Inkjet Research Articles

A novel structure luminous flexible fiber was prepared via aerosol jet printing

Utilizing aerosol jet printing (AJP), this study achieves a breakthrough in fabricating luminescent fibers with superior optical performance and flexibility. The Y2O3:Eu3+ coated high silica glass fibers demonstrate luminous efficiency twice that of traditional methods, retaining 80% after 250 bending cycles and 90% after sweat immersion. This AJP technique not only elevates the potential of smart fabrics but also represents a significant innovation in lighting technology, providing new ideas for advanced functional fiber fabrication.

Optimized Photochromic Performance of Spiropyran through Incorporation into Hydrogen-Bonded Organic Frameworks and Applications in Anticounterfeiting and Information Encryption.

Photostimulus-responsive fluorescent materials are promising for anticounterfeiting and UV printing due to rapid response and simple preparation. In this paper, we propose a novel strategy to prepare photostimulus-responsive materials SP@HOF-olefin by integrating the photochromic molecule spiropyran (SP) with postsynthetic modified hydrogen-bonded organic frameworks (HOF-olefin). Compared to SP@HOF, the composites SP@HOF-olefin exhibit enhanced photochromic properties, such as a fast response speed, pronounced color contrast, and exceptional fatigue resistance. The improvements can be attributed to the reduction of residual carboxyl groups in the framework, which subsequently decreases the polarity of the framework. Besides, the SP loading content in SP@HOF-olefin was significantly enhanced. Furthermore, HOF-olefin can be transformed into HOF films via photopolymerization. These films demonstrated excellent flexibility, which can be folded and twisted at any angle ranging from 0 to 180°. By utilizing the photomask method, letters such as "Z", "T", "S", and "U", along with other patterns were successfully imprinted on the film. Besides, we investigated the utilization of these films in advanced anticounterfeiting applications. This work serves as a representative case demonstrating how functionalized HOFs improved the photochromic properties of SP, showcasing potential applications in anticounterfeiting and information encryption.

Study of Different Types of Printed Documents and Photocopied Documents and to Estimate the Type of Printers and Photocopiers Used

The primary goal of this study is to estimate the type of the printers and photocopiers used based on their characteristics. Thus, the total number of samples is 40 in which 15 samples from 7 models of photocopiers, 15 samples from 7 models of laser printers, 10 samples from 9 models of inkjet printers. All the samples are collected from different shops and different models in the location of kirumampakkam, Pondicherry. With the help of stereo microscope, Magnifier the sample were analysed and interpreted the class characteristics between one models to another. The borders, edges, patches, ink flow, and drum marks were shown differences in one to other samples. At the end of the study we can estimate the types of printers and photocopiers used to make the document.

A systematic approach to evaluate jetability of high-viscosity resins for 3D inkjet printing applications

Abstract Recent advances in piezo inkjet printing technology have enabled the use of high-viscosity materials previously unsuitable for inkjet applications. This technology facilitates the printing of vat photopolymerization resins, traditionally used to produce single-material components with superior properties compared to those achieved with conventional UV inks in material jetting. The ability to print these resins with piezo inkjet technology opens new fields of application for producing multimaterial functional parts. To fully exploit this potential, it is essential to evaluate the compatibility of these resins with the new technology. This study systematically evaluates the jetability, printability, and performance of high-viscosity materials to optimize the printing process and provides a detailed understanding of the factors influencing the jetability of high-viscosity resins and develops guidelines for optimizing their use in 3D inkjet printing applications.

Pneumatic conveying inkjet bioprinting for the processing of living cells

Inkjet printing techniques are often used for bioprinting purposes because of their excellent printing characteristics, such as high cell viability and low apoptotic rate, contactlessmodus operandi, commercial availability, and low cost. However, they face some disadvantages, such as the use of bioinks of low viscosity, cell damage due to shear stress caused by drop ejection and jetting velocity, as well as a narrow range of available bioinks that still challenge the inkjet printing technology. New technological solutions are required to overcome these obstacles. Pneumatic conveying printing, a new type of inkjet-based printing technique, was applied for the bioprinting of both acellular and cellular fibrin-hydrogel droplets. Drops of a bioink containing 6 × 106HEK293H cells ml-1were supplied from a sterile nozzle connected to a syringe pump and deposited on a gas stream on a fibrinogen-coated glass slide, here referred to as biopaper. Fibrinogen film is the substrate of the polymerization reaction with thrombin and Ca2+present in the bioink. The pneumatic conveying printing technique operates on a mechanism by which drop ejection and deposition in a stream of gas occurs. The percentage of unprinted and printed dead HEK293H cells was 5 ± 2% and 7 ± 4%, respectively. Thus, compared to normal handling, pneumatic conveying printing causes only little damage to the cells. The velocity of the drop approaching the biopaper surface is below 0.2 m s-1and does not cause any damage to the cells. The cell viability of printed cells was 93%, being an excellent value for inkjet printing technology. The HEK293H cells exhibited approximately a 24 h lag time of proliferation that was preceded by intense migration and aggregation. Control experiments proved that the cell migration and lag time were associated with the chemical nature of the fibrin hydrogel and not with cell stress.

Improving the light extraction efficiency of white-light perovskite light-emitting diodes based on quantum dot nanowires.

This study introduces an innovative strategy to enhance the light extraction efficiency (LEE) of white-light perovskite light-emitting diodes (PeLEDs) by incorporating quantum dot nanowires (QD-NWs) that are prepared by a porous anodic aluminum (PAA) substrate. The QD-NWs were synthesized through a combination of inkjet printing and vacuum deposition based on the PAA substrate which features a unique waveguiding structure that redirects post-color conversion fluorescence along its axis, effectively minimizing energy losses such as reabsorption loss and total internal reflection (TIR) loss. Empirical evidence indicates a significant luminance enhancement of 43.79%, accompanied by an enhancement in current efficiency, for PeLEDs incorporating the QD-NWs. By fine-tuning the structural attributes of the PAA substrate to regulate the size of QD-NWs, this research has successfully developed white-light PeLEDs based on quasi-2D blue perovskite, offering a universal strategy for boosting LEE and propelling the evolution of white-light PeLED technology.

Spray-Printed Light-Emitting Diodes with Perovskite/Polymer Composite Emitters on Various Transparent Substrates.

Advancements in printing techniques are essential for fabricating next-generation displays. Lead halide perovskites demonstrate great potential as light emitters of solution-processed light-emitting diodes (LEDs). In particular, the perovskite/polymer composite emitters exhibit exceptional luminescent characteristics, mechanical flexibility, and environmental stability due to the improved film morphologies and defect passivation achieved through the introduction of polymer additives. However, solution-based conventional processing methods, such as spin-coating, slot-die coating, and inkjet printing are limited to planar substrates. Spray printing is a promising coating process, which can be applied for depositing composite emitters across various substrate types. In this study, we employed a spray-coating process to design planar and curved perovskite LEDs (PeLEDs) by incorporating methylammonium lead bromide (MAPbBr3) and poly(vinylpyrrolidone) (PVP) composite-based emitters. PVP played a critical role in enhancing the MAPbBr3 morphology through a strong coordination between Pb2+ ions and lone pair electrons in the PVP chains. Under optimized conditions of air pressure, spray time, and PVP concentration, the planar PeLEDs achieved a maximum luminance (Lmax) of 18,850 cd m-2, a current efficiency of 12.26 cd A-1, and an external quantum efficiency of 4.19%. The flexible PeLEDs retained their performance even after 1000 bending cycles at a bending radius of 10 mm. Furthermore, the spray-printed curved PeLEDs constructed on glass pipet- and spherical glass-based substrates demonstrated Lmax values of 3792 and 3368 cd m-2, respectively.

Electrochromic Fabric Device Based on Lamellar Polyaniline through Inkjet Printing.

Flexible electrochromic devices (FECD) have been widely applied in smart displays, wearable devices, and other fields, however, the synchronous improvement of electrochromic performance and flexibility is still a challenge. In this paper, a fabric-based FECD with "side-by-side" structure is designed and constructed through inkjet printing. The polyaniline nanosheets with good dispersion are used as ink and electrochromic material, and the self-developed semi-solid electrolyte based on polyvinyl alcohol serves as gel electrolyte. Benefiting from the improved structure and excellent performance of individual components, the obtained FECD achieves a reflectivity change of 22.9%, and maintains the electrochromic ability after bending for 1000 times. This shows the potential in the field of wearable smart clothing and other flexible textile displays.

Mixed-Dimensional Semiconductors-Based Ternary Circuits with Tunable Negative Transconductance Characteristics.

