrWO4/KTP yellow laser is presented for the first time. As high as 1.02W average output power was obtained at a pump power of 14.0W with a pulse repetition frequency of 21.9kHz and the corresponding diode-to-yellow conversion efficiency was 7.29%. The highest pulse energy of 56.2μJ was obtained at a pump power of 7.2W. [Copyright &y& Elsevier]

Abstract: Two new Schiff base derivatives {2,2′-diphenyl-N,N′-bis(2-pyridylmethylene)biphenyl-4,4′-diamine} (1) and {2,2′-diphenyl-N,N′-bis(salicylidene)biphenyl-4,4′-diamine} (2) were synthesized and characterized by means of elemental analysis, 1H NMR, FT-IR, and standard spectroscopy techniques. The molecular structure of 2 has been determined by X-ray single crystal analysis. The analyses of fluorescence properties of the compounds revealed that 1 and 2 are both poorly fluorescent and display sensitive fluorescence responses to a panel of 24 monovalent, divalent, and trivalent metal ions in CH3CN–DMSO (9:1, v/v). Results with imine 1 showed that Fe3+, Cu2+, Zn2+, Cd2+, Mn2+, Zr4+, Hg2+, Cr2+, Pb2+, Sn2+, Bi2+, Al3+, Ce3+, La3+, Sm3+, Gd3+, Nd3+, Eu3+ and Dy3+ yields red shifts in emission and increases in intensity. And the greatest spectral changes for imine 2 include enhancements in emission intensity coupled with red shifts (Zr4+, Sn2+, Al3+ and Zn2+) and strong quenching (Fe3+). The fluorescence enhancement mechanism of 1 and 2 for metal ions is based on: (i) Czation; (ii) chelation-enhanced fluorescence (CHEF) effect; and (iii) excited-state intra/intermolecular proton transfer (ESPT). [Copyright &y& Elsevier]

Pain‐perceptual Nociceptors (PPNs) in the biological sensory system are critical for the human body to perceive noxious stimuli from the outside world and start appropriate motor responses to minimize potential physical damage. Realization artificial nociceptors with unique synaptic and pain‐perceptual functions of the human nervous system is a key step to develop the next‐generation artificial intelligence systems. Here, an artificial pain‐perceptual device based on an ionic liquid‐polymer solid‐state electrolyte‐gated poly(3‐hexylthiophene) (P3HT) transistor is reported. With the drift motion of mobile ions in the electrolyte layer and the formation of an electric double layer (EDL) at electrolyte/semiconductor interface under an applied electric field, the channel conductance can be tuned progressively to exhibit synaptic weight modulation function. On top of the artificial synaptic functions, the P3HT/electrolyte‐based transistor successfully emulates the pain‐perception process in a biological nociceptor, with all unique features of threshold, no adaptation, sensitization/desensitization, and relaxation. Moreover, the pain conditioning process (i.e., hyperalgesic response, and pain extinction effect) through associative learning is demonstrated using the artificial synaptic transistor, indicating its potential application in bio‐inspired neural systems. [ABSTRACT FROM AUTHOR]

Abstract Previous studies have shown that BMS-345541 (BMS, a specific IκB kinase β inhibitor) sensitized various tumor cells including MCF-7 breast cancer cells to ionizing radiation (IR). However, the mechanisms of BMS action are unknown. Since the expression of E1A-like inhibitor of differentiation 3 (EID3) was highly upregulated in MCF-7 cells after BMS treatment, we investigated the role of EID3 in the response of MCF-7 cells to IR. We found that BMS induced EID3 expression in MCF-7 cells in a time- and dose-dependent manner. Knockdown of EID3 by specific shRNA attenuated BMS-induced radiosensitization in MCF-7 cells. In contrast, induction of EID3 expression in an inducible EID3 expressing MCF-7 cell line with doxycycline sensitized the cells to IR. EID3-mediated sensitization of MCF-7 cells to IR was not attributed to an increase in apoptosis. Instead, EID3-expressing MCF-7 cells exhibited significantly higher levels of senescence associated β-galactosidase (SA-β-gal) activity and higher levels of p21 and p57 than EID3-MCF-7 cells without induction of EID3 after exposure to IR. Similar findings were observed when EID3-expressing MCF-7 cells were treated with etoposide, a topoisomerase II inhibitor. Taken together, our findings reveal a novel function of EID3 and suggest that the induction of EID3 by BMS may be exploited as a new strategy to sensitize breast cancer cells to IR and chemotherapy by inducing cancer cell senescence. [ABSTRACT FROM AUTHOR]

A continuous roll-to-roll microcontact printing (MCP) platform promises large-area nanoscale patterning with significantly improved throughput and a great variety of applications, e.g. precision patterning of metals, bio-molecules, colloidal nanocrystals, etc. Compared with nanoimprint lithography, MCP does not require a thermal imprinting step (which limits the speed and material choices), but instead, extreme precision with multi-axis positioning and misalignment correction capabilities for large area adaptation. In this work, we exploit a flexure-based mechanism that enables continuous MCP with 500 nm precision and 0.05 N force control. The fully automated roll-to-roll platform is coupled with a new backfilling MCP chemistry optimized for high-speed patterning of gold and silver. Gratings of 300, 400, 600 nm line-width at various locations on a 4-inch plastic substrate are fabricated at a speed of 60 cm/min. Our work represents the first example of roll-to-roll MCP with high reproducibility, wafer scale production capability at nanometer resolution. The precision roll-to-roll platform can be readily applied to other material systems. [ABSTRACT FROM AUTHOR]

Many advanced materials have been developed for organic field‐effect transistors (OFETs) or thin‐film transistors (TFTs) based on organic and organic hybrid materials. However, although many new OFETs exhibit superior characteristic parameters (such as high mobility), most of them show nonideal performances that have strongly limited progress in the design of molecules, the understanding of transport mechanisms, and the circuit applications of OFETs. In this review, the device physics of ideal and nonideal OFETs is discussed first to understand the factors that limit effective mobility in semiconducting channels, distort the potential distribution, or reduce the drift electric field. Then, recent advances in optimizing the material combinations, device structures, and fabrications of OFETs toward ideal transistors are discussed. Based on the good control of materials and interfaces, some new and novel concepts to utilize the nonideal properties of OFETs to build low‐power circuits and integrated sensors are also discussed. [ABSTRACT FROM AUTHOR]

The rapid sintering of printable metal nanoparticle inks is vital for the industrial mass production of electronic devices. In this paper, we report a rapid laser annealing method for printed Ag nanoparticle-based inks. We also fabricate Ag circuits and organic thin-film transistors (OTFTs) on flexible plastic substrates through spontaneous patterning under deep ultraviolet (DUV) exposure. Compared to the conventional thermal annealing, laser annealing significantly reduces the processing time from 3600 to 10 s while preventing damage caused by excessive heat. The OTFT with laser-annealed Ag source/drain electrodes achieved good performance with saturated mobility of 1.68 cm $^{{2}}\cdot \text{V}^{-{1}}\cdot \text{s}^{-{1}}$ , high-reliability factor of 86.75%, and large saturated drain current resulting from the small channel resistance. This rapid laser annealing method is feasible for printing flexible electronics using metal nanoparticle-based inks in industrial mass production. [ABSTRACT FROM AUTHOR]

Abstract: A new ternary samarium complex Sm(β-NBM)3·(PD) has been synthesized by the reaction of SmCl3·6H2O with β-naphthoylbenzoylmethane (β-HNBM) and 1,10-phenanthroline-5,6-dione (PD) in stoichiometry. The new samarium complex obtained was characterized by elemental analysis, 1H NMR, and FT-IR spectroscopy. The absorption and emission of this complex were systematically investigated. Photoluminescence studies indicated that the energy absorbed by the organic ligands was efficiently transferred to the central Sm3+ ions and the complex showed intensely and characteristically orange emission due to the 4 G 5/2→6 H j transitions of the central Sm3+ ions. The energy levels (HOMO and LUMO) of the ligands and the complex were further confirmed by computer simulation and cyclic voltammetry, respectively. All the results suggested that the synthesized Sm(β-NBM)3·(PD) would have the potential application for organic light-emitting diodes. [Copyright &y& Elsevier]

