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Printing techniques have been extensively studied as a promising route towards large-scale, low-cost and high-throughput manufacturing process for electronic devices. With the recently emerging applications in wearable electronics and customizable conformal electronics, it calls for the necessity to develop printed electronics that function on complex, 3D nonplanar architectures. In this study, aerosol printing and flash sintering of conformal conductors on nonplanar surfaces are demonstrated. Various printed patterns are fabricated by aerosol printing of conductive ink by copper nanoparticles (Cu NPs) on both planar and nonplanar surfaces. Pulsed flash light introduces rapid sintering of the printed Cu patterns in the ambient environment. For the nonplanar patterns, a back reflector is utilized to improve the uniformity of sintering. As a result, highly conductive customizable nonplanar Cu patterns with conductivity at 10%–12% of that of bulk Cu are obtained. Effects of different sintering conditions, including sintering voltage and mounting distance on the conductivity of sintered patterns are studied. For nonplanar patterns, conductivity values at different localized spots on the nonplanar rod are also investigated to evaluate the uniformity of nonplanar sintering. The processes of aerosol printing and flash sintering have provided a facile manufacturing route for conformal conductors on arbitrary nonplanar objects.

Fabrication of electronic devices on different flexible substrates is an area of significant interest due to low cost, ease of fabrication, and manufacturing at ambient conditions over large areas. Over the time, a number of printing technologies have been developed to fabricate a wide range of electronic devices on nonconventional substrates according to the targeted applications. As an increasing interest of electronic industry in printed electronics, further expansion of printed technologies is expected in near future to meet the challenges of the field in terms of scalability, yield, and diversity and biocompatibility. This chapter presents a comprehensive review of various printing electronic technologies commonly used in the fabrication of electronic devices, circuits, and systems. The different printing techniques based on contact/noncontact approach of the printing tools with the target substrates have been explored. These techniques are assessed on the basis of ease of operation, printing resolutions, processability of materials, and ease of optimization of printed structures. The various technical challenges in printing techniques, their solutions with possible alternatives, and the potential research directions are highlighted. The latest developments in assembling various printing tools for enabling high speed and batch manufacturing through roll-to-roll systems are also explored. Other information Published in: Hybrid Nanomaterials - Flexible Electronics Materials License: https://creativecommons.org/licenses/by/3.0/legalcode See chapter on publisher's website: http://dx.doi.org/10.5772/intechopen.89377

Printed electronics is an emerging research field and is going to play a vital role in our everyday-life in the near future. Luminescent printed electronic devices can be very thin and flexible, which makes them feasible for new applications. Such EL-devices are already being applied in automobiles. For the school-implementation of printed electronics the authors have developed a flexible EL-device, which can be hand-printed using low-cost materials and methods.

The enabling electrohydrodynamic (EHD) printing technology in a one-step forming, continuous, and controllable manner has gained wide attention in the field of flexible printed electronics. The evaporation characteristic of ink solvent during the EHD printing greatly affects the shape of the jet as well as the penetration and diffusion of inks on fabrics, which is crucial to the formation of high-quality printed electronics. However, few works have deeply investigated the control of ink solvent evaporation to adjust the formability of EHD printing electronics on rough and porous textiles. Here, conductive inks with different solvent evaporation rates are formulated. The effect of solvent evaporation on the motion of inks is evaluated by the contact angle over time. Furthermore, the morphology and electrical properties under different deformation of EHD-printed conductive lines are observed and measured. The results show that the morphology of conductive lines printed on fabric could be accurately controlled by the ratios of the solvent in inks, and the solvent evaporation rate has a significant inverse-parabolic effect on electrical resistance and its stability under deformation. Moreover, the serviceability of the optimal ink is demonstrated by the performance of an EHD-printed antenna for ultra-high frequency radio frequency identification tags, and its maximum reading range is 9.1 m under typical application examples. These findings will provide a guide for ink formulation and process control of EHD printing in flexible textile-based electronics.

The use of hydrogen as a clean and renewable energy source is increasing rapidly for both vehicle and stationary applications. There are safety concerns for the locations in which hydrogen is made, used, and transported (i.e., pipelines and tanker trucks). Sensors are needed to comply with safety regulations and to enable a smooth and safe rollout of hydrogen as an alternative energy. However, hydrogen sensors do not yet exist that have the combined features of small size and low power for easy deployment coupled with high-volume manufacturability and low cost. This is necessary to accommodate the emerging fixed and mobile markets while retaining critical metrological metrics, including measurement range, detection limits, selectivity, fast response, stability, and long lifetime. An amperometric gas sensor for hydrogen (AGS) has been developed using an innovative manufacturing method. The sensor was designed using scalable fabrication strategies based on “Printed Electronics” (PE) methodology which are compatible with large-scale production. Prototype sensors were batch fabricated with multiple individual elements on a substrate compatible in size with a standard 8-inch wafer to enable high-volume, low-cost manufacturing, thereby leveraging PE and semiconductor fabrication infrastructure. This novel AGS was instrumented with control circuitry and evaluated for hydrogen detection in the range of 0–5000 ppmv H2 in air. Specific performance evaluations included assessment of the sensor measurement range, repeatability, and selectivity.

A new direction in 3D printing was investigated – prototyping of single-sided, double-sided and multilayer printed circuit boards. The current capabilities and limitations of 3D printed circuit board printing technology were identified. A comparative analysis of the characteristics of two desktop 3D printers presented in the industry for prototyping radio electronics, as well as the first professional machine DragonFly LDM 2020, which is a mini-factory for prototyping multilayer printed circuit boards, was carried out. The first practical experience of working and printing on DragonFly LDM 2020 supplied to the megalaboratory “3D prototyping and control of multilayer printed circuit boards” of the Institute of Radio Engineering and Telecommunication Systems MIREA – Russian Technological University is presented. The first samples of electronic boards printed on a 3D printer by the method of inkjet printing were obtained. An additive technology for the production of multilayer printed circuit boards is considered: printing with two printheads with conductive and dielectric nano-ink with two curing systems: an infrared sintering system for conductive ink and a UV curing system for dielectric ink. The LDM (Dragonfly Lights-out Digital Manufacturing) production method with the necessary maintenance is presented. The method allows the system to work roundthe-clock with minimal human intervention, significantly increasing the productivity of 3D printing and expanding the possibilities of prototyping. The materials used for 3D printing of multilayer printed circuit boards and their characteristics were investigated: dielectric acrylate nano-ink (Dielectric Ink 1092 – Dielectric UV Curable Acrylates Ink), conducting ink with silver nanoparticles (AgCite™ 90072 Silver Nanoparticle Conductive Ink). The research carried out allows us to compare the technological standards of printed electronics with traditional methods of manufacturing multilayer printed circuit boards for a number of parameters.

The flashlight annealing process has been widely used in the field of flexible and printed electronics because it can instantly induce chemical and structural modifications over a large area on an electronic functional layer in a subsecond time range. In this study, for the first time, we explored a straightforward method to develop strong self-adhesion on a metal nanowire-based flexible and transparent conductive film via flashlight irradiation. Nanowire interlocking, for strong mechanical bonding at the interface between the nanowires and polyamide film, was achieved by simple hot pressing. Then, by irradiating the nanowire-impregnated film with a flashlight, several events such as interdiffusion and melting of surface polymers could be induced along with morphological changes leading to an increase in the film surface area. As a result, the surface of the fabricated film exhibited strong interfacial interactions while forming intimate contact with the heterogeneous surfaces of other objects, thereby becoming strongly self-adhesive. This readily achievable, self-attachable, flexible, and transparent electrode allowed the self-interconnection of a light-emitting diode chip, and it was also compatible for various applications, such as defogging windows and transparent organic light-emitting diodes.

Highlights Fully inkjet-printed transparent high-performance thin-film transistors (TFTs) with ultrathin indium tin oxide (ITO) as semiconducting channels were achieved. The energy band alignment at ITO/Al2O3 channel/dielectric interface was investigated by in-depth spectroscopy analysis. Fully printed n-type metal–oxide–semiconductor inverters based on ITO TFTs exhibited extremely high gain of 181 at a low-supply voltage of 3 V, promising for applications in advanced electronic devices and circuits. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00694-4., Metal oxide thin-films transistors (TFTs) produced from solution-based printing techniques can lead to large-area electronics with low cost. However, the performance of current printed devices is inferior to those from vacuum-based methods due to poor film uniformity induced by the “coffee-ring” effect. Here, we report a novel approach to print high-performance indium tin oxide (ITO)-based TFTs and logic inverters by taking advantage of such notorious effect. ITO has high electrical conductivity and is generally used as an electrode material. However, by reducing the film thickness down to nanometers scale, the carrier concentration of ITO can be effectively reduced to enable new applications as active channels in transistors. The ultrathin (~10-nm-thick) ITO film in the center of the coffee-ring worked as semiconducting channels, while the thick ITO ridges (>18-nm-thick) served as the contact electrodes. The fully inkjet-printed ITO TFTs exhibited a high saturation mobility of 34.9 cm2 V−1 s−1 and a low subthreshold swing of 105 mV dec−1. In addition, the devices exhibited excellent electrical stability under positive bias illumination stress (PBIS, ΔVth = 0.31 V) and negative bias illuminaiton stress (NBIS, ΔVth = −0.29 V) after 10,000 s voltage bias tests. More remarkably, fully printed n-type metal–oxide–semiconductor (NMOS) inverter based on ITO TFTs exhibited an extremely high gain of 181 at a low-supply voltage of 3 V, promising for advanced electronics applications. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-021-00694-4.

Low-frequency noise is a critical characteristic of transistors, but there are only a few experimental works on the noise in printed electronics. In this work, we characterize the low-frequency noise of inkjet-printed electrolyte-gated thin-film transistors (EGTs) with indium-oxide semiconductors. We confirm that the carrier number fluctuation with correlated mobility fluctuation is the dominating noise generation mechanism. Also, we present the benchmark analysis on the noise level of various thin-film technologies. Notably, the extracted value of trap density near the insulator-channel interface is high, indicating an inferior quality of solution-processed and inkjet-printed thin-films. However, because of electrolyte-gating, the large areal gate capacitance compensates the negative effect of the high trap density, effectively reducing the flat-band voltage noise. As a result, the normalized drain current noise is considerably lower than solution-processed transistors and comparable with sputtered inorganic transistors with dielectric gating. This renders the electrolyte-gating approach useful in reducing the noise for printed/solution-based transistors, suitable for low-noise applications.

Inkjet printing has proven to be a promising alternative method in the fabrication of printed electronics, besides screen printing and photolithography etching. In this work, we characterize the electrical performance of inkjet printed circuits on flexible PET and glossy photo paper. The electrical circuits were printed using a commercial Epson L310 piezoelectric printer, and the NB series silver ink and chemical-sintering PET substrate from Mitsubishi Paper Mills. This method allows rapid prototyping of electronic circuits (~ 30 min design, ~ 5 s fabrication) and quick iteration of prototypes. The system has a resolution of 250 µm electrodes and 300 µm electrical gaps, and on average, 1.5 ± 0.2 µm in thickness. The effect of printing on different substrates, geometry and overprinting on sheet resistance was also studied. It was found that double printing produced better electrodes with lower resistances. A stable conducting circuit has a sheet resistivity of

This article deals with the problem of printing current-conducting circuits on various substrates. The article provides an overview of modern technologies for solving this problem. The author describes a hybrid laser system that solves the problem under consideration. This device uses modern technologies and materials that show good results in research. A brief description of the software for preparing data for this system is also provided.

Here, we report a previously unreported low-temperature curable barium strontium titanate (BaXSr1−XTiO3) or BST dielectric nanoparticle ink which shows a high dielectric tunability for printed electronics/additive manufacturing applications. The newly formulated BST ink is optimized to print in aerosol jet printers and can be cured at 150°C, which will allow the fabrication of tunable radio-frequency (RF) and microwave (MW) devices on a wide range of flexible substrates. Characterization of high-frequency dielectric properties showed a high dielectric tunability (~ 15% at 10 GHz with 10 V/µm) and a high dielectric constant (~ 16 at 10 GHz). The linear-reversible tunability, which is very important for tunable devices, was confirmed by the tunability testing at 10 GHz. Characterization of temperature-dependent dielectric properties found < 10% variations of the dielectric constant at 10 GHz from −50°C to 125°C for this BST ink. Detailed information on BST nanoparticle characterization, ink formulation and characterization of dielectric properties is discussed.

Printed electronics employing flexible substrate offers prospective features for various applications such as, tactile sensing, energy harvesting, wearable electronics and acoustic wave sensors. In this work, an acoustic FPW (flexural plate wave) sensor is printed on thin and flexible PZT-PDMS (lead zirconate titanate-poly dimethyl siloxane) composite film with silver ink. The prototype FPW resonator has a resonant frequency of 22.65 MHz with an attenuation of −1.552 dBm. Gravimetric mass sensitivity of the sensor was measured by applying PDMS layers in between the input and output interdigital transducers (IDTs). The mass sensitivity was measured to be −7.8 cm2/g. The sensor is highly responsive to VOCs (volatile organic compounds) with PDMS as a sensing layer. Gas sensitivities with acetic acid and toluene concentrations were measured to be 0.66 and 160.63 kHz/ppm, respectively. The limit of detection for acetic acid and toluene were 10.9 and 0.03 ppm, respectively. Further, the sensor shows good repeatability and response time with both the VOCs. The thermal stability and high piezoelectric charge coefficient of PZT-PDMS composite compared to other piezoelectric composite and polymer substrates are advantageous for the flexible printed sensor. The reported FPW gas sensor shows potential for low concentration measurement of VOCs.

Made available in DSpace on 2021-06-25T10:27:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-06-01 Wireless communication employing radio-frequency identification (RFID) tags is progressively more widespread in a variety of industrial and commercial sectors. Aspects as demanding specific needs regarding reading distance, production cost, and processability are requested for commercial applications. Nowadays, printing of optical barcodes is the most economically technology for short distance (up to ~30 cm) reading applications. However, the large-scale and low-cost printing of RFID tags would be a competitive alternative to barcode technology because it allows quicker identification with much less reading errors. Here we demonstrate a semi-transparent, screen printed RFID antennas using a non-metallic and environmentally friendly conductive paste. The variation of the film thickness (from 2.5 up to 15 µm) permitted the fabrication of antennas with reading range (0.84–3.29 m), sheet resistance (6.2–36 Ω/sq), and optical transmittance (0–32.3%), which are compatible to commercial or industrial applications aiming short to moderate reading distances. Indústria de Tintas Condutivas TICON Flextronics Instituto de Tecnologia (FIT) Institute of Geosciences and Exact Sciences Department of Physics São Paulo State University (Unesp) Institute of Geosciences and Exact Sciences Department of Physics São Paulo State University (Unesp)

Successful precision agriculture decision making requires characterizing soil heterogeneity at high spatiotemporal resolution in real-time in order to optimize input (such as water and nutrient) amounts and location. In order to achieve this goal, a printed soil moisture sensor fabricated from biodegradable materials is demonstrated. These devices are intended to function during the growing season and then harmlessly degrade afterward, enabling high-density deployment, eliminating the need for sensor retrieval, and enabling the use of simple device structures and low-cost materials and fabrication techniques. A capacitive structure is used with a water-soluble zinc electrode printed onto a biodegradable substrate. Rapidly degrading substrate and electrode are encapsulated in a slowly degrading wax blend that protects the device, reduces drift, and controls degradation time. A linear capacitance response is observed for soil samples with a volumetric water content from 0 to 72%. Accelerated degradation testing demonstrates that the sensor responds predictably and stably until the encapsulation is breached, at which point the sensor fails rapidly, providing a clear distinction between the functional and nonfunctional lifetimes of the sensor. These results demonstrate the potential of biodegradable sensors to allow maintenance-free, affordable, and real-time soil moisture measurement at high spatial density for precision irrigation control.

The new ink feed unit (IFU) developed and installed based on the serial model of Anycubic I3 Mega 3D printer. The developed unit can be easily integrated into the control system of the printer by connecting the control line of the standard step motor responsible for supplying the plastic wire. The minimum volume 0.3 mm3 ink drops were reached using the syringe with an inner diameter of 10 mm and the volume can be reduced to 0.01 mm3 by using the syringe with 2 mm diameter. The tracks of various widths were printed using needles of different diameters and the 0.5% aqueous colloidal solution of carbon nanotubes (CNTs) in 1 wt% of polyvinyl alcohol (PVA) ink was used. The electrical resistivity values of the printed tracks were obtained on a 5 mm section by the standard four-probe method, and they were within 0.040–0.008 Oh m−1.

Many researchers claim that graphene, a specially studied carbon allotrope, has a single layer of atoms organized in a two-dimensional honeycomb lattice. Because of its exceptional electronic and mechanical properties, it has a significant job to perform in redefining future technologies. Although graphene has made a major breakthrough to be considered for a wide area of applications, most of the interesting properties of graphene are still at the early stage of research. Graphene dependent attenuators and single and multi-frequency constructible antennas are designed employing the tunability of graphene. As the name indicates, the form of RF technology that uses electromagnetic fields for automatic identification purposes of tags attached to objects is termed as radio frequency identification (RFID). For years, the use of pricy raw materials and intricate fabrication processes in metal coating and metal based conductive inks in printed electronics kept the involved cost very high. So, it is inevitable to replace the existing fabrication process with cheaper materials and simpler techniques. Researchers assert that printed graphene has the potential to be a competent alternative for RFID applications.

Hybrid structural electronics (HSE) consists of printed electronics, conventional rigid electronics, and load-bearing supporting parts of a device (plastic, glass etc.). Extra-large area and flexible lighting elements with embedded light-emitting diodes (LEDs) are an example of such applications. LEDs can be used, for example, as light sources, to create smart surfaces for the architectural or automotive industry. Once the LEDs are embedded into the structure, they cannot be replaced. To make sustainable HSE products with long lifetime, the new type of designs is needed. The elements of HSE undergo conditions with elevated thermal stresses while in operation. That is known to have an impact on their performance and lifetime, thus making a proper heat management of the LED crucial. Due to the novel additive manufacturing methods, structures, and unconventional material combinations, many thermal management related aspects are not known. In this study, a two-step hybrid method, including thermal modeling and measurements, is used to estimate the thermal behavior of a surface-mounted LED on polymer substrate used in HSE. The model is created and simulated in COMSOL Multiphysics. The validity and accuracy of the model’s thermal behavior are verified through measurements with thermal transient measurements. Based on the experimental verification, the proposed simulation model only has small (less than 2%) temperature variations when compared with measurements. Hence, the developed model can be used as a basis for designing structural LED elements and predicting their performance characteristics in different user cases.

The innate capability of direct heat–electricity conversion endows thermoelectric (TE) materials with great application potential in the fields of low-grade heat harvesting, solid-state cooling, and sensing. Recently, the rapid development of information technology such as the Internet of Things and the popularization of wearable electronic devices have stimulated a period of prosperity for the research on flexible thermoelectric (FTE) devices. At the same time, the research on printed electronics (PEs) is expected to provide scalable and cost-effective manufacturing approaches for FTE devices. This review focuses on the recent progress in printed flexible thermoelectric (PFTE) devices and their applications. At first, the fundamental theories behind TEs and the related performance optimization strategies for FTE devices, as well as the history and applications of PEs, are introduced. Then, the state-of-the-art materials adopted in FTE devices, including materials for TE legs, solvents, dispersants, surfactants, and adhesives for printable inks/pastes, substrates, and electrodes, and the related printing methods are summarized. Subsequently, the applications and device performance of PFTE devices in thermoelectric generators (TEGs), thermoelectric coolers (TECs) and thermoelectric sensors (TESs) over the last decade are reviewed. At last, the challenges existing currently in the PFTE field are discussed and some perspectives on the future investigations toward high-performance, low-cost PFTE devices are proposed.

This work investigated the photophysical pathways for light absorption, charge generation, and charge separation in donor–acceptor nanoparticle blends of poly(3-hexylthiophene) and indene-C60-bisadduct. Optical modeling combined with steady-state and time-resolved optoelectronic characterization revealed that the nanoparticle blends experience a photocurrent limited to 60% of a bulk solution mixture. This discrepancy resulted from imperfect free charge generation inside the nanoparticles. High-resolution transmission electron microscopy and chemically resolved X-ray mapping showed that enhanced miscibility of materials did improve the donor–acceptor blending at the center of the nanoparticles; however, a residual shell of almost pure donor still restricted energy generation from these nanoparticles.

Evaporative self-assembly of semiconducting polymers is a low-cost route to fabricating micrometer and nanoscale features for use in organic and flexible electronic devices. However, in most cases, rate is limited by the kinetics of solvent evaporation, and it is challenging to achieve uniformity over length- and time-scales that are compelling for manufacturing scale-up. In this study, we report high-throughput, continuous printing of poly(3-hexylthiophene) (P3HT) by a modified doctor blading technique with oscillatory meniscus motion-meniscus-oscillated self-assembly (MOSA), which forms P3HT features ∼100 times faster than previously reported techniques. The meniscus is pinned to a roller, and the oscillatory meniscus motion of the roller generates repetitive cycles of contact-line formation and subsequent slip. The printed P3HT lines demonstrate reproducible and tailorable structures: nanometer scale thickness, micrometer scale width, submillimeter pattern intervals, and millimeter-to-centimeter scale coverage with highly defined boundaries. The line width as well as interval of P3HT patterns can be independently controlled by varying the polymer concentration levels and the rotation rate of the roller. Furthermore, grazing incidence wide-angle X-ray scattering (GIWAXS) reveals that this dynamic meniscus control technique dramatically enhances the crystallinity of P3HT. The MOSA process can potentially be applied to other geometries, and to a wide range of solution-based precursors, and therefore will develop for practical applications in printed electronics.

Gravure printing is known to be cost competitive in manufacturing of printed electronic devices due to its capability to mass produce at lower costs. Current standard of gravure printed feature sizes is in a range of around 50 μm down to sub-10 μm, predominantly through small scale setups and specialized engraving. However, reliance on gravure cell design limits the scalability of printing over a large area due to the setup cost. In this study, ink viscoelastic behavior was modified to improve replication of gravure printed features over a large printing area of 300 mm web-width without a reduction in gravure cell dimension. Fine lines were printed using a high viscosity ink with a good replication of the nominal line width. Control over the printed features was performed through the variation of printing speed and the alteration of ink viscosity. The effects of ink viscosity and printing speed on the printed ink particle distribution and size were also examined. New methodologies of characterizing ink transfer were also developed to help understand the ink transfer processes: mass transfer and particle transfer. A deeper understanding of the thixotropic effect and shear recovery behavior of inks was achieved through simulations of shearing conditions.

The conductivity of screen printing films at microwave frequency is one of the most important properties of conductive ink when applied in printed electronics. However, the existing methods of conductivity characterization at microwave frequency focus on homogeneous metal films or semiconductors, which are not suitable for conductive composite materials with poor thickness uniformity, like screen printing films. In this research, by applying a classic stripline ring resonator, a rigorous electromagnetic model was set up, and the conductivity of the screen printing film was able to be deduced by comparison between the measurement and simulation results. As a result, the equivalent conductivity of the film is 2 × 106 S/m at 1–3 GHz, which is a little higher than its average direct current conductivity of 1.82 × 106 S/m. This method has been proved to be feasible in measuring the conductivity of screen printing films at microwave frequency. Furthermore, it has great potential in the characterization of other printed conductive composite materials on rough surfaces, like textiles.

Printed electronics (PE) enables disruptive applications in wearables, smart sensors, and healthcare since it provides mechanical flexibility, low cost, and on-demand fabrication. The progress in PE raises trust issues in the supply chain and vulnerability to reverse engineering (RE) attacks. Recently, RE attacks on PE circuits have been successfully performed, pointing out the need for countermeasures against RE, such as camouflaging. In this article, we propose a printed camouflaged logic cell that can be inserted into PE circuits to thwart RE. The proposed cell is based on three components achieved by changing the fabrication process that exploits the additive manufacturing feature of PE. These components are optically look-alike, while their electrical behaviors are different, functioning as a transistor, short, and open. The properties of the proposed cell and standard PE cells are compared in terms of voltage swing, delay, power consumption, and area. Moreover, the proposed camouflaged cell is fabricated and characterized to prove its functionality. Furthermore, numerous camouflaged components are fabricated, and their (in)distinguishability is assessed to validate their optical similarities based on the recent RE attacks on PE. The results show that the proposed cell is a promising candidate to be utilized in camouflaging PE circuits with negligible overhead.

In printed electronics, coating is a key process used not only in the fabrication of solar cell and organic light-emitting diodes but also in display devices. For this purpose, coating devices are designed with several unique characteristics. In particular, slot die coaters and inkjet coaters are advantageous in terms of high-quality morphology and a small dispensing area, respectively. This study proposes a slot die with a narrow-width coating as a fusion device derived from a slot die coater and an inkjet printer. This device is termed a micro-slot die and comprises a micro pump and a narrow-width slot. The device was designed and assembled with appropriate consideration of both dynamic and fluid motions. Consequently, the fabricated device achieves a high-quality coating suitable for application in the display industry. The proposed device is expected to be used in laboratory-scale research applications that require a minimal coating of ink.

Solar cells are critical source of energy and very needed nowadays, the use of solar photovoltaic to generate electricity in terms of solar parks and solar panels on rooftops is growing, those devices that converts sunlight into heat to generate power has achieved greater efficiency than pervious such devices, inkjet solar cells uses now to alternate the pervious types of energy with a clean and cheap one’ and flexibility of use, for that nations become very immersive and involved in new technologies can produce it in a quality models, by using a new features of digital printing . The research methodology is the descriptive approach, which is based on describing the innovative techniques used in fabrication of organic solar cells and factors affecting the production process, to increase its productivity, also to study the effect of using it on several organic material with the ability to produce it in new freedom designs that could allow creating solar cells on blinds, in windows, curtains, shade umbrellas, tents and almost everywhere in or outside home.

CuInSe2 nanocrystals offer promise for optoelectronics including thin-film photovoltaics and printed electronics. Additive manufacturing methods such as photonic curing controllably sinter particle...

E-jet is a novel microfabrication technology of producing high-resolution patterns for various application areas like printed electronics, biotechnology, etc. Judicious selection of the operating scenario can improve the quality of the fabrication performance of E-jet. The objective of this study is to experimentally evaluate different operating scenarios of the E-jet microfabrication process while considering the deposited droplet diameter and droplet ejection frequency as performance characteristics simultaneously. Experimentations were carried out on the developed E-jet setup according to the design of experiment technique considering nozzle stand-off height, applied voltage, and ink flow rate as process control parameters. The effect of each control parameter on the process response is investigated. The relative weight values of each performance characteristic or response variable are determined by principal component analysis, which makes the weight evaluation procedure more rigorous and eliminates the dependence on the practitioner’s judgment. A hybrid grey relational grade analysis and technique for order preference by similarity to ideal solution methodology is employed to evaluate the optimal operating scenario of E-jet. Both methodologies indicated a similar desirable operating condition for E-jet. Moreover, the variance study called analysis of variance is employed to discover the pattern in which the control parameters affect the fabrication process. The variance study suggests that the ink flow rate is the most dominant parameter in the experimental domain.

Flexible and printed electronics are attracting considerable attention since they offer new capabilities that are not possible with conventional rigid substrates. Carbon nanotubes (CNTs) were used here to develop a sensor to detect ultraviolet (UV) radiation. The sensors were made on various flexible substrates including polyimide (PI) films and cellulose paper, and also on glass substrate for comparison. CNT in aqueous solution with varying concentrations was drop-cast onto the active region between the electrodes for resistor type devices. An optimum CNT concentration was identified and the distribution and topographies of the nanotube networks on the substrates were investigated by scanning electron microscopy and atomic force microscopy. All the sensors respond immediately to UV on/off cycles with a change in resistance due to the ability of the nanotubes to adsorb and desorb oxygen on their surface. The sensors with the lowest concentration of CNTs (0.0005 wt.%) exhibit the best response. The sensor made on PI substrate yields the highest response at 71%. The functionality is maintained even after mechanically bending the flexible sensors 1000 times at a curvature radius of 10 mm, which is an advantage for practical applications. Electrodes were printed on the PI substrate and tested outdoor under natural sunlight. The sensor accurately detects UV radiation and could be developed for potential applications such as in wristband or sunglass.

Recent advances in nanomaterials and nano-microfabrication have enabled the development of flexible wearable electronics. However, existing manufacturing methods still rely on a multi-step, error-prone complex process that requires a costly cleanroom facility. Here, we report a new class of additive nanomanufacturing of functional materials that enables a wireless, multilayered, seamlessly interconnected, and flexible hybrid electronic system. All-printed electronics, incorporating machine learning, offers multi-class and versatile human-machine interfaces. One of the key technological advancements is the use of a functionalized conductive graphene with enhanced biocompatibility, anti-oxidation, and solderability, which allows a wireless flexible circuit. The high-aspect ratio graphene offers gel-free, high-fidelity recording of muscle activities. The performance of the printed electronics is demonstrated by using real-time control of external systems via electromyograms. Anatomical study with deep learning-embedded electrophysiology mapping allows for an optimal selection of three channels to capture all finger motions with an accuracy of about 99% for seven classes., Though wearable electronics remain an attractive technology for bioelectronics, fabrication methods that precisely print biocompatible materials for electronics are needed. Here, the authors report an additive manufacturing process that yields all-printed nanomaterial-based wireless electronics.

Advances in printed electronics (PE) enables new applications, particularly in ultra-low-cost domains. However, achieving high-throughput printing processes and manufacturing yield is one of the major challenges in the large-scale integration of PE technology. In this article, we present a programmable printed circuit based on an efficient printed lookup table (pLUT) to address these challenges by combining the advantages of the high-throughput advanced printing and maskless point-of-use final configuration printing. We propose a novel pLUT design which is more efficient in PE realization compared to existing LUT designs. The proposed pLUT design is simulated, fabricated, and programmed as different logic functions with inkjet printed conductive ink to prove that it can realize digital circuit functionality with the use of programmability features. The measurements show that the fabricated LUT design is operable at 1 V.

For the commercialization of a resistive switching memory device, many researchers are designing different memory structures for a crossbar array. In the present work, we propose a flexible Schottky diode-based resistive memory device based on a zinc oxide (ZnO) and methylene blue (MB) heterojunction. The operating voltage of the proposed memory device is ±3 V, and high-resistance state (HRS) and low-resistance state (LRS) are 20.408 GΩ and 126.795 MΩ, respectively, and the Roff/Ron ratio is ∼ 160.97 at a voltage read of −0.30 V. It shows high retention and endurance performance for more than 500 cycles and 30 days, respectively, with bending capability up to 10 mm. The proposed device can be used in flexible and printed electronics for memory and storage purposes.

Eddy current heating with synchronized thermography (ST) is utilized for the contactless characterization of flexible hybrid electronics. A proposed approach is used for analyzing the uniformity of large area electronics being the basis for the quality assurance of hybrid electronics manufacturing. Flexible polymer substrate with printed conductors, bonded conventionally manufactured light-emitting diode (LED) chips and current regulators were used as test samples. Obtained results show that ST with eddy current heating is an effective and roll-to-roll compatible measurement tool for in-situ quality monitoring of hybrid electronics manufacturing.

Electrochromic devices (ECDs) with reversible transmittance change represent a promising alternative to smart windows. However, the low−cost facile fabrication of ECDs, particularly flexible devices, remains challenging. In this study, novel NiO is synthesized by a solid state method, and the as−prepared NiO is introduced as an electrochromic anodic layer and fabricated onto a transparent conductive electrode (indium tin oxide, ITO or flexible silver nanowires, AgNW) by a sol–gel spin coating and low temperature annealing (80 °C-150 °C). The solvent, thickness of NiO, and annealing temperature are evaluated to obtain higher ECD performance. NiO/ITO ECDs exhibit very high transmittance variation (ΔT = ~84%) at 700 nm with applied potentials of −3.0 and 0 V. The stability and transmittance variation of NiO/ITO are significantly improved in the presence of a WO3 cathodic electrode at lower applied voltages of 1.5 to 0 V. The low processing temperature of 80 °C demonstrates the potential of the flexible ECDs. The flexible NiO–WO3 device achieves a transmittance variation of ~38% at 700 nm with applied potential of 2.0 and 0 V, and retains the ECD performance. The application of low−cost solution−processed NiO and NiO/WO3−based ECDs in flexible transparent conductive electrodes provides a new pathway for the fabrication of optical devices and printed electronics.

Supercapacitors are attractive due to their high power density and durability relative to batteries. Printing technology has been rapidly emerging as manufacturing friendly, with a quick turn aroun...

An all three-dimensional (3D)-printed flexible ZnO ultraviolet (UV) photodetector is demonstrated, where the 3D-printing method is used not only for the electrode and photosensitive material but also for creating a substrate. An ultraflat and flexible substrate capable of serving as the backbone layer is developed using a water-dissolvable polymer layer for surface planarization. A two-layered printing followed by surface treatment is demonstrated for the substrate preparation. As mechanical support but flexible, a thick and sparse thermoplastic polyurethane layer is printed. On its surface, a thin and dense poly(vinyl alcohol) (PVA) is then printed. A precise control of PVA reflow using a microwater droplet results in a flexible and extremely uniform substrate. A Cu-Ag nanowire network is directly 3D printed on the flexible substrate for the conducting layer, followed by ZnO for the photosensitive material. Unlike the planar two-dimensional printing that provides thin films, 3D printing allows the electrode to have a step height, which can be made like a dam to accommodate a thick film of ZnO. Photosensitivity as a function of various ZnO thickness values was investigated to establish an optimal thickness for UV response. The device was also tested in natural sunlight along with stability and reliability.

A printed flexible hybrid electronics (FHE) technology platform is described, which combines a thin-film audio speaker, printed interconnects, and printed passive components in a highly flexible system. Bimorph piezoelectric polymer speaker structures were developed and shown to give increased loudness compared with a single layer speaker, with good fidelity and easily recognizable sound. Speakers were fabricated on flexible thin polyimide substrates, which enables integration with printed electronics and other thin-film devices. Two demonstrator circuits were designed to operate the speakers and were fabricated using printed FHE techniques. One circuit was an amplifier for a portable music player, and the second provides a record and playback function using an audio integrated circuit. The fabrication of these devices included ink-jet printed interconnects and ink-jet printed resistors, which showed a good long-term stability and flexibility.

A reverse offset-printed stacked-structure complementary ring oscillator and operational amplifier (OPA) circuits were constructed on a large-area substrate. Uniform and fine electrodes were fabric...

In printed electronics, self-aligned transistors are a key technology toward scalable and low-cost electronics. However, significant misalignment between components restricts transistors to a print...

Materials exhibiting higher mobilities than conventional organic semiconducting materials such as fullerenes and fused thiophenes are in high demand for applications in printed electronics. To discover new molecules in the heteroacene family that might show improved charge mobility, a massive theoretical screen of hole conducting properties of molecules was performed by using a cloud-computing environment. Over 7 000 000 structures of fused furans, thiophenes and selenophenes were generated and 250 000 structures were randomly selected to perform density functional theory (DFT) calculations of hole reorganization energies. The lowest hole reorganization energy calculated was 0.0548 eV for a fused thioacene having 8 aromatics rings. Hole mobilities of compounds with the lowest 130 reorganization energy were further processed by applying combined DFT and molecular dynamics (MD) methods. The highest mobility calculated was 1.02 and 9.65 cm

Each year, Cu is used in more than 60% of electrical applications due to its excellent electrical, thermal, and mechanical properties. Here, we report all-printed flexible conformal electronics con...

In light of society's increasing demand for ubiquitous connectivity and high-speed communication, printed electronics could play a disruptive role in the design and manufacturing of high frequency radiofrequency (RF) passives. However, traditional ink-based printing technologies face significant challenges in their planar device geometries, limited material choices, and poor resolution (∼100 μm), which constrain the design of printable RF passives typically operatable in the kilohertz (kHz) to megahertz (MHz) frequency range. The low resolution of printing technologies also makes it challenging to integrate printed passives with lithography-manufactured active electronics to form RF circuitries with diverse wireless functionalities. Direct ink writing (DIW), on the other hand, allows the high-resolution manufacturing of three-dimensional (3D) device architectures that are critical for applications beyond the frequency of one gigahertz (GHz). However, current DIW-printed RF passives only employ a single conductive ink, which limits the passive device's performance. For example, in solenoidal inductors, the inclusion of a magnetic core would greatly enhance the per-area inductance. Here, we designed and synthesized a permalloy/PDMS magnetic nanocomposite ink by dispersing surface modified permalloy nanoparticles into a PDMS matrix. The optimal weight ratio of permalloy in PDMS was determined based on Bruggeman effective medium theory to afford a high operational frequency while maintaining high-resolution printability. By harnessing the multimaterial DIW of both a conductive silver nanoparticle ink and our new permalloy magnetic ink, we demonstrate printed solenoidal inductors and LC tanks integrating magnetic cores with enhanced inductance.