Search

To obtain soft electronics, it is essential to develop high-performance and mechanically flexible energy storage at the industry level. Herein, we report flexible high-energy-density lithium-sulfur (Li–S) batteries based on all-fibrous sulfur cathodes and separators. To implement free-standing and flexible sulfur cathodes, electrically conductive single-walled carbon nanotubes (CNTs) are impregnated with cellulose nanofibers. This fibrous structure forms a 3D porous electrode with a large surface area to improve redox kinetics and achieve a high sulfur loading content without the use of a metal collector, which can then be applied in high-energy-density batteries. These flexible sulfur cathodes are combined with a commercial glass fiber separator coated with a CNT layer through a cost-effective solution process to suppress the shuttle effects of lithium–polysulfide, thereby exhibiting robust cycling stability. The prepared Li–S batteries exhibit high capacities of 940 mAh g−1 at a charge current density of 1.57 mA cm−2 and at 25 °C, and the Coulombic efficiency exceeds 90% even after 50 charge/discharge cycles. Moreover, Li-S batteries with a high gravimetric energy density of 443 Wh kg−1 per cell is achieved, and these batteries demonstrate excellent reliability in regard to electrochemical performance even under severe mechanical stress conditions for over 100 cycles. Flexible and high-energy-density lithium-sulfur (Li-S) batteries based on all-fibrous sulfur cathodes and separators have structural uniqueness and chemical functionality, exhibit a high gravimetric energy density of 435 Wh kg−1 per cell and excellent reliability in terms of electrochemical performance with a slow decay rate of

Solution-processed nonvolatile organic transistor memory devices are fabricated by employing semiconductor blends of p-channel 6,13-bis(triisopropylsilylethynyl)pentacene and n-channel poly{[ N, N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]- alt-5,5'-(2,2'-bithiophene)} (P(NDI2OD-2T); N2200) on polystyrene-brush as a polymer electret. Electret-based memory characteristics are significantly changed depending on the frontier molecular orbitals of the active semiconductors because the charge-trapping efficiency is mainly determined by the energy barrier to transfer electrons and holes from the active channel to the electret layer. A semiconductor mixture with an optimized blending ratio results in an efficient programming and erasing process. Thus, we obtained a remarkably high ratio of ON/OFF current (memory ratio) about 107 and a large amount of shifts in the threshold voltage (memory window) between the programmed and erased states of 55 V, while single-component N2200 showed only writing-once-read-many (WORM)-type memory. Especially, the programmed data can be stably retained more than 10 years with a sufficient memory ratio of 103. Furthermore, our semiconductor blend system leads to preferable vertical phase separation, which affords good reliability under a sequential memory operation condition as well as stability in ambient air. It is expected that our memory devices can be applied for versatile data storage in printed and flexible electronic applications.

We demonstrate 3-D self-aligned stacked NMOS-on-PMOS multiple Si nanoribbon transistors with successful integration of vertically stacked dual source/drain EPI process and vertically stacked dual metal gate process. Both top NMOS and bottom PMOS show high on-state performance and superior short channel control. A functional CMOS inverter is also demonstrated with well-balanced voltage transfer characteristics. The 3-D self-aligned stacked CMOS nanoribbon transistor is demonstrated as a promising transistor architecture to continue Moore’s law scaling.

We report on controllable ambipolar charge transport in polymeric semiconductors by the incorporation of viologen-based molecular additives. The viologen dopants selectively contribute to an increase in the charge carrier density of the electrons while enhancing the fibril-like crystalline thin-film morphology of the polymers to provide favourable charge transport in staggered-structure organic field-effect transistors. A well-balanced ambipolar behaviour is obtained at the optimised viologen concentration in donor-acceptor conjugated polymers by conversely modulating the p- and n-channel carrier mobilities within a given active layer. Complementary-like inverter circuits are demonstrated through the application of a simple blanket coating of a viologen-doped ambipolar semiconductor, which exhibits high ideal voltage switching at around half of the applied bias, a high gain of more than 50, and sufficient noise immunity to enable various applications for printed electronics and optoelectronics.

Expandability of organic electronics has stimulated ongoing research for the development of a variety of flexible and/or large-area optoelectronic applications. Among these electronic devices, organic non-volatile memories are emerging as suitable components for solid-state data storage because of their low-cost fabrication, large storage capacity, light weight, and conformable mechanical properties. To fully integrate organic memories with wearable and flexible/stretchable electronic systems, it is important to develop a device in which the properties such as threshold voltage and operating regime are controllable. This leads to improvement in the adaptability of the device to peripheral circuitry and encourages the development of multi-functional organic electronic components. Here, we investigate the tunable electrical properties of charge-trap (electret) memory devices based on organic field-effect transistors, obtained by the doping of an ambipolar polymer semiconductor. The electret memory devices using the doped semiconductor showed a remarkable enhancement in the charge-storage capacity, an excellent charge retention time of more than 107 s, and four-fold increase in charge carrier mobility. The improved memory characteristics associated with the controllable molecular doping could pave the way for the development of next-generation memory devices that are compatible with flexible and printed electronic technology.

Semiconducting single-walled carbon nanotubes (semi-SWNTs) are attractive as they can be used enable high-performance nano-electronic devices. We report the enhanced ambipolar charge transport characteristics of the semi-SWNT field-effect transistors (FETs) based on a top-gated staggered device structure. SWNTs were selectively dispersed in non-polar organic solvents and sorted by a π-conjugated polymer wrapping method. The sorted semi-SWNTs solution was used simply to form a well-percolated CNT-network, and the top-gate and bottom-contact FETs showed relatively high and equivalent electron and hole mobilities with very high on/off-current ratios and steep subthreshold slopes. The equivalent ambipolar charge transport behavior of semi-SWNTs was used to demonstrate a reliable complementary-like electronic circuits. The inverters showed a good switching threshold near the ideal point at half the driving bias, high gain, low hysteresis, and stability under repeatable operating conditions. They can thus be broadly applied as a fundamental circuit element in printed and flexible electronics.

