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Inkjet printing is a more sustainable and scalable fabrication method than spin coating for producing perovskite solar cells (PSCs). Although spin-coated SnO2 has been intensively studied as an effective electron transport layer (ETL) for PSCs, inkjet-printed SnO2 ETLs have not been widely reported. Here, we fabricated inkjet-printed, solution-processed SnOx ETLs for planar PSCs. A champion efficiency of 17.55% was achieved for the cell using a low-temperature processed SnOx ETL. The low-temperature SnOx exhibited an amorphous structure and outperformed high-temperature crystalline SnO2. The improved performance was attributed to enhanced charge extraction and transport and suppressed charge recombination at ETL/perovskite interfaces, which originated from enhanced electrical and optical properties of SnOx, improved perovskite film quality, and well-matched energy level alignment between the SnOx ETL and the perovskite layer. Furthermore, SnOx was doped with Cu. Cu doping increased surface oxygen defects and upshifted energy levels of SnOx, leading to reduced device performance. A tunable hysteresis was observed for PSCs with Cu-doped SnOx ETLs, decreasing at first and turning into inverted hysteresis afterwards with increasing Cu doping level. This tunable hysteresis was related to the interplay between charge/ion accumulation and recombination at ETL/perovskite interfaces in the case of electron extraction barriers.

[Display omitted] Energy storage devices are progressively advancing in the light-weight, flexible, and wearable direction. Ti 3 C 2 T x flexible film electrodes fabricated via a non-contact, cost-effective, high-efficiency, and large-scale inkjet printing technology were capable of satisfying these demands in our previous report. However, other MXenes that can be employed in flexible energy storage devices remain undiscovered. Herein, flexible V 2 CT x film electrodes (with the low formula weight vs Ti 3 C 2 T x film electrodes) with both high capacities and excellent photoelectric properties were first fabricated. The area capacitances of V 2 CT x film electrodes reached 531.3–5787.0 μF⋅cm−2 at 5 mV⋅s−1, corresponding to the figure of merits (FoMs) of 0.07–0.15. Noteworthy, V 2 CT x film electrode exhibited excellent cyclic stability with the capacitance retention of 83 % after 7,000 consecutive charge–discharge cycles. Furthermore, flexible all solid-state symmetric V 2 CT x supercapacitor was assembled with the area capacitance of 23.4 μF⋅cm−2 at 5 mV⋅s−1. Inkjet printing technology reaches the combination of excellent photoelectric properties and high capacities of flexible V 2 CT x film electrodes, which provides a new strategy for manufacturing MXene film electrodes, broadening the application prospect of flexible energy storage devices. [ABSTRACT FROM AUTHOR]

Recent manufacturing of perovskite solar cells (PSC) is moving beyond a spin coating technique. Among several new methods of the large‐area PSCs, inkjet printing (IJP) has emerged as a promising alternative to spin coating due to the high degree of control on printed film area and low material waste. In the IJP of PSCs, one important question is how to remove redundant excess solvent and facilitate the crystallization of the perovskite phase. Along with IJP, an antisolvent bathing is employed. This work reports how the IJP parameters and antisolvent bathing compositions affect the microstructure and initial efficiency of inkjet‐printed PSCs. The halide perovskite films are submerged in the antisolvent of different temperatures to observe the formation of an intermediate phase and the evolution of perovskite phase. By observing the phase evolution using X‐Ray diffraction, an optimized antisolvent bath duration is achieved for diethyl ether (DE) condition. An enhanced power conversion efficiency (PCE) and larger grain size with two sequential passes of inkjet‐deposited perovskite are also reported, and the dissolution of homogeneous nucleation sites as a mechanism for larger grains is proposed. Finally, with multipass IJP and cold antisolvent DE bathing, a champion device with 15.02% PCE is achieved. [ABSTRACT FROM AUTHOR]

In recent years, inkjet digital printing technology has become a popular research area. This paper focuses on the spreading behavior of single ink drops on coated paper in digital inkjet printing. It explores the impact of ink drop spreading on monochromatic spectral reflectance, providing new insights for the theoretical development of spectral prediction models. The study involves constructing a spreading behavior model through theoretical modeling. Numerical simulations were conducted using the Volume of Fluid (VOF) method in Fluent software to assess the feasibility of the theoretical model. Finally, experimental fitting was used to validate the accuracy of the theoretical model. Considering the feathering effect in practical printing, a comprehensive monochromatic extended Clapper-Yule spectral prediction model was developed based on the spreading behavior of single ink drops. The prediction results of this model showed significant accuracy improvements in monochromatic spectral prediction compared to the traditional segmented Clapper-Yule model. This research offers new perspectives for spectral prediction and provides theoretical guidance for enhancing print image quality. [ABSTRACT FROM AUTHOR]

This work presents a simple process for the development of flexible acetone gas sensors based on zinc oxide/graphene/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate). The gas sensors were prepared by inkjet printing, which was followed by a metal sparking process involving different sparking times. The successful decoration of ZnO nanoparticles (average size ~19.0 nm) on the surface of the graphene–PEDOT:PSS hybrid ink was determined by characterizations, including Raman spectroscopy, Fourier transform infrared spectroscopy, field-emission transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffractometry. The ZnO nanoparticle-decorated graphene–PEDOT:PSS with a sparking time of 2 min exhibited the highest response of 71.9% at 10 ppm of acetone, above those of samples treated with other sparking times and the undecorated control. In addition, the optimal sensor revealed high selectivity for acetone over several other kinds of gases, such as ammonia, toluene, dimethylformamide, ethanol, methanol, and benzene, at room temperature. The gas sensor also revealed a low limit of detection (0.4 ppm), high sensitivity (6.18 ppm−1), and high stability (5-week long-term) to acetone. The response and recovery times of the sensor were found to be 4.6 min and 4.2 min, respectively. The acetone-sensing mechanism was attributed to the formation of p-n heterojunctions, which were responsible for the significantly enhanced sensitivity. [ABSTRACT FROM AUTHOR]

