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In the past decade, organic mixed ion-electron conductors have been successfully adopted in innovative bioelectronic, neuromorphic, and electro-optical technologies, as well as in multiple energy harvesting and printed electronics applications. However, despite the intense research efforts devoted to these materials, organic mixed conductors have not yet found application in electronic/photonic devices operating in key regions of the electromagnetic spectrum, such as the microwave (>5 GHz) and terahertz (0.1-10 THz) ranges. A possible reason for this technological gap is the widespread notion that organic electronic materials are unsuitable for high-frequency applications. In this work, we demonstrate for the first time the utility of high-performance polymer mixed conductors as electro-active tuning layers in reconfigurable terahertz metasurfaces, achieving modulation performances comparable with state-of-the-art inorganic and 2D semiconductors. Through time-domain terahertz spectroscopy, we show that the large conductivity modulations of these polymers, until now probed only at very low frequencies, are effectively preserved in the terahertz range, leading to optimal metadevice reconfigurability. Finally, we leverage the unique processability of organic materials to develop fully direct-written electrically tuneable metasurfaces onto both rigid and flexible substrates, opening new opportunities for the mass-scale realization of flexible and light-weight terahertz optics with unique mechanical characteristics and environmental footprint. Organic mixed ion-electron conductors are emerging as promising platforms for innovative bioelectronic, neuromorphic, and electro-optical technologies. In this work, authors explore the potential of this class of electronic materials in THz technologies by developing reconfigurable metasurfaces via direct-writing methods. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) enables the production of complex geometries that are not accessible by conventional processes. Fused deposition modeling (FDM) 3D printing is an important choice for many industries, particularly for additive manufacturing of microelectronic systems. The various physical properties of printing polymer materials, such as geometry, rheological behavior, and others, need to be taken into account in the printing process. In our study, a semi-crystalline polypropylene polymer PP is used in the FDM process, as it is characterized by deformability due to crystallization. We investigate the thermomechanical behavior of a semi-crystalline polymer PP (polypropylene) with different material deposition geometries ranging from a parallelepiped filament to a cylindrical filament in a numerical model developed. A coupling (to temperature vs. time evolution during printing) of solid mechanics, heat transfer, and crystallization kinetics equations was considered to build the Multiphysics numerical model capable of predicting temperature profiles, residual stresses, and degree of crystallization during the FDM process. The results obtained with the numerical model provide a reliable approach to predicting and adjusting the actual thermomechanical behavior of a printed electronics package. The values are calculated and compared to the six points in the two samples. The results show that the change in deposit shape resulted in a maximum deviation of 3.3 MPa for residual stress and 0.376 for the degree of crystallization, while a decrease was observed in the selected points with an average deviation of 1.81 MPa and 0.193 for residual stress and the degree of crystallization, respectively. This is due to the effects of the modification of the shape model on the temperature profile model, with the change in the 3D structures of the printed polymer material; the methodology presented in this paper allows the numerical model to be validated with an experimental study of the literature. The paper proposes future work and an experimental study to validate the results of the numerical model. [ABSTRACT FROM AUTHOR]

Reactive inkjet (RIJ) printing represents an important approach for printed electronics. Different from the traditional inkjet printing of colloidal inks with nanosized metal particles, RIJ prints the solution of metal organic compound, that is, metal‐organic decomposition (MOD) ink, and reduces it to the pure metal during the post‐treatment to form conductive electrodes. Successful RIJ printing of MOD inks has been demonstrated; however, the fundamental understanding of droplet deposition involved in RIJ printing is lacking. Herein, the effect of substrate temperature and nozzle temperature during inkjet printing of copper MOD ink on the deposition morphology is investigated. It exhibits distinct behaviors in the deposition morphology at elevated temperatures when compared with the ones at room temperature. The different deposition morphology of the copper ink at various temperatures is attributed to the generation of a localized seeding layer which attracts the copper ions to deposit. In addition, the copper MOD ink printing is compared with a silver MOD ink. The different deposition morphology between the copper ink and silver ink is due to the solvent system. Understanding the deposition mechanism for reactive inks provides valuable information and guidance in the fabrication of printed functional devices using particle‐free reactive inks. [ABSTRACT FROM AUTHOR]

With the constant increase of electronic waste globally, society is demanding and governments are boosting the development of electronics with less pollutant materials and reduced environmental impact. One way to achieve this is to implement materials that are functional and structural at the same time, reducing material use and assembling parts. Further, printing techniques, such as screen printing, reduce considerably costs and time compared with conventional electronics; combined with methods to conform printed electronics to a 3D shape, such as thermoforming, allow to obtain nonplanar surface electronics simply and efficiently. Herein, screen‐printable inks made of styrene–ethylene/butylene–styrene and different aspect‐ratio carbon‐based materials for conformable electronics are reported. The inks are prepared with carbon black, carbon nanotubes, and reduced graphene oxide as conductive fillers, printed on a flexible substrate and thermoformed. Carbon black and carbon nanotube samples are functional after the process, with conductivities of 96 and 141 S m−1 for the best performing sample of each filler, respectively. Rheological, morphological, thermal, and electrical properties of the materials are also characterized. This study shows the influence of the filler's type and aspect ratio on the morphology and electrical conductivity of the printed materials before and after thermoforming. [ABSTRACT FROM AUTHOR]

Liquid metal (LM) electronic ink (e‐ink) is a promising new‐generation material for printed electronics. Extended from this ideal platform, such ink can be post‐processed or loaded with semiconductor nanoparticles to further make semiconductors in the forms of dots, wires, and films on its surface. In this way, targeted semiconductors can be quickly fabricated and patterned as desired with low cost at around room temperature. This leads to the unconventional bottom‐up strategy for direct manufacture of functional devices. Along this direction, a series of p–n junction diodes, field‐effect transistors, and light‐emitting devices have been developed. LM‐printed semiconductor would significantly innovate the classical processes of preparing integrated circuits and electronic devices. To push forward further progress of this cutting‐edge frontier, this article is dedicated to present an overview of LM‐printed semiconductor. The material category of LM semiconductor e‐inks and their synthesis approaches is introduced. Then the core strategies toward printing semiconductors are systematically outlined. Following that, the typical printed semiconductor materials and electronic devices thus constructed as well as their potential applications are summarized. Finally, scientific and technical challenges thus raised are interpreted. Perspective in the area is given. [ABSTRACT FROM AUTHOR]

Electronic devices are being produced in substantial quantities and have become an essential component of our daily existence. Furthermore, interest in printed electronics has increased due to the straightforwardness of the manufacturing process, decreased expenses, and diminished ecological footprint. Despite these advantages, there are still some challenges in the field of printed electronics. In this study, a process for manufacturing electrical wiring on a three-dimensional (3D) plastic substrate was developed using a pneumatic dispenser that utilizes a continuous-wave laser for laser sintering, and enables rapid and selective sintering at ambient temperature and pressure. The metal paste consists of spherical Ag-coated Cu with a diameter of 5–10 µm, Sn-Bi powders, and epoxy binders and has a high viscosity. In addition, a thermo-mechanical characterization of the metal paste was performed to explain the metallurgical bonding behavior during sintering. Using a pneumatic-based dispenser equipped with a rotary valve, a high-viscosity metal paste was precisely patterned at a pressure of 1.0 bar and a dispensing speed of 5 mm/s. The patterned metal paste was then sintered with a continuous-wave laser to achieve electrical conductivity. When sintering with a power of 5 W and a scanning speed of 5 mm/s, at which the induced temperature is 280 ℃, a specific resistivity of 0.193 mΩ·cm was determined. Under these conditions, the metal paste was directly patterned and sintered onto a 3D plastic substrate as electrical wiring, and LEDs were then affixed to the substrate to validate the interconnections' functionality. In addition, the feasibility of industrial applications was demonstrated by fabricating a garnish model for automotive interiors. [ABSTRACT FROM AUTHOR]

The implementation of the laser sintering for inkjet-printed nanoparticles and metal organic decomposition (MOD) inks on a flexible polymeric film has been analyzed in detail. A novel approach by implementing, next to a commonly 3.2 mm diameter spot laser optic, a line laser optic with a laser beam area of 2 mm × 80 mm, demonstrates the high potential of selective laser sintering to proceed towards a fast and efficient sintering methodology in printed electronics. In this work, a multiplicity of laser parameters, primary the laser speed and the laser power, have been altered systematically to identify an optimal process window for each ink and to convert the dried and non-conductive patterns into conductive and functional silver structures. For each ink, as well as for the two laser optics, a suitable laser parameter set has been found, where a conductivity without any damage to the substrate or silver layer could be achieved. In doing so, the margin of the laser speed for both optics is ranging in between 50 mm/s and 100 mm/s, which is compatible with common inkjet printing speeds and facilitates an in-line laser sintering approach. Considering the laser power, the typical parameter range for the spot laser lays in between 10 W and 50 W, whereas for the line optics the full laser power of 200 W had to be applied. One of the nanoparticle silver inks exhibits, especially for the line laser optic, a conductivity of up to 2.22 × 107 S‧m−1, corresponding to 36% of bulk silver within a few seconds of sintering duration. Both laser sintering approaches together present a remarkable facility to use the laser either as a digital tool for sintering of defined areas by means of a spot beam or to efficiently sinter larger areas by means of a line beam. With this, the utilization of a laser sintering methodology was successfully validated as a promising approach for converting a variety of inkjet-printed silver patterns on a flexible polymeric substrate into functionalized conductive silver layers for applications in the field of printed electronics. [ABSTRACT FROM AUTHOR]

Polyimide‐based dielectric films are widely used in various thin film devices including organic field‐effect transistors (OFETs) owing to their promising thermal/chemical stability, mechanical flexibility, and insulating properties. On the other hand, considerable attention is paid to lowering the process temperature to allow coating on plastic substrates because high‐temperature annealing (≈200 °C) is usually required to convert precursors to polyimide films with those excellent properties. In addition, polyimide‐based dielectric films have low dielectric constants (k) (<4). Therefore, modifying the k properties of polyimide is a critical issue for applications as an insulating thin film for practical transistors. This paper reports a new type of polyimide‐based gate dielectric comprising methacryloyl moiety (PI‐MA) as a side chain for photo‐pattern/processability and high‐k properties. This study shows that the photocured PI‐MA thin films show excellent insulating properties (leakage current densities < 10−8 A cm⁻2 at 4 MV cm⁻1) and high‐k properties (≈8) even without a post‐annealing process. Finally, the use of PI‐MA in printed field‐effect transistors results in high performance with low‐voltage operation (within 5 V) and integrated logic‐gate devices (NOT, NAND, and NOR gates). [ABSTRACT FROM AUTHOR]

The sense of touch and perception of hand motion form an essential part of the somatic sensory system. Although piezoelectric sensors demonstrate high sensitivity and linearity, they are traditionally not employed for electronic skins because of their limited stretchability. Here, a printed, skin‐conformal, electronic system consisting of stretchable piezoelectric pressure sensors and carbon nanotube strain gauges capable of identifying tactile sensations and joint movements on the hand is introduced. The pressure sensor demonstrates both high sensitivity (19.9 mV kPa−1) and linearity (0.1–1000 kPa) while being reliably stretchable to above 15%. To complement the pressure sensing functionality, a strain gauge is fabricated in a rapid stamp printing process and designed to demonstrate excellent mechanical reliability with up to 70% strain and high sensitivity (36.5‐gauge factor). These sensors can seamlessly conform to numerous anatomical regions and cover wide areas of the skin, making them ideal for deployment in an electronic skin. Finally, the sensors are integrated with a flexible microelectronic device to demonstrate their functionality in human touch and prosthetic hand applications. [ABSTRACT FROM AUTHOR]

Printed electronics have made remarkable progress in recent years and inkjet printing (IJP) has emerged as one of the leading methods for fabricating printed electronic devices. However, challenges such as nozzle clogging, and strict ink formulation constraints have limited their widespread use. To address this issue, a novel nozzle‐free printing technology is explored, which is enabled by laser‐generated focused ultrasound, as a potential alternative printing modality called Shock‐wave Jet Printing (SJP). Specifically, the performance of SJP‐printed and IJP‐printed bottom‐gated carbon nanotube (CNT) thin film transistors (TFTs) is compared. While IJP required ten print passes to achieve fully functional devices with channel dimensions ranging from tens to hundreds of micrometers, SJP achieved comparable performance with just a single pass. For optimized devices, SJP demonstrated six times higher maximum mobility than IJP‐printed devices. Furthermore, the advantages of nozzle‐free printing are evident, as SJP successfully printed stored and unsonicated inks, delivering moderate electrical performance, whereas IJP suffered from nozzle clogging due to CNT agglomeration. Moreover, SJP can print significantly longer CNTs, spanning the entire range of tube lengths of commercially available CNT ink. The findings from this study contribute to the advancement of nanomaterial printing, ink formulation, and the development of cost‐effective printable electronics. [ABSTRACT FROM AUTHOR]

Affordable and versatile power sources become crucial as miniaturized electronics and sensors become more widespread. Organic thermoelectric generators (TEGs), capable of tapping into wasted heat sustainably and economically, are viewed as key enablers for powering the sensor networks of the future. Until recently, the performance of n‐type organic thermoelectric materials has severely lagged behind their p‐type counterparts. However, reports of a stable and highly conductive n‐type polymer, poly(benzodifurandione) (PBFDO), are changing this notion. Nonetheless, validation of PBFDO as a suitable ink for scalable fabrication processes and integration of the material into a scalable organic TEG have yet to be demonstrated. This work presents the development, characterization, and optimization of a PBFDO ink for use in a scalable inkjet printing process. The n‐type ink is then integrated into a screen‐printed origami‐inspired architecture, resulting in a 21‐leg PEDOT:PSS/PBFDO organic TEG capable of delivering a record‐high normalized power density among reported polymer‐based TEGs of 0.718 nW cm−2 K−2. Moreover, the module ambient stability is demonstrated for up to 90 d, while its use for potential applications in harsh environments is validated for a temperature range of ‐8 °C to 200 °C and up to 90% relative humidity, a first for organic TEGs. [ABSTRACT FROM AUTHOR]

Printing technologies have the potential to reduce the manufacturing costs of many electronic devices significantly. Here, a scalable manufacturing route for high‐performance fully printed thermoelectric generators (TEGs) as a cost‐effective solution for energy harvesting is demonstrated. This work presents a facile one‐pot synthesis method to develop a high‐performance Ag2Se‐based n‐type paste, which is used to fabricate a fully printed origami TEG by employing the Ag2Se‐based material for the n‐type legs and a previously reported Bi‐Sb‐Te‐based paste for the p‐type legs. The n‐type film exhibits a power factor of 13.5 µW cm−1 K−2 and a maximum figure‐of‐merit (ZT) of ≈ 0.92. Furthermore, printable carbon paste is introduced as an effective interface between the thermoelectric and electrode materials, which reduces the contact resistances in the thermoelectric device. The origami folded TEG exhibits an open‐circuit voltage (VOC) of 284 mV, a power output of 370.88 µW, and an exceptionally high power density (pmax) of 10.72 Wm−2 at a temperature difference (∆T) of 80.7 K, considering that the TEG fabrication does not involve any pressure treatment and vacuum sintering. These results underscore the scalability of the presented manufacturing process and the capability of printed origami TEGs for powering the Internet of Things (IoT) with low‐grade waste heat. [ABSTRACT FROM AUTHOR]

Aerosol jet printing is a promising technology for printing functional materials on a variety of substrates with high precision and resolution. This technology has the potential to revolutionize the manufacturing industry by providing a low‐cost, high‐resolution printing technique that can be used to produce additively printed electronics, sensors, and energy devices. However, the optimization of this process has traditionally relied on time‐consuming trial‐and‐error methods, hampering its efficiency and scalability. Machine learning (ML) models have the potential to overcome these challenges and improve the quality, speed, and efficiency of the printing process. In this paper, we propose an approach that leverages ML algorithms to streamline and enhance the aerosol jet printing optimization process. Our methodology involves data collection through systematic experimentation with various parameter settings. This data set serves as the foundation for training different ML model capable of predicting printed line characteristics and optimal printing process parameter. We validate our approach by performing experiments on different inks, and we compare the results of our ML‐based optimization approach to those obtained using traditional trial‐and‐error methods. The results demonstrate that our approach offers significantly higher accuracy and efficiency. To enhance our approach's accessibility and ease of use, we incorporate AutoML techniques which automates the process of selecting the most suitable ML algorithms and hyperparameters, reducing the burden of manual configuration. Furthermore, we introduce a user‐friendly web‐based interface that facilitates the entire ML pipeline, from data preprocessing to prediction and batch processing. This interface empowers users to efficiently manage and manipulate their data, select appropriate ML algorithms, and execute predictions, ultimately improving accuracy and model performance. [ABSTRACT FROM AUTHOR]

A modified polyol process was used to produce low-cost silver nanowires, which were analyzed using surface plasmon resonance, x-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. These nanowires were used to create silver ink with specific properties suitable for inkjet and aerosol printing. The ink's electrical resistivity was 140 µΩ cm on paper and 200 µΩ cm on polyethylene terephthalate and polypropylene. [ABSTRACT FROM AUTHOR]

Printing technology holds great potential for resource‐efficient development of electronic devices and circuits. However, even after decades of research, achieving uniformly responding nanowires (NWs) based printed devices is still a challenge. To date, there is no design rule that clearly guides the fabrication of NW ensemble‐based field‐effect transistors (FETs) and the variables that influence device‐level uniformity remain unclear. The lack of fundamental understanding severely limits the large‐scale and very large‐scale integration (LSI and VLSI). Herein this longstanding issue is addressed with a holistic approach that starts with optimization of the synthesis of ZnO NWs, their printing, and further processing to fabricate transistors with uniform responses (e.g., on‐state current, threshold voltage). Monte Carlo simulation based on statistical analysis of printed ZnO NWs is carried out to develop a probabilistic framework that can predict the large‐scale performance of FETs. As a proof of concept, inverter circuits have been developed using printed ZnO NWs based FETs. This work provides a valuable toolkit to handle the stochastic nature of FETs based on printed ZnO NW ensemble, which can be used for neuromorphic integrated circuit in the future. [ABSTRACT FROM AUTHOR]

The advance of printed electronics is significantly bolstered by the development of liquid‐state electronics that overcome the inherent limitations in flexibility and reconfigurability of solid‐state electronics. By integrating the biocompatibility and conductivity of sulfonated polyaniline (S‐PANI) and phytic acid (PA) with the reconfigurability of structured liquids, highly conductive all‐liquid threads are developed. The dense packing and overlap of PA/S‐PANI complexes at an oil/water interface promotes in‐plane electron transport, and standard four‐point probe measurements of PA/S‐PANI interfacial assemblies demonstrate enhanced electrical properties. Notably, the rapid jetting of the ink phase into the matrix phase allows for liquid threads to be printed, enabling the fabrication of large‐scale, conductive pathways between two electrodes and liquid circuits. Upon mechanical cleavage of the liquid wires, circuits can be broken, but will easily self‐repair using an electric field, making this motif useful in the design of switches as well as restoring conductive pathways in series or in parallel. The demonstrated flexibility and reconfigurability these PA/S‐PANI wires possess hold significant promise for their practical use in the design of flexible and adaptive bioelectronics that can be repaired on demand, signifying a transformative step in the evolution of liquid electronic materials. [ABSTRACT FROM AUTHOR]

The tension system is one of the most critical systems in gravure printed electronic equipment. It possesses a complex structure that spans the entire feeding process, from unwinding through printing to rewinding. This article focuses on the research of multi-span tension control for printing systems. Firstly, the characteristics and requirements of the tension-control system in the printing section were analyzed, and a multi-span tension-control structure was devised. Then, based on the coupled mathematical model of the multi-span tension system, a static decoupling model was formulated, and a first-order active disturbance rejection control (ADRC) controller was designed utilizing active disturbance rejection control technology. Finally, to verify the control performance of the ADRC decoupling controller for the printing tension system, simulation and experimental studies were conducted using MATLAB/Simulink R2018a and a dedicated experimental platform, and the results were then compared with those obtained from a traditional PID controller. The research findings indicate that the designed multi-span tension-control system demonstrates outstanding decoupling performance and anti-interference capabilities, effectively enhancing the tension-control accuracy of gravure printed electronic equipment. [ABSTRACT FROM AUTHOR]

The rapid evolution of wearable devices, the Internet of Things, and flexible displays has underscored the need for thin, flexible batteries. Screen‐printing has emerged as a mature technique for manufacturing these batteries, particularly those using a zinc chemistry. This study presents a commercially viable polymer electrolyte using a low‐cost organic electrolyte solvent, ethylene glycol. This first‐of‐its‐kind electrolyte formulation overcomes challenges associated with either water‐based or ionic‐liquid‐based solvents. The simple fabrication process allows for printing under ambient conditions and eliminates additional processing steps. Rheological analysis confirms that the developed polymer electrolyte is suitable for screen‐printing. Using this polymer electrolyte, a secondary printed battery with a 4 mAh cm−2 areal capacity is achieved. The study also investigates the mechanical behavior of the printed battery and emphasizes the importance of understanding interfacial stresses and bonding for designing optimal multilayered flexible batteries. This research offers an integrated solution, combining practical printed battery fabrication with battery testing and mechanical characterization, promising advancements in printed batteries and electronics. [ABSTRACT FROM AUTHOR]

Displays have become ubiquitous in our modern and highly interconnected lives. Complex vacuum processed multi‐stacks are widely integrated into high tech, high value products such as smart phones, while solution processed large area single‐layer OLEDs appear more adequate for basic applications focusing on recyclability such as packaging, road signage, advertising, and single‐use health care products. In this context, we report herein the design, synthesis, and characterization of an accessible series of oligothiophenes end‐capped triphenylamines that were preprepared by atom‐economical direct (hetero)arylation reactions and successfully used as emitter in solution processed devices, from lab scale to large area printed and flexible demonstrator. [ABSTRACT FROM AUTHOR]

Mesoscopic carbon‐based perovskite solar cells (C‐PSCs) have the potential to be manufactured at an industrial scale by utilizing screen‐printing, a simple, affordable, and commercially mature process. As such, many recent publications have focused on enhancing performance through modifying cell architecture and perovskite chemistries. This work examines how ink rheology can be tuned to optimize cell performance through reducing the occurrence of common print defects to create higher quality m‐TiO2 films. Inks with different solvent dilutions and rheological profiles are assessed using high‐speed imaging through the screen‐printing visualization (SPV) technique, to investigate the impact of the viscosity and elasticity on ink separation mechanisms. The resultant film quality and its influence on device performances are then assessed. Ink separation lengths are minimized, and the formation of filaments ceases during printing, leading to improved TiO2 film topography and homogenous infiltration of the perovskite precursor. Consequently, PCE is improved by over 10% of the original efficiency in cells and 224 cm2 active area modules due to enhanced Voc and FF. These results not only provide key insights into tailoring ink rheology, to achieve improved print homogeneity and higher performing cells, but also aid further work on enhancing the performance of other screen‐printed functional films. [ABSTRACT FROM AUTHOR]

Ballistocardiography (BCG) studies ballistic forces on the body generated during a heartbeat. As it is an unobtrusive detection method, that requires sensors measuring small dynamic forces. Piezoelectric sensors are ideal, but improvements in sensitivity are needed. Here, a universal method is demonstrated to obtain enhanced effective transverse charge constants by utilizing thin and long sensors fabricated upon compliant substrates. This approach is validated using the uniquely printable and patternable piezoelectric polymer, poly(vinylidene fluoride‐co‐trifluoroethylene) (P(VDF‐TrFE). Discrete sensors detect displacements of less than 1 µm, dynamic forces of ∼mN, and accelerations of ≈1 mm−1 s2. Since the sensor is screen‐printable, it is upscaled to a human‐sized array (60 × 90 cm, 255 sensors). High quality spatially resolved BCG measurements of a person is demonstrated in seated and supine positions. The obtained heart rate is verified using photoplethysmography. This development opens the door to ever‐more sensitive piezoelectric sensors, crucial for applications including and beyond healthcare. [ABSTRACT FROM AUTHOR]

Flexible hybrid electronics (FHE) is an emerging area that combines printed electronics and ultra‐thin chip (UTC) technology to deliver high performance needed in applications such as wearables, robotics, and internet‐of‐things etc. The integration of UTCs on flexible substrates and the access to devices on them requires high resolution interconnects, which is a challenging task as thermal and mechanical mismatches do not allow conventional bonding methods to work. To address this challenge, the resource‐efficient, area‐efficient, and low‐cost printing routes for obtaining vertical interconnection accesses (VIAs) are demonstrated here. It is demonstrated how high‐resolution printers (electrohydrodynamic and extrusion‐based direct‐ink writing printers) can be used for patterning of high‐resolution, freeform, vertical conductive structures. To access the transistors on UTCs, the VIAs, obtained using conventional photolithography and plasma etching steps, are filled with conductive silver nanoparticle‐based ink/paste using high‐resolution printers. Comprehensive studies are performed to compare and benchmark in terms of: i) the printing speed and throughput of the printers, ii) the electrical performance of vertically connected transistors in UTCs, and iii) the electrical performance stability of FHE system (interconnects and UTCs) under mechanical bending conditions. This in‐depth study shows the potential use of printing technologies for development of high‐density 3D integrated FHE systems. [ABSTRACT FROM AUTHOR]

The hybridization of single-walled carbon nanotubes (SWCNTs) and Cu nanoparticles offers a promising strategy for creating highly conductive and mechanically stable fillers for flexible printed electronics. In this study, we report the ultrafast synthesis of SWCNT/Cu hybrid nanostructures and the fabrication of flexible electrodes under ambient conditions through a laser-induced photo-thermal reaction. Thermal energy generated from the nonradiative relaxation of the π-plasmon resonance of SWCNTs was utilized to reduce the Cu-complex (known as a metal–organic decomposition ink) into Cu nanoparticles. We systematically investigated the effects of SWCNT concentration and output laser power on the structural and electrical properties of the SWCNT/Cu hybrid electrodes. The SWCNT/Cu electrodes achieved a minimum electrical resistivity of 46 μohm·cm, comparable to that of the metal-based printed electrodes. Mechanical bending tests demonstrated that the SWCNT/Cu electrodes were highly stable and durable, with no significant deformation observed even after 1000 bending cycles. Additionally, the electrodes showed rapid temperature increases and stable Joule heating performance, reaching temperatures of nearly 80 °C at an applied voltage of less than 3.5 V. [ABSTRACT FROM AUTHOR]

This paper describes the process of producing chemosensors based on hybrid nanostructures obtained from Al2O3, as well as ZnO ceramic nanotubes and the following conducting polymers: poly(3-hexylthiophene), polyaniline emