Drying stability enhancement of red-perovskite colloidal ink via ligand-derived coating for inkjet printing

Today, inkjet printing techniques has many merits such as high printing yield and mask-free process for the various field. As one of the candidate ink materials, the perovskite is appropriate for inkjet printing due to the colloidal state and excellent optoelectronic properties such as high photoluminescence quantum yield (PLQY) and narrow full width at half maximum (FWHM). Those characteristics are an advantage to fabricating ink and realize wide color-gamut in the small area with micro-patterning. However, perovskite application in inkjet printing with various color has limitations due to the low drying stability of mixed halide perovskite.Herein, we report on improving the drying stability of red perovskite by inducing aggregation during the drying process. Silane ligand has applied to induce the aggregation, and we confirmed that the thin coating layer has formed on the perovskite surface. The synthesized red-perovskite using silane ligands is well dispersed in the solvent as a colloidal state. And it maintained the emission intensity over 50% after drying. As-prepared perovskite ink has successfully printed on the ethyl cellulose film with 338 dpi with maintaining transparency of the film. These results are beneficial not only display applications but also security applications such as double anti-counterfeiting.     

纳米金属喷墨导电墨水研究进展

喷墨印刷电子技术是电子及微电子行业未来的一种高效、绿色环保型生产技术。本文详细阐述了纳米金属喷墨导电墨水的制备及性能研究、墨滴控制、涂层后处理与应用4个方面的研究进展,说明了纳米金属喷墨导电墨水是未来喷墨印刷电子研究的关键技术之一,指出了纳米金属喷墨导电墨水目前存在的不足,如固含量与稳定性之间的矛盾、导电性能不理想等。并对喷墨印刷电子技术的发展提出了展望,指出其在RFID天线、印刷线路板、印刷电子产业领域有广阔的应用前景。     

喷墨打印材料的制备及颜料用量对其性能的影响

为改善已有喷墨材料的吸墨性能,用SiO2@Al13核壳结构材料作为颜料制备吸墨材料;利用黏度杯、色差仪等进行测试,从涂料黏度、涂布量、涂布打印效果及色差四个方面,讨论了颜料用量对吸墨材料的影响。结果表明,颜料用量对吸墨材料性能影响显著,颜料的增加,利于材料吸墨,但不宜过高。颜料比例为75％时,材料性能优异。     

十二烷基硫酸钠对亚麻织物喷墨印花性能的影响

为提高亚麻织物的喷墨印花颜色效果,将十二烷基硫酸钠（SDS）与海藻酸钠（SA）协同作用于亚麻织物的预处理工艺,对处理后织物表面墨滴的铺展面积、喷墨印花色块的颜色参数进行了测试,使用接触角测量仪、扫描电子显微镜（SEM）、固体表面zeta电位仪、X射线光电子能谱仪（XPS）和傅里叶变换红外光谱仪（FTIR）对预处理前后亚麻织物表面物理和化学性能进行了表征。结果表明：与SA预处理织物相比,表面活性剂的引入可使亚麻织物表面墨滴铺展面积减小14%,墨滴渗化程度也明显减小;青色和黑色印花色块的表观颜色深度增加,摩擦色牢度略有降低,断裂强力和耐日晒色牢度无明显改变。同时从SEM图看出,经预处理后,SDS+SA预处理剂在亚麻织物表面上形成了薄膜,纤维间以锯齿状的膜结构堵塞了孔隙,促使更多的活性染料在滴落的位置与纤维发生共价结合;此外,预处理处理后织物的亲水性增加,有利于染料对亚麻纤维的上染。     

Optimisation of CGO suspensions for inkjet-printed SOFC electrolytes

A detailed procedure for the preparation of gadolinium doped (10 mol%) cerium (IV) oxide (CGO) suspension for inkjet printing is described in this paper. The optimisation of inkjet printing parameters for the deposition of solid oxide fuel cell electrolytes was also performed using a custom-built drop visualisation system. Additionally, the uniformity of the deposited drop relics on porous substrates was evaluated. The ink used in this study was an evaporative type comprising a solvent mixture of terpineol and methanol, ethyl cellulose and CGO powder. Successful printing of regular drops was achieved after printing optimisation. It has been demonstrated that inkjet printing is a promising technique for high quality membrane fabrication for applications including solid oxide fuel cells. The ink formulation and optimisation procedure would also be applicable for other ceramic ink development.     