A specific design for solution-processed doping of active semiconducting materials would be a powerful strategy in order to improve device performance in flexible and/or printed electronics. Tetrabutylammonium fluoride and tetrabutylammonium hydroxide contain Lewis base anions, F− and OH−, respectively, which are considered as organic dopants for efficient and cost-effective n-doping processes both in n-type organic and nanocarbon-based semiconductors, such as poly[[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)] (P(NDI2OD-T2)) and selectively dispersed semiconducting single-walled carbon nanotubes by π-conjugated polymers. The dramatic enhancement of electron transport properties in field-effect transistors is confirmed by the effective electron transfer from the dopants to the semiconductors as well as controllable onset and threshold voltages, convertible charge-transport polarity, and simultaneously showing excellent device stabilities under ambient air and bias stress conditions. This simple solution-processed chemical doping approach could facilitate the understanding of both intrinsic and extrinsic charge transport characteristics in organic semiconductors and nanocarbon-based materials, and is thus widely applicable for developing high-performance organic and printed electronics and optoelectronics devices.

Many soft-electronic applications, such as internet of things (IoTs) and wearable smart devices, must be operated at extremely low power because of their limited power sources. Here, we report the fabrication and performance of ultralow operating-voltage organic-inorganic hybrid thin-film transistors (TFTs) and their complementary-like circuits using solid-state-electrolyte gate insulators (SEGIs). The high specific capacitance of SEGIs, which is of the order of a few μF·cm−2, enables the supply of enough power to fully turn on TFT devices with operating voltages below ±2 V. For low-cost printable electronic circuitries, n-type amorphous metal-oxide semiconductors and p-type polythiophene-based π-conjugated organic molecules are sequentially deposited via solution processes, and their corresponding p- and n-channel TFT performances exhibit relatively well-balanced ambipolar charge-transport, with high hole and electron mobilities of more than 1 cm2 V−1 s−1. The ambipolar hybrid TFTs based on bi-layered organic and inorganic hetero-interfaces are then used to construct complementary-like inverters with very low operation bias (

BIPV system not only produces electricity at building, but also acts as a material for building envelope. Thus, it can increase the economical efficiency of PV system by saving the cost for building materials. Bifacial solar cell can convert solar energy to electrical energy from both sides of the cell. In addition, it is designed as 3 busbar layout which is the same with ordinary mono-facial solar cells. Therefore, many of the module manufacturers can easily use the bifacial solar cells without changing their manufacturing equipments. Moreover, bifacial PV system has much potential in building application by utilizing glass-to-glass structure of PV module. However, the electrical generation of the bifacial PV module depends on the characteristics of the building surface which faces the module, as well as outdoor environment. Therefore, in order to apply the bifacial PV module to building envelope as BIPV system, its power generation characteristics are carefully evaluated. For this purpose this study focused on the electrical performance of the bifacial BIPV system through the comparative outdoor experiments. As a result, the power generation performance of the bifacial BIPV system was improved by up to 21% compared to that of the monofacial BIPV system. Therefore, it is claimed that the bifacial BIPV system can replace the conventional BIPV system to improve the PV power generation in buildings.

Monolithically structured reduced graphene oxide (rGO), prepared from a highly concentrated and conductive rGO paste, is introduced as an anode material for lithium ion batteries with high rate capacities. This is achieved by a mixture of rGO paste and the water-soluble polymer sodium carboxymethylcellulose (SCMC) with freeze drying. Unlike previous 3D graphene porous structures, the monolithic graphene resembles densely branched pine trees and has high mechanical stability with strong adhesion to the metal electrodes. The structures contain numerous large surface area open pores that facilitate lithium ion diffusion, while the strong hydrogen bonding between the graphene layers and SCMC provides high conductivity and reduces the volume changes that occur during cycling. Ultrafast charge/discharge rates are obtained with outstanding cycling stability and the capacities are higher than those reported for other anode materials. The fabrication process is simple and straightforward to adjust and is therefore suitable for mass production of anode electrodes for commercial applications.

In this paper, a technique using mixed transition-metal oxides as contact interlayers to modulate both the electron- and hole-injections in ambipolar organic field-effect transistors (OFETs) is presented. The cesium carbonate (Cs2CO3) and vanadium pentoixide (V2O5) are found to greatly and independently improve the charge injection properties for electrons and holes in the ambipolar OFETs using organic semiconductor of diketopyrrolopyrrolethieno[3,2-b]thiophene copolymer (DPPT-TT) and contact electrodes of molybdenum (Mo). When Cs2CO3 and V2O5 are blended at various mixing ratios, they are observed to very finely and constantly regulate the Mo's work function from −4.2 eV to −4.8 eV, leading to high electron- and hole-mobilities as high as 2.6 and 2.98 cm2 V−1 s−1, respectively. The most remarkable finding is that the device characteristics and device performance can be gradually controlled by adjusting the composition of mixed-oxide interlayers, which is highly desired for such applications as complementary circuitry that requires well matched n-channel and p-channel device operations. Therefore, such simple interface engineering in conjunction with utilization of ambipolar semiconductors can truly enable the promising low-cost and soft organic electronics for extensive applications.

The selective tuning of the operational mode from ambipolar to unipolar transport in organic field-effect transistors (OFETs) by printing molecular dopants is reported. The field-effect mobility (μFET) and onset voltage (Von) of both for electrons and holes in initially ambipolar methanofullerene [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) OFETs are precisely modulated by incorporating a small amount of cesium fluoride (CsF) n-type dopant or tetrafluoro-tetracyanoquinodimethane (F4-TCNQ) p-type dopant for n-channel or p-channel OFETs either by blending or inkjet printing of the dopant on the pre-deposited semiconductor. Excess carriers introduced by the chemical doping compensate traps by shifting the Fermi level (EF) toward respective transport energy levels and therefore increase the number of mobile charges electrostatically accumulated in channel at the same gate bias voltage. In particular, n-doped OFETs with CsF show gate-voltage independent Ohmic injection. Interestingly, n- or p-doped OFETs show a lower sensitivity to gate-bias stress and an improved ambient stability with respect to pristine devices. Finally, complementary inverters composed of n- and p-type PCBM OFETs are demonstrated by selective doping of the pre-deposited semiconductor via inkjet printing of the dopants.

