Simple Printing Method Research Articles

Paper-based thermoelectric generator based on multi-walled carbon nanotube/carboxylated nanocellulose

Cellulose is the most abundant polymer material in nature. After being produced on the nanometer scale, it is widely used in research on flexible energy storage equipment and power supply equipment. Therefore, this study has prepared a nanocomposite thermoelectric material based on multi-walled carbon nanotube (MWCNT) and carboxylated nanocellulose fiber (C-CNF) and obtained a free-standing paper-based thermoelectric generator (TEG) through a simple printing method. The equipment exhibits excellent mechanical flexibility. At the same time, the thermal conductivity is significantly reduced under the dual effects of paper and C-CNF (is reduced to 0.02–0.09 W/mK). The TEG prototype has four P-shaped feet. Under a temperature gradient of 70 K, the open circuit voltage is 3.3 mV, and the output power is up to 3.7 nW. This work not only confirms the improvement of MWCNT thermoelectric performance by C-CNF but also provides a new strategy for the preparation of low-cost and environmentally friendly thermoelectric generators.

High‐Performance Flexible Micro‐Supercapacitors Printed on Textiles for Powering Wearable Electronics

AbstractFabrication of flexible micro‐supercapacitors (MSCs) on textiles as miniaturized power supplies for wearable electronics is still a great challenge. In this work, we proposed a facile protocol to fabricate MSCs directly on textiles by combining inkjet printing and extrusion printing. Benefiting from its multi‐step printing strategy, the textile‐based MSCs still maintain their unique porous electrode structure as well as rapid electron transferability. Compared with only extrusion printing, the MSCs with a multi‐step printing strategy exhibit a remarkably enhanced electrochemical performance (8.8 mF cm−2 @0.5 mA cm−2, 1.0 mF cm−2 @5 mF cm−2), an elongated cycle life (6000 times), and superior mechanical flexibility (2000 times @90°). Moreover, benefiting from the digital printing capability, flexible MSCs in serials can be directly prepared and conveniently integrated with conductive textiles to support wearable electronics systems. This simple printing method would show extensive potential in the fabrication of energy‐based devices and wearable functional electronics.

Customized Kirigami Electrodes for Flexible and Deformable Lithium-Ion Batteries.

Customized deformable lithium-ion batteries (LIBs) have attracted interest in the emerging power systems for flexible and wearable electronics. However, a key challenge for developing these batteries is the fabrication of customized deformable electrodes that exhibit strong mechanical tolerance and robust electrochemical performance during deformation. Here, free-standing customized kirigami electrodes for deformable LIBs are fabricated by an evolutionary printing method with universal viscous electrode inks and a customizable polydimethylsiloxane template. The electrodes comprise lithium iron phosphate or lithium titanium oxide nanoparticles with a conductive carbon nanotubes/poly(vinylidene fluoride) scaffold, which is ideal for electron transfer. The compact microstructure and kirigami pattern endow the electrodes with superior mechanical robustness (over 500 stretch-release cycles) and resistance stability both in unstretched and stretched states. Finite element analysis and corresponding experiment tests reveal ultralow strain inside the materials, showing less than 3% strain even under 100% stretch ratio. With 500-times stretched electrodes, the full-cell LIBs can still deliver a considerable discharge capacity of average 94.5 mA h g-1 at 0.3 C after 100 discharge/charge cycles. The integration of such outstanding mechanical stability, excellent electrochemical performance, and simple printing method with accessible starting materials presents promising opportunities for customizing deformable components for flexible energy storage devices.

Three-dimensional transport fabrics with ultrafast water transporting and diffusion inspired by river-diversion

Inspired by the phenomenon of river diversion, a simple printing method is employed to prepare a three-dimensional (3D) transport fabric by coating a discontinuous hydrophobic pattern on inner side and a discontinuous superhydrophilic pattern on outer side of the cotton fabric. The hydrophobic pattern endows the fabric with directional water transport property, and superhydrophilic pattern improves the water diffusion performance. MMT test is used to characterize the moisture management performance of samples. The resulting fabric possesses a high accumulative one-way transport index of 500.06%, and an excellent diffusion performance. Meanwhile, the obtained fabric has a desired washing durability. The novel fabric could serve as a source of inspiration for the development of moisture management fabric.