彩色喷墨记录材料的吸墨层研究进展

综述了国内外彩色喷墨记录材料的吸墨层结构、制备方法、性能评价等方向的研究进展。在吸墨层结构与制备的讨论中,着重介绍了多种前沿颜料的选择和使用,同时也讨论了胶黏剂和助剂的选择。综合提出了吸墨层主要性能评价指标,包括吸墨层对油墨的吸收性、图像的分辨率、吸墨层的光泽度、图像的保存性等方面。系统分析了影响油墨吸收性能的各种因素。展望了国内外彩喷记录材料的研究前景和热门方向。     

Preparation and microcosmic structural analysis of recording coating on inkjet printing media

Preparation of recording coating on inkjet printing (RC-IJP) media was proposed. The microstructure and roughness of RC-IJP was analyzed by scanning electron microscopy (SEM) and atomic force microscope (AFM). The surface infiltration process of RC-IJP was studied by a liquid infiltration instrument. The distribution of C, O and Si composites on recording coating surface is analyzed by energy dispersive spectrum (EDS). The transmission electron microscopy (TEM) analysis showed that the nanoscale silica could be dissolved uniformly in water. Finally, the print color is shown clearly by the preparative recording coating.     

Impact of ink formulation on carbon nanotube network organization within inkjet printed conductive films

The inkjet printing of an aqueous suspension of carboxylic acid-functionalized single walled carbon nanotubes (SWCNT-COOH) and of a conductive ink combining SWCNT-COOH with the conductive polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid) (PEDOT-PSS) was studied. A dimensionless study predicted the behavior of these two fluids in a given printing system. Observations at different scales were performed on the printed samples to visualize the arrangement of the carbon nanotube (CNT) network within the printed layer. An innovative way to localize CNTs within the printed patterns was developed by using a mapping technique of surface sample, based on a scanning electron microscope coupled with an energy dispersive X-ray spectroscope. The SWCNT-COOH aqueous suspension is subject to the halo (or “coffee ring”) effect, which is a well-known phenomenon in inkjet printing, whereas the SWCNT-COOH/PEDOT-PSS ink offers a more homogeneous CNT network. The CNT orientation has also been under investigation. For the SWCNT-COOH suspension, specific orientations of the CNTs were recorded, whereas for the SWCNT-COOH/PEDOT-PSS ink, a more homogeneous CNT distribution with a random orientation was obtained. This study proved also that the droplet ejection velocity can have an impact on the CNT distribution and consequently on the electrical performances of the ink.     

Novel Insights into Inkjet Printed Silver Nanowires Flexible Transparent Conductive Films

Silver nanowire (AgNWs) inks for inkjet printing were prepared and the effects of the solvent system, wetting agent, AgNWs suspension on the viscosity, surface tension, contact angle between ink droplet and poly(ethylene) terephthalate (PET) surface, and pH value of AgNWs ink were discussed. Further, AgNWs flexible transparent conductive films were fabricated by using inkjet printing process on the PET substrate, and the effects of the number printing layer, heat treatment temperature, drop frequency, and number of nozzle on the microstructures and photoelectric properties of AgNWs films were investigated in detail. The experimental results demonstrated that the 14-layer AgNWs printed film heated at 60 °C and 70 °C had an average sheet resistance of 13 Ω∙sq⁻¹ and 23 Ω∙sq⁻¹ and average transparency of 81.9% and 83.1%, respectively, and displayed good photoelectric performance when the inkjet printing parameters were set to the voltage of 20 V, number of nozzles of 16, drop frequency of 7000 Hz, droplet spacing of 15 μm, PET substrate temperatures of 40 °C and nozzles of 35 °C during printing, and heat treatment at 60 °C for 20 min. The accumulation and overflow of AgNWs at the edges of the linear pattern were observed, which resulted in a decrease in printing accuracy. We successfully printed the heart-shaped pattern and then demonstrated that it could work well. This showed that the well-defined pattern with good photoelectric properties can be obtained by using an inkjet printing process with silver nanowires ink as inkjet material.     

Some properties of a thickener for preparing inkjet printing ink for nylon carpet

The properties of a thickener for nylon carpet inkjet printing are presented in this work. A water-based ink was prepared from polyacrylate-based thickener. The physical and chemical properties of the polyacrylate-based thickener used for preparing the inkjet printing ink, as well as its printing effects on carpet, were investigated. Before printing, the properties of the ink, including its surface tension, electrolyte resistance, storage stability, and percentage removal, were investigated. After printing, the efficiency of coloration of printed carpet and the fastness of printed carpet were studied. The results concerning the surface tension and percentage removal of printing ink show that the polyacrylate-based thickener printing ink is suitable for nylon carpet inkjet printing. Meanwhile, its storage stability and electrolyte resistance make it suitable for printing. The efficiency of coloration of printed carpet and the fastness of printed carpet satisfy the requirements of application at appropriate ink concentration and viscosity.     

Evaluation of expanded gamut software solutions for spot color reproduction

Expanded gamut printing is an approach in color reproduction that expands the color gamut of conventional CMYK printing processes via the use of additional colorants, such as Orange, Green, and Violet inks. This study evaluates the ability of commercial color management software to create an accurate solution for an expanded gamut printing system. In this study, two printing processes were used, an Epson SureColor P9000 inkjet printer/proofer and an HP Indigo 7900 digital production press, both with 7-color expanded gamut ink sets. Software solutions from Alwan, CGS ORIS, ColorLogic, GMG Color, Heidelberg, and Kodak were evaluated. The systems were tested to see how well they could reproduce the colors in the entire PANTONE+ Solid Coated spot color library. It is shown that the solutions are able to reproduce 89% to 94% of the spot colors on the Epson P9000 inkjet printer and 77% to 87% of the library on the Indigo 7900, both to less than two CIEDE2000 (a typical tolerance in label and packaging work). The number of color patches in expanded gamut characterization test charts was noted, as this is still an area of proprietary, nonstandardized working practice. There are many different colorant combinations that can make the same color in expanded gamut printing. The ink build created by the different software solutions was studied, as it relates to press stability through appropriate choice of colorants. Pantone and Adobe provide everyday commercial tools for expanded color workflows. The study identified some issues with products from these companies that could confuse a less-skilled user in a busy production environment. The conclusion of the study is that expanded gamut solutions for spot color printing produce totally acceptable results for digital printing processes; expanded gamut printing is ready, here and now. The findings show that expanded gamut printing can replace cumbersome conventional spot color workflows creating considerable savings and advantages, especially for label and packaging printers.     

Improved thin film stability of differently formulated,printed, and crosslinked polymer layers against successive solvent printing

Interface control remains a top challenge of solution-processed organic light emitting diodes (OLED) stacks since the device performance heavily relies on it. Film stability of an inkjet deposited and crosslinked layer against subsequent exposure to a suitable inkjet printed solvent has been investigated. Impact of processing solvent (solvent used to prepare the polymer layer) on solution-cast thin film properties has already been shown for polymer films. To our knowledge, this study is the first one analyzing thin films stability against solvent exposure using technology relevant materials processed via inkjet printing (IJP). The outcome of this research showed that the stability of the crosslinked films is affected by the solvent used for ink formulation. These findings are of great interest for multilayered semiconductors devices, such as OLEDs, field-effect transistors and dye-sensitized solar cells. Differential scanning calorimetry (DSC) was used to quantify the efficiency of the polymer crosslinking reaction in pure powder and in thin films, as processed from different solvents. Crosslinking efficiency measured by DSC correlated well with the deformation induced by the solvent and observed on layer surfaces. The interaction in solution between polymer and solvent has also been evaluated to explain its impact on thin film stability against successive solvent printing. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48895.     

Direct selective growth of ZnO nanowire arrays from inkjet-printed zinc acetate precursor on a heated substrate

Inkjet printing of functional materials has drawn tremendous interest as an alternative to the conventional photolithography-based microelectronics fabrication process development. We introduce direct selective nanowire array growth by inkjet printing of Zn acetate precursor ink patterning and subsequent hydrothermal ZnO local growth without nozzle clogging problem which frequently happens in nanoparticle inkjet printing. The proposed process can directly grow ZnO nanowires in any arbitrary patterned shape, and it is basically very fast, low cost, environmentally benign, and low temperature. Therefore, Zn acetate precursor inkjet printing-based direct nanowire local growth is expected to give extremely high flexibility in nanomaterial patterning for high-performance electronics fabrication especially at the development stage. As a proof of concept of the proposed method, ZnO nanowire network-based field effect transistors and ultraviolet photo-detectors were demonstrated by direct patterned grown ZnO nanowires as active layer.     

Improvement of the mechanical and aesthetic properties of a coating by inkjet technology

Different amounts of ink, made up almost entirely of a frit that devitrified abundant small crystals of anorthoclase, were applied by inkjet printing onto a traditional unfired glaze substrate. The rheological properties of the ink and porous texture of the unfired glaze substrate were characterized. The fired coatings were analyzed by SEM–EDX to determine the elemental composition at different surface depths, and their microstructure was observed. The results confirmed the validity of the ink penetration model, developed in a previous study, for describing the composition profile in inkjet coatings as a function of the applied amount of ink and pore size and volume in the unfired glaze substrate relative to average ink particle size. Microhardness and indentation modulus of the fired glaze substrate without an ink application and of the fired ink-containing coatings were determined. The values of these properties were verified to fit a Weibull distribution function. The coatings containing an ink application at 400 and 600 dots per inch (dpi), respectively, displayed the best mechanical behavior. The study confirmed that inkjet printing a suspension with appropriate physico-chemical characteristics onto an unfired glaze substrate substantially improved the aesthetic characteristics and mechanical properties of the resulting fired coating.     

Product design: Metal nanoparticle‐based conductive inkjet inks

A systematic procedure that provides an efficient workflow for formulating conductive inks is developed. Qualitative product attributes of the inkjet ink are first identified and transformed into quantitative product specifications. Ingredients are then selected based on heuristics, mechanistic, and empirical models to meet the product specifications. Printability checks based on theoretical criteria are used to ensure that stable droplets can in principle be formed and coalesced properly to form a printed line of ink. Then, the conductive ink is prepared and printed to evaluate the performance of the inkjet ink experimentally. An example of preparing a copper ink for inkjet printing is used to illustrate the systematic procedure. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2740–2753, 2016     

纸张对喷墨打印线条质量的影响分析

实验针对普通的彩色喷墨打印机,检测了不同类型纸张上线条输出的质量特性。基于ISO 13660标准中定义的线条属性指标,实验开发了基于工业CCD捕获的数字影像进行线条属性指标求解的工具软件;其后,根据打印机的输出分辨率,设计了含有不同宽度的水平和竖直线条图标,并由7种纸张打印输出和测量分析。结果表明:喷墨打印的线条质量与纸张性能有明显的关系,而与打印技术关系不大;此外,照片打印纸在线条的密度、对比度、线宽增量和线边缘粗糙度方面较普通打印纸有较佳的表现,但线边缘的模糊度性能却不及后者。     

Optimizing inkjet printing process to fabricate thick ceramic coatings

This article describes the use of Taguchi optimization and ANOVA techniques on inkjet printing process to determine optimal parameters for fabrication of thick ceramic coatings over glass substrates. Stable nanoparticle suspensions are synthesized through high energy milling of precursor powders with adequate quantities of binder and suspending solvent. Most often, inkjet printing process is being used for developing fine and thin layers (<10 µm). However, an attempt is made to fabricate thick ceramic films by varying only IJP process parameters and without multiple layer deposition, thereby reducing efforts in ink synthesis and processing time of coated substrates. Three parameters of IJP were varied for developing a model that was used for precisely predicting the printed layer thickness under varying process parameters. ANOVA technique showed that open time interval in combination with nano particle concentration in the ink could potentially lead to thick coatings. The higher volume % of solvent in the diluted suspension ink under the influence of substrate heating contributed significantly to coffee stain effect with irregular surface coatings. However, increasing the concentration of nanoparticles in the diluted ink resulted in substantial improvement in thickness of the layer with simultaneous control of coating defects.     

喷墨打印相纸及打印图像质量的分析

喷墨打印相纸随着数码相机的发展近几年在国内发展迅速。针对目前产品质量没有测量标准的现状,提出喷墨相纸的质量指标主要为4个,即白度、光泽度、油墨吸收性和防水性。给出了相应的测量方法。并指出相纸上油墨点的面积是衡量质量的第一重要指标,其次是点的圆度。另外对图像输出的质量介绍了一种科学的评价方法,即图像的逼真性分析。说明图像的打印墨点直径不应小于方形像素的对角线长,图像才能真实再现。     

A Novel Polymeric Substrate with Dual-Porous Structures for High-Performance Inkjet-Printed Flexible Electronic Devices

Inkjet printing has emerged as a promising low-cost and high-performance method for manufacturing printing-based devices. However, the development of optimized substrates for inkjet printing using novel materials is limited. In this study, a novel polymeric substrate optimized for flexible electronic devices is fabricated using thin-film processing and phase inversion of polyethersulfone (PES). The PES film consists of two layers of pores; the upper layer has nano-sized pores that filter the nanoparticles in the conductive ink and allow for high-density aggregation on the substrate, while the lower layer contains micro-scale pores that quickly absorb and drain the ink solvent. The two porous structures lead to higher conductivity and high-resolution printed patterns by minimizing solvent lateral diffusion. Additionally, the PES printing substrate can undergo high-temperature curing of metal nanoparticles, enabling high-resolution pattern printing with low resistance. The PES substrate is highly transparent and flexible, allowing for the fabrication of various printed electronic patterns and the production of high-performance flexible electronic devices.     

喷墨相纸中PVA粘合剂与打印性能的关系

本文研究了彩色喷墨打印相纸的粘合剂与性能的关系。讨论了PVA粘合剂的聚合度对相纸性能以及PVA粘合剂用量对吸墨性能的影响。结果显示,粘合剂聚合度大有利于相纸性能的提高,粘合剂用量对相纸吸墨性能影响较大,合适的PVA聚合度和用量可以得到各项性能优良的喷墨打印相纸。