In this study, we investigated chemically exfoliated two-dimensional (2-D) nanoflakes of molybdenum disulfide (MoS2) as charge-storing elements for use in organic multilevel memory devices (of the printed/flexible non-volatile type) based on organic field-effect transistors (OFETs) containing poly(3-hexylthiophene) (P3HT). The metallic MoS2 nanoflakes were exfoliated in 2-methoxyethanol by the lithium intercalation method and were deposited as nano-floating gates between polystyrene and poly(methyl methacrylate), used as bilayered gate dielectrics, by a simple spin-coating and low temperature (150 °C) process. In the developed OFET memory devices, electrons could be trapped/detrapped in the MoS2 nano-floating gates by modulating the charge carrier density in the active channel through gate bias control. Optimal memory characteristics were achieved by controlling the thickness and concentration of few-layered MoS2 nanoflakes, and the best device showed reliable non-volatile memory properties: a sufficient memory window of ∼23 V, programming-reading-erasing cycling endurance of10(2) times, and most importantly, quasi-permanent charge-storing characteristics, i.e., a very long retention time (longer than the technological requirement of commercial memory devices (10 years)). In addition, we successfully developed multilevel memory cells (2 bits per cell) by controlling the gate bias magnitude.

We present a straightforward method for simultaneously enhancing the electrical conductivity, environmental stability, and photocatalytic properties of graphene films through one-step transfer of CVD graphene and integration by introducing TiO2/graphene oxide layer. A highly durable and flexible TiO2 layer is successfully used as a supporting layer for graphene transfer instead of the commonly used PMMA. Transferred graphene/TiO2 film is directly used for measuring the carrier transport and optoelectronic properties without an extra TiO2 removal and following deposition steps for multifunctional integration into devices because the thin TiO2 layer is optically transparent and electrically semiconducting. Moreover, the TiO2 layer induces charge screening by electrostatically interacting with the residual oxygen moieties on graphene, which are charge scattering centers, resulting in a reduced current hysteresis. Adsorption of water and other chemical molecules onto the graphene surface is also prevented by the passivating TiO2 layer, resulting in the long term environmental stability of the graphene under high temperature and humidity. In addition, the graphene/TiO2 film shows effectively enhanced photocatalytic properties because of the increase in the transport efficiency of the photogenerated electrons due to the decrease in the injection barrier formed at the interface between the F-doped tin oxide and TiO2 layers.

Clean chemical vapor deposition (CVD)-grown graphene surfaces with intrinsic electrical properties were obtained by a modified poly(methylmethacrylate) (PMMA) transfer method. The modified method entails UV irradiation, followed by wet cleaning of the UV-irradiated PMMA layer using a mixture of isopropyl alcohol (IPA), acetone, and methyl isobutyl ketone (MIBK). The chemical structure of the PMMA layer degrades following UV irradiation under atmospheric conditions, via side-chain cleavage of the ester groups, resulting in reduced intermolecular interactions between the PMMA layer and the underlying graphene film. Furthermore, the IPA/MIBK/acetone mixture is shown to be a powerful solvent that can effectively remove the PMMA layer without leaving any PMMA residue, which could act as a source of cracks and scattering centers for charge carrier transport, on the graphene surface. Graphene transistors fabricated by this modified transfer method show high electron and hole mobilities with ideal threshold voltages of near 0 V.

We report the effect of the conductivity of the gate electrode on operation speeds in printed organic ring oscillators (RO). The highly conducting gate electrode leads to a superior oscillation frequency (as high as ~ 30 kHz) for the printed ROs. Above the optimum thickness of the gate electrodes (~ 30 nm), inkjet-printed p-type poly(3-hexylthiophene) (P3HT) and n-type poly([ N , N -9-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]- alt -5,59-(2,29-bithiophene)) (P(NDI2OD-T2)) organic field-effect transistors showed reasonably high hole and electron mobilities of ~ 0.05 cm 2 V − 1 s − 1 and ~ 0.25 cm 2 V − 1 s − 1 , respectively. Complementary inverters and ring oscillators based on these p- and n-type semiconductor transistors were constructed, where the inverters showed the inverting voltage, ( V inv ) near the ideal switching points at 1/2 the drain voltage ( V DD ), high gain (~ 10), low static power consumptions, as well as high noise margin (~ 60% of 1/2 V DD ). Finally, printed P3HT complementary ring oscillators with a gate thickness over 30 nm exhibited the highest oscillation frequency (~ 30 kHz).

Nonvolatile ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) memory based on an organic thin-film transistor with inkjet-printed dodecyl-substituted thienylenevinylene-thiophene copolymer (PC12TV12T) as the active layer is developed. The memory window is 4.5 V with a gate voltage sweep of -12.5 V to 12.5 V. The field effect mobility, on/off ratio, and gate leakage current are 0.1 , , and A, respectively. Although the retention behaviors should be improved and optimized, the obtained characteristics are very promising for future flexible electronics.

For at least the past ten years printed electronics has promised to revolutionize our daily life by making cost-effective electronic circuits and sensors available through mass production techniques, for their ubiquitous applications in wearable components, rollable and conformable devices, and point-of-care applications. While passive components, such as conductors, resistors and capacitors, had already been fabricated by printing techniques at industrial scale, printing processes have been struggling to meet the requirements for mass-produced electronics and optoelectronics applications despite their great potential. In the case of logic integrated circuits (ICs), which constitute the focus of this Progress Report, the main limitations have been represented by the need of suitable functional inks, mainly high-mobility printable semiconductors and low sintering temperature conducting inks, and evoluted printing tools capable of higher resolution, registration and uniformity than needed in the conventional graphic arts printing sector. Solution-processable polymeric semiconductors are the best candidates to fulfill the requirements for printed logic ICs on flexible substrates, due to their superior processability, ease of tuning of their rheology parameters, and mechanical properties. One of the strongest limitations has been mainly represented by the low charge carrier mobility (μ) achievable with polymeric, organic field-effect transistors (OFETs). However, recently unprecedented values of μ ∼ 10 cm(2) /Vs have been achieved with solution-processed polymer based OFETs, a value competing with mobilities reported in organic single-crystals and exceeding the performances enabled by amorphous silicon (a-Si). Interestingly these values were achieved thanks to the design and synthesis of donor-acceptor copolymers, showing limited degree of order when processed in thin films and therefore fostering further studies on the reason leading to such improved charge transport properties. Among this class of materials, various polymers can show well balanced electrons and holes mobility, therefore being indicated as ambipolar semiconductors, good environmental stability, and a small band-gap, which simplifies the tuning of charge injection. This opened up the possibility of taking advantage of the superior performances offered by complementary "CMOS-like" logic for the design of digital ICs, easing the scaling down of critical geometrical features, and achieving higher complexity from robust single gates (e.g., inverters) and test circuits (e.g., ring oscillators) to more complete circuits. Here, we review the recent progress in the development of printed ICs based on polymeric semiconductors suitable for large-volume micro- and nano-electronics applications. Particular attention is paid to the strategies proposed in the literature to design and synthesize high mobility polymers and to develop suitable printing tools and techniques to allow for improved patterning capability required for the down-scaling of devices in order to achieve the operation frequencies needed for applications, such as flexible radio-frequency identification (RFID) tags, near-field communication (NFC) devices, ambient electronics, and portable flexible displays.