The rate equations for the quasi-three-level actively Q-switched lasers are obtained by considering the reabsorption of the lower laser level and the spatial distributions of the intracavity photon density and the population inversion density. These rate equations are normalized by introducing three new parameters. By solving the normalized rate equation numerically, a group of general curves is generated. These curves can give a good understanding of the dependences of the laser pulse characteristics on the new parameters. The curves and the related formulae can also be used to estimate the laser pulse characteristics of any quasi-three-level actively Q-switched laser. A sample calculation for a 946-nm actively Q-switched Nd:YAG ceramic laser is presented to demonstrate the use of the related formulae. [ABSTRACT FROM AUTHOR]

Abstract: Three dimethylgallium complexes of type Me2GaL [L=3,4-dimethoxyphenylmethyleneiminophenolato (1), 4-butoxylphenyl methyleneiminophenolato (2), 2-pyridylphenolato (3)] have been synthesized by the reaction of trimethylgallium with appropriate N-arylmethyleneiminophenol. The complexes obtained have been characterized by elemental analysis, 1H NMR, FT-IR and mass spectroscopy, respectively. The solid structure of 1 has been determined by X-ray single crystal analysis. The gallium atom was bonded by an oxygen atom and coordinated by an imine nitrogen atom forming one five-membered ring. The stable dimmer was formed by the coordination of bridging oxygen atom of phenolate to another gallium atom. The photoluminescence of complexes 1–3 were studied. The maximum emission wavelengths of 1–3 are between 338 and 362nm upon radiation by UV light. The Electroluminescent properties of diodes using 1–3 as emitters were measured. The blue/green electroluminescence has been observed. [Copyright &y& Elsevier]

Abstract: Three dimethylgallium complexes of type Me2GaL [L=2-methoxylphenylmethyleneiminophenolato (1), N-(4-N,N′-dimethylamino)phenylmethyleneiminophenolato (2), N-(2-naphthyl)methyleneiminophenolato (3)] have been synthesized by the reaction of trimethylgallium with appropriate N-arylmethyleneiminophenol. The complexes obtained have been characterized by elemental analysis, 1H, 13C{1H} NMR, IR and mass spectroscopy, respectively. The solid structure of 2 has been determined by X-ray single crystal analysis. The gallium atom was bonded by an oxygen atom and coordinated by an imine nitrogen atom forming one five-membered ring. The stable dimmer was formed by the coordination of bridging oxygen atom of phenolate to another gallium atom. The photoluminescence of complexes 1–3 were studied. The maximum emission wavelengths of 1–3 are between 305 and 320nm upon radiation by UV light. The electroluminescent properties of diodes using 1–3 as emitting material were measured. The blue/green electroluminescence has been observed. [Copyright &y& Elsevier]

Nonideal Transistors: Understanding, Optimizing, and Utilizing Nonideal Transistors Based on Organic or Organic Hybrid Semiconductors (Adv. Funct. Keywords: device physics; field-effect transistor; organic semiconductor; reliability; thin-film transistor EN device physics field-effect transistor organic semiconductor reliability thin-film transistor 1 1 1 05/18/20 20200515 NES 200515 In article number 1903889, Chuan Liu and co-workers review the origins and critical factors that lead to organic field-effect transistors (OFETs) with deviations from the ideal device models in terms of device physics. Device physics, field-effect transistor, organic semiconductor, reliability, thin-film transistor. [Extracted from the article]

In this paper, a high‐performance pressure sensor that imitates the sensing functions of human skin is proposed. A rough poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) film transferred from abrasive paper acts as the sensing layer, while silver nanowires deposited on the bottom Ecoflex film with a 3D microstructure serve as the electrodes. Because of the bionic hierarchical structure, the resulting sensor exhibits a high pressure sensitivity of 6.13 kPa−1, low limit of detection (20 Pa), low operating voltage (0.1 V), and broad sensing range (up to 90 kPa). Furthermore, as the sensor is ultrathin, ultraflexible, and stretchable, it can easily conform to the uneven surface of human skin to allow monitoring of physical signals from the human body or detect the tactile stimulation of objects. In addition, a sensor array consisting of 4 × 4 pixels is assembled to realize the precise mapping of spatial pressure distribution. By virtue of its superior performance and low‐cost fabrication, the proposed pressure sensor may potentially be applied to next‐generation wearable devices such as e‐skin, soft robotics, and human–machine interaction systems. [ABSTRACT FROM AUTHOR]