Multifunctional Soft Actuators Based on Anisotropic Paper/Polymer Bilayer Toward Bioinspired Applications

AbstractDesigning artificial muscle actuators with diversely complex deformation and multifunction is crucial to the soft robots and their bioinspired applications. Herein, by combing the hygroexpansion and thermal expansion commonly existed in nature, electrically driven paper‐based bilayer actuator is fabricated by a simple printing method. This actuator exhibits large (270°) and anisotropic deformation coupled with features of low‐cost, superior stability, and additional reversible color‐change function. More importantly, the tailoring and heat setting are used to further design the actuator shape, thus obtain multiform deformation (bending, elongation, and folding), and more complicated deformation similar to the arm motion. Based on these actuators, variously bioinspired motions can be constructed. Inspired by the structure of the crystalline lens and ciliary muscle in human eyeball, a biomimetic lens which can change the focal length under electrical stimulation is fabricated. Moreover, W‐shaped robotic arm for manipulating microliquid in 3D direction and catapulting the object into air, in‐pipe spiral robotic arm for pushing objects out of the pipe, and artificial snake capable of deformation and color‐change simultaneously, are also fabricated. This paper‐based actuator together with bioinspired design may open new perspective on the multifunctional smart robots and biomimetic devices.

Paper-based supercapacitor with screen-printed poly (3, 4-ethylene dioxythiophene)-poly (styrene sulfonate)/multiwall carbon nanotube films actuating both as electrodes and current collectors

Here we describe a screen-printed supercapacitor produced onto filter paper using poly (3, 4-ethylene dioxythiophene)-poly (styrene sulfonate) (PEDOT:PSS)/multiwall carbon nanotube (MWCNT) composite as active materials. We use a gel-like electrolyte based on poly (vinyl alcohol) and phosphoric acid (PVA/H3PO4), serving as both an ionic conductor and as an electrode separator. The electrodes are physically characterized through micro-Raman scattering analyses, sheet resistance measurements as a function of the printed number of layers and through scanning electron microscopy. The supercapacitor performance is investigated through impedance spectroscopy, equivalent circuit fitting, cyclic voltammetry (CV), long-term cycle stability and galvanostatic charge/discharge. The electrodes exhibit a low sheet resistance, reaching 17 Ω sq−1, being suitable for use as both electrode and the current collector. The supercapacitor shows good capability behavior over impedance spectroscopy and CV measurements, and 72% of capacitance retention after 1000 cycles. We find a maximum specific capacitance of 20,3 F g−1 for a charge/discharge current of 1 mA, and equivalent series resistance of 60 Ω, leading to energy and power densities of 3,1 Wh kg−1 and 420 W kg−1, respectively. In conclusion, we describe here a flexible supercapacitor without metal collectors produced by a simple printing method.

Lead Iodide Microcrystals in Carbon Composite Matrix for Low Power Photodetectors

AbstractLead iodide (PbI2) microcrystals based photodetector were developed by a simple printing method. Carbon composite paste was fabricated by homogeneous mixing of PbI2 microcrystals, commercial graphite powder, and activated carbon. Composite carbon paste was printed on top of thermally deposited Al electrodes on the glass substrates to fabricate the photodetector. Controlled variation of PbI2 loading established that 10% PbI2 in carbon composite is the best candidate for the highest On/Off ratio. The photo generated current was manifested by the defect present in the graphite and the PbI2 microcrystals interfaces. The effect enables us to develop cost effective printing based photodetector which can work in very low voltage region for low‐power printed electronics.

Development of simple high-resolution embedded printing for transparent metal grid conductors

We developed a simple embedded printing method that is capable of forming high-resolution patterns for transparent metal grid conductors. The simple printing method involves embedding conductive ink in a groove structure formed by nanoimprinting. Since this printing utilizes capillary force, conductive ink easily fills groove structures with small widths of several microns to the submicron scale. An embedded pattern with a line width of 300 nm was printed. In addition, a high aspect ratio of 3.1 was achieved with a 1.6 μm embedded pattern. A prototype transparent conductive film was developed with excellent optical and electrical performances: a high transmittance of 82.7% and a low sheet resistance of 5.1 Ω/sq at a grid width of 3.0 μm and a grid pitch of 150 μm. The grid parameters can easily be changed by mold design during the nanoimprint process. The transparent conductive film (TCF) showed excellent bending resistance compared with indium tin oxide.