We report the development of high-performance inkjet-printed organic field-effect transistors (OFETs) and complementary circuits using high- k polymer dielectric blends comprising poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) and poly(methyl methacrylate) (PMMA) for high-speed and low-voltage operation. Inkjet-printed p -type polymer semiconductors containing alkyl-substituted thienylenevinylene (TV) and dodecylthiophene (PC12TV12T) and n -type P(NDI2OD-T2) OFETs showed high field-effect mobilities of 0.1–0.4 cm 2 V −1 s −1 and low threshold voltages down to 5 V. These OFET properties were modified by changing the blend ratio of P(VDF-TrFE) and PMMA. The optimum blend – a 7:3 wt% mixture of P(VDF-TrFE) and PMMA – was successfully used to realize high-performance complementary inverters and ring oscillators (ROs). The complementary ROs operated at a supplied bias ( V DD ) of 5 V and showed an oscillation frequency ( f osc ) as high as ∼80 kHz at V DD = 30 V. Furthermore, the f osc of the complementary ROs was significantly affected by a variety of fundamental parameters such as the electron and hole mobilities, channel width and length, capacitance of the gate dielectrics, V DD , and the overlap capacitance in the circuit configuration.

Solution-processed organic semiconductors are of great potential for large-area, inexpensive, lightweight, and fl exible electronic applications. With respect to these materials, tremendous effort has recently been focused on developing several types of organic electronic and optoelectronic devices, such as organic light-emitting diodes (OLEDs), organic photovoltaics (OPVs), organic fi eld-effect transistors (OFETs), and organic memory and sensors, using graphic-art printing methods on fl substrates. [ 1‐5 ] OFETs are a fundamental building block of integrated circuits (ICs) and drivers for active-matrix fl at-panel displays. Accordingly, they are a promising candidate to replace the vacuum-processed amorphous inorganic ICs; this would enable the use of drivers in printed and fl exible radio-frequency identifi cation tags, memories, sensors, and display backplanes. [ 6 , 7 ] To realize high-speed organic printed ICs, the complementary IC geometry, which consists of p- and n-channel transistors, has an advantage over those that comprise unipolar transistors because of reduced transition delays, higher noise immunity, and negligible power consumption in the static state. [ 8 ] In solution-processed devices, p- and n-type active channels have been patterned at resolutions as low as a few micrometers using a variety of printing methods such as inkjet, spray, and gravure printing. [ 9 ] However, these printing processes typically result in device-to-device performance deviations because of diffi culties inherent in controlling the morphology (e.g., roughness and crystallinity) of micrometre-sized deposits. For example, organic semiconductor droplets that are deposited via ink jet onto non-absorbing substrates typically show signifi cant coffee

The effects of using a blocking dielectric layer and metal nanoparticles (NPs) as charge-trapping sites on the characteristics of organic nano-floating-gate memory (NFGM) devices are investigated. High-performance NFGM devices are fabricated using the n-type polymer semiconductor, poly{[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (P(NDI2OD-T2)), and various metal NPs. These NPs are embedded within bilayers of various polymer dielectrics (polystyrene (PS)/poly(4-vinyl phenol) (PVP) and PS/poly(methyl methacrylate) (PMMA)). The P(NDI2OD-T2) organic field-effect transistor (OFET)-based NFGM devices exhibit high electron mobilities (0.4–0.5 cm2 V−1 s−1) and reliable non-volatile memory characteristics, which include a wide memory window (≈52 V), a high on/off-current ratio (Ion/Ioff ≈ 105), and a long extrapolated retention time (>107 s), depending on the choice of the blocking dielectric (PVP or PMMA) and the metal (Au, Ag, Cu, or Al) NPs. The best memory characteristics are achieved in the ones fabricated using PMMA and Au or Ag NPs. The NFGM devices with PMMA and spatially well-distributed Cu NPs show quasi-permanent retention characteristics. An inkjet-printed flexible P(NDI2OD-T2) 256-bit transistor memory array (16 × 16 transistors) with Au-NPs on a polyethylene naphthalate substrate is also fabricated. These memory devices in array exhibit a high Ion/Ioff (≈104 ± 0.85), wide memory window (≈43.5 V ± 8.3 V), and a high degree of reliability.

We report here the development of high-performance p- and n-channel organic field-effect transistors (OFETs) and complementary circuits using inkjet-printed semiconducting layers and high-k polymer dielectric blends of poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) and poly(methyl methacrylate) (PMMA). Inkjet-printed p-type polymer semiconductors containing alkyl-substituted thienylenevinylene (TV) and dodecylthiophene (PC12TV12T) and n-type poly{[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-dithiophene)} (P(NDI2OD-T2)) OFETs typically show high field-effect mobilities (μ(FET)) of 0.2-0.5 cm²/(V s), and their operation voltage is effectively reduced to below 5 V by the use of P(VDF-TrFE):PMMA blends. The main interesting result is that the OFET characteristics could be tuned by controlling the mixing ratio of P(VDF-TrFE) to PMMA in the blended dielectric. The μ(FET) of the PC12TV12T OFETs gradually improves, whereas the P(NDI2OD-T2) OFET properties become slightly worse as the P(VDF-TrFE) content increases. When the mixing ratio is optimized, well-balanced hole and electron mobilities of more than 0.2 cm²/(V s) and threshold voltages below ±3 V are obtained at a 7:3 ratio of P(VDF-TrFE) to PMMA. Low-voltage-operated (∼2 V) printed complementary inverters are successfully demonstrated using the blended dielectric and exhibit an ideal inverting voltage of nearly half of the supplied bias, high voltage gains of greater than 25, and excellent noise margins of more than 75% of the ideal values.

