Printable Electronics Research Articles

Influence of Humidity on the Performance of Composite Polymer Electrolyte-Gated Field-Effect Transistors and Circuits

In the domain of printed electronics (PE), field-effect transistors (FETs) with an oxide semiconductor channel are very promising. In particular, the use of high gate-capacitance of the composite solid polymer electrolytes (CSPEs) as a gate-insulator ensures extremely low voltage requirements. Besides high gate capacitance, such CSPEs are proven to be easily printable, stable in air over wide temperature ranges, and possess high ion conductivity. These CSPEs can be sensitive to moisture, especially for high surface-to-volume ratio printed thin films. In this paper, we provide a comprehensive experimental study on the effect of humidity on CSPE-gated single transistors. At the circuit level, the performance of ring oscillators (ROs) has been compared for various humidity conditions. The experimental results of the electrolyte-gated FETs (EGFETs) demonstrate rather comparable currents between 30%–90% humidity levels. However, the shifted transistor parameters lead to a significant performance change of the RO frequency behavior. The study in this paper shows the need of an impermeable encapsulation for the CSPE-gated FETs to ensure identical performance at all humidity conditions.

Transparent Inorganic Copper Bromide (CuBr) p-Channel Transistors Synthesized From Solution at Room Temperature

Transparent polycrystalline p-channel copper bromide (CuBr) thin-film transistors (TFTs) are fabricated using a simple one-step spin coating at room temperature. Optimized CuBr TFTs operate in depletion mode with an on-voltage of 35 V and exhibit a hole mobility of 0.15 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , high on/off current ratio ~10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> and cycling bias sweep/air stabilities. The performance is superior to that of most solution-processed p-type oxide TFTs, highlighting CuBr as a promising p-type candidate for nextgeneration printable transparent electronics.

Arylacetylene end capped naphthodithiophene diimide (NDTI)-based semiconductors for air-stable, solution-processed n-channel organic field-effect transistors: Effect of terminal aryl groups on charge transport

Solution-processable n-channel organic field-effect transistors (OFETs) are crucial for realizing low-cost, large-area, and all organic logic/complementary circuits. Herein, we present the synthesis, characterization and OFET characteristics of a series of arylacetylene end capped NDTI-based n-channel small molecule semiconductors with four different arylacetylene groups, i.e., thiophenylethynyl (TE, NDTI-BTE), phenylethynyl (PE, NDTI-BPE), 2-pyridinylethynyl (2PdE, NDTI-B2PdE), 4-pyridinylethynyl (4PdE, NDTI-B4PdE). All four NDTIs exhibit excellent solubility behavior in common organic solvents. Electrochemical and optical studies reveal that the introduction of the arylacetylene groups at the thiophene α-positions of NDTI endowed these molecules have sufficiently low-lying LUMO energy levels from −4.12 to −4.24 eV, suitable for better air-stable electron transport. Under ambient atmosphere, we found that solution-processed bottom-gate top-contact (BGTC) transistors based on 120 °C-annealed thin-films of these NDTIs exhibit the best performance with the maximum electron mobilities of 0.049, 0.023, 0.011 and 0.033 cm2 V−1 s−1 for NDTI-BTE, NDTI-BPE, NDTI-B2PdE and NDTI-B4PdE, respectively, due to better thin film microstructures. AFM measurements reveal that the spin-coated films of these materials exhibited quite smooth and uniform morphology although these are small molecules forming crystalline structures. These results clearly demonstrate that arylacetylene groups are potential functional moieties for developing ambient-stable solution-processable small molecular electron-transporting materials for printable organic electronics.

Additive-free MXene inks and direct printing of micro-supercapacitors

Direct printing of functional inks is critical for applications in diverse areas including electrochemical energy storage, smart electronics and healthcare. However, the available printable ink formulations are far from ideal. Either surfactants/additives are typically involved or the ink concentration is low, which add complexity to the manufacturing and compromises the printing resolution. Here, we demonstrate two types of two-dimensional titanium carbide (Ti3C2Tx) MXene inks, aqueous and organic in the absence of any additive or binary-solvent systems, for extrusion printing and inkjet printing, respectively. We show examples of all-MXene-printed structures, such as micro-supercapacitors, conductive tracks and ohmic resistors on untreated plastic and paper substrates, with high printing resolution and spatial uniformity. The volumetric capacitance and energy density of the all-MXene-printed micro-supercapacitors are orders of magnitude greater than existing inkjet/extrusion-printed active materials. The versatile direct-ink-printing technique highlights the promise of additive-free MXene inks for scalable fabrication of easy-to-integrate components of printable electronics.

