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Lithium-ion batteries (LIBs) have revolutionized portable electronics, yet their conventional graphite anodes face capacity limitations. Integrating graphene and 3D molybdenum disulfide (MoS2) offers a promising solution. Ensuring a uniform distribution of 3D MoS2 nanostructures within a graphene matrix is crucial for optimizing battery performance and preventing issues like agglomeration and capacity degradation. This study focuses on synthesizing a uniformly distributed paper wad structure by optimizing a composite of reduced graphene oxide RGO@MoS2 through structural and morphological analyses. Three composites with varying graphene content were synthesized, revealing that the optimized sample containing 30 mg RGO demonstrates beneficial synergy between MoS2 and RGO. The interconnected RGO network enhances reactivity and conductivity, addressing MoS2 aggregation. Experimental results exhibit an initially superior capacity of 911 mAh g−1, retained at 851 mAh g−1 even after 100 cycles at 0.1 A g−1 current density, showcasing improved rate efficiency and long-term stability. This research underscores the pivotal role of graphene content in customizing RGO@MoS2 composites for enhanced LIB performance. [ABSTRACT FROM AUTHOR]

We report for the first time MoS2/CNT hybrid nanostructures for memristor applications on flexible and bio-degradable cellulose paper. In our approach, we varied two different weight percentages (10% and 20%) of CNT's in MoS2 to improve the MoS2 conductivity and investigate the memristor device characteristics. The device with 10% CNT shows a low V SET voltage of 2.5 V, which is comparatively small for planar devices geometries. The device exhibits a long data retention time and cyclic current–voltage stability of ∼104 s and 102 cycles, making it a potential candidate in flexible painted electronics. Along with good electrical performance, it also demonstrates a high mechanical stability for 1000 bending cycles. The conduction mechanism in the MoS2-CNT hybrid structure is corroborated by percolation and defect-induced filament formation. Additionally, the device displays synaptic plasticity performance, simulating potentiation and depression processes. Furthermore, such flexible and biodegradable cellulose-based paper electronics may pave the way to address the environmental pollution caused by electronic waste in the near future. [ABSTRACT FROM AUTHOR]

Filter cloth brush-coating (FCBC), using soft filter cloth as a brush-coating medium, in conjunction with viscous silver nanowire (AgNW) conductive solution, is used to prepare AgNW conductive films. The density and uniformity of AgNWs deposited on the substrate are controlled by the interplay between the filter cloth aperture, the conductive solution viscosity, and the brush-coating speed. Further, with appropriate AgNW concentration and flow rate, uniform AgNW transparent conductive film with sheet resistance of 18 Ω sq−1 and transmittance of 94% at 550 nm is acquired by FCBC. Due to the precise control of the coating process in FCBC, large-area uniform AgNW conductive film fabricated on printing paper has a low non-uniformity factor of 1.2% at a sheet resistance of 19.0 Ω sq−1. The resultant paper-based AgNW film heater shows sensitive and stable heating performance. FCBC shows great potential in producing large-area uniform AgNW films on various substrates. [ABSTRACT FROM AUTHOR]

Recent progress in the in situ synthesise of various nanomaterials has gained tremendous interest and wide applications in various fields. For the first time to the best of our knowledge, this work reports a methodology of ultra-fast in situ synthesis of cobalt–cobalt oxide-reduced graphene oxide (Co−Co3O4−rGO (CC–rGO)) composite by laser ablation. The photothermal reduction technique was leveraged to develop the CC–rGO. For this, a low-cost 450 nm blue diode laser was irradiated onto a grade 1 filter paper in the presence of cobalt ions readily patterns the carbon matrix of paper to the composite material. Moreover, the variation of cobalt concentrations from 0.1–0.5 M led to structural and morphological changes. Standard techniques were adopted for thorough characterizations of developed sensor material for conductivity analysis, specific surface area, crystal-structural information, surface morphology, and chemical composition. The observed results were highly promoting towards the electrochemical sensing applications. Further, the developed sensor was found to be highly selective toward detecting a vital bio analyte alkaline phosphatase (ALP). The sensors performance was highly significant in the linear range of 10–800 mU l−1 with a detection limit of 10.13 mU l−1. The sensors applicability was further validated in actual human serum samples via a recovery-based approach. In the future, the developed in situ material methodology can begin a rapid composite material synthesis at a larger scale. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate a microwave-assisted chemical reduction technique to exfoliate a few layers of graphene from the natural waste material, ‘coconut shell’. The microwave irradiation coconut shell is subjected to structural, morphological and functional groups characterization methods including SEM, Raman, FTIR and XPS spectroscopic analyses. The formation of biomass reduced graphene (BRG) has been confirmed through Raman and FTIR spectroscopic analyzes with the presence of D, G and 2D and other functional spectral bands, respectively. The surface topography of the BRG exhibits two-dimensional mat structures with wrinkle topography, imaged by electron microscopic techniques. The metallic behaviour of the BRG is evaluated by band structure calculation using density functional theory. The synthesized nanostructure has been evaluated for exhaled diabetic breath sensing application by fabricating sensor device on the paper-based substrate by roll-to-roll coating technique. The BRG sensor exhibited enhanced sensing response at a very lower concentration of diabetic biomarker with long term stability and rapid response/recovery time of 1.11 s/41.25 s, respectively. Based on our findings, the microwave-assisted BRG is a potential candidate for fabricating highly scalable, inherently safe, economically viable and excellent sensing performance to detect exhaled diabetic breath at room temperature. [ABSTRACT FROM AUTHOR]

Glucose electrochemical sensors based on nanostructures of CuO/Cu(OH)2 onto graphene paper were prepared by thermal (solid) and nanosecond pulsed laser (molten phase) dewetting of a CuO layer 6 nm thin deposited by sputtering. Dewetted systems, obtained without the use of any binder, act as array of nanoelectrodes. Solid state and molten phase dewetting produce nanostructures of copper oxide-hydroxide with different average size, shape and surface composition. Molten phase dewetting originates particles with size below 100 nm, while solid state dewetting produces particles with average size of about 200 nm. Moreover, molten phase dewetting produce drop-shaped nanostructures, conversely nanostructures derived from solid state dewetting are multifaceted. X-ray photoelectron spectroscopy (XPS) characterization revealed that the surface of nanostructures is formed by a copper(II) species CuO and Cu(OH)2. Shape of anodic branch of the cyclic voltammograms of glucose in alkali solution evidenced a convergent diffusion mechanism. Analytical performances in amperometric mode are as good as or better than other sensors based on copper oxide. Amperometric detection of glucose was done at potential as low as 0.4 V versus saturated calomel electrode by both types of electrodes. Linear range from 50 ÎĽ M to 10 mM, sensitivity ranging from 7 to 43 ÎĽ A cmâˆ'2 mMâˆ'1 and detection limit of 7 ÎĽ M was obtained. Good analytical performances were obtained by laser dewetted electrodes with a low copper content up to 1.2 by atoms percentage of the surface. Analytical performance of the proposed electrodes is compliant for the determination of glucose both in blood serum, saliva or tear. [ABSTRACT FROM AUTHOR]

High-performance electronics demand extremely sensitive piezo-resistive sensors with important features such as low-fabrication cost, easy implementation, low power consumption and high-pressure sensitivity over broad pressure range. Herein, we report a flexible piezo-resistive paper-based device functionalised by WSe2 nanosheets. An efficient and low-cost fabrication strategy using Whatman filter paper and tissue paper is adopted for versatile sensing applications. The WSe2 nanosheets were synthesized by high-yield and size-controlled liquid phase exfoliation technique. The flexible WSe2 nanosheets-paper sensor shows excellent response in broad pressure range of 1 Pa–100 kPa with exceptionally high sensitivity of 29.24 kPa−1, current responsivity of 70 and response time of 100 ms. The pressure sensor is also employed to recognize the pressure generated due to finger tapping. Encouragingly, the piezo-resistive sensors can also sense extremely small pressure differences of about 1.4 Pa generated by water drops. [ABSTRACT FROM AUTHOR]

This work demonstrates the fabrication of tellurium-nanowires (Te-NWs)/paper based device encapsulated using laser assisted mircopyramid patterned polydimethylsiloxane (PDMS) films. Although there are multiple reports published on 1D Te, most of them are limited to establishing its properties and studying its behavior as a sensor and research on the utilization of Te-NWs for physical sensors remain unexplored. Further, reports on p-type photodetectors also remain scarce. The fabricated Te-NWs/paper with micropyramid structured PDMS films encapsulation was used as a strain sensor, and it exhibited considerable improvement (∼60%) in sensitivity compared to smooth PDMS films. The gauge factor of the developed strain sensor was found to be ∼15.3. In addition, fabricated Te-NWs/paper device with contacts was used as a photodetector and it showed photoresponsivity of ∼22.5 mA W−1 and ∼14.5 mA W−1 in visible and NIR regions, respectively. Furthermore, the device exhibited long-term mechanical stability under harsh deformations. Fabricated 1D Te-NWs/paper device was utilized as a strain sensor to monitor the angular movements in the human body and successfully monitored various human motions, including wrist bending, finger knuckle, elbow joint, and knee joint. The successful demonstration of Te-NWs based physical sensors and utilization in broadband photodetectors opens avenues of research for tellurium based flexible and wearable devices. [ABSTRACT FROM AUTHOR]

In this study, a novel paper biosensor based on Fe3O4@SiO2–NH2 magnetic polymer microspheres and multi walled carbon nanotubes (MWCNTs) for rapid detection of pseudorabies virus (PRV) was first developed. Fe3O4@SiO2–NH2 were functionalized with PRV antibody and doped in cellulose nitrate paper to fabricate the magnetic paper biosensor with good magnetic response and biocompatibility. Using MWCNTs to build conductive network of sensors, PRV antigen binds specifically to the immunomagnetic microspheres on the sensor, and the resulting immune complex changes the magnetic domain structure of the sensor and the structural gap of MWCNTs, causing the magnetic property and impedance change. TEM and EDS characterization proved that the biosensor was successfully doped with Fe3O4@SiO2–NH2 and effectively recognized PRV. Under optimized conditions, the impedance variation was found to be linearly related to the logarithm value of PRV concentrations in the range of 10–1 mg ml−1, with the detection limit of 10 ng ml−1. This paper biosensor demonstrated advantages of portability, high sensitivity and specificity, providing a valuable method for early control of PRV. [ABSTRACT FROM AUTHOR]

Flexible photodetectors functionalized by transition metal dichalcogenides have attracted great attention due to their excellent photo-harvesting efficiency. However, the field of optoelectronics still requires advancement in the production of large-area, broad band and flexible photodetectors. Here we report a flexible, stable, broad band and fast photodetector based on a MoS2/WSe2 heterostructure on ordinary photocopy paper with pencil-drawn graphite electrodes. Ultrathin MoS2/WSe2 nanohybrids have been synthesized by an ultrahigh yield liquid-phase exfoliation technique. The thin sheets of WSe2, and MoS2 contain two to four layers with a highly c-oriented crystalline structure. Subsequently, the photodetector was exploited under ultra-broad spectral range from 400 to 780 nm. The photodetector exhibits excellent figure of merit such as on/off ratio of the order of 103, photoresponsivity of 124 mA W−1 and external quantum efficiency of 23.1%. Encouragingly, rise/decay time of about 0.1/0.3 s was realized, which is better than in previous reports on paper-based devices. [ABSTRACT FROM AUTHOR]

Nanostructured dielectric composite has been considered as a promising manner in improving the flashover performance of oil-paper which has been widely used in power systems. In this paper, plasma-enhanced chemical vapor deposition (PECVD) is used to deposit SiO2 on the ceramic fiber-reinforced insulating paper. Scanning electron microscope images show a large number of SiO2 nanoparticles with diameters of 100 nm–250 nm uniformly attached to the fiber surface after the plasma deposition. The surface flashover voltage of the insulating paper was tested in the air and the transformer oil, respectively. Results show that the corresponding DC surface flashover voltages increased by 15.1% in the air and breakdown between liquid and solid interface increased by 24.6% after the PECVD. It is believed that nanoparticles constructed in ceramic fibers change the electron injection barrier which inhibits the injection of negative charges and hinders the accumulation of charges in the dielectric. Nanoparticles can capture electric charges formed in the transformer oil which affects the generation and development of streamers, resulting in an increased dielectric strength. This study provides a new method to comprehensively improve the surface insulating property which has the prospect of promoting other dielectric materials. [ABSTRACT FROM AUTHOR]

A multilayer coated paper substrate, combining barrier and printability properties was manufactured utilizing a pilot-scale slide curtain coating technique. The coating structure consists of a thin mineral pigment layer coated on top of a barrier layer. The surface properties, i.e. smoothness and surface porosity, were adjusted by the choice of calendering parameters. The influence of surface properties on the fine line printability and conductivity of inkjet-printed silver lines was studied. Surface roughness played a significant role when printing narrow lines, increasing the risk of defects and discontinuities, whereas for wider lines the influence of surface roughness was less critical. A smooth, calendered surface resulted in finer line definition, i.e. less edge raggedness. Dimensional stability and its influence on substrate surface properties as well as on the functionality of conductive tracks and transistors were studied by exposure to high/low humidity cycles. The barrier layer of the multilayer coated paper reduced the dimensional changes and surface roughness increase caused by humidity and helped maintain the conductivity of the printed tracks. Functionality of a printed transistor during a short, one hour humidity cycle was maintained, but a longer exposure to humidity destroyed the non-encapsulated transistor. [ABSTRACT FROM AUTHOR]

Temperature sensors have extensive applications in industrial production, defense, and military sectors. However, conventional temperature sensors are limited to operating temperatures below 200 °C and are unsuitable for detecting extremely high temperatures. In this paper, a method for thermal protection of molybdenum disulfide (MoS2) films is proposed and a MoS2 high temperature sensor is prepared. By depositing silicon nitride (Si3N4) films onto monolayer MoS2, not only is the issue of high-temperature oxidation effectively addressed, but also the prevention of contamination by impurities that could potentially compromise the performance of MoS2. Moreover, the width of the Schottky barrier of metal/MoS2 is reduced by using plasma-enhanced chemical vapor deposition of 400 nm Si3N4 to form an ohmic contact, which improves the electrical performance of the device by three orders of magnitude. The sensor exhibits a positive temperature coefficient measurement range of 25 °C–550 °C, with a maximum temperature coefficient of resistance of 0.89%·°C−1. The thermal protection method proposed in this paper provides a new idea for the fabrication of high-temperature sensors, which is expected to be applied in the high-temperature field. [ABSTRACT FROM AUTHOR]

In the context of 'energy shortage', developing a novel energy-based power system is essential for advancing the current power system towards low-carbon solutions. As the usage duration of lithium-ion batteries for energy storage increases, the nonlinear changes in their aging process pose challenges to accurately assess their performance. This paper focuses on the study LiFeO4(LFP), used for energy storage, and explores their performance degradation mechanisms. Furthermore, it introduces common battery models and data structures and algorithms, which used for predicting the correlation between electrode materials and physical parameters, applying to state of health assessment and thermal warning. This paper also discusses the establishment of digital management system. Compared to conventional battery networks, dynamically reconfigurable battery networks can realize real-time monitoring of lithium-ion batteries, and reduce the probability of fault occurrence to an acceptably low level. [ABSTRACT FROM AUTHOR]

Interactions between carbon nanotubes (CNTs) and fluid flows are central to the operation of several emerging nanotechnologies. In this paper, we explore the fluid-structure interaction of CNT micropillars in wall-bounded shear flows, relevant to recently developed microscale wall shear stress sensors. We monitor the deformation of CNT micropillars in channel flow as the flow rate and wall shear stress are gradually varied. We quantify how the micropillars bend at low wall shear stress, and then will commonly tilt abruptly from their base above a threshold wall shear stress, which is attributed to the lower density of the micropillars in this region. Some micropillars are observed to flutter rapidly between a vertical and horizontal position around this threshold wall shear stress, before settling to a tilted position as wall shear stress increases further. Tilted micropillars are found to kink sharply near their base, similar to the observed buckling near the base of CNT micropillars in compression. Upon reducing the flow rate, micropillars are found to fully recover from a near horizontal position to a near vertical position, even with repeated on–off cycling. At sufficiently high wall shear stress, the micropillars were found to detach at the catalyst particle-substrate interface. The mechanical response of CNT micropillars in airflow revealed by this study provides a basis for future development efforts and the accurate simulation of CNT micropillar wall shear stress sensors. [ABSTRACT FROM AUTHOR]

In this paper, we present a novel polylactic-acid/flax-composite substrate and the implementation of a demonstrator: a microcontroller board based on commercial design. The substrate is developed for printed circuit board (PCB) applications. The pre-preg is biodegradable, reinforced, and flame-retarded. The novel material was developed to counter the increasing amount of e-waste and to improve the sustainability of the microelectronics sector. The motivation was to present a working circuit in commercial complexity that can be implemented on a rigid substrate made of natural, bio-based materials with a structure very similar to the widely used Flame Retardant Class 4 (FR4) substrate at an early technological readiness level (2–3). The circuit design is based on the Arduino Nano open-source microcontroller board design so that the demonstration could be programmable and easy to fit into education, IoT applications, and embedded designs. During the work, the design was optimized at the level of layout. The copper-clad pre-preg was then prepared and processed with subtractive printed wiring technology and through hole plating. The traditional surface mounting methodology was applied for assembly. The resulting yield of PCB production was around 50%. Signal analysis was successful with analogue data acquisition (voltage) and low-frequency (4 kHz) tests, indistinguishable from sample FR4 boards. Eventually, the samples were subjected to highly accelerated stress test (HAST). HAST tests revealed limitations compared to traditional FR4 printed circuit materials. After six cycles, the weight loss was around 30% in the case of PLA/Flax, and as three-point bending tests showed, the possible ultimate strength (25 MPa at a flexural state) was reduced by 80%. Finally, the sustainability aspect was assessed, where we found that ∼95 vol% and ∼90 wt% of the traditional substrate can be substituted, significantly easing the load of waste on the environment. [ABSTRACT FROM AUTHOR]

The number of layers present in a two-dimensional (2D) nanomaterial plays a critical role in applications that involve surface interaction, for example, gas sensing. This paper reports the synthesis of 2D WS2 nanoflakes using the facile liquid exfoliation technique. The nanoflakes were exfoliated using bath sonication (BS-WS2) and probe sonication (PS-WS2). The thickness of the BS-WS2 was found to range between 70 and 200 nm, and that of PS-WS2 varied from 0.6 to 80 nm, indicating the presence of single to few layers of WS2 when characterized using atomic force microscope. All the WS2 samples were thoroughly characterized using electron microscopes, x-ray diffractometer, Raman spectroscopy, UV–Visible spectroscopy, Fourier transform infrared spectroscope, and thermogravimetric analyser. Both the nanostructured samples were exposed to 2 ppm of NO2 at room temperature. Interestingly, BS-WS2 which comprises of a greater number of WS2 layers exhibited −14.2% response as against −3.4% response of PS-WS2, the atomically thin sample. The BS-WS2 sample was found to be highly selective towards NO2 but was slower (with incomplete recovery) as compared to PS-WS2. The PS-WS2 sample was observed to exhibit −11.9% to −27.4% response to 2–10 ppm of CO and −3.4%–35.2% response to 2–10 ppm of NO2 at room temperature, thereby exhibiting the potential to detect two gases simultaneously. These gases could be accurately predicted and quantified if the response times of the PS-WS2 sample were considered. The atomically thin WS2-based sensor exhibited a limit of detection of 131 and 81 ppb for CO and NO2, respectively. [ABSTRACT FROM AUTHOR]