Enhanced Performance of Li-S Batteries By PANI Printing Method

Lithium-sulfur (Li-S) batteries have received considerable attention, since their theoretical energy density (2500Wh kg-1) is ~7 times larger than those of the current LIBs (~387Wh kg-1) utilizing the unparalleled theoretical capacity of sulfur (1,675 mAh g-1). The practical application of Li-S cell is still limited mainly due to the low conductivity of sulfur (~10-30 S cm-1), the volumetric expansion up to 80% during the discharge and the dissolution of polysulfides resulting shuttling effect in the charge-discharge process. In the present investigation, we develop a printing method for enhancing the lithium sulfur batteries. PANI layer coated sulfur electrode was demonstrated by a simple printing method. The role of printed layer is confirmed by in-situ UV/Vs test. The PANI layer avoids the chronic issues previously reported in lithium-sulfur batteries. In particular, the printing method is able to enhance the lithium-sulfur cell and the printed layer plays an important role as an electrolyte-blocking layer, preventing the dissolution of polysulfides. In the printed sulfur electrode, the capacity retention was 96.4% with 99.6% of average Coulombic efficiency (1C cycle), and 105% of the original capacity was still retained with 99.3% of average Coulombic efficiency (0.1C cycle). This effect induces the stable cycling capacity of sulfur electrode. The strategy employed in this work to produce a uniform PANI layer printed onto electrode surface is also applicable to all of other sulfur electrode to develop stable cell that avoid the shuttling effect.

Synthesis of AlON materials for UV emitting devices

AbstractAluminum oxynitride (AlON), which is conventionally used as one of the ceramics with good thermal and chemical stability, has an attractive candidate for a tunable extreme UV luminous material due to its unique combination of properties and UV luminescence. In this paper, we have synthesized the novel AlON UV emitting materials, which have a wavelength from 4.29 to 4.54 eV, and discovered the core (AlON)‐shell (Al2O3) like structures in a transmission electron microscopy. Furthermore, their potential application in a UV light emitter has been demonstrated by applying the combination with a CNT field emission cold cathode, which has been made by a simple printing method. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

From Perception to Paint: the Practical Use of the Camera Obscura in the Time of Vermeer

This is a report of a studio experiment to explore how images from the camera obscura could have been used directly by artists of Vermeer’s era. It has a pragmatic and practical approach, bringing a painter’s eye and experience to the problems of transferring images from the lens to a canvas, using the primitive technology and unrefined materials available then. It addresses how an artist could use the condensed, flattened images from camera obscura projections in his painting process, when the subject could appear reversed and inverted on the screen or on the wall. It considers how the limitations of the materials that make transfers possible might affect studio practice, and ultimately the stylistic qualities of the work produced. This paper outlines a simple printing method that would enable the seventeenth-century painter to transfer monochrome images, corrected in orientation, from the lens to a canvas with relative ease, for use as the painting progressed in the stages prescribed at the time. Prints made on the ground layer could form the basis of underpainting, while those on top layers could transfer highlights and optical effects, not seen with the naked eye. This technique would allow the painter to be in the light of his studio, facing his motif, when working in colour. Reference is made to art historical literature and contemporary workshop treatises, and all materials used are authentic. The results obtained using this process are consistent with the visual evidence of the way in which Vermeer applied his paint, and with recent scientific examination of his work. The findings suggest possible causes for some of the unusual qualities of Vermeer’s work, in particular the strong tonal polarity in the underpainting with no evidence of drawing, his choice of material in the ground layers, and the qualities of variable focus.

Nanotransfer Printing with sub‐10 nm Resolution Realized using Directed Self‐Assembly

An extraordinarily facile sub-10 nm fabrication method using the synergic combination of nanotransfer printing and the directed self-assembly of block copolymers is introduced. The approach is realized by achieving the uniform self-assembly of polydimethylsiloxane (PDMS)-containing block copolymers on a PDMS mold through the stabilization of the block copolymer thin films. This simple printing method can be applied on oxides, metals, polymers, and non-planar substrates without pretreatments. The fabrication of well-aligned metallic and polymeric functional nanostructures and crossed wire structures is also presented.