Polygonal-feature-based shape context for flexible surface vision positioning

In the manufacturing process of curved flexible electronics, flexible electronics are transferred from a plate to a conformal curved surface before electrohydrodynamic printing. Machine vision is adopted for the localization of the process of transfer printing. However, traditional vision positioning algorithms mainly focus on the localization of a rigid object in a plate. To overcome this limitation, a novel robust and rotation-invariant algorithm, namely surface deformable localization based on shape context, is proposed for surface transfer printing of flexible electronics. First, a new localization model used in surface deformable localization is established. The proposed algorithm consists of two phases. In the off-line phase, an improved polygonal approximation is proposed to select the feature points from an image, and a rotation-invariant shape context is used to describe the feature points. In the on-line phase, the correspondence of feature points between the template image and the search image is established by the dynamic programming algorithm. Finally, the result of localization is obtained by searching for the maximum of the proposed matching mode. The experimental results show the effectiveness of the proposed method for surface deformable localization and its robustness to noise, blur, and non-linear illumination.

Plasma jet based in situ reduction of copper oxide in direct write printing

Printing of nanostructured films with tailored oxidation state and electronic structure can have far reaching applications in several areas including printable electronics, optoelectronics, solar cells, catalytic conversion, and others. Widely used inkjet/aerosol/screen printing techniques require pre- and postprocessing for enhanced adhesion and tailoring of the chemical state of the thin film. Herein, we demonstrate atmospheric pressure plasma jet printing with unique capability to print and tune in situ the electronic properties and surface morphology of nanomaterials. Plasma printing of copper thin films with tailored oxidation state from an inexpensive copper oxide precursor is demonstrated and characterized using x-ray absorption spectroscopy, Raman spectroscopy, and electrical measurements.

Twofold Variation Propagation Modeling and Analysis for Roll-to-Roll Manufacturing Systems

Roll-to-roll (R2R) manufacturing has emerged as one of the most cost-effective manufacturing techniques for high-volume production of flexible printing electronics, graphene films, thin-film batteries, and solar cells, as opposed to low-volume batch production. However, in practice, real-time monitoring of the R2R process and in situ measurement of fabricated materials during production are challenging because of the high speed and dynamic variation of the web. In addition, due to the lack of cost-effective sensors and in-line metrology systems with a large range and high resolution, effective quality control and defect diagnosis are difficult to achieve. To address these challenges, this paper aims to develop analytical models that can serve as virtual sensing and metrology tools to quantify process state variation and estimate product quality in R2R processes with limited accessibility of in situ sensor. First, the quality variation propagation mechanism in R2R processes is investigated. Second, a hybrid multistage modeling method is proposed to characterize the twofold variation propagation—product-centric and process-centric variations, and its relationship with product quality in R2R processes. Note to Practitioner s—The novel modeling method developed in this paper employs both physics-based analysis (e.g., web handling system dynamics) and regression methods [e.g., censored regression and linear/logistic regression (LG)] using multisensor signals. The estimation results from the model can serve as virtual sensing and virtual metrology tools to increase the system visibility and be applied for process monitoring and error detection in real time. A print registration unit of elastic film in a roll-to-roll system is employed to demonstrate and validate the proposed modeling method in terms of the accuracy of state estimates and quality prediction. Based on the comparison results, the hybrid modeling method shows higher accuracy in state estimation and quality prediction than do the models with data-driven methods only.

Metallic Nanoparticle Inks for 3D Printing of Electronics

AbstractThe three‐dimensional (3D) printed electronics additive manufacturing industry sector has grown substantially in the past few years, and there is increasing demand for different types of metallic nanoparticle inks in electronics printing for various applications. Metallic nanoparticle inks are commonly used for fabricating conductive tracks and patterns due to their relatively high electrical conductivity as compared to other types of inks, and they can be further categorized into single‐element metallic nanoparticle inks, alloy metallic nanoparticle inks, metallic oxide nanoparticle inks, and core–shell bimetallic nanoparticle (BNP) inks. It is critical to gain a deep understanding of the metallic nanoparticle inks used in 3D printed electronics as the material properties of these inks can directly affect the final electrical and mechanical properties of the printed patterns. This review presents an overview of the available metallic nanoparticle inks used for 3D printing of electronics, and critically reviews the strengths and weaknesses of each type of ink. Finally, the challenges of metallic nanoparticle inks in 3D printed electronics are also discussed along with the future outlook for 3D printed electronics.