There is a strong interest in the use of biopolymers in the electronic and biomedical industries, mainly towards low-cost applications. The possibility of developing entirely new kinds of products based on cellulose is of current interest, in order to enhance and to add new functionalities to conventional paper-based products. We present our results towards the development of paper-based microfluidics for molecular diagnostic testing. Paper properties were evaluated and compared to nitrocellulose, the most commonly used material in lateral flow and other rapid tests. Focusing on the use of paper as a substrate for microfluidic applications, through an eco-friendly wax-printing technology, we present three main and distinct colorimetric approaches: (i) enzymatic reactions (glucose detection); (ii) immunoassays (antibodies anti-Leishmania detection); (iii) nucleic acid sequence identification (Mycobacterium tuberculosis complex detection). Colorimetric glucose quantification was achieved through enzymatic reactions performed within specific zones of the paper-based device. The colouration achieved increased with growing glucose concentration and was highly homogeneous, covering all the surface of the paper reaction zones in a 3D sensor format. These devices showed a major advantage when compared to the 2D lateral flow glucose sensors, where some carryover of the coloured products usually occurs. The detection of anti-Leishmania antibodies in canine sera was conceptually achieved using a paper-based 96-well enzyme-linked immunosorbent assay format. However, optimization is still needed for this test, regarding the efficiency of the immobilization of antigens on the cellulose fibres. The detection of Mycobacterium tuberculosis nucleic acids integrated with a non-cross-linking gold nanoprobe detection scheme was also achieved in a wax-printed 384-well paper-based microplate, by the hybridization with a species-specific probe. The obtained results with the above-mentioned proof-of-concept sensors are thus promising towards the future development of simple and cost-effective paper-based diagnostic devices. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) free-standing nanostructures based on electron-beam lithography (EBL) have potential applications in many fields with extremely high patterning resolution and design flexibility with direct writing. In numerous EBL processes designed for the creation of 3D structures, the multilayer resist system is pivotal due to its adaptability in design. Nevertheless, the compatibility of solvents between different layers of resists often restricts the variety of feasible multilayer combinations. This paper introduces an innovative approach to address the bottleneck issue by presenting a novel concept of multilayer resist dry stacking, which is facilitated by a near-zero adhesion strategy. The poly(methyl methacrylate) (PMMA) film is stacked onto the hydrogen silsesquioxane (HSQ) resist using a dry peel and release technique, effectively circumventing the issue of HSQ solubilization by PMMA solvents typically encountered during conventional spin-coating procedures. Simultaneously, a dry lift-off technique can be implemented by eschewing the use of organic solvents during the wet process. This pioneering method enables the fabrication of high-resolution 3D free-standing plasmonic nanostructures and intricate 3D free-standing nanostructures. Finally, this study presents a compelling proof of concept, showcasing the integration of 3D free-standing nanostructures, fabricated via the described technique, into the realm of Fabry–Perot cavity resonators, thereby highlighting their potential for practical applications. This approach is a promising candidate for arbitrary 3D free-standing nanostructure fabrication, which has potential applications in nanoplasmonics, nanoelectronics, and nanophotonics. [ABSTRACT FROM AUTHOR]

In this paper, we present the design and fabrication of a plasmonic metasurface based on titanium dioxide (TiO2) nanowire arrays integrated with plasmonic layers. The structure is engineered to produce Fano resonances within the visible spectrum, resulting from the coupling of localized surface plasmon resonances, lattice modes, and nanowire's optical modes. Experimentally, we show that by tuning the geometrical features of the metasurface, such as the length, diameter, and period of the nanowires, a high-quality factor single peak can be achieved in the reflection spectra, resulting in vivid structural colors in bright field. To our knowledge, this is the first demonstration of such vivid colors with nanowire arrays in bright field reflections. When characterized by refractive index fluids around the refractive index of water, the plasmonic metasurface also showed great potential for biochemical colorimetric sensing. The best design demonstrated a bulk sensitivity of 183 nm/RIU with high Q resonance features and linear changes in color values using image processing. [ABSTRACT FROM AUTHOR]

Paper electronics is a topic of great interest due the possibility of having low-cost, disposable and recyclable electronic devices. The final goal is to make paper itself an active part of such devices. In this work we present new approaches in the selection of tailored paper, aiming to use it simultaneously as substrate and dielectric in oxide based paper field effect transistors (FETs). From the work performed, it was observed that the gate leakage current in paper FETs can be reduced using a dense microfiber/nanofiber cellulose paper as the dielectric. Also, the stability of these devices against changes in relative humidity is improved. On other hand, if the pH of the microfiber/nanofiber cellulose pulp is modified by the addition of HCl, the saturation mobility of the devices increases up to 16 cm2 V−1 s−1, with an ION/IOFF ratio close to 105. [ABSTRACT FROM AUTHOR]

Pentacene-based organic thin-film transistors (OTFTs) were fabricated on several types of flexible substrate: commercial photo paper, ultra-smooth specialty paper and ultra-thin (100 μM) flexible glass. The transistors were fabricated entirely through dry-step processing. The transconductance and field-effect mobility of OTFTs on photo paper reached values of ∼0.52 mS m−1 and ∼0.1 cm2 V −1 s−1, respectively. Preliminary results on the lifetime of OTFTs on photo paper yielded stable transconductance and mobility values over a period of more than 250 h. The comparable characteristics of OTFTs fabricated on widely available, low cost paper and high quality expensive liquid crystal display glass indicate the potential importance of cellulose-based electronic devices. [ABSTRACT FROM AUTHOR]

Printed electronics is a rapidly developing field where many components can already be manufactured on flexible substrates by printing or by other high speed manufacturing methods. However, the functionality of even the most inexpensive microcontroller or other integrated circuit is, at the present time and for the foreseeable future, out of reach by means of fully printed components. Therefore, it is of interest to investigate hybrid printed electronics, where regular electrical components are mounted on flexible substrates to achieve high functionality at a low cost. Moreover, the use of paper as a substrate for printed electronics is of growing interest because it is an environmentally friendly and renewable material and is, additionally, the main material used for many packages in which electronics functionalities could be integrated. One of the challenges for such hybrid printed electronics is the mounting of the components and the interconnection between layers on flexible substrates with printed conductive tracks that should provide as low a resistance as possible while still being able to be used in a high speed manufacturing process. In this article, several conductive adhesives are evaluated as well as soldering for mounting surface mounted components on a paper circuit board with ink-jet printed tracks and, in addition, a double sided Arduino compatible circuit board is manufactured and programmed. [ABSTRACT FROM AUTHOR]

Low-voltage (1.5 V) indium zinc oxide (IZO)-based electric-double-layer (EDL) thin-film transistors (TFTs) gated by nanogranular proton conducting SiO2 electrolyte films are fabricated on paper substrates. Both enhancement-mode and depletion-mode operation are obtained by tuning the thickness of the IZO channel layer. Furthermore, such flexible IZO protonic/electronic hybrid EDL TFTs can be used as artificial synapses, and synaptic stimulation response and short-term synaptic plasticity function are demonstrated. The protonic/electronic hybrid EDL TFTs on paper substrates proposed here are promising for low-power flexible paper electronics, artificial synapses and bioelectronics. [ABSTRACT FROM AUTHOR]

Most sensors are based on ceramic or semiconducting substrates, which have no flexibility or biocompatibility. Polymer-based sensors have been the subject of much attention due to their ability to collect molecules on their sensing surface with flexibility. Beyond polymer-based sensors, the recent discovery of cellulose as a smart material paved the way to the use of cellulose paper as a potential candidate for mechanical as well as electronic applications such as actuators and sensors. Several different paper-based sensors have been investigated and suggested. In this paper, we review the potential of cellulose materials for paper-based application devices, and suggest their feasibility for chemical and biosensor applications. [ABSTRACT FROM AUTHOR]

