Inkjet Printing Of Inks Research Articles

Micro‐Supercapacitors: Aqueous MXene/PH1000 Hybrid Inks for Inkjet‐Printing Micro‐Supercapacitors with Unprecedented Volumetric Capacitance and Modular Self‐Powered Microelectronics (Adv. Energy Mater. 23/2021)

In article number 2100746, Shengzhong (Frank) Liu, Zhong-Shuai Wu and co-workers report an aqueous MXene/PH1000 hybrid ink for inkjet printing of planar micro-supercapacitors, which can serve as a flexible energy storage unit for Si film solar cells and can supply power for printable temperature sensors. Such printable inks are expected to allow for scalable and customizable fabrication of power sources for next-generation, self-sustaining, wearable, and implantable microelectronics.

Combination of few-layer graphene and commercial cosmetic film for tetrahydrofuran-sensitive smart film

A shear exfoliation of graphite in Arabic gum solution is one of the interesting non-toxic methods for production of few-layer graphene. While the utilization of Arabic-based graphene is mainly as conductive ink for inkjet or screen printing of circuit for sensing or electronic device, it is noted that there is lack of works reporting on the role of this polysaccharide class-based graphene for smart vapour-driven sensing film. In this brief report, the effect of Arabic gum/graphene presence on the cosmetic oil control film (Clean and Clear®) for bending-unbending performance of vapour-driven film was investigated. It is discovered that the film was able to complete a bending cycle within 13 s while the maximum recorded bending radius was measured at 0.48 cm after exposure to tetrahydrofuran (THF) in controlled environment condition (50%rh and 25 °C). By controlling the distance between THF source and the smart film, we further show the crawling motion of this film that resembling leech with a speed of 0.5 cm/48 s.

Development of environmentally friendly inkjet printable carbon nanotube‐based conductive ink for flexible sensors: effects of concentration and functionalization

The fabrication of environmentally friendly printed flexible sensors is still an emerging technology, but with vast potential applications. Among the available printing techniques, inkjet printing is considered as a promising technique for flexible electronics because it enables high volume and versatile manufacturing, at low environmental impact. This study demonstrates a simple and facile method of preparing an environmentally benign water-based conductive ink, by dispersing functionalized and non-functionalized multi-walled carbon nanotubes (MWCNTs) in aqueous solution with the help of a biopolymer surfactant. The concentration of CNTs in the ink formulation was varied from 0.25 to 0.75 wt%, and additives such as triton-x 100, polypropylene glycol, and defoamer were added to achieve desirable ink properties. Inkjet printable ink was produced, and it was observed that the conductivity of the printed pattern is dependent on the printing pass. In addition, it was found that as the number of printing layer increases, there is higher synergy between concentration and number of printing pass in F-MWCNTs printed ink to produce higher electrical conductivity, compared to MWCNTs printed ink. Generally, the findings of this study could potentially open opportunities for global economic growth through the applications of printed, low cost and environmentally friendly flexible sensors.

Transparent water-based UV-curable urethane acrylate ink-jet ink

Attention has recently been paid to ink-jet printing inks to more environmentally friendly types and faster methods with lower energy consumption. The ink-jet printing industry has a preference to use ultraviolet-curable inks for packaging and labeling applications. This research reports a simple approach to prepare a water-based UV-curable ink-jet ink based on urethane acrylate to print onto the transparent flexible polyethylene terephthalate substrate. Isophorone diisocyanate, dimethylolpropionic acid, a low molecular weight polyester resin, and 2-hydroxyethyl methacrylate used to synthesize the urethane acrylate resin. Then, the prepared resin was neutralized with triethylamine and emulsified in deionized water. Fourier transformed infrared spectroscopy spectra characterized the chemical structure of synthesized resin. The gel permeation chromatography was used to determine the synthesized resin's molecular weight. The hydroxyl value, acid value, conversion percentage under UV radiation, transparency, haze, and surface tension results of the emulsified resin were measured. The physical properties of prepared ink-jet ink, such as rheology, surface tension, and dynamic light scattering, were measured. The ink-jet ink could fabricate uniform patterns by a general ink-jet printer onto the transparent polyethylene terephthalate flexible substrate. Eventually, the acceptable appearance was achieved due to the transparency and clarity of the printed polyethylene terephthalate.