Microneedles are mainly used for pain-free drug administration and in biosensing for wearable systems. They are also promising for fields such as agronomy for precision farming, but their fabrication is not straightforward, often requiring expensive equipment and cleanroom protocols, being unsuitable for mass production. Here, we report a new and simple method for the scalable fabrication of all-inkjet-printed conductive microneedles based on silver nanoparticles (extensible to any other metallic nanoparticle ink) and a simple example of their application for monitoring the electrochemical properties of plants. [ABSTRACT FROM AUTHOR]

In the quest for sustainable and efficient solutions for modern electronics, flexible electronic devices have garnered global attention due to their potential to revolutionize various technological applications. The manufacturing of these devices poses significant challenges, particularly regarding environmental sustainability and ease of production. A novel method employing direct inkjet printing of silver nanoparticle (npAg) ink onto cellulose nanocrystal (CNC) substrates is presented, offering a promising alternative to conventional methods. This study demonstrates the ability of CNCs to serve as a flexible and biodegradable substrate that does not require complex post-printing treatments to achieve adequate electrical performance. This method was implemented in the fabrication of an electrowetting-on-dielectric (EWOD) device, achieving circuit patterns with high resolutions and reduced resistances. The findings not only validate the use of CNCs in flexible electronic applications but also underscore the potential of advanced printing techniques to develop flexible electronics that are environmentally sustainable and technically feasible. [ABSTRACT FROM AUTHOR]

In recent years, 3D printing has emerged as a promising technology in energy storage, particularly for the fabrication of Li-ion battery electrodes. This innovative manufacturing method offers significant material composition and electrode structure flexibility, enabling more complex and efficient designs. While traditional Li-ion battery fabrication methods are well-established, 3D printing opens up new possibilities for enhancing battery performance by allowing for tailored geometries, efficient material usage, and integrating multifunctional components. This article examines three key 3D printing methods for fabricating Li-ion battery electrodes: (1) material extrusion (ME), which encompasses two subcategories—fused deposition modeling (FDM), also referred to as fused filament fabrication (FFF), and direct ink writing (DIW); (2) material jetting (MJ), including inkjet printing (IJP) and aerosol jet printing (AJP) methods; and (3) vat photopolymerization (VAT-P), which includes the stereolithographic apparatus (SLA) subcategory. These methods have been applied in fabricating substrates, thin-film electrodes, and electrolytes for half-cell and full-cell Li-ion batteries. This discussion focuses on their strengths, limitations, and potential advancements for energy storage applications. [ABSTRACT FROM AUTHOR]

Recent advancements in artificial intelligence (AI) have highlighted the critical need for energy‐efficient hardware solutions, especially in edge‐computing applications. However, traditional AI approaches are plagued by significant power consumption. In response, researchers have turned to biomimetic strategies, drawing inspiration from the ion‐mediated operating principle of biological synapses, to develop organic neuromorphic devices as promising alternatives. Organic mixed ionic‐electronic conductor (OMIEC) materials have emerged as particularly noteworthy in this field, due to their potential for enhancing neuromorphic computing capabilities. Together with device performance, it is crucial to select devices that allow fabrication via scalable techniques. This study investigates the fabrication of OMIEC‐based neuromorphic devices using inkjet printing, providing a scalable and material‐efficient approach. Employing a commercially available polymer mixed ionic‐electronic conductor (BTEM‐PPV) and a lithium salt, inkjet‐printed devices exhibit performance comparable to those fabricated via traditional spin‐coating methods. These two‐terminal neuromorphic devices demonstrate functionality analogous to literature‐known devices and demonstrate promising frequency‐dependent short‐term plasticity. Furthermore, comparative studies with previous light‐emitting electrochemical cells (LECs) and neuromorphic OMIEC devices validate the efficacy of inkjet printing as a potential fabrication technique. The findings suggest that inkjet printing is suitable for large‐scale production, offering reproducible and stable fabrication processes. By adopting the OMIEC material system, inkjet printing holds the potential for further enhancing device performance and functionality. Overall, this study underscores the viability of inkjet printing as a scalable fabrication method for OMIEC‐based neuromorphic devices, paving the way for advancements in AI hardware. [ABSTRACT FROM AUTHOR]

Poly(ethylene glycol) diacrylate (PEGDA) is a common polymer in the field of biomedical engineering and can be used for the production of drug delivery systems (DDS). The main advantages of PEGDA are biocompatibility and the ability to alter the physical and chemical properties, thereby ensuring individualized drug release behaviour. The processing of PEGDA via inkjet printing is relevant for the production of DDS. This can be challenging due to the high viscosity of pure PEGDA. In this work, PEGDA, with a molecular weight of 250 g/mol (PEGDA250), was inkjet printed using a Nanoplotter 2.1 with a piezoelectric heatable NanoTip HV-J-H printhead (GeSiM mbH, Radeberg, Germany) at different voltages and temperatures. Droplet generation was analysed in terms of droplet volume and angle deviations. PEGDA250 can be inkjet printed reproducibly in a voltage range of 60 V - 80 V at room temperature (20 °C) or heated up to 38 °C. The average volume of heated (38 °C) PEGDA250 droplets was approximately 110 pl - 150 pl higher than the droplet volume of PEGDA250 in the unheated state. The average angle deviations of main and satellite droplets were mostly < 3°. Increasing voltage or excessive heating of more than 38 °C caused greater instabilities in the droplet generation as well as larger satellite droplets which can affect the accuracy negatively. The studies have shown that PEGDA250 can be processed via inkjet printing and thus can be used as a drug carrier for DDS without the need for mixing with a solvent. [ABSTRACT FROM AUTHOR]