Multivalued logic (MVL) systems, in which data are processed with more than two logic values, are considered a viable solution for achieving superior processing efficiency with higher data density and less complicated system complexity without further scaling challenges. Such MVL systems have been conceptually realized by using negative transconductance (NTC) devices whose channels consist of van der Waals (vdW) heterojunctions of low-dimensional semiconductors; however, their circuit operations have not been quite ideal for driving multiple stages in real circuit applications due to reasons such as a reduced output swing and poorly defined logic states. Herein, we demonstrate ternary inverter circuits with near rail-to-rail swing and three distinct logic states by employing vdW p-n heterojunctions of single-walled carbon nanotubes (SWCNT) and MoS2 where the SWCNT layer completely covers the MoS2 layer. In particular, SWCNTs are inkjet printed to form heterojunctions with MoS2 grown by chemical vapor deposition (CVD), and both inkjet printing and CVD are fully scalable device fabrication methods for low-dimensional materials. In addition, the NTC characteristics of heterojunction field-effect transistors (H-FETs) are explained based on the electrical characteristics of individual SWCNT and MoS2 channels. By adjustment of the p-channel characteristics in H-FETs by exploiting the advantages of the inkjet printing technology, the widths of the NTC regions are easily adjusted accordingly. The extended NTC region enables stable middle logic state operations of low-dimensional semiconductors-based ternary inverters over a sufficiently wide input voltage range.

Advanced Fine Line Printing With Glass Stencils: Achieving Metal Contact Fingers Below 10 μm

ABSTRACTFor high‐efficiency solar cells, such as Si‐III‐V tandem solar cells, implementing narrow contact fingers is essential for achieving optimal conversion efficiencies. By achieving narrower contact fingers without compromising electrical performance, more sunlight reaches the active areas of the cell, thus reducing front‐side shading and enhancing overall energy conversion efficiency. In this work, we demonstrate a proof of principle for a novel low‐temperature metallization process using glass stencils to print ultra‐fine line contacts. The narrowest contacts achieved have a width of = 8.4 ± 1.3 with an aspect ratio of = 0.19 ± 0.05. Through optimization described in this work, contact fingers with = 9.7 ± 0.6 μm and a substantially greater aspect ratio of = 0.45 ± 0.1 could be achieved. To realize these ultra‐fine line fingers, glass stencils with tailored aperture channels were realized using a two‐step laser induced deep etching (LIDE) process that enables complex three‐dimensional aperture channel geometries.

Droplet Trajectory Movement Modeling Using a Drop-on-Demand Inkjet Printhead Simulations

Previous studies of the authors were focused on the vertical movement of the jet print when the printed head was stationary. In this work, the following study was presented, in which the movement of droplets is achieved using a moving horizontal print head. The printed head moves at various velocities, which affects the time of printing and deposition accuracy. This study provides a 3D numerical model with a complete turnover/interchange of the droplet shape at different time steps during the formation and movement process. By considering the dynamics of a droplet surrounded by air, we modeled them using the two-phase flow coupling and level set function from the computational fluid dynamics module by COMSOL Multiphysics. The trajectory shifts of the inkjet droplet are considered from its ejection to its impact on the surface at each time step. The conclusions summarize all the factors responsible for the trajectory shift of the droplet during vertical fall.

A Stable Zn(II) Metal-Organic Framework as Turn-On and Blue-Shift Fluorescence Sensor for Amino Acids and Dipicolinic Acid in Living Cells or Using Aerosol Jet Printing.

Amino acids and dipicolinic acid (DPA) are important biomarkers for identifying human health. Establishing rapid, accurate, sensitive, and simple assays is essential for disease prevention and early diagnosis. In this work, a novel Zn(II) metal-organic framework (MOF) with the formula {[Zn5(μ3-OH)2(BTDI)2(dpp)2]·dpp·4H2O·2DMF}n (JXUST-53, where JXUST denotes Jiangxi University of Science and Technology, H4BTDI = 5,5'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diisophthalic acid; dpp = 1,3-di(4-pyridyl)propane) was successfully synthesized via a mixed-ligands strategy. JXUST-53 exhibits a three-dimensional (4,10)-connected deh1 topological structure, which remains stable after soaking in aqueous solutions with different pH values (1-12) and organic solvents for at least 24 h, showing high chemical and pH stability. As a potential fluorescence sensor, JXUST-53 can specifically recognize l-threonine (l-Thr), l-histidine (l-His), and DPA in EtOH solutions through fluorescence enhancement and a blue-shift effect. It is worth noting that JXUST-53 is the first MOF-based fluorescence sensor capable of recognizing l-Thr. In addition, the university logo of JXUST with JXUST-53 deposited on it was printed by aerosol jet printing technology, enabling a portable and convenient method for monitoring DPA. More importantly, JXUST-53 has good biocompatibility and low cytotoxicity to sense l-Thr, l-His, and DPA in living cells.