Ultra-high quantum yield nitrogen-doped carbon quantum dots and their versatile application in fluorescence sensing, bioimaging and anti-counterfeiting

The exploration of carbon quantum dots (CQDs) with ultra-high quantum yield, simple synthesis path, and satisfying output to facilitate their wide applications in numerous fields are always the research focus. In this work, nitrogen-doped carbon quantum dots (N-CQDs) with strong blue fluorescence were synthesized with a simple one-step hydrothermal method using citric acid and o-phenylenediamine as raw materials, and the absolute quantum yield was as high as 92.1%. The detailed research results demonstrate that the N-CQDs have outstanding fluorescence stability, high selectivity, and anti-interference in Hg2+ detection. The obtained N-CQDs also possess excellent biocompatibility, which can also be successfully applied in cell imaging and intracellular Hg2+ detection. Most importantly, due to their high quantum yield and excellent dispersibility, the N-CQDs solution can be used as a quick-drying fluorescent ink for ink-jet printing. Therefore, the as-prepared N-CQDs have great potential in fluorescence sensing, biomedical diagnosis, data encryption, and anti-counterfeiting.

A chemical milling process to produce water-based inkjet printing ink from waste tire carbon blacks

In this study, a chemical milling process is developed to convert carbon residues from pyrolyzed waste tires into valuable water-based inkjet printing inks. The residues after waste tire pyrolysis were first sieved to remove ash components and ground into powder (~80 μm). The resulting waste tire carbon blacks (TCB) processed by regular dry or wet milling with the help of compatible solvent can only produce particle sizes around 250 nm. To further reduce particle size under the same mechanical energy, aqueous potassium hydroxide was used in the milling process to leach silica in TCB to create loose and vulnerable structure. Moreover, an ionic surfactant, poly (sodium 4-styrenesulfonate) (PSS), was used to decorate the TCB surface and to inhibit particle aggregation. After chemical milling, the PSS/TCB had a primary particle size around 50 nm and a hydraulic diameter around 110 nm. The PSS/TCB suspension possessed a high zeta potential of −73 mV to stably disperse in water for more than 30 days. To help adhesion of the ink on substrates, the PSS/TCB particles were further mixed with waterborne polyurethane (WPU). The WPU/PSS/TCB ink could be inkjet printed into various black patterns, which showed a higher blackness (jetness value = 342.83) than commercial black inks. Moreover, the printed patterns were water-proof and had a pencil scratch hardness of 4H. In summary, this study provides a guideline to convert waste carbon materials into useful printing supplies, and offers a potential application for waste tire recycling.

Fabrication and characterization of entirely inkjet-printed polysilicon thin film transistors

In this paper, the fabrication and material innovation involved in the first and only entirely inkjet-printed polysilicon thin film transistors (TFTs) are described. To form TFT layers, five inkjet printing inks were developed with the goal of fabricating TFTs by using purely additive processing without vacuum deposition or conventional lithography. A silicon ink was developed to form both the channels and polysilicon gates, and boron and phosphorus dopant inks were developed for N+ and P+ doping. In addition, a silver nanoparticle (NP) ink was developed to form interconnect traces, and a palladium chloride ink was formulated to create palladium silicide for the ohmic contacts between the source and the drain. The first N-type metal-oxide-semiconductor (MOS) polysilicon TFT was fabricated with a top-gate self-alignment scheme. This exhibited a mobility of approximately 80 cm2 V s−1. Next, P-type MOS transistors as well as complementary MOS devices were also successfully fabricated.

Enhancing the electrical properties of inkjet-printed silver ink by electrolyte sintering, photonic sintering, and electroless plating

Conductive inkjet printing is an emerging rapid manufacturing technology in the field of smart clothing and wearable electronics. The current challenge in conductive inkjet printing includes upgrading of electrical performance of printed inks to the equivalent level to traditional conductors such as bulk silver and copper, especially for high-performance electronic applications such as flexible antennas and circuits. Post-treatments are commonly employed to enhance the electrical conduction of inkjet-printed tracks. This research discusses the effects of electrolyte sintering, photonic sintering and electroless copper plating on the DC electrical resistance and resistivity of inkjet-printed silver nanoparticles. From experimental results and measurements, it was found that all the post-treatment methods effectively improved the electrical properties of printed silver ink, but in different ways. The lowest resistance of 4.5 ? (in 0.1 mm ? 10 mm) and thickest (4.5 ?m) conductor were achieved by electroless copper plating, whereas the lowest resistivity (7.5?10-8 ??m) and thinnest (1.0 ?m) conductor were obtained by photonic sintering.

Printability and electrical conductivity of silver nanoparticle-based conductive inks for inkjet printing

Inkjet printing conductive ink was prepared with the as-prepared silver nanoparticles as conductive fillers and deionized water as the solvent and leveling agent (MY-3000) and silicone defoamer (NXZ) and wetting agent (TRITONX-405) and moisturizer (glycerol) as functional additives. We investigated the effects of viscosity and surface tension of conductive ink and the inkjet print parameters including number of nozzle, print speed, and ink droplet spacing on inkjet printability of conductive ink. The research results show that the inks with the viscosity range of 2.8–9.1 mPa·s and the surface tension of 33.4 mN·m−1 are suitable for inkjet printing. The printing accuracy of the print pattern is related to the number of nozzles and droplet space and the printing layer, but not to the printing speed, but can be changed appropriately to improve the print efficiency. When the mass content of silver nanoparticles is 6.91 wt%, the sheet resistance of the printing pattern with four layers is 2.71 Ω·cm−1, which is in appropriate printing conditions of the inkjet printing voltage of 21 V, printing speed of 60 m· S−1, ink droplet space of 20 μm, and nozzles of 2. The systematic studies of printability and electrical conductivity of inkjet printing silver nanoparticles conductive ink prove the feasibility of the ink and provide some ideas for future applications.

Insights into Influences of Dye Hydrophobicity on Cleanliness and Resolution of Fabric Ink-Jet Printing

Fabric ink-jet printing is a crucial technology of clean production in the textile industry. Reactive dyes and organic solvents are the important component of ink-jet printing ink. The structure, h...

Acid-induced tunable white light emission based on triphenylamine derivatives

A series of triphenylamine (TPA) derivatives with various substituent groups were prepared and showed different absorption and fluorescence characteristics due to the substituent effect. On account of the existence of pyridine units, these TPA derivatives exhibited acid-induced tunable multicolor fluorescence emission including white light emission. In addition, acid-induced fluorescence regulation of these compounds has been also realized in the solid state, which enable them to be successfully constructed the stimuli-responsive fluorescent films and fluorescent inks for inkjet printing.

Development of inkjet printing ink based on component solubility parameters and its properties

In textile inkjet printing, it is important to understand the design theory of ink jet printing ink. In this study, according to the solubility parameters of printing ink components (humectant, penetrant, pH regulator, viscosity regulator and deionized water), twelve different complex solvents were designed to prepare disperse ink. By observing the particle size, stratification, rheological property and viscosity of the prepared inks, the ink meeting the requirements was subsequently selected. The low field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) analyses were used to analyze the water distribution and structure information of the ink at the micro level, which provide opportunities to subsequently interpret the macro properties (fluidity) of ink. The ink before and after filtration was tested using an ultraviolet-visible spectrophotometer (UV), and the content of the disperse dye in the ink was observed to be reduced after filtration. The viscosity of the ink before and after filtration were also analyzed. The viscosity of the ink was noted to significantly decrease after filtration, which indicated that the content of the disperse dye in the ink exhibited a vital influence on the ink viscosity. LF-NMR was applied to study the stability of ink (1a, 1c, 3a, 3c, 4a, 4c, 5a, 5c, 6a and 6c) in cold and hot environments. No new peak was found in T2 relaxation time inversion spectra of disperse ink, which indicates that there is no physical or chemical change among the components in disperse ink. The voltage of the driving waveform was adjusted and ejection performance of different inks was characterized. The results indicated linear driving voltage and ligament length of the inks. Different fixation temperatures (160 ℃-190 ℃) were used to optimize the fixation temperature of the printed fabrics, and 180 ℃ was determined to be the optimal fixation condition. Finally, the color fastness of the printed fabric was tested and analyzed. The findings revealed that the color fastness of the printed fabric met the use requirements.

Testing of novel nano gold ink for inkjet printing

Testing of novel nano gold ink for inkjet printing

Preparation and characterization of green glazes using ferrochromium slag waste

Green glazes were successfully prepared using ferrochromium slag waste as chromium and iron precursors by introducing Co2O3 as coloring agent. The performance of the glazes was investigated by XRD, EDS, FT-IR, and UV-vis. A chromatic mechanism was proposed to explain the variation of glaze colors with the increase of Co2O3 content. The results showed that the Co-doped glazes had Co-Fe-Cr mixed spinel-type structures when Co-doped contents were 0.5–1.5 wt%. Green glazes could be prepared by adjusting the blue component (Co2+) proportion, which was achieved with different amounts of Co2O3, to balance the color proportion of blue and yellow in glazes according to subtractive color process. The intensity of green color in glaze samples was related to the presence of d-d transitions of tetrahedral Fe3+, 4A2(F) → 4T(P) of tetrahedral Co2+, and 4A2g → 4T2g of octahedral Cr3+ in spinel structures. These results indicated that environment-friendly, Co-doped, spinel-type structured, coloring agents, prepared using ferrochromium slag waste, can be applied to produce green glazes or inkjet printer ink as well as to provide a means for preparing green glaze using ferrochromium slag waste.

Investigations on the Processing of Ceramic Filled Inks for 3D InkJet Printing.

3D inkjet printing is moving from a technology of rapid prototyping to rapid manufacturing. The introduction of ultraviolet curable composites filled with functional ceramics could expand the possibilities of this technology. In this work, a simple and scalable process was investigated as a template for the production of inkjet printable functional ceramics. Pyrogenic alumina particles with an average size of 13 nm, 35 nm and 100 nm were used as fillers in an acrylate mixture. The physical coating of the ceramics with 2-[2-(2-methoxyethoxy)ethoxy] acetic acid results in a low-viscosity dispersion with a ceramic content of up to 2 vol%, Newtonian behavior and surface tension within the limits allowed for inkjet printing. The material has sufficient stability for printing tensile specimens. Tensile tests have shown that modulus of elasticity, tensile strength and toughness can be kept constant despite the light scatter caused by the particles. The final production steps could be reduced to grinding and drying of the powders, their resuspension in the organic matrix and inkjet printing. The process can be used in an industrial-scale production of materials for abrasion-resistant components with adapted tribology.

3D Crumpled Ultrathin 1T MoS2 for Inkjet Printing of Mg-Ion Asymmetric Micro-supercapacitors.

Metallic molybdenum disulfide (MoS2), e.g., 1T phase, is touted as a highly promising material for energy storage that already displays a great capacitive performance. However, due to its tendency to aggregate and restack, it remains a formidable challenge to assemble a high-performance electrode without scrambling the intrinsic structure. Here, we report an electrohydrodynamic-assisted fabrication of 3D crumpled MoS2 (c-MoS2) and its formation of an additive-free stable ink for scalable inkjet printing. The 3D c-MoS2 powders exhibited a high concentration of metallic 1T phase and an ultrathin structure. The aggregation-resistant properties of the 3D crumpled particles endow the electrodes with open space for electrolyte ion transport. Importantly, we experimentally discovered and theoretically validated that 3D 1T c-MoS2 enables an extended electrochemical stable working potential range and enhanced capacitive performance in a bivalent magnesium-ion aqueous electrolyte. With reduced graphene oxide (rGO) as the positive electrode material, we inkjet-printed 96 rigid asymmetric micro-supercapacitors (AMSCs) on a 4-in. Si/SiO2 wafer and 100 flexible AMSCs on photo paper. These AMSCs exhibited a wide stable working voltage of 1.75 V and excellent capacitance retention of 96% over 20 000 cycles for a single device. Our work highlights the promise of 3D layered materials as well-dispersed functional materials for large-scale printed flexible energy storage devices.

Enhancing inkjet image quality through controlling the interaction of complex dye and diol molecules

Digital inkjet printing has been widely used in the textile industry due to the advantages of low cost, high efficiency, flexible processing and so on. Although a number of methods have been reported on inkjet printing of high-quality images on fabrics, challenges still remain in preparing homogeneous inks and printing high resolution images. Herein, we describe a simple method to prepare stable inks for high performance digital inkjet printing on cotton fabrics. Two ecofriendly organic solvents of ethylene glycol and diethylene glycol were applied in the Reactive Black 8 in. solutions, respectively. By adjusting the interaction between dye and diol molecules, the resulted Reactive Black 8 inks showed an increased viscosity and decreased surface tension, which facilitated the formation of complete and stable inkjet droplets during the printing process. Moreover, introducing these solvents into the dye solution can effectively disaggregate the clusters of Reactive Black 8. When 5 mol/L diethylene glycol or ethylene glycol was used in the Reactive Black 8 solution, complete and stable ink drops can be formed, and the diffusion area of the ink drops on fabric was obviously reduced, thus clear and high-resolution patterns can be produced on the cotton fabrics. We characterized the chemical and physical properties of the inks and evaluated their printing performances on cotton fabrics. The mechanism of interaction between dye molecules and organic solvents was also investigated. Results from this work may promote the wide development of inkjet printing techniques and extend its application in high performance textiles.

Preparation and investigation of a stable hybrid inkjet printing ink of reactive dye and CHPTAC

In this research, a hybrid ink of reactive dye and cationic modifier 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) was developed. The zeta potential and stability of the hybrid ink have been specifically studied. By careful selection, the stability of the hybrid ink was improved with the surfactant Tween-80, proved by the calculations of binding constants and frontier molecular orbitals as well as the electrostatic potential maps. Importantly, the hybrid ink indicated good storage stability by analyzing the surface tension, viscosity, and pH value of the ink in a period of 90 days, meeting the requirements of commercial application. The K/S value of the cotton fabric printed with the hybrid ink (containing 30% CHPTAC) was 21.68 and the dye fixation was 91.56%, which were separately 35.33% and 26.85% higher than those of the cotton fabric printed with the reactive dye ink without CHPTAC. The higher dye fixation is beneficial to significantly reduce the content of hydrolyzed dyes in the wastewater, reducing the environmental pollution. Moreover, the fabrics inkjet printed with the hybrid ink presented a good colorfastness to laundering or crocking.

Inkjet printing porous graphene/silver flexible electrode with enhanced electrochemical performance based on vapor phase reduction

In this work, inkjet printing of porous graphene/silver composite with low temperature vapor phase reduction was studied. Silver precursor and graphene oxide (GO) with a low weight ratio were used as ink for inkjet printing into a film. After vapor phase reduction, the inserted silver nanoparticles between reduced graphene oxide (RGO) layers acted as physical separators to prevent agglomeration of the RGO and reduce the Van Der Waals force between graphene sheets. The fabricated RGO/Ag electrode presented a high electrical conductivity of 2.9 × 105 S/m, and could keep stable after multiple bending. Meanwhile, the reducing agent vapor entered the interior of the RGO during the vapor reducing process, which generated porous channels in the RGO/Ag electrode. The porous channels could facilitate the penetration of the electrolyte into the graphene/silver electrode, resulting in a good electrochemical performance with a specific capacitance of 60.6 mF/cm2 at a scan rate of 5 mV/s, which greatly improves the property compared with the previous reports.

Layer Morphology and Ink Compatibility of Silver Nanoparticle Inkjet Inks for Near-Infrared Sintering.

The field of printed electronics is rapidly evolving, producing low cost applications with enhanced performances with transparent, stretchable properties and higher reliability. Due to the versatility of printed electronics, industry can consider the implementation of electronics in a way which was never possible before. However, a post-processing step to achieve conductive structures—known as sintering—limits the production ease and speed of printed electronics. This study addresses the issues related to fast sintering without scarifying important properties such as conductivity and surface roughness. A drop-on-demand inkjet printer is employed to deposit silver nanoparticle-based inks. The post-processing time of these inks is reduced by replacing the conventional oven sintering procedure with the state-of-the-art method, named near-infrared sintering. By doing so, the post-processing time shortens from 30–60 min to 6–8 s. Furthermore, the maximum substrate temperature during sintering is reduced from 200 °C to 120 °C. Based on the results of this study, one can conclude that near-infrared sintering is a ready-to-industrialize post-processing method for the production of printed electronics, capable of sintering inks at high speed, low temperature and with low complexity. Furthermore, it becomes clear that ink optimization plays an important role in processing inkjet printable inks, especially after being near-infrared sintered.