Ultramicrotomy is a well-established technique that has been applied in biology and medical research to produce thin sections or a blockface of an embedded sample for microscopy. Recently, this technique has also been applied in materials science or micro- and nanotechnology as a sample preparation method for subsequent characterization. In this work, an application of ultramicrotomy for the cross-section preparation of an inkjet-printed multilayer structure is demonstrated. The investigated device is a capacitor consisting of three layers. The top and bottom electrodes are printed with silver nanoparticle ink and the dielectric layer with a ceramic nanoparticle/polymer ink. A 3D profilometer is initially used to study the surface morphology of the printed multilayer. The measurements show that both electrodes exhibit a coffee-ring effect, which results in an inhomogeneous layer structure of the device. To obtain precise 3D information on the multilayer, cross-sections must be prepared. Argon ion beam milling is the current gold standard to produce a single cross-section in good quality, however, the cross-section position within the multilayer volume is poorly defined. Moreover, the milling process requires a significant investment of time and resources. Herein, we develop an efficient method to realize repetitive cross-section preparation at well-defined positions in the multilayer volume. Repetitive cross-sections are exposed by trimming with an ultramicrotome (UM) and this blockface is subsequently transferred into a scanning electron microscope (SEM) for imaging. A combination of custom-modified UM and SEM specimen holders allows repeated transfer of the clamped multilayer sample between instruments without damage and with high positioning accuracy. This novel approach enhances the combination of an established ultramicrotome and a SEM for multilayer sample volume investigation. Thus, a comprehensive understanding of printed multilayer structures can be gained, to derive insights for optimization of device architecture and printing process. [ABSTRACT FROM AUTHOR]

The 2D Ti3C2Tx MXene has a large specific surface area, abundant functional groups, and low work function, which has potential in the field of photocatalytic materials. However, the manufacturing of controllable films with high photocatalytic properties and desirable transmittance is a challenging task. Herein, low‐cost, large‐scale, and rapid preparation of Ti3C2Tx/TiO2 flexible composite films have been successfully prepared by inkjet printing technology, which can be applied in complex and special environments, as well as in photoelectrically controllable places for photocatalytic performance. With the increase of the anatase TiO2, the transmittance of Ti3C2Tx/TiO2 films increases from 55.37% to 73.27% at 780 nm, corresponding to the square resistance of 1.112–206.496 kΩ sq−1 and the figure of merit of 0.48–0.005. When the amount of anatase TiO2 is 15%, the film has the best photocatalytic effect on methylene blue (MB) dye, reaching 68.94%. After five cycles of testing, the degradation efficiency of MB dye decreases by only 5.68%, showing that the film has good cycling stability. This work provides a new research direction for photoelectrically controllable photocatalytic degradation in complex and special environments. [ABSTRACT FROM AUTHOR]

Zn anode-based electrochromic devices (ZECDs) stand out as a highly promising technology in the upcoming era of multifunctional electronic devices, offering a blend of electrochromic capabilities and energy storage functions within a single transparent platform. However, significant challenges persist in achieving efficient patterning, ensuring long-term stability, and fast color-switching kinetics for these devices. In this study, heterogeneous tungsten oxide nanowires (W17O47/Na0.1WO3, WNOs) are formulated into inkjet printing ink to assemble patternable ZECDs. The heterogeneous electrode structure of WNO enables a highly capacitive-controlled mechanism that promotes fast electrochromic/electrochemical behavior. Notably, by utilizing a three-dimensional MXene mesh modified substrate, the inkjet-printed ZECDs exhibit a wide optical modulation range of 69.13%, rapid color-changing kinetics (tc = 4.1 s, tb = 5.4 s), and highly reversible capacities of 70 mAh cm-2 over 1000 cycles. This scalable strategy develops the patterned electrodes with a wide optical modulation range and substantial energy storage properties, offering promising prospects for their application in next-generation smart electronics. [ABSTRACT FROM AUTHOR]

Cellular interactions, such as intercellular communication and signal transduction, can be enhanced within three-dimensional cell spheroids, contributing significantly to cellular viability and proliferation. This is crucial for advancements in cancer research, drug testing, and personalized medicine. The dimensions of the cell spheroids play a pivotal role in their functionality, affecting cell proliferation and differentiation, intercellular interactions, gene expression, protein synthesis, drug penetration, and metabolism. Consequently, different spheroid sizes may be required for various drug sensitivity experiments. However, conventional 3D cell spheroid cultures suffer from challenges such as size inconsistency, poor uniformity, and low throughput. To address these issues, we have developed an automated, intelligent system based on inkjet printing. This system allows for precise control of droplet volume by adjusting algorithms, thereby enabling the formation of spheroids of varying sizes. For spheroids of a single size, the printing pattern can be modified to achieve a coefficient of variation within 10% through a bidirectional compensation method. Furthermore, the system is equipped with an automatic pipetting module, which facilitates the high-throughput preparation of cell spheroids. We have implemented a 3 × 3 spheroid array in a 24-well plate, printing a total of 216 spheroids in just 11 min. Last, we attempted to print mouse small intestinal organoids and cultured them for 7 days, followed by immunofluorescent staining experiments. The results indicate that our equipment is capable of supporting the culture of organoids, which is of great significance for high-throughput drug screening and personalized medicine. [ABSTRACT FROM AUTHOR]

In this work, a gate insulator poly (4-vinylphenol) (PVP) of an organic field effect transistor (OFET) was deposited using an inkjet printing technique, realized via a high printing resolution. Various parameters, including the molecular weight of PVP, printing direction, printing voltage, and drop frequency, were investigated to optimize OFET performance. Consequently, PVP with a smaller molecular weight of 11 k and a printing direction parallel to the channel, a printing voltage of 18 V, and a drop frequency of 10 kHz showed the best OFET performance. With a direct ink writing-printed organic semiconductor, this work paves the way for fully inkjet-printed OFETs.

The visualization of the spatial distributions of gases from various sources is essential to understanding the composition, localization, and behavior of these gases. In this study, an inkjet-printed localized surface plasmon resonance (LSPR) subpixel gas sensor array was developed to visualize the spatial distributions of gases and to differentiate between acetic acid, geraniol, pentadecane, and cis-jasmone. The sensor array, which integrates gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), and fluorescent pigments, was positioned 3 cm above the gas source. Hyperspectral imaging was used to capture the LSPR spectra across the sensor array, and these spectra were then used to construct gas information matrices. Principal component analysis (PCA) enabled effective classification of the gases and localization of their sources based on observed spectral differences. Heat maps that visualized the gas concentrations were generated using the mean squared error (MSE) between the sensor responses and reference spectra. The array identified and visualized the four gas sources successfully, thus demonstrating its potential for gas localization and detection applications. The study highlights a straightforward, cost-effective approach to gas sensing and visualization, and in future work, we intend to refine the sensor fabrication process and enhance the detection of complex gas mixtures. [ABSTRACT FROM AUTHOR]

Anode-free lithium batteries (AFLBs) present an opportunity to eliminate the need for conventional graphite electrodes or excess lithium–metal anodes, thus increasing the cell energy density and streamlining the manufacturing process. However, their attributed poor coulombic efficiency leads to rapid capacity decay, underscoring the importance of achieving stable plating and stripping of Li on the negative electrode for the success of this cell configuration. A promising approach is the utilization of lithiophilic coatings such as silver to mitigate the Li nucleation overpotential on the Cu current collector, thereby improving the process of Li plating/stripping. On the other hand, inkjet printing (IJP) emerges as a promising technique for electrode modification in the manufacturing process of lithium batteries, offering a fast and scalable technology capable of depositing both thin films and patterned structures. In this work, a Fujifilm Dimatix inkjet printer was used to deposit Ag sites on a Cu current collector, aiming to modulate the interfacial electrochemistry of the system. Samples were fabricated with varying areas of coverage and the electrochemical performance of the system was systematically evaluated from bare Cu (non-lithiophilic) to a designed pattern (partially lithiophilic) and the fully coated thin film case (lithiophilic). Increasing lithiophilicity resulted in lower charge transfer resistance, higher exchange current density and reduced Li nucleation overpotential (from 55.75 mV for bare Cu to 13.5 mV for the fully coated case). Enhanced half-cell cyclability and higher coulombic efficiency were also achieved (91.22% CE over 76 cycles for bare Cu, 97.01% CE over 250 cycles for the fully coated case), alongside more uniform lithium deposition and fewer macroscopic irregularities. Moreover, our observations demonstrated that surface patterning through inkjet printing could represent an innovative, easy and scalable strategy to provide preferential Li nucleation sites to guide the subsequent Li deposition. [ABSTRACT FROM AUTHOR]

Electrochemical paper-based analytical devices (ePADs) offer an innovative, low-cost, and environmentally friendly approach for real-time diagnostics. In this study, we developed a functional all-inkjet paper-based electrochemical immunosensor using gold (Au) printed ink to detect salivary cortisol. Covalent binding of the cortisol monoclonal antibody onto the printed Au surface was achieved through electrodeposition of 4-carboxymethylaniline (CMA), with ethanolamine passivation to prevent non-specific binding. The ePAD exhibited a linear response within the physiological cortisol range (5–20 ng/mL), with sensitivities of 25, 23, and 19 Ω·ng/mL and R2 values of 0.995, 0.979, and 0.99, respectively. Additionally, interference studies against tumor necrosis factor-α (TNF-α) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) yielded excellent results. This novel ePAD, fabricated using inkjet printing technology on paper, simplifies the process, reduces environmental impact, and lowers fabrication costs. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) ink is a primary type of ink used in additive manufacturing with 3D inkjet printing. However, ink aggregation presents a challenge in nano-inkjet printing, affecting the stability and quality of the printing fluid and potentially leading to the clogging of nanometer-sized nozzles. This paper utilizes a Dissipative Particle Dynamics (DPD) simulation to investigate the aggregation behavior of alumina in a blend of 1,6-Hexanediol diacrylate (HDDA) and Trimethylolpropane triacrylate (TMPTA). By analyzing the effects of solid content, polymer component ratios, and dispersant concentration on alumina aggregation, the optimal ink formulation was identified. Compared to traditional experimental methods, DPD simulations not only reduce experimental costs and time but also reveal particle aggregation mechanisms that are difficult to explore through experimental methods, providing a crucial theoretical basis for optimizing ink formulations. This study demonstrates that alumina ceramic ink achieves optimal performance with a solid content of 20%, an HDDA-to-TMPTA ratio of 4:1, and 9% oleic acid as a dispersant. [ABSTRACT FROM AUTHOR]

The micro-scale detonation sequence prepared by the inkjet printing using all-liquid 2,4,6,8,10,12-hexanitro- 2,4,6,8,10,12-hexaazawurtzitan (CL-20)-based energetic inks enables the micro-space fine-scale assembly and stable propagation of detonation. However, the easy crystallization and high mechanical sensitivity of all-liquid CL-20 limit its applications to the microelectromechanical system (MEMS)-based pyrotechnics. This study developed a simple micro-nano CL-20-based polyvinyl alcohol (PVA) colloidal suspension suitable for inkjet printing to control the crystal structures and mechanical sensitivities of energetic composites. The results show that the CL-20-based multilayer films formed by inkjet printing had dense microstructures, with the porosity decreasing to 13.81% and ε-type crystals. Compared with micro-nano CL-20 particles, the impact and friction sensitivities of CL-20-based multilayer films were reduced by 100% and 122%, respectively, and their apparent activation energy increased by 44.7 kJ mol-1, thus effectively improving the safety performance of micro-nano structured explosive agents. Therefore, CL-20-based multilayer films have great potential for application to the micro-scale detonation sequence of MEMS. [ABSTRACT FROM AUTHOR]

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In this work, a gate insulator poly (4-vinylphenol) (PVP) of an organic field effect transistor (OFET) was deposited using an inkjet printing technique, realized via a high printing resolution. Various parameters, including the molecular weight of PVP, printing direction, printing voltage, and drop frequency, were investigated to optimize OFET performance. Consequently, PVP with a smaller molecular weight of 11 k and a printing direction parallel to the channel, a printing voltage of 18 V, and a drop frequency of 10 kHz showed the best OFET performance. With a direct ink writing-printed organic semiconductor, this work paves the way for fully inkjet-printed OFETs. [ABSTRACT FROM AUTHOR]

The droplet formation process in inkjet printing is studied numerically and verified through a simulation model. The droplet formation process decides the printing quality of the coating, and a mathematical model is developed to understand the complete process from droplet formation to detachment. The Navier-Stokes equation is used to mathematically derive the droplet radius (rnumerical). COMSOL multiphysics is used for simulation and the radius (rsimulation) is calculated from the droplet mass. The rnumerical and rsimulation are compared for inks containing nickel, graphene, and nickel-graphene composite ink it is observed that the composite ink radiuses have the lowest difference (rsimulation - rnumerical = 0.085 µm). A droplet is formed at 1.47 mm from the nozzle inlet, for nickel-graphene ink, and after 1.5mm for other pristine inks. The results are verified through Z number, velocity profile, and droplet mass. The droplet formation observed from the velocity profile is earliest at 120 µs. It is seen that a stable droplet is generated at 100µs for nickel-graphene ink and at 200 µs for individual inks. [ABSTRACT FROM AUTHOR]

The concept of personalized medicine tailored to individual patients has garnered considerable attention recently, particularly in exploring the potential of 3D printing technology within the pharmaceutical and healthcare industries. 3D printing involves the layer-by-layer creation of threedimensional objects from digital designs. This review aim to provide an in-depth discussion focusing on 3D printing technology, its role in drug delivery systems, and its application in the pharmaceutical product development process. Commonly categorized by material layering methods, 3D printers typically fall into inkjet, extrusion, or laser-based systems. The review delves into these different types of 3D printers and their diverse applications in drug delivery across various sectors. Additionally, it encompasses a selection of recent research conducted in the pharmaceutical realm concerning 3D printing for drug delivery applications and challenges. [ABSTRACT FROM AUTHOR]

Herein, a YAG/10 at% Yb:YAG/YAG transparent ceramic planar waveguide (PWG) gain medium has been molded via inkjet printing and dry pressing molding. The composition and rheological property of ink are optimized along with the printing process to enhance the printing accuracy and quality. The PWG has dimensions of 13.5 × 8.0 × 1.8 mm3, while the thickness of the core Yb:YAG layer is ≈190 μm. The in‐line transmittance of the PWG reaches 81.7% at 1030 nm, and the average grain size is ≈2.3 μm. The diffusion characteristics of Yb ions across the interface between the cladding YAG layer and the core Yb:YAG layer are investigated by calculating the diffusion coefficient and the mean diffusion distance of 172Yb ions. The Yb:YAG PWG oscillator, which is pumped from a single end by a 940 nm laser diode, produces continuous wave laser at a wavelength of 1030 nm and exhibits the highest power (3.8 W) and highest absorbed–output slope efficiency (64.6%). [ABSTRACT FROM AUTHOR]

Recent manufacturing of perovskite solar cells (PSC) is moving beyond a spin coating technique. Among several new methods of the large‐area PSCs, inkjet printing (IJP) has emerged as a promising alternative to spin coating due to the high degree of control on printed film area and low material waste. In the IJP of PSCs, one important question is how to remove redundant excess solvent and facilitate the crystallization of the perovskite phase. Along with IJP, an antisolvent bathing is employed. This work reports how the IJP parameters and antisolvent bathing compositions affect the microstructure and initial efficiency of inkjet‐printed PSCs. The halide perovskite films are submerged in the antisolvent of different temperatures to observe the formation of an intermediate phase and the evolution of perovskite phase. By observing the phase evolution using X‐Ray diffraction, an optimized antisolvent bath duration is achieved for diethyl ether (DE) condition. An enhanced power conversion efficiency (PCE) and larger grain size with two sequential passes of inkjet‐deposited perovskite are also reported, and the dissolution of homogeneous nucleation sites as a mechanism for larger grains is proposed. Finally, with multipass IJP and cold antisolvent DE bathing, a champion device with 15.02% PCE is achieved.

With the rapid development of synthetic biology and genomic research, the demand for high-throughput DNA synthesis has been steadily increasing. Inkjet printing technology has gradually emerged as an ideal method for customized oligonucleotide synthesis due to its high precision and flexibility. However, the traditional solvent acetonitrile (ACN), due to its low viscosity and high permeability, fails to meet the stability requirements for inkjet head operation, resulting in unstable droplet formation that affects synthesis accuracy and efficiency. This study proposes propylene carbonate (PC) as a novel solvent for inkjet DNA synthesis, comparing the stability of inkjet droplets and the performance of oligonucleotide synthesis between PC and ACN, while further optimizing the concentrations of phosphoramidite monomers and activator. Experimental results indicate that the PC solvent not only exhibits good inkjet stability but also significantly enhances the purity of oligonucleotide synthesis products and stepwise coupling efficiency under optimal conditions. When synthesizing a target sequence of 30 nucleotides, a stepwise coupling efficiency of 99.01 % was achieved. This study achieved a new DNA synthesis reagent formulation that supports inkjet-based DNA synthesis and exhibits excellent coupling efficiency. This research outcome is expected to promote the further development of high-throughput DNA synthesis using inkjet technology.

Radio frequency identification (RFID) is an emerging technology that has a crucial role in many areas. To be suitable for these applications, RFID tags must be flexible, which presents greater manufacturing challenges. Printing as an additive manufacturing method is preferred over subtractive processes due to its efficient use of materials and environmental friendliness. This review presents key properties of the printed patterns, namely electrical conductivity, layer thickness, and surface morphology. It links them to the reading distance between the RFID tag and the reader. The types of conductive inks and their role in achieving a long-read distance of flexible antennas are also discussed. The properties of flexible substrates linked to the printing process are also presented. These substrates were classified into paper, polymer, and textiles. This article considers two laboratory-scale printing techniques commonly used in research: inkjet and screen printing. The printing parameters of these printing techniques that affect the printing quality are covered. Furthermore, electroless plating is presented as a metallization process or a complementary method to other printing techniques.

Abstract Recent advancements in artificial intelligence (AI) have highlighted the critical need for energy‐efficient hardware solutions, especially in edge‐computing applications. However, traditional AI approaches are plagued by significant power consumption. In response, researchers have turned to biomimetic strategies, drawing inspiration from the ion‐mediated operating principle of biological synapses, to develop organic neuromorphic devices as promising alternatives. Organic mixed ionic‐electronic conductor (OMIEC) materials have emerged as particularly noteworthy in this field, due to their potential for enhancing neuromorphic computing capabilities. Together with device performance, it is crucial to select devices that allow fabrication via scalable techniques. This study investigates the fabrication of OMIEC‐based neuromorphic devices using inkjet printing, providing a scalable and material‐efficient approach. Employing a commercially available polymer mixed ionic‐electronic conductor (BTEM‐PPV) and a lithium salt, inkjet‐printed devices exhibit performance comparable to those fabricated via traditional spin‐coating methods. These two‐terminal neuromorphic devices demonstrate functionality analogous to literature‐known devices and demonstrate promising frequency‐dependent short‐term plasticity. Furthermore, comparative studies with previous light‐emitting electrochemical cells (LECs) and neuromorphic OMIEC devices validate the efficacy of inkjet printing as a potential fabrication technique. The findings suggest that inkjet printing is suitable for large‐scale production, offering reproducible and stable fabrication processes. By adopting the OMIEC material system, inkjet printing holds the potential for further enhancing device performance and functionality. Overall, this study underscores the viability of inkjet printing as a scalable fabrication method for OMIEC‐based neuromorphic devices, paving the way for advancements in AI hardware.

As miniaturization of semiconductor memory devices is reaching its physical and technological limits, there is a demand for memory technologies that operate on new principles. Atomic switches are nanoionic devices that show repeatable resistive switching between high-resistance and low-resistance states under bias voltage applications, based on the transport of metal ions and redox reactions in solids. Their essential structure consists of an ion conductor sandwiched between electrochemically active and inert electrodes. This review focuses on the resistive switching mechanism of atomic switches that utilize a solid polymer electrolyte (SPE) as the ion conductor. Owing to the superior properties of polymer materials such as mechanical flexibility, compatibility with various substrates, and low fabrication costs, SPE-based atomic switches are a promising candidate for the next-generation of volatile and nonvolatile memories. Herein, we describe their operating mechanisms and key factors for controlling the device performance with different polymer matrices. In particular, the effects of moisture absorption in the polymer matrix on the resistive switching behavior are addressed in detail. As potential applications, atomic switches with inkjet-printed SPE and quantum conductance behavior are described. SPE-based atomic switches also have great potential in use for neuromorphic devices. The development of these devices will be enhanced using nanoarchitectonics concepts, which integrate functional materials and devices.

One interesting way of enhancing the properties of lithium-ion batteries is to produce electrodes with a 3D design. The aim of the 3D design is to allow the electrolyte to penetrate through the electrode volume, increasing the surface-to-volume ratio and reducing ion diffusion paths. To achieve these designs, additive shaping processes are promising. In this article, we analyze the possibility of printing 3D structured electrodes using inkjet printing. The study focuses on Nickel Cobalt Manganese (NMC) based electrodes, commonly used as cathode materials. The importance of initial powder size and formulation will be discussed in terms of printability. Finally, we show that it is possible to print 3D structures using NMC inks. Improvements need to be made to ensure greater printing stability.

The high-resolution, inkjet-printed zinc oxide (ZnO) microdot arrays with suppressed coffee-ring effect was demonstrated by investigating the correlation between drying and solidification processes. The internal microfluidic behavior of an ejected droplet and the associated drying process is geometry-dependent, which can be controlled by the temperature and surface energy of the substrate. During evaporation, droplets in contact with a wettable surface exhibit a dominant outward convective flow, resulting in a pronounced coffee-ring effect. In contrast, for droplets with minimal contact area on a substrate with low surface energy, the surface energy gradient along the relatively long thermal conducting path length reinforces the Marangoni flow, which retards the pinning of the contact line, resulting in tiny microdots with suppressed coffee-ring effect. The controlled ZnO microdots exhibit a diameter of approximately 3 μm with a thickness of 50 nm, which is one of the smallest microstructures produced by the inkjet printing method. Additionally, the integration of the ZnO microdot arrays into organic solar cells aimed to alter the light path length, leading to enhanced internal absorption. The P3HT:PCBM, PTB7-Th:PCBM, and PM6:Y6 devices with ZnO microdot arrays exhibit higher power conversion efficiencies of 3.54%, 9.04%, and 15.61% compared to reference devices of 3.38%, 8.85%, and 15.25% respectively.

Abstract Additive manufacturing of conductive layers on a dielectric substrate has garnered significant interest due to its promise to produce printed electronics efficiently and its capability to print on curved substrates. A considerable challenge encountered is the conductive layer’s potential peeling due to inadequate adhesion with the dielectric substrate, which compromises the durability and functionality of the electronics. This study strives to facilitate the binding force through dielectric substrate surface modification using concentrated sulfuric acid and ultraviolet (UV) laser treatment. First, polyetheretherketone (PEEK) and nanoparticle silver ink were employed as the studied material. Second, the surface treatment of PEEK substrates was conducted across six levels of sulfuric acid exposure time and eight levels of UV laser scanning velocity. Then, responses such as surface morphology, roughness, elemental composition, chemical bonding characteristics, water contact angle, and surface free energy (SFE) were assessed to understand the effects of these treatments. Finally, the nanoparticle silver ink layer was deposited on the PEEK surface, and the adhesion force measured using a pull-off adhesion tester. Results unveiled a binding force of 0.37 MPa on unmodified surface, which escalated to 1.99 MPa with sulfuric acid treatment and 2.21 MPa with UV laser treatment. Additionally, cross-approach treatment investigations revealed that application sequence significantly impacts results, increasing binding force to 2.77 MPa. The analysis further delves into the influence mechanism of the surface modification on the binding force, elucidating that UV laser and sulfuric acid surface treatment methods hold substantial promise for enhancing the binding force between heterogeneous materials in the additive manufacturing of electronics.

Inkjet printing of magnetic materials has increased in recent years, as it has the potential to improve research in smart, functional materials. Magnetostriction is an inherent property of magnetic materials which allows strain or magnetic fields to be detected. This makes it very attractive for sensors in the area of structural health monitoring by detecting internal strains in carbon fibre-reinforced polymer (CFRP) composite. Inkjet printing offers design flexibility for these sensors to influence the magnetic response to the strain. This allows the sensor to be tailored to suit the location of defects in the CFRP. This research has looked into the viability of printable soft magnetic materials for structural health monitoring (SHM) of CFRP. Magnetite and nickel ink dispersions were selected to print using the JetLab 4 drop-on-demand technique. The printability of both inks was tested by selecting substrate, viscosity and solvent evaporation. Clogging was found to be an issue for both ink dispersions. Sonicating and adjusting the jetting parameters helped in distributing the nanoparticles. We found that magnetite nanoparticles were ideal as a sensor as there is more than double increase in saturation magnetisation by 49 Am2/kg and more than quadruple reduction of coercive field of 5.34 kA/m than nickel. The coil design was found to be the most sensitive to the field as a function of strain, where the gradient was around 80% higher than other sensor designs. Additive layering of 10, 20 and 30 layers of a magnetite square patch was investigated, and it was found that the 20-layered magnetite print had an improved field response to strain while maintaining excellent print resolution. SHM of CFRP was performed by inducing a strain via bending and it was found that the magnetite coil detected a change in field as the strain was applied. [ABSTRACT FROM AUTHOR]

This paper presents an innovative method for fabricating reflectarray antennas using inkjet printing technology on flexible substrates, markedly enhancing integration and manufacturability compared to traditional PCB methods. The technique employs inkjet printing to deposit conductive inks directly onto a flexible polyethylene naphthalate (PEN) substrate, seamlessly integrating feed and reflectarray components without complex assembly processes. This streamlined approach not only reduces manufacturing complexity and costs but also improves mechanical flexibility, making it ideal for applications requiring deployable antennas. The design process includes an origami-inspired folding of the substrate to achieve the desired three-dimensional antenna structures, optimizing the focal length to dimension ratio (F/D) to ensure maximum efficiency and performance. The feed and the reflectarray geometry are optimized for an F/D of 0.6, which achieves high gain and aperture efficiency, demonstrated through detailed simulations and measurements. For normal incidence, the configuration achieves a peak gain of 9.3 dBi and 48% radiation efficiency at 10 GHz; for oblique incidence, it achieves 7.3 dBi and 40% efficiency. The study underscores the significant potential of inkjet-printed antennas in terms of cost-efficiency, precision, and versatility, paving the way for new advancements in antenna technology with a substantial impact on future communication systems. [ABSTRACT FROM AUTHOR]

Hybrid organic‐inorganic perovskite solar cells (PSCs) have rapidly advanced in the new generation of photovoltaic devices. As the demand for energy continues to grow, the pursuit of more stable, highly efficient, and cost‐effective solar cells has intensified in both academic research and the industry. Consequently, the development of scalable fabrication techniques that yield a uniform and dense perovskite absorber layer with optimal crystallization plays a crucial role to enhance stability and higher efficiency of perovskite solar modules. This review provides a comprehensive summary of recent advancements, comparison, and future prospects of scalable deposition techniques for perovskite photovoltaics. We discuss various techniques, including solution‐based and physical methods such as blade coating, inkjet printing (IJP), screen printing, slot‐die coating, physical vapor deposition, and spray coating that have been employed for fabrication of perovskite modules. The advantages and challenges associated with these techniques, such as contactless and maskless deposition, scalability, and compatibility with roll‐to‐roll processes, have been thoroughly examined. Finally, the integration of multiple subcells in perovskite solar modules is explored using different scalable deposition techniques. [ABSTRACT FROM AUTHOR]

Silver-based metal–organic decomposition inks composed of silver salts, complexing agents and volatile solvents are now the subject of much research due to the simplicity and variability of their preparation, their high stability and their relatively low sintering temperature. The use of this type of ink in inkjet printing allows for improved cost-effective and environmentally friendly technology for the production of electrical devices, including flexible electronics. An approach to producing a silver salt-based reactive ink for jet printing has been developed. The test images were printed with an inkjet printer onto polyimide substrates, and two-stage thermal sintering was carried out at temperatures of 60 °C and 100–180 °C. The structure and electrical properties of the obtained conductive lines were investigated. As a result, under optimal conditions an electrically conductive film with low surface resistance of approximately 3 Ω/square can be formed. [ABSTRACT FROM AUTHOR]

This study reports the use of tin oxide (SnO 2) octahedral nanoparticles with exposed high-energy facets as sensing material in inkjet-printed carbon monoxide (CO) gas sensors. The nanoparticles were synthesized via a hydrothermal method aimed at encouraging high-indexed (221) crystal planes to be exposed as facets, since their high surface energy may encourage interactions with gases. Studies by X-ray diffraction (XRD) confirmed the identity of the SnO 2 , while transmission electron microscopy (TEM) revealed formations of octahedral-shaped SnO 2 nanoparticles, with features confirming the exposure of high-energy (221) crystal facets. The nanoparticles' reductive behavior in a CO environment was studied using temperature-programmed reduction (TPR). A stable ink based on the SnO 2 nanoparticles was successfully prepared and utilized to fabricate, via inkjet printing, homogenous films onto electrically conductive graphene-based interdigitated electrodes. Optimizing the inkjet printing parameters enhanced the CO gas sensing performance of the fabricated sensors. For example, at 200 ppm, the sensor with 10 printed layers recorded a sensitivity of about 20%, as compared to a sensitivity of not more than 14% recorded in each of the sensors with 5, 15, and 20 printed layers. As a result of having homogenous films, the inkjet-printed sensors also exhibited almost double the sensitivity of similar sensors prepared by drop-casting method. [Display omitted] [ABSTRACT FROM AUTHOR]

This review encompasses additive manufacturing techniques for crafting 5G electronics, showcasing how these methods innovate device creation with novel examples. A wearable phased array device on commonplace 3D printed material is described, with integrated microfluidic cooling channels used for thermal regulation of integrated circuit bulk components. Mechanical and electrical tunability are exemplified in an origami-inspired phased array structure. A 3D printed IoT cube structure shows the flexibility in the number of geometries additively manufactured 5G devices can adhere to. Finally, integrating 3D optical lenses with 5G electronics is shown. [ABSTRACT FROM AUTHOR]

This study investigated the influence of microstructure on the performance of Ag inkjet-printed, resistive temperature detectors (RTDs) fabricated using particle-free inks based on a silver nitrate (AgNO3) precursor and ethylene glycol as the ink solvent. Specifically, the temperature coefficient of resistance (TCR) and sensitivity for sensors printed using inks that use monoethylene glycol (mono-EG), diethylene glycol (di-EG), and triethylene glycol (tri-EG) and subjected to a low-pressure argon (Ar) plasma after printing were investigated. Scanning electron microscopy (SEM) confirmed previous findings that microstructure is strongly influenced by the ink solvent, with mono-EG inks producing dense structures, while di- and tri-EG inks produce porous structures, with tri-EG inks yielding the most porous structures. RTD testing revealed that sensors printed using mono-EG ink exhibited the highest TCR (1.7 × 10−3/°C), followed by di-EG ink (8.2 × 10−4/°C) and tri-EG ink (7.2 × 10−4/°C). These findings indicate that porosity exhibits a strong negative influence on TCR. Sensitivity was not strongly influenced by microstructure but rather by the resistance of RTD. The highest sensitivity (0.84 Ω/°C) was observed for an RTD printed using mono-EG ink but not under plasma exposure conditions that yield the highest TCR. [ABSTRACT FROM AUTHOR]

The inkjet printing of water-based graphene and graphene oxide inks on five substrates, two rigid (silicon and glass) and three flexible (cellulose, indium tin oxide-coated polyethylene terephthalate (ITO-PET) and ceramic coated paper (PEL paper)), is reported in this work. The physical properties of the inks, the chemical/topographical properties of selected substrates, and the inkjet printing (IJP) of the graphene-based materials, including the optimisation of the printing parameters together with the morphological characterisation of the printed layers, are investigated and described in this article. Furthermore, the impact of both the chemical and topographical properties of the substrates and the physical properties of graphene-based inks on the morphology, wettability and surface coverage of the inkjet-printed graphene patterns is studied and discussed in detail. [ABSTRACT FROM AUTHOR]

Organic thin layers are highlighted as crucial components of flexible and printed electronic products due to their ability to provide mechanical flexibility in various applications, such as flexible displays and wearable electronics. The thickness and uniformity of these layers are crucial factors that influence surface planarization, mechanical stress relief, and the enhancement of optical performance. Therefore, accurate measurement of their thickness distribution is essential. In this study, the two-dimensional thickness distributions of spin-coated and inkjet-printed organic microlayers on glass substrates were measured using a light extinction image method. Using a 300 nm wavelength light source and a camera, images with an area of 4872 × 3640 μm2 and an XY resolution of 3.5 μm were obtained through single measurements. The precision of the measured thickness could be enhanced to several nanometers through pixel binning and image overlaying. Using this light extinction measurement system, we measured and analyzed the thickness distribution of the center and edge of the spin-coated and inkjet-printed organic layers with thicknesses of several micrometers. [ABSTRACT FROM AUTHOR]

Robust anti‐counterfeiting techniques aim for easy identification while remaining difficult to forge, especially for high‐value items such as currency and passports. However, many existing anti‐counterfeiting techniques rely on deterministic processes, resulting in loopholes for duplication and counterfeiting. Therefore, achieving high‐level encryption and easy authentication through conventional anti‐counterfeiting techniques has remained a significant challenge. To address this, this work proposes a solution that combined fluorescence and structural colors, creating a physically unclonable multiplex encryption system (PUMES). In this study, the physicochemical properties of colloidal photonic inks are systematically adjusted to construct a comprehensive printing phase diagram, revealing the printable region. Furthermore, the brightness and color saturation of inkjet‐printed colloidal photonic crystal structural colors are optimized by controlling the substrate's hydrophobicity, printed droplet volume, and the addition of noble metals. Finally, fluorescence is incorporated to build PUMES, including macroscopic fluorescence and structural color patterns, as well as microscopic physically unclonable fluorescence patterns. The PUMES with intrinsic randomness and high encoding capacity are authenticated by a deep learning algorithm, which proved to be reliable and efficient under various observation conditions. This approach can provide easy identification and formidable resistance against counterfeiting, making it highly promising for the next‐generation anti‐counterfeiting of currency and passports. [ABSTRACT FROM AUTHOR]