Research on the Application and Optimization of Stepper Motors in Ink jet Printers

Ink jet printers have become an indispensable tool in various fields due to their high resolution, cost-effectiveness, and versatility. The performance of these printers heavily relies on precise mechanical control. Stepper motors, as key actuators in these systems, play a vital role in ensuring smooth operation and maintaining print quality. Understanding and optimizing these components are essential for addressing the growing demands for speed, accuracy, and energy efficiency in modern printing technologies. This article explores the basic structure of ink jet printers, analyzes their application functions, and focuses on the driving mechanism of print heads and paper transport systems. Studied the components, operating modes, and principles of the stepper motors used in these devices, emphasizing their functionality based on electromagnetic induction. In addition, this article proposes optimization strategies aimed at improving the accuracy and speed control of stepper motors in ink jet printers. Experimental data shows that through these optimizations, performance and response time have been significantly improved. The research results emphasize that the integration of enhanced stepper motor technology not only improves the market competitiveness of ink jet printers, but also promotes technological innovation and industrial progress

Electrically tunable InAs/GaAs QD in a nanocavity with a transfer-printed ITO electrode

We demonstrate the electrical tuning of InAs/GaAs quantum dots (QDs) embedded in a photonic-crystal (PhC) cavity with transparent indium tin oxide (ITO) electrodes hybrid-integrated by transfer printing. The design includes spacer layers between the cavity and the electrodes to reduce absorption loss while still maintaining a significant bias field. The bottom electrode, PhC cavity, and top electrode were fabricated independently and integrated by transfer printing, and an electrical connection was made by inkjet printing, both implemented locally without affecting the entire chip. We observed the electrical tuning of QD emissions into the cavity mode and Purcell enhancement. This work paves the way for utilizing multiple hybrid-integrated QDs on the same chip.

Colorful patterns prepared using alicyclic epoxy-based cholesteric liquid crystal inks for decoration

ABSTRACT Cholesteric liquid crystal polymer network (CLCN) films have attracted much attention for decoration and displays. Herein, an alicyclic epoxy liquid crystal exhibiting an enantiotropic nematic phase was synthesised. CLCN films with a structural colour were prepared using the mixtures of this epoxy liquid crystal and a chiral dopant. These CLCN films showed high adhesion on the surfaces of poly(ethylene terephthalate), glass and stainless steel. Based on the thermochromic property of the CLC mixtures, colour patterns were prepared on their surfaces through screen printing. Moreover, a colourful pattern was prepared using a left- and a right-handed CLC mixture through inkjet printing. These patterns are potentially applied for decoration and anti-counterfeiting.

A Brief Introduction of Inkjet Printing Technology and Optimizations

Inkjet printing technology has developed for several years, and it has made a great difference in peoples lives. The inkjet printing technology can be divided into two types, which are Continuous Inkjet (CIJ) technology and Drop-on-Demand (DOD) inkjet technology. The Drop-on-Demand inkjet includes piezoelectric inkjet, thermal inkjet, electrostatic inkjet, and acoustic inkjet. These technologies have their own benefits and weaknesses. The Drop-on-Demand printer has better precision than Continuous Inkjet. Optimizations to the printing quality can be carried out from three factors, which are the ink, the substrate, and the coffee ring effect. The ink can be improved by controlling the temperature. The substrate can be improved by changing its structure. The coffee ring effect can be suppressed by using hydro-soluble polymer additives or controlling the temperature. Future advancements in inkjet printing technology are expected to focus on optimizing these factors through interdisciplinary approaches, including material science, fluid dynamics, and advanced manufacturing techniques

Parallel manipulation of multiple ink droplets via near-infrared light on lubricant infused surface

Previous studies on light-driven droplet transport often use light to heat the substrate to generate a temperature difference, thereby changing the wettability or surface tension at two ends of a droplet, to propel the droplet forward, and not much attention has been paid to the droplets with photothermal properties. Herein, we introduce a method of ink droplet manipulation via near infrared light-driven on lubricant infused surfaces. Rather than heating the substrate itself, this method uses near-infrared light to irradiate one end of an ink droplet, creating a temperature gradient inside it and forming a Marangoni flow that pushes the droplet forward. It is demonstrated that the ink droplets would experience two stages during sliding, and the movement ability of the ink droplets depends on their absorbance and size; specifically, the average acceleration and steady velocity of the droplets are both positively correlated with their absorbance and negatively correlated with their volume. The work not only proves that the method can realize conventional individual droplet manipulation such as controllable transport along arbitrary paths, but also proposes a unique customized transport and merging strategy for multiple ink droplets. This investigation offers a simple and versatile manipulation approach for ink droplets, and the relevant results have potential applications in the fields of precise maneuver of light-driven droplets and droplet-based inkjet printing.

Fully Inkjet-Printed Flexible Graphene-Prussian Blue Platform for Electrochemical Biosensing.

Prussian Blue (PB) is commonly incorporated into screen-printed enzymatic devices since it enables the determination of the enzymatically produced hydrogen peroxide at low potentials. Inkjet printing is gaining popularity in the development of electrochemical sensors as a substitute for screen printing. This work presents a fully inkjet-printed graphene-Prussian Blue platform, which can be paired with oxidase enzymes to prepare a biosensor of choice. The graphene electrode was inkjet-printed on a flexible polyimide substrate and then thermally and photonically treated with intense pulsed light, followed by inkjet printing of a PB nanoparticle suspension. The optimization of post-printing treatment and electrode deposition conditions was performed to yield a platform with minimal sheet resistance and peak potential differences. A thorough study of PB deposition was conducted: the fully inkjet-printed system was compared against sensors with PB deposited chemically or by drop casting the PB suspension on different kinds of carbon electrodes (glassy carbon, commercial screen-printed, and in-house inkjet-printed electrodes). For hydrogen peroxide detection, the fully inkjet-printed platform exhibits excellent sensitivity, a wider linear range, better linearity, and greater stability towards higher concentrations of peroxide than the other tested electrodes. Finally, lactate oxidase was immobilized in a chitosan matrix, and the prepared biosensor exhibited analytical performance comparable to other lactate sensors found in the literature in a wide, physiologically relevant linear range for measuring lactate concentration in sweat. The development of mediator-modified electrodes with a single fabrication technology, as demonstrated here, paves the way for the scalable production of low-cost, wearable, and flexible biosensors.

Optimization of Inkjet Printers and Exploration of Human Development and Electromagnetic Valve Technology

With the rapid development of digital technology, inkjet printing technology is being increasingly applied in various fields. The electromagnetic valve, as the core component controlling ink droplet ejection, determines the precision and stability of the printing process. This paper delves into the optimization of inkjet printers, underscoring their pivotal role in sustainable development and the critical function of solenoid valves in controlling ink ejection for achieving high-quality printing. It discusses thermal and piezoelectric inkjet technologies, addressing the challenges faced by solenoid valves, such as environmental adaptability and durability. The paper further explores optimization solutions and future trends, including miniaturization and enhanced environmental adaptability. Conclusively, advancements in inkjet printers and solenoid valves are essential for improving efficiency, reducing costs, and promoting environmental sustainability. The optimization of inkjet printers not only enhances printing efficiency and quality but also positively impacts energy conservation, emission reduction, and resource utilization, making them increasingly significant in the digital transformation across various industries.

Aerosol‐Jet‐Printed Silver Nanowires as Top Electrodes in Organic Photovoltaic Devices

Aerosol jet printing (AJP) is an effective method for manufacturing organic photovoltaic (OPV) devices for indoor use. Its noncontact deposition, without posttreatment, and high‐resolution 3D pattern printing capabilities make it ideal for using functional nanomaterial inks. This study explores ultrasonic AJP (uAJP) atomization to deposit silver nanowires (AgNW) as the top electrode layer (TEL) in OPV devices. The OPV stack is fabricated up to the hole transport layer using high‐throughput screening (HTS) methodologies. Different deposition techniques, including spin‐coating, blade‐coating, and uAJP of AgNW inks, as well as thermal evaporation of silver, are compared. Scanning electron microscopy analysis shows that the E2X AgNW ink formed a compact TEL layer. Combining HTS setups, right selection of interlayers and uAJP method, automated, solution‐processed OPV devices with power conversion efficiencies of 9.54% on an active layer of 0.0232 cm2 are achieved, the highest reported for OPV devices using uAJP AgNW inks as top electrodes.