To assess the anti-adhesive effect of treatment with hyaluronic acid-carboxymethylcellulose following laparoscopic radical prostatectomy. This was a randomized, controlled, single-blind, parallel-group study using hyaluronic acid-carboxymethylcellulose in patients who underwent laparoscopic radical prostatectomy. Sixty patients were enrolled in the study. All patients were randomly assigned to either the hyaluronic acid-carboxymethylcellulose treatment group (n = 30) or the control group (n = 30). Viscera slide ultrasounds and plain X-rays were obtained at enrollment (V0), postoperative week 12 (V1), and 24 (V2). The primary end point was the difference in the excursion distance in the viscera slide ultrasound between V0 and V2. A total of 50 patients completed this study. The average excursion distance at V2 in the experimental group (n = 25) was significantly longer than in the control group (n = 25, 2.7 ± 1.2 vs. 1.3 ± 1.0 cm, respectively; p

High-performance top-gated organic fi eld-effect transistor (OFET) memory devices using electrets and their applications to flprinted organic NAND fl ash are reported. The OFETs based on an inkjet-printed p-type polymer semiconductor with effi ciently chargeable dielectric poly(2-vinylnaphthalene) (PVN) and high-k blocking gate dielectric poly(vinylidenefl trifl uoroethylene) (P(VDF-TrFE)) shows excellent non-volatile memory characteristics. The superior memory characteristics originate mainly from reversible charge trapping and detrapping in the PVN electret layer effi ciently in low-k/high-k bilayered dielectrics. A strategy is devised for the successful development of monolithically inkjet-printed fl exible organic NAND fl ash memory through the proper selection of the polymer electrets (PVN or PS), where PVN/- and PS/P(VDF-TrFE) devices are used as non-volatile memory cells and ground- and bit-line select transistors, respectively. Electrical simulations reveal that the fl exible printed organic NAND fl ash can be possible to program, read, and erase all memory cells in the memory array repeatedly without affecting the non-selected memory cells.

Herein is a description of the mass production of poly(9, 9-dioctylfluorene-co-benthiadiazole) (F8BT) and poly(9, 9-dioctylfluorene) (PFO) nanowires (NWs) using a melt-assisted wetting method with an anodic alumina membrane. The conjugated polymer NWs had a uniform shape (D = 250-300 nm/L = 10-30 microm) and a defect-free smooth surface. Optical properties were investigated by UV-vis, photoluminescent spectroscope, and fluorescent optical microscope. Individual F8BT and PFO NWs had a bright yellow (lambda = 541 nm) andblue (lambda = 442 nm) luminescence, respectively, under UV light irradiation.

We investigated the effects of a gate dielectric and its solvent on the characteristics of top-gated organic fieldeffect transistors (OFETs). Despite the rough top surface of the inkjet-printed active features, the charge transport in an OFET is still favorable, with no significant degradation in performance. Moreover, the characteristics of the OFETs showed a strong dependency on the gate dielectrics used and its orthogonal solvents. Poly(3hexylthiophene) OFETs with a poly(methyl methacrylate) dielectric showed typical p-type OFET characteristics. The selection of gate dielectric and solvent is very important to achieve high-performance organic electronic circuits.

Magnesium borate ball of wires, nanowires and petaliforms were prepared via calcination of magnesium borate hydroxide synthesized by hydrothermal route. Results of SEM characterization indicated that the morphology of magnesium borate hydroxide and magnesium borate could be talored via varying reaction temperature, reaction time and water's volume. And pure magnesium borate could be achieved when magnesium borate hydroxide was calcinated at 700°C.

Ambipolar π-conjugated polymers may provide inexpensive large-area manufacturing of complementary integrated circuits (CICs) without requiring micro-patterning of the individual p- and n-channel semiconductors. However, current-generation ambipolar semiconductor-based CICs suffer from higher static power consumption, low operation frequencies, and degraded noise margins compared to complementary logics based on unipolar p- and n-channel organic field-effect transistors (OFETs). Here, we demonstrate a simple methodology to control charge injection and transport in ambipolar OFETs via engineering of the electrical contacts. Solution-processed caesium (Cs) salts, as electron-injection and hole-blocking layers at the interface between semiconductors and charge injection electrodes, significantly decrease the gold (Au) work function (∼4.1 eV) compared to that of a pristine Au electrode (∼4.7 eV). By controlling the electrode surface chemistry, excellent p-channel (hole mobility ∼0.1-0.6 cm(2)/(Vs)) and n-channel (electron mobility ∼0.1-0.3 cm(2)/(Vs)) OFET characteristics with the same semiconductor are demonstrated. Most importantly, in these OFETs the counterpart charge carrier currents are highly suppressed for depletion mode operation (I(off)70 nA when I(on)0.1-0.2 mA). Thus, high-performance, truly complementary inverters (high gain50 and high noise margin75% of ideal value) and ring oscillators (oscillation frequency ∼12 kHz) based on a solution-processed ambipolar polymer are demonstrated.

Aluminum borate (Al4B2O9) nanomaterials were synthesized via a sol-gel process using Na2B4O7·10H2O and Al (NO3)3·9H2O. The effect of reaction volume concentration, calcination temperature and feeding modes on the morphology of Aluminum borate was investigated. The material was characterized with SEM and XRD. Results reveal that Al4B2O9 nanowires, nanorods could be synthesized, and its morphology also can be tailored by controlling calcination temperature and feeding modes.

InxGa1−xAs (0 ≤ x ≤ 1) alloy nanowires (average diameter = 50 nm) were synthesized at 800 °C with complete composition tuning by the thermal evaporation of GaAs/InAs powders. X-ray diffraction and Raman spectroscopy confirmed the complete composition tuning over the whole range. They exhibit exclusively a superlattice structure composed of zinc blende phase twinned octahedral slice segments having alternating orientations along the axial [111] direction and wurtzite phase twin planes. When the mole fraction (x) approaches 0.5, the period of the twinned superlattice structures becomes shorter, showing a controlled wurtzite−zinc blende polytypism. At x = 0.5, the wurtzite phase is dominant with the shortest superlattice periodicity (∼2 nm). The smaller diameter consistently induces shorter periodic superlattice structures. This unique polytypism shows that the incorporation of In (or Ga) and the smaller diameter promotes the crystallization of the nanowires in the wurtzite phase. These InxGa1−xAs nanowires ...