This study utilized ion implantation to modify the material properties of silicon carbide (SiC) to mitigate subsurface damage during SiC machining. The paper analyzed the mechanism of hydrogen ion implantation on the machining performance of SiC at the atomic scale. A molecular dynamics model of nanoscale cutting of an ion-implanted SiC workpiece using a non-rigid regular tetrakaidecahedral diamond abrasive grain was established. The study investigated the effects of ion implantation on crystal structure phase transformation, dislocation nucleation, and defect structure evolution. Results showed ion implantation modification decreased the extension depth of amorphous structures in the subsurface layer, thereby enhancing the surface and subsurface integrity of the SiC workpiece. Additionally, dislocation extension length and volume within the lattice structure were lower in the ion-implanted workpiece compared to non-implanted ones. Phase transformation, compressive pressure, and cutting stress of the lattice in the shear region per unit volume were lower in the ion-implanted workpiece than the non-implanted one. Taking the diamond abrasive grain as the research subject, the mechanism of grain wear under ion implantation was explored. Grain expansion, compression, and atomic volumetric strain wear rate were higher in the non-implanted workpiece versus implanted ones. Under shear extrusion of the SiC workpiece, dangling bonds of atoms in the diamond grain were unstable, resulting in graphitization of the diamond structure at elevated temperatures. This study established a solid theoretical and practical foundation for realizing non-destructive machining at the atomic scale, encompassing both theoretical principles and practical applications. [ABSTRACT FROM AUTHOR]

Perovskite quantum dots (QDs) and organic materials have great research potential in the field of optoelectronic devices. In this paper, MEH-PPV/CsPbBr3 heterojunction photodetectors (PDs) are prepared by spin coating method based on the good photoelectric properties of CsPbBr3 perovskite QDs and MEH-PPV. The MEH-PPV/CsPbBr3 heterojunction improves the energy level arrangement, and CsPbBr3 QDs can passivate the surface defects of MEH-PPV films to achieve effective charge separation and transfer, thus inhibiting the dark current and improving the photoelectric performance of the device. Under 532 nm laser irradiation, the responsivity (R) of MEH-PPV/CsPbBr3 heterojunction PD is 11.98 A W−1, the specific detectivity (D *) is 6.98 × 1011 Jones, and the response time is 15/16 ms. This work provides experience for the study of perovskite QDs and organic materials heterojunction optoelectronic devices. [ABSTRACT FROM AUTHOR]

The noble metal-based electrochemical sensor design for efficient and stable formaldehyde(FA) detection is important ongoing research. In this paper, PtPd/Nafion/GCE is prepared by electrochemical cyclic voltammetry deposition method based on electrodepositing nanostructured platinum (Pt)-palladium (Pd) nanoparticles in Nafion film-coated glassy carbon electrode (GCE). The influence of deposition parameters and chemical composition (atomic ratio of Pt and Pd) on the electrochemical behaviour of PtPd/Nafion/GCE has been investigated. PtPd/Nafion/GCE displays a remarked electrocatalytic activity for the oxidation of FA and exhibits a linear relationship in the range of 10–5000 μ M, with a detection limit of 3.3 μ M in 0.1 M H2SO4 solution. It is proved that the detection performance of PtPd/Nafion/GCE electrode is valuable for further application with low detection limit, wide linear range, favourable selectivity and high response. [ABSTRACT FROM AUTHOR]

Twisted moiré photonic crystal is an optical analog of twisted graphene or twisted transition metal dichalcogenide bilayers. In this paper, we report the fabrication of twisted moiré photonic crystals and randomized moiré photonic crystals and their use in enhanced extraction of light in light-emitting diodes (LEDs). Fractional diffraction orders from randomized moiré photonic crystals are more uniform than those from moiré photonic crystals. Extraction efficiencies of 76.5%, 77.8% and 79.5% into glass substrate are predicted in simulations of LED patterned with twisted moiré photonic crystals, defect-containing photonic crystals and random moiré photonic crystals, respectively, at 584 nm. Extraction efficiencies of optically pumped LEDs with 2D perovskite (BA)2(MA) n −1PbnI3 n +1 of n = 3 and (5-(2′-pyridyl)-tetrazolato)(3-CF3−5-(2′-pyridyl)pyrazolato) platinum(II) (PtD) have been measured. [ABSTRACT FROM AUTHOR]

Numerous efforts have been undertaken to mitigate the Debye screening effect of FET biosensors for achieving higher sensitivity. There are few reports that show sub-femtomolar detection of biomolecules by FET mechanisms but they either suffer from significant background noise or lack robust control. In this aspect, deformed/crumpled graphene has been recently deployed by other researchers for various biomolecule detection like DNA, COVID-19 spike proteins and immunity markers like IL-6 at sub-femtomolar levels. However, the chemical vapor deposition (CVD) approach for graphene fabrication suffers from various surface contamination while the transfer process induces structural defects. In this paper, an alternative fabrication methodology has been proposed where glass substrate has been initially texturized by wet chemical etching through the sacrificial layer of synthesized silver nanoparticles, obtained by annealing of thin silver films leading to solid state dewetting. Graphene has been subsequently deposited by thermal reduction technique from graphene oxide solution. The resulting deformed graphene structure exhibits higher sensor response towards glial fibrillary acidic protein (GFAP) detection with respect to flat graphene owing to the combined effect of reduced Debye screening and higher surface area for receptor immobilization. Additionally, another interesting aspect of the reported work lies in the biomolecule capture by dielectrophoretic (DEP) transport on the crests of the convex surfaces of graphene in a coplanar gated topology structure which has resulted in 10 aM and 28 aM detection limits of GFAP in buffer and undiluted plasma respectively, within 15 min of application of analyte. The detection limit in buffer is almost four decades lower than that documented for GFAP using biosensors which is is expected to pave way for advancing graphene FET based sensors towards ultrasensitive point-of-care diagnosis of GFAP, a biomarker for traumatic brain injury. [ABSTRACT FROM AUTHOR]

Achieving energy-efficient and high-performance field-effect transistors (FETs) is one of the most important goals for future electronic devices. This paper reports semiconducting single-walled carbon nanotube FETs (s-SWNT-FETs) with an optimized high- k relaxor ferroelectric insulator P(VDF-TrFE-CFE) thickness for low-voltage operation. The s-SWNT-FETs with an optimized thickness (∼800 nm) of the high- k insulator exhibited the highest average mobility of 14.4 cm2 V−1s−1 at the drain voltage (I D) of 1 V, with a high current on/off ratio (I on/off >105). The optimized device performance resulted from the suppressed gate leakage current (I G) and a sufficiently large capacitance (>50 nF cm−2) of the insulating layer. Despite the extremely high capacitance (>100 nF cm−2) of the insulating layer, an insufficient thickness (<450 nm) induces a high I G, leading to reduced I D and mobility of s-SWNT-FETs. Conversely, an overly thick insulator (>1200 nm) cannot introduce sufficient capacitance, resulting in limited device performance. The large capacitance and sufficient breakdown voltage of the insulating layer with an appropriate thickness significantly improved p-type performance. However, a reduced n-type performance was observed owing to the increased electron trap density caused by fluorine proportional to the insulator thickness. Hence, precise control of the insulator thickness is crucial for achieving low-voltage operation with enhanced s-SWNT-FET performance. [ABSTRACT FROM AUTHOR]

Many studies suggest that probabilistic spiking in biological neural systems is beneficial as it aids learning and provides Bayesian inference-like dynamics. If appropriately utilised, noise and stochasticity in nanoscale devices can benefit neuromorphic systems. In this paper, we build a stochastic leaky integrate and fire (LIF) neuron, utilising a Mott memristor's inherent stochastic switching dynamics. We demonstrate that the developed LIF neuron is capable of biological neural dynamics. We leverage these characteristics of the proposed LIF neuron by integrating it into a population-coded spiking neural network and a spiking restricted Boltzmann machine (sRBM), thereby showcasing its ability to implement probabilistic learning and inference. The sRBM achieves a software-comparable accuracy of 87.13%. Unlike CMOS-based probabilistic neurons, our design does not require any external noise sources. The designed neurons are highly energy efficient and ultra-compact, requiring only three components: a resistor, a capacitor and a memristor device. [ABSTRACT FROM AUTHOR]

Surface enhanced Raman spectroscopy (SERS) is a powerful analytical technique that has found application in the trace detection of a wide range of contaminants. In this paper, we report on the fabrication of 2D silver nanodendrites, on silicon chips, synthesized by electrochemical reduction of AgNO3 at microelectrodes. The formation of nanodendrites is tentatively explained in terms of electromigration and diffusion of silver ions. Electrochemical characterization suggests that the nanodendrites do not stay electrically connected to the microelectrode. The substrates show SERS activity with an enhancement factor on the order of 106. Density functional theory simulations were carried out to investigate the suitability of the fabricated substrate for pesticide monitoring. These substrates can be functionalized with cyclodextrin macro molecules to help with the detection of molecules with low affinity with silver surfaces. A proof of concept is demonstrated with the detection of the herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA). [ABSTRACT FROM AUTHOR]

PIN diodes, due to their simple structure and variable resistance characteristics under high-frequency high-power excitation, are often used in radar front-end as limiters to filter high power microwaves (HPM) to prevent its power from entering the internal circuit and causing damage. This paper carries out theoretical derivation and research on the HPM effects of PIN diodes, and then uses an optimized neural network algorithm to replace traditional physical modeling to calculate and predict two types of HPM limiting indicators of PIN diode limiters. We proposes a neural network model for each of the following two prediction scenarios: in the scenario of time-junction temperature curves under different HPM irradiation, the weighted mean squared error (MSE) between the predicted values from the test dataset and the simulated values is below 0.004. While in predicting PIN limiter's power limitation threshold, insertion loss, and maximum isolation under different HPM irradiation, the MSE of the test set prediction values and simulation values are all less than 0.03. The method proposed in this research, which applies an optimized neural network algorithm to replace traditional physical modeling algorithms for studying the high-power microwave effects of PIN diode limiters, significantly improves the computational and simulation speed, reduces the calculation cost, and provides a new method for studying the high-power microwave effects of PIN diode limiters. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is a wide-band gap semiconductor that exceeds other semiconducting materials (except diamond) in electrical, mechanical, chemical, and radiation stability. In this paper, we report a novel approach to fabrication of SiC nano films on a Si substrate, which is based on the endotaxial growth of a SiC crystalline phase in a graphite-like carbon (GLC) matrix. GLC films were formed by carbonization of rigid rod polyimide (PI) Langmuir–Blodgett (LB) films on a Si substrate at 1000 °C in vacuum. After rapid thermal annealing of GLC films at 1100 °C and 1200 °C, new types of heterostructures SiC(10 nm)/GLC(20 nm)/Si(111) and SiC(20 nm)/GLC(15 nm)/SiC(10 nm)/Si(111) were obtained. The SiC top layer was formed due to the Si-containing gas phase present above the surface of GLC film. An advantage of the proposed method of endotaxy is that the SiC crystalline phase is formed within the volume of the GLC film of a thickness predetermined by using PI LB films with different numbers of monolayers for carbonization. This approach allows growing SiC layers close to the 2D state, which is promising for optoelectronics, photovoltaics, spintronics. [ABSTRACT FROM AUTHOR]

The need for photosensors and gas sensors arises from their pivotal roles in various technological applications, ensuring enhanced efficiency, safety, and functionality in diverse fields. In this paper, interlinked PbS/Sb2O5 thin film has been synthesized by a magnetron sputtering method. We control the temperature to form the nanocomposite by using their different nucleation temperature during the sulfonation process. A nanostructured PbS/Sb2O5 with cross-linked morphology was synthesized by using this fast and efficient method. This method has also been used to grow a uniform thin film of nanocomposite. The photo-sensing and gas-sensing properties related to the PbS/Sb2O5 compared with those of other nanomaterials have also been investigated. The experimental and theoretical calculations reveal that the PbS/Sb2O5 exhibits extraordinarily superior photo-sensing and gas-sensing properties in terms of providing a pathway for electron transport to the electrode. The attractive highly sensitive photo and gas sensing properties of PbS/Sb2O5 make them applicable for many different kinds of applications. The responsivity and detectivity of PbS/Sb2O5 are 0.28 S/mWcm−2 and 1.68 × 1011 Jones respectively. The sensor response towards NO2 gas was found to be 0.98 at 10 ppb with an limit of detection (LOD) of 0.083 ppb. The PbS/Sb2O5 exhibits high selectivity towards the NO2 gas. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were used to analyze the geometries, electronic structure, and electronic absorption spectra of a light sensor fabricated by PbS/Sb2O5. The results are very analogous to the experimental results. Both photosensors and gas sensors are indispensable tools that contribute significantly to the evolution of technology and the improvement of various aspects of modern life. [ABSTRACT FROM AUTHOR]

With the increasing integration density of silicon-based circuits, traditional electrical interconnections have shown their technological limitations. In recent years, GeSn materials have attracted great interest due to their potential direct bandgap transition and compatibility with silicon-based technologies. GeSn materials, including GeSn films, GeSn alloys, and GeSn nanowires, are adjustable, scalable, and compatible with silicon. GeSn nanowires, as one-dimensional (1D) nanomaterials, including out-of-plane GeSn nanowires and in-plane GeSn nanowires, have different properties from those of bulk materials due to their distinctive structures. However, the synthesis and potential applications of out of plane GeSn nanowires are rarely compared to highlighting their current development status and research trends in relevant review papers. In this article, we present the preparation of out-of-plane GeSn nanowires using top-down (etching and lithography) and bottom-up (vapor–liquid–solid) growth mechanism in the vapor-phase method and supercritical fluid–liquid–solid, solution-liquid–solid, and solvent vapor growth mechanisms in the liquid-phase method) methods. Specifically, the research progress on typical out of plane GeSn nanowires are discussed, while some current development bottlenecks are also been identified. Finally, it is also provided a brief description of the applications of out-of-plane GeSn nanowires with various Sn contents and morphologies. [ABSTRACT FROM AUTHOR]

Over the past few decades, single-element semiconductors have received a great deal of attention due to their unique light-sensitive and heat-sensitive properties, which are of great application and research significance. As one promising material, selenium, being a typical semiconductor, has attracted significant attention from researchers due to its unique properties including high optical conductivity, anisotropic, thermal conductivity, and so on. To promote the application of selenium nanomaterials in various fields, numerous studies over the past few decades have successfully synthesized selenium nanomaterials in various morphologies using a wide range of physical and chemical methods. In this paper, we review and summarise the different methods of synthesis of various morphologies of selenium nanomaterials and discuss the applications of different nanostructures of selenium nanomaterials in optoelectronic devices, chemical sensors, and biomedical applications. Finally, we discuss possible challenges for selenium nanodevices and provide an outlook on the future applications of selenium nanomaterials. [ABSTRACT FROM AUTHOR]

Graphene and its derivatives are widely used in the field of energy conversion and management due to their excellent physical and chemical properties. In this paper, ultra-thin graphite film (GF) with thickness of 100–150 nm prepared by chemical vapor deposition was transferred to oxygen plasma-treated polyimide (PI) substrate as flexible heating film. The electrothermal and photothermal properties of GF on PI substrates with different treatment time were studied. The experimental results show that the PI substrate pretreated by oxygen plasma can change the surface morphology of GF, increase its electrical conductivity and light absorption capacity, and significantly improve the electrothermal and photothermal properties of GF heater. Under the low applied voltage of 5 V (power density of 0.81 W cm−2), the surface temperature of GF on 40 min plasma-treated PI substrate can rise to 250 °C, which is nearly 50 °C higher than that of GF on untreated PI substrate. When 100 nm thick commercial multilayer graphene film (MLG) is used, plasma-treated PI substrate can increase the electric heating temperature of MLG by 70 °C. In terms of photothermal performance, the surface temperature of GF on 50 min plasma-treated PI substrate can reach 73 °C under one Sun irradiation, which is 8 °C higher than that on untreated substrate. The experimental results are in good agreement with the simulation research. Our strategy has important implications for the development of efficient and energy-saving graphene/graphite-based heating films for advanced electrothermal and photothermal conversion devices. [ABSTRACT FROM AUTHOR]

Flexible piezoelectric devices have attracted much attention in the fields of intelligent devices and biomedicine because of their high sensitivity, stability, and flexibility. In this paper, a multifunctional flexible pressure sensor was prepared by adding polyacrylonitrile (PAN) and carboxylic-terminated multi-walled carbon nanotubes (c-MWCNTs) with polyvinylidene difluoride (PVDF) as the substrate. The β -phase content of PVDF/PAN blended fibers compounded with c-MWCNT was up to 95%. At the same time, when PAN was added, the mechanical properties of the composite fibers were constantly improved. The results show that the polymer blending method can improve the comprehensive properties of PVDF composite. The flexible sensor prepared from the PVDF/PAN/c-MWCNT composite film has an output voltage of 2.1 V and a current of 7 μ A. The addition of c-MWCNT can largely improve the sensitivity of the sensor (4.19 V N−1). The sensor is attached to the finger and shows good output performance under different degrees of bending of the finger. The maximum output voltage of the sensor is 0.4 V, 0.56 V and 1.15 V when the finger bending angle is 30°, 60°, and 90°, respectively. Moreover, the developed piezoelectric sensor can monitor large-scale movements of various parts of the human body. Therefore, this composite material shows potential in areas such as motion monitoring and energy storage devices. [ABSTRACT FROM AUTHOR]

Achieving highly efficient broadband absorption is an important research area in nanophotonics. In this paper, a novel method is proposed to design broadband near-perfect absorbers, consisting of a four-layer hemispherical concentric nanoshell array. The proposed nanostructure supports absorptivity exceeding 95% in the entire visible region, and the absorption bandwidth is determined by the interaction or 'hybridization' of the plasmons of the inner and outer metal-based nanoshells. Moreover, the designed absorber has wide-angle capability and is insensitive to polarization. The simple structure, as well as the stable absorption properties, suggests that such core–shell nanostructures can serve as a potential candidate for many applications such as solar energy harvesting, photo-detection, and emissivity control. [ABSTRACT FROM AUTHOR]

An electrothermochromic paper display composed of colorimetrically reversible polydiacetylenes (PDAs), utilizing screen printing on photopaper and patterning of electrically conductive wires on the reverse side, was developed. Heat generated by passing a current through the wires on the back of the photopaper induced a blue-to-red color transition of the PDA on the front at regions corresponding to the wires. This resulted in the generation of red-colored images, which disappeared when the supplied electric current was removed. The voltage at which the PDAs changed color could be controlled by using structured diacetylene (DA) monomers. A PDA-based seven-segment display has also been developed. By applying voltages, red-colored numeric digits from 0 to 9 can be displayed on the surface of the PDA layer. [ABSTRACT FROM AUTHOR]

In this study, two different supramolecular recognition architectures for impedimetric detection of DNA hybridization have been formed on disposable paper-supported inkjet-printed gold electrodes. The gold electrodes were fabricated using a gold nanoparticle based ink. The first recognition architecture consists of subsequent layers of biotinylated self-assembly monolayer (SAM), streptavidin and biotinylated DNA probe. The other recognition architecture is constructed by immobilization of thiol-functionalized DNA probe (HS-DNA) and subsequent backfill with 11-mercapto-1-undecanol (MUOH) SAM. The binding capacity and selectivity of the recognition architectures were examined by surface plasmon resonance (SPR) measurements. SPR results showed that the HS-DNA/MUOH system had a higher binding capacity for the complementary DNA target. Electrochemical impedance spectroscopy (EIS) measurements showed that the hybridization can be detected with impedimetric spectroscopy in picomol range for both systems. EIS signal indicated a good selectivity for both recognition architectures, whereas SPR showed very high unspecific binding for the HS-DNA/MUOH system. The factors affecting the impedance signal were interpreted in terms of the complexity of the supramolecular architecture. The more complex architecture acts as a less ideal capacitive sensor and the impedance signal is dominated by the resistive elements. [ABSTRACT FROM AUTHOR]

A quadruple-function dynamically tunable terahertz absorber that uses a hybrid configuration of graphene and vanadium dioxide is proposed in this paper. The absorber achieves dynamic conversion of four functions in one structure: ultra-broadband, broadband, single-frequency narrowband and dual-frequency narrowband, by utilizing the electrical control properties of graphene and the phase-shifting properties of vanadium dioxide. Furthermore, the paper also reveals the physical mechanism of the proposed absorber through the electric field distribution and impedance matching theory. In addition, the influences of the Fermi energy level of graphene and the electrical conductivity of vanadium dioxide on the absorption spectra are investigated, demonstrating the structure's dynamic tunability. Due to the above features, the designed absorber is expected to have potential applications in terahertz imaging, modulation and filtering. [ABSTRACT FROM AUTHOR]

Non-enzymatic screen-printed chemiresistive interdigitated electrodes (SPCIE) were designed and fabricated using a low-cost screen-printing method for detection of the glucose. The interdigitated electrodes (IDE) pattern was printed using conductive graphene ink on the glossy surface of the photo paper. The proposed glossy photo paper-based SPCIE are functionalized with multi-walled carbon nanotubes-zinc oxide (MWCNTs-ZnO) nanofibers to create the chemiresistive matrix. Further, to bind these nanofibers with the graphene electrode surface, we have used the green synthesized silver nanoparticles (AgNPs) with banana flower stem fluid (BFSF) as a binder solution. AgNPs with BFSF form the conductive porous natural binder layer (CPNBL). It does not allow to increase the resistivity of the deposited material on graphene electrodes and also keeps the nanofibers intact with paper-based SPCIE. The synthesized material of MWCNT-ZnO nanofibers and green synthesized AgNPs with BFSF as a binder were characterized by Ultraviolet-visible spectroscopy (UV–vis), scanning electron microscope (SEM), x-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The amperometric measurements were performed on the proposed SPCIE sensor to detect the glucose sample directly. The innovative paper-based SPCIE glucose sensor exhibits a linear corelation between current measurements and glucose concentration in the range between 45.22 μ m and 20 mm, with a regression coefficient (R 2) of 0.9902 and a lower limit of detection (LoD) of 45.22 μ m (n = 5). The sensitivity of the developed SPCIE sensor was 2178.57 μ AmM−1cm−2, and the sensor's response time determined was approximately equal to 18 s. The proposed sensor was also tested for real blood serum sample, and relative standard deviation (RSD) was found equal to 2.95%. [ABSTRACT FROM AUTHOR]

In the development of surface structures, nanowire arrays (NWAS) have been widely studied because of their trapping effect. In this paper, the finite difference time domain (FDTD) method is used to simulate homogeneous and inhomogeneous NWAS. We studied the influence of the structural parameters of InGaN NWAS and inhomogeneous arrays on optical response properties. The optical response includes light absorptivity and cutoff wavelength sensitivity. The simulation results show that the inhomogeneous NWAS can increase the effective transmission distance of light on the surface, thus greatly improving the optical absorption capacity of InGaN NWAS. We can obtain high sensitivity of cut-off wavelength by adjusting the structural parameters of the side nanowires. We find that by reducing the diameters and heights of the side nanowires, a higher light absorption rate can be obtained, which is a 5% improvement compared to uniform NWAS. Therefore, the research in this paper can provide some theoretical reference for the experiment and preparation of InGaN photocathodes. [ABSTRACT FROM AUTHOR]

The resistance of inkjet printed lines using a silver nanoparticle based ink can be very dependent on the substrate. A very large difference in resistivity was observed for tracks printed on paper substrates with aluminum oxide based coatings compared to silica based coatings. Silica based coatings are often cationized with polymers using chloride as a counter ion. It is suggested that the precipitation of silver salts is the cause of the high resistivity, since papers pretreated with salt solutions containing ions that precipitate silver salts gave a high resistance. Silver nitrate has a high solubility and paper pretreated with nitrate ions gave a low resistivity without sintering. The results obtained show that, by choosing the correct type of paper substrate, it is possible to manufacture printed structures, such as interconnects on paper, without the need for, or at least to reduce the need for, post-print sintering. This phenomenon is, of course, ink specific. Inks without or with a low silver ion content are not expected to behave in this manner. In some sensor applications, a high resistivity is desired and, by using the correct combination of ink and paper, these types of sensors can be facilitated. [ABSTRACT FROM AUTHOR]

With the aim of preparing paper-based writing electronics, a kind of conductive pen was made with nano-silver ink as the conductive component and a rollerball pen as the writing implement. This was used to direct-write conductive patterns on Epson photo paper. In order to decrease the sintering temperature, pressure was introduced to enhance the driving forces for sintering. Compared with hot sintering without pressure, hot-pressure can effectively improve the conductivity of silver coatings, reduce the sintering time and thus improve productivity. Importantly, pressure can achieve a more uniform and denser microstructure, which increases the connection strength of the silver coating. At the optimum hot-pressure condition (sintering temperature 120 °C/sintering pressure 25 MPa/sintering time 15 min), a typical measured resistivity value was 1.43 × 10-7 Ω m, nine greater than that of bulk silver. This heat treatment process is compatible with paper and does not cause any damage to the paper substrates. Even after several thousand bending cycles, the resistivity values of writing tracks by hot-pressure sintering stay almost the same (from 1.43 × 10-7 to 1.57 × 10-7 Ω m). The stability and flexibility of the writing circuits are good, which demonstrates the promising future of writing electronics. [ABSTRACT FROM AUTHOR]

The combination of self-assembly (bottom up) and nano-imprint lithography (top down) is an efficient and effective way to record information at the nanoscale by writing. The use of an electron beam for writing is quite a promising strategy; however, the 'paper' on which to save the information is not yet fully realized. Herein, graphene was selected as the thinnest paper for recording information at the nanoscale. In a transmission electron microscope, in situ high precision writing and drawing were achieved on graphene nanosheets by manipulating electrons with a 1 nm probe (probe current ∼2 × 10-9 A m-2) in scanning transmission electron microscopy (STEM) mode. Under electron probe irradiation, the carbon atom tends to displace within a crystalline specimen, and dangling bonds are formed from the original sp2 bonding after local carbon atoms have been kicked off. The absorbed random foreign amorphous carbon assembles along the line of the scanning direction induced by secondary electrons and is immobilized near the edge. With the ultralow secondary electron yield of the graphene, additional foreign atoms determining the accuracy of the pattern have been greatly reduced near the targeting region. Therefore, the electron probe in STEM mode serves as invisible ink for nanoscale writing and drawing. These results not only shed new light on the application of graphene by the interaction of different forms of carbon, but also illuminate the interaction of different carbon forms through electron beams. [ABSTRACT FROM AUTHOR]

All-solid-state flexible supercapacitors were fabricated using carbon nanotubes (CNTs), regular office papers, and ionic-liquid-based gel electrolytes. Flexible electrodes were made by coating CNTs on office papers by a drop-dry method. The gel electrolyte was prepared by mixing fumed silica nanopowders with ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]). This supercapacitor showed high power and energy performance as a solid-state flexible supercapacitor. The specific capacitance of the CNT electrodes was 135 Fg-1 at a current density of 2 A g-1, when considering the mass of active materials only. The maximum power and energy density of the supercapacitors were 164 kW kg-1 and 41 Whkg-1, respectively. Interestingly, the solid-state supercapacitor with the gel electrolyte showed comparable performance to the supercapacitors with ionic-liquid electrolyte. Moreover, the supercapacitor showed excellent stability and flexibility. The CNT/paper- and gel-based supercapacitors may hold great potential for low-cost and high-performance flexible energy storage applications. [ABSTRACT FROM AUTHOR]