Wettability control with self-assembler patterning for printed electronics

We investigated the lyophobic/lyophilic patterning method of self-assembled monolayers (SAMs) as gate dielectrics for printable electronics. Lyophobic/lyophilic patterning has been previously shown to damage the substrate surface. Therefore, it is mainly used for electrodes, but not semiconductors. We reduced the damage by partially removing the alkyl chains of the lyophobic SAM with oxygen plasma or vacuum ultraviolet treatment and replacing them with lyophilic molecules. This lyophilic area was formed in a room-temperature process, and we obtained a solution-processed organic transistor with a mobility of 2 × 10−2 cm2 V−1 s−1 at 2.5 V operation. The transistor retained 54% of its mobility without the SAM replacement. By integrating a p-type transistor prepared in the same way, we achieved 2 V operation of an organic inverter and ring oscillator with gain of 30 and oscillation frequency of 3.1 Hz.

Design of a register controller considering inherent characteristics of a roll-to-roll continuous manufacturing system

Roll-to-roll (R2R) continuous printing has served as a breakthrough for the mass production of flexible electronic devices. However, high-precision register control is an obstacle in the printing of multilayer flexible electronics with complex structures. In this study, we investigated the characteristics of register control and determined the inherent factors of register controllers that can generate register errors that cannot be solved by theory-based control methods. Considering these innate factors, we propose a design for a high-precision register controller. Our experimental results show that register errors that could not be solved by previous control methods are not generated in the proposed register control design. Further, the proposed design provides high-precision and stable control while maximizing the control rate in an industrial R2R printing machine. The study results suggest that innate factors in register controllers must be considered to achieve high-precision and stable register control within ± 10–30 μm. We also present guidelines for designing a high-precision register controller.

All-printed multilayer high voltage capacitors with integrated processing feedback

Template-free 3D printing of electronic devices has the potential to broaden electronics integration to include complex integrated form factors, but success requires precise, adaptive control over materials processing. The development of such manufacturing technologies requires exploration of new combinations of ink sets, printing techniques, and automation strategies. In this work, solution-cast direct-write (SC-DW) was used to print poly(methyl methacrylate) (PMMA) dielectric films with breakdown fields of 790 V/μm, similar to commercially available biaxial-oriented polypropylene (BOPP) films. Furthermore, a complementary composite ink for printing conductive features was developed with conductivities of ˜10,000 Scm-1. A closed-loop feedback system that links deposition parameters with characterization was necessary to maintain μm-precision deposition for over 20 h without human involvement. This closed-loop control scheme enabled 3D printing of both single- and double-layer high-voltage capacitors with capacitances as large as 314 pF (at 1 kHz) and breakdown voltages over 1000 V, which is significant step towards repeatable template-free, 3D printing of electronics for rapid prototyping of multifunctional devices. The precise control over low minimum feature dimension, high breakdown voltage, and long print duration enables the exploration of a broader range of printed electronics application than conventional 3D printing techniques.

PVP-Mediated Galvanic Replacement Synthesis of Smart Elliptic Cu–Ag Nanoflakes for Electrically Conductive Pastes

Elliptic Cu-Ag nanoflakes were syntheszied via facile in situ galvanic replacement between prepared Cu particles and Ag ions. Alloy nanoflakes with high purity and uniformity present a size of 700 × 500 nm, with a thinness of 30 nm. Nontoxic and low-cost polyvinyl pyrrolidone was used as a dispersant and structure-directing agent, promoting the formation of the remarkable structure. Synthesized nanoflakes were utilized as a filler for conductive paste in an epoxy resin matrix. Conductive patterns on flexible substrates with a resistivity of 3.75 × 10-5 Ω·cm could be achieved after curing at 150 °C for 2 h. Compared with traditional silver microflakes, smart alloy nanoflakes provide much improved conductive interconnection, whose advantage could be attributed to their nanoscale thicknesses. It is also noteworthy that the conductive patterns are able to tolerate multiple bendings at different angles, having good conductivity even after 200 repeated bendings. Therefore, alloy nanoflakes could be a promising candidate conductive filler for flexible printing electronics, electronic packaging, and other conductive applications.

Focus on analytical equipment, sensors, and instrumentation

Focus on analytical equipment, sensors, and instrumentation

Emission inventory of anthropogenic air pollutant sources and characteristics of VOCs species in Sichuan Province, China

The purpose of this paper is to develop an emission inventory of anthropogenic air pollutants and VOCs species in Sichuan Province. Based on the anthropogenic source activity data collected in different cities of Sichuan Province and the selected emission factors, the 1 km × 1 km gridded atmospheric air pollutant emission inventory of 2015 was developed in the “bottom-up” and “top-down” approaches with the GIS technology. The results showed that the emissions of SO2, NOX, CO, PM10, PM2.5, BC, OC, VOCs and NH3 from anthropogenic sources in Sichuan Province were 444.9 kt, 820.0 kt, 3773.1 kt, 1371.6 kt, 537.5 kt, 28.7 kt, 53.1 kt, 923.6 kt and 988.0 kt, respectively. Power plants and other industrial combustion boilers contributed more than 95% of SO2 emission. Transportation, fossil fuel burning and industrial process contributed 54%, 23% and 20% of NOx emission respectively. Industrial process dominated by steel production and building material manufacturing contributed 20% of PM10 emission and 34% of PM2.5 emission. Fugitive dust dominated by road fugitive dust contributed 60% of PM10 emission and 35% of PM2.5 emission respectively. Biomass burning contributed 33% of BC emission and 51% of OC emission respectively. Solvent use of mechanical processing, building decoration, electronic equipment manufacturing, printing and furniture industry contributed 46% of VOCs emission. NH3 mainly came from the emission of agricultural sectors, such as livestock breeding and N-fertilizer application, which contributed 70% and 25% of NH3 emission respectively. The percentage of alkanes, alkenes, alkynes, aromatics, OVOCs, halohydrocarbons and other VOCs in the total VOCs emission were 17%, 9%, 2%, 23%, 22%, 4% and 23%, respectively. Ethene, m-xylene, toluene, propene, formaldehyde, o-xylene, 1, 2, 4-trimethyl benzene, 1-butene, p-xylene and ethyl benzene were the most critical chemical species for the formation of ozone pollution in Sichuan Province contributing 50% of the total OFP. Various air pollutants and OFP were mainly distributed in places with the densest population and well-developed agriculture and industry in Sichuan Basin and some areas of Panzhihua. The Chengdu Plain urban agglomerations, represented by Chengdu, Deyang and Mianyang, were the main areas with concentrated pollutant emissions in Sichuan Basin.

Stabilization of a Highly Concentrated Colloidal Suspension of Pristine Metallic Nanoparticles

A colloidal suspension containing a high concentration of metallic nanoparticles (NPs) finds potential applications in flexible electronic printing, nanofluids, healthcare, antifouling coating, and so on. Here, we demonstrate a generic, easily scalable, simple, and contamination-free cryogenic temperature grinding method, which can effectively be used to prepare pristine NPs that can be stabilized in polar liquids in high concentrations. These surfactant-free pristine NPs have been found to remain dispersed in different polar liquids (CH3OH, C2H5OH, glycol, etc.) for weeks. The long-term stability of the NPs in these liquids has been investigated using zeta potential, in situ Fourier transform infrared spectroscopy, indicating electrostatic stabilization for ultrapure, surfactant-free NPs. Furthermore, stabilization of the NPs has been probed with detailed calculations using the Derjaguin Landau Verwey Overbeek theory as well as atomistic molecular dynamics simulation (MD). Experimental measurements along with theoretical calculations categorically indicate that the electrostatic energy is helping these NPs to be stabilized in a polar liquid.

Stimuli-Responsive Conductive Nanocomposite Hydrogels with High Stretchability, Self-Healing, Adhesiveness, and 3D Printability for Human Motion Sensing.

Self-healing, adhesive conductive hydrogels are of great significance in wearable electronic devices, flexible printable electronics, and tissue engineering scaffolds. However, designing self-healing hydrogels with multifunctional properties such as high conductivity, excellent mechanical property, and high sensitivity remains a challenge. In this work, the conductive self-healing nanocomposite hydrogels based on nanoclay (laponite), multiwalled carbon nanotubes (CNTs), and N-isopropyl acrylamide are presented. The presented nanocomposite hydrogels displayed good electrical conductivity, rapid self-healing and adhesive properties, flexible and stretchable mechanical properties, and high sensitivity to near-infrared light and temperature. These excellent properties of the hydrogels are demonstrated by the three-dimensional (3D) bulky pressure-dependent device, human activity monitoring device, and 3D printed gridding scaffolds. Good cytocompatibility of the conductive hydrogels was also evaluated with L929 fibroblast cells. These nanocomposite hydrogels have great potential for applications in stimuli-responsive electrical devices, wearable electronics, and so on.

PENGARUH PROMSI DAN ATRIBUT PRODUK TERHADAP KEPUTUSAN PEMBELIAN SEPATU SNEAKERS (Studi pada konsumen Bjo SneakersMind di Kota Malang)

This study aims to examine the effect of promotion and product attributes (consisting of brand, product quality, product features, product design, labels, warranties, and complementary services) to consumers' buying decisions as sneakers Bjo SneakersMind in Malang. Analytical techniques used are multiple linear regression analysis and classical assumption test. From the data collected by using the questionnaire (questionnaire) with the number of samples of 100 respondents. The results show that promotion (through electronic media, print media, and personal sales) and product attributes (consisting of brand, product quality, product features, product design, labels, guarantee and complementary services) have a positive and significant effect on purchasing decisions Sneakers on Bjo SneakersMind consumers.

Compulsory Childhood Vaccination in Malaysia: Public Health versus Parental Autonomy

Background: Following the death of two unvaccinated siblings, eleven months and two years old of diphtheria in June 2016, the Ministry of Health Malaysia is now emphasizing the need to enforce compulsory childhood vaccination in Malaysia. Vaccination is the main health intervention to reduce child mortality. Despite the success of vaccination, there has been an increase in the number of vaccine hesitancy, especially among parents. Research has identified many factors associated with parental vaccine refusal and hesitancy toward childhood vaccination, which varies from religious, medical as well as personal belief factors. This complicates matters as childhood vaccination involves a balance between parents’ autonomy in deciding whether to vaccinate their children and the benefits to public health. Between parental autonomy in deciding to vaccinate their children and the benefits of vaccination to public health, which will prevail? Objective: This paper seeks to examine the ethical issues of enforcing compulsory vaccination for children in Malaysia. Results: if Malaysia were to come up with a legal framework of compulsory childhood vaccination, reference can be made to the legislated statutes in other countries, taking into account that some provisions such as exemptions to vaccination may be modified to suit it with Malaysian local circumstances and inhabitants. Conclusion: In improving health communication, aside from two way communications between parents and health officers, many other communication tools are also available. They include mass electronic media, digital media, print media, social mobilization and mobile technology.

Laser Sintering of Zn Microparticles and Its Application in Printable Biodegradable Electronics

AbstractThe rapid expansion of electronic technology and short lifespan of consumer devices create a huge amount of electronic waste. The disposal of discarded devices represents a serious environmental challenge. Biodegradable devices are able to decompose into benign components after a period of stable operation during its service life, which represents a potential solution to reduce the environmental footprint of electronic technology. The widespread applications of biodegradable electronics are still hampered by the lack of facile manufacturing approach for high quality devices. Here, a laser sintering technique to weld naturally oxidized Zn microparticles into biodegradable conductors is reported. The sintering process is carried out under ambient conditions and compatible with various biodegradable substrates. A low‐cost fabrication procedure involving stencil printing and laser treatment is established to create conductive features with excellent conductivity and mechanical durability. The practical suitability of printed Zn conductor is demonstrated by fabricating near‐field communication tags, which are flexible and fully functional with the transient behavior modulated by the choice of packaging materials. The printed biodegradable conductor may find potential applications in eco‐friendly sensors, transient printed circuit boards, and implantable medical devices.

Graphene Printed Electronics

Scientists develop low cost method to produce graphene printed electronics