In the present study, we demonstrate inkjet-printed n-type organic field-effect transistors (OFETs) and their complementary inverters with high performance uniformity, using soluble N,N′-bis(n-octyl)-(1,7&1,6)-dicyanoperylene-3,4:9,10-bis(dicarboximide) (PDI8-CN2). The device performance and uniformity were improved by ink-jet printing a PDI8-CN2 solution onto a heated substrate (60 °C). The printed features, which were discontinuous crystalline films at RT, were uniform films when the substrate temperature was increased to 60 °C. Optimized n-channel PDI8-CN2 FETs showed a high field-effect mobility of 0.05–0.06 cm2/Vs, a high on/off ratio of ∼106, and a high uniformity that was within 10% with a bottom-gate/bottom-contact device configuration. Inkjet-printed organic complementary inverters were constructed by direct inkjet-printing of n-channel (PDI8-CN2) and p-channel (6,13-bis(triisopropyl-silylethynyl)-pentacene or poly(3-hexylthiophene)) organic semiconductors onto silicon dioxide gate dielectrics. The inkjet-printed organic complementary inverters exhibited a high voltage gain of more than 15 and small standard deviation of inverting voltage and gain of ±0.95 V and ±0.56, respectively, for measuring 12 samples from four difference batches.

Organic molecules and semiconductors have been proposed as active part of a large variety of nonvolatile memory devices, including resistors, diodes and transistors. In this review, we focus on electrically reprogrammable nonvolatile memories. We classify several possible devices according to their operation principle and critically review the role of the π-conjugated materials in the device operation. We propose specifications for applications for organic nonvolatile memory and review the state of the art with respect to these target specifications. Conclusions are drawn regarding further work on materials and device architectures.

Inkjet-printed high speed polymeric complementary circuits are fabricated using an n-type ([poly{[N,N'-bis(2-octyldo-decyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-dithiophene)} [P(NDI2OD-T2), Polyera Activlnk N2200] and two p-type polymers [poly(3-hexylthiophene) (P3HT) and a dithiophene-based polymer (Polyera ActivInk P2100)]. The top-gate/bottom-contact (TG/BC) organic field-effect transistors (OFETs) exhibit well-balanced and very-high hole and electron mobilities (μ FET ) of 0.2-0.5 cm 2 /Vs, which were enabled by optimization of the inkjet-printed active features, small contact resistance both of electron and hole injections, and effective control over gate dielectrics and its orthogonal solvent effect (selection of poly(methyl methacrylate) and 2-ethoxyethanol). Our first demonstrated inkjet-printed polymeric complementary devices have been integrated to high-performance complementary inverters (gain >30) and ring oscillators (oscillation frequency ~50 kHz). We believe that the operating frequency of printable organic circuits can be further improved more than 10 MHz by fine-tuning of the device architecture and optimization of the p- and n-channel semiconductor processing.

Organic field-effect transistor (FET) memory is an emerging technology with the potential to realize light-weight, low-cost, flexible charge storage media. Here, solution-processed poly[9,9-dioctylfluorenyl-2,7-diyl]-co-(bithiophene)] (F8T2) nano floating gate memory (NFGM) with a top-gate/bottom-contact device configuration is reported. A reversible shift in the threshold voltage (V Th ) and reliable memory characteristics was achieved by the incorporation of thin Au nanoparticles (NPs) as charge storage sites for negative charges (electrons) at the interface between polystyrene and cross-linked poly(4-vinylphenol). The F8T2 NFGM showed relatively high field-effect mobility (μ FET ) (0.02 cm 2 V -1 s -1 ) for an amorphous semiconducting polymer with a large memory window (ca. 30 V), a high on/off ratio (more than 10 4 ) during writing and erasing with an operation voltage of 80 V of gate bias in a relatively short timescale (less than 1 s), and a retention time of a few hours. This top-gated polymer NFGM could be used as an organic transistor memory element for organic flash memory.

We investigate here charge transfer and trapping characteristics of various chargeable polymer dielectric layers, polystyrene (PS), poly(4-vinyl naphthalene) (PVN), and amorphous fluoropolymer (Teflon ® AF) in non-volatile pentacene field-effect transistor (FET) memory devices. Non-volatile memory properties, i.e., the degree of threshold voltage ( V Th ) shifts (memory window), the programming and erasing bias, and the retention time, strongly depended on the selection of a charge storage layer, due to its electronic and dielectric properties. The pentacene FETs with PVN or PS showed reversible positive and negative V Th shifts by an application of external gate bias. In Teflon ® AF device, most significant positive V Th shift was obtained indicating a efficient electron injection whereas showed inefficient erasing characteristics via hole injection and storing due to a high electronegative properties of fluorine units in the dielectric. This result indicates importance of a selection of the chargeable polymer dielectric to obtain efficient organic non-volatile memory with a long retention time.

Conventionally, P–N junctions have played an important role as a key unit in most semiconductor electronic devices. P–N junctions based on organic semiconductors have also been researched widely, but it is difficult to develop solution-processing-based organic semiconductor P–N junctions because of their similar solubility in common organic solvents. For this reason, most organic planar heterojunctions have been based on deposition by thermal evaporation or transfer film via additional complicated processing. In this study, using p-type and n-type conjugated polymers with selection of their orthogonal solvents, a conjugated polymer bilayer P–N heterojunction structure is developed via simple solution processing. The developed structure is then used in novel organic electronic applications, such as organic rectifier diodes, organic field-effect transistors with highly balanced ambipolar charge transport properties, integrated circuits, and even organic phototransistors that display a photoresponse from the visible to the near-infrared (NIR) range with the generation of a photocurrent at the P–N heterointerface in the channel region. The polymeric P–N junction structure can be applied in various organic electronic devices via a simple printing process, which can contribute to the development of new functionalized organic electronics systems.

These func-tionalities arise from field-effect modulation by the chargesstored in chargeable polymer gate dielectrics, referred to aspolymer electrets.An electret is a piece of dielectric material that exhibits aquasi-permanent electrical charges or dipolar polarization,including ferro-, piezo-, and pyro-electric polymers.

We introduce a high-performance molecular sensor using self-corrugated chemically modified graphene as a three dimensional (3D) structure that indicates anisotropic charge distribution. This is capable of room-temperature operation, and, in particular, exhibiting high sensitivity and reversible fast response with equilibrium region. The morphology consists of periodic, “cratered” arrays that can be formed by condensation and evaporation of graphene oxide (GO) solution on interdigitated electrodes. Subsequent hydrazine reduction, the corrugated edge area of the graphene layers have a high electric potential compared with flat graphene films. This local accumulation of electrons interacts with a large number of gas molecules. The sensitivity of 3D-graphene sensors significantly increases in the atmosphere of NO2 gas. The intriguing structures have several advantages for straightforward fabrication on patterned substrates, high-performance graphene sensors without post-annealing process.

OBJECTIVE The aim of this randomized, sham-controlled study was to investigate the therapeutic effects of underlying neurobiological changes after 2-week repetitive transcranial magnetic stimulation (rTMS) treatment using functional connectivity magnetic resonance imaging in patients with major depression. METHODS Twenty-four patients with major depressive disorder diagnosed with DSM-IV-TR criteria were randomly assigned to the active rTMS (n = 13) or sham (n = 11) groups from January 2009 to June 2011. rTMS was given for 2 weeks at 110% of the motor threshold for 10 minutes at 10 Hz over the left dorsolateral prefrontal cortex (DLPFC). Resting state functional connectivity was evaluated before and after rTMS. The 17-item Hamilton Depression Rating Scale (HDRS) was administered, and neurocognitive tasks were performed. We examined between-group differences in functional connectivity changes from the bilateral DLPFC. RESULTS Participants in the active rTMS group showed significant clinical improvement in HDRS scores compared to those in the sham group (P < .001). After 2-week rTMS, there were significant differences in changes in DLPFC-left caudate connectivity (corrected P < .05): the active group showed a greater reduction of connectivity strength between the DLPFC and left caudate compared to the sham group. Reduced levels of DLPFC-left caudate connectivity predicted improvement in depressive symptoms (r = 0.58, P = .001). Additionally, a positive correlation between residual depressive symptoms and connectivity strength after 2-week rTMS was found (r = 0.46, P = .023). CONCLUSIONS High-frequency rTMS over the left DLPFC showed therapeutic effects in patients with major depression. The therapeutic effect of rTMS is related to the modulation of functional connectivity in the frontostriatal network. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT01325831​.

The universal role of high-k fluorinated dielectrics in assisting the carrier transport in transistors for a broad range of printable semiconductors is explored. These results present general rules for how to design dielectric materials and achieve devices with a high carrier concentration, low disorder, reliable operation, and robust properties.

Nanocarbon-based conducting fibres have been produced using solution- or dry-spinning techniques. Highly conductive polymer-composite fibres containing large amounts of conducting nanomaterials have not been produced without dispersants, however, because of the severe aggregation of conducting materials in high-concentration colloidal solutions. Here we show that highly conductive (electrical conductivity ~1.5 × 105 S m−1) polymer-composite fibres containing carbon nanotubes and silver nanowires can be fabricated via a conventional solution-spinning process without any other treatment. Spinning dopes were fabricated by a simple mixing of a polyvinyl alcohol solution in dimethylsulfoxide with a paste of long multi-walled carbon nanotubes dispersed in organic solvents, assisted by quadruple hydrogen-bonding networks and an aqueous silver nanowire dispersion. The high electrical conductivity of the fibre was achieved by rearrangement of silver nanowires towards the fibre skin during coagulation because of the selective favourable interaction between the silver nanowires and coagulation solvents. The prepared conducting fibres provide applications in electronic textiles such as a textile interconnector of light emitting diodes, flexible textile heaters and touch gloves for capacitive touch sensors.

GaN-based ultraviolet (UV) LEDs are widely used in numerous applications, including white light pump sources and high-density optical data storage. However, one notorious issue is low hole injection rate in p-type transport layer due to poorly activated holes and spontaneous polarization, giving rise to insufficient light emission efficiency. Therefore, improving hole injection rate is a key step towards high performance UV-LEDs. Here, we report a new method of suppressing spontaneous polarization in p-type region to augment light output of UV-LEDs. This was achieved by simply passivating graphene oxide (GO) on top of the fully fabricated LED. The dipole layer formed by the passivated GO enhanced hole injection rate by suppressing spontaneous polarization in p-type region. The homogeneity of electroluminescence intensity in active layers was improved due to band filling effect. As a consequence, the light output was enhanced by 60% in linear current region. Our simple approach of suppressing spontaneous polarization of p-GaN using GO passivation disrupts the current state of the art technology and will be useful for high-efficiency UV-LED technology.

The oxygen-free dehydroaromatization of methane is of great scientific importance and industrial benefit for the effective utilization of natural gas and biogas to provide alternative petrochemical feed stocks and COx-free hydrogen production for fuel cells.1 Methane oxygen-free conversion into aromatics and hydrogen is not thermodynamically favorable at low temperatures ( 773 K); the equilibrium CH4 conversion at 973 K is 12%. At this temperature, benzene and naphthalene, in approximately equimolar amounts, are the thermodynamically preferred hydrocarbon products.2 The thermodynamic limitation is the main barrier for this process. To enhance the conversion of methane into aromatics beyond thermodynamic equilibrium, studies using H2-permeation membrane catalytic reactors are already underway by several research groups.3,4 However, preliminary reports on this approach are not very optimistic, and catalyst deactivation was more pronounced in a membrane catalytic reactor than in a fixed-bed reactor because of continuous withdrawal of the coproduced H2. Atmospheric nonthermal equilibrium plasma has been used as an efficient method for oxygen-free conversion of methane into C2 hydrocarbons (mainly acetylene) and H2 using pulsed corona/streamer discharges, or pulsed spark discharges.5-10 Only small amounts of C3-C5 hydrocarbons and trace amounts of aromatics were usually coproduced. Recently, Heintze and Magureanu reported the conversion of CH4 into aromatics in pulsed microwave plasma at atmospheric pressure in the presence of a heterogeneous catalyst.11 In their work, the authors suggested that methane aromatization is very likely catalyzed on coke surfaces and highly unlikely by the trimerization of acetylene. The most abundant aromatic formed was benzene, and 5% of the maximum benzene yield was obtained. Herein, we show a two-stage plasma-followed-bycatalyst (PFC) reactor for the oxygen-free conversion of methane into aromatic-rich hydrocarbons and coproduced H2. Methane is converted to acetylene by plasma in the first stage, with the second stage for acetylene trimerization on nickel-loaded HZSM-5 catalyst. Oxygen-free conversion of methane was performed at atmospheric pressure in a two-stage PFC reactor, as shown in Figure 1. The first stage of the PFC reactor, for generating pulsed spark discharge, was located in the upper part of a quartz tube (i.d. 10 mm) and consisted of a stainless steel wire (2 mm diameter) as the high-voltage electrode and a perforated iron plate (9 mm diameter) as the ground electrode. The distance between the two electrodes was 10 mm. The high-voltage power supply source for generating pulsed spark discharge was described before.10 The second stage of the PFC reactor was filled with 0.5 g of HZSM-5 or Ni/HZSM-5 pellets of 20-40 mesh. The Ni/HZSM-5 catalysts were prepared by the conventional impregnation method using HZSM-5 (SiO2/Al2O3 25, Nankai University, China) and aqueous solution of nickel nitrate. The impregnated samples were dried at 393 K for 4 h, calcined at 723 K for 4 h in air, and reduced at 673K for 2 h in hydrogen. The flow rates for CH4, H2, and N2 were controlled through a mass flow controller. The feed gas mixture of CH4 (99.99%) and H2 (99.99%) with a molar ratio of CH4/H2 1 was introduced into the PFC reactor at a flow rate of 9.2 cm/min. 2.2 cm/min of N2 (99.99%) was used as an internal standard for analysis and introduced into the effluent gas from the PFC reactor to avoid conversion of N2 in the plasma. Hydrocarbon products were sampled by a six-way valve heated to 473 K and analyzed on-line by a gas chromatograph (Agilent 1790F) with a flame ionization detector (FID) and using a 2 mm (i.d.) 3m Porapak-P column with N2 as the carrier gas. N2 and CH4 were analyzed on-line by another gas chromatograph (Agilent 1790T) with a thermoconductive deY. Xu and A.-M. Zhu are also affiliated with State Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Dalian 116024, China. Correspondence concerning this article should be addressed to A.-M. Zhu at amzhu@dlut.edu.cn.

High-performance inkjet-printed top-gate/bottom-contact organic field-effect transistors (OFETs) and complementary electronic circuitry are reported. Blends of poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) and poly(methyl methacrylate) (PMMA) dielectrics effectively reduce the operation voltage. At the optimized blend ratio of 7 : 3 wt.% for P(VDF-TrFE) and PMMA, both p- and n-type printed OFETs show well-balanced high field-effect mobility values (~ 0.5 cm2/V·s) and low threshold voltages ( ±5 V). The high-performance inverters and various digital logic gates such as nand, nor, or, and xor are demonstrated on flexible plastic substrates. The inverter shows a high gain (>; 25), an ideal inverting voltage near half of the supplied bias (1/2VDD), and a high noise immunity (up to 79 % of 1/2VDD).

We report on a technique using mixed self-assembled monolayers (SAMs) to finely regulate ambipolar charge injection in polymer organic field-effect transistors. Differing from the other works that employ single SAM specifically for efficient charge injection in p-type and n-type transistors, we blend two different SAMs of alkyl- and perfluoroalkyl thiols at different ratios and apply them to ambipolar OFETs and inverter. Thanks to the utilization of ambipolar semiconductor and one SAM mixture, the device and circuit fabrications are facile with only one step for semiconductor deposition and another for SAM treatment. This is much simpler with respect to the conventional scheme for the unipolar-device-based complementary circuitry that demands separate deposition and processing for individual p-channel and n-channel transistors. Our results show that the mixed-SAM treatments not only improve ambipolar charge injection manifesting as higher hole- and electron-mobility and smaller threshold voltage but also gradually tune the device characteristics to reach a desired condition for circuit application. Therefore, this simple but useful approach is promising for ambipolar electronics.

The aim of the present study was to assess whether procalcitonin (PCT) can be used as a diagnostic marker for ventilator-associated pneumonia (VAP) in cardiac surgery patients. Between January 2012 and June 2013, a total of 92 patients were recruited and divided into non-VAP (59 patients) and VAP (33 patients) groups. The preoperative and postoperative characteristics of the patients were recorded. Serum levels of PCT, interleukin (IL)-6 and C-reactive protein (CRP) were measured using an electrochemiluminescence immunoassay. Subsequently, receiver operating characteristic curves of the PCT, IL-6 and CRP levels were constructed. In addition, associations between the sequential organ failure assessment (SOFA) scores and the serum levels of PCT, IL-6 and CRP in the VAP patients were analyzed. No statistically significant difference was observed between the non-VAP and VAP patients in the occurrence of postoperative complications. However, the SOFA scores (days 1 and 7), the duration of stay in the intensive care unit and the mechanical ventilation time were all significantly higher in the VAP group when compared with the non-VAP group (P

Modulation of the junction resistance between metallic nanowires is a crucial factor for high performance of the network-structured conducting film. Here, we show that under current flow, silver nanowire (AgNW) network films can be stabilised by minimizing the Joule heating at the NW-NW junction assisted by in-situ interconnection with a small amount (less than 3 wt%) of single-walled carbon nanotubes (SWCNTs). This was achieved by direct deposition of AgNW suspension containing SWCNTs functionalised with quadruple hydrogen bonding moieties excluding dispersant molecules. The electrical stabilisation mechanism of AgNW networks involves the modulation of the electrical transportation pathway by the SWCNTs through the SWCNT-AgNW junctions, which results in a relatively lower junction resistance than the NW-NW junction in the network film. In addition, we propose that good contact and Fermi level matching between AgNWs and modified SWCNTs lead to the modulation of the current pathway. The SWCNT-induced stabilisation of the AgNW networks was also demonstrated by irradiating the film with microwaves. The development of the high-throughput fabrication technology provides a robust and scalable strategy for realizing high-performance flexible transparent conductor films.

Layered materials must be exfoliated and dispersed in solvents for diverse applications. Usually, highly energetic probe sonication may be considered to be an unfavourable method for the less defective exfoliation and dispersion of layered materials. Here we show that judicious use of ultrasonic cavitation can produce exfoliated transition metal dichalcogenide nanosheets extraordinarily dispersed in non-toxic solvent by minimising the sonolysis of solvent molecules. Our method can also lead to produce less defective, large graphene oxide nanosheets from graphite oxide in a short time (within 10 min), which show high electrical conductivity (>20,000 S m(-1)) of the printed film. This was achieved by adjusting the ultrasonic probe depth to the liquid surface to generate less energetic cavitation (delivered power similar to 6 W), while maintaining sufficient acoustic shearing (0.73 m s(-1)) and generating additional microbubbling by aeration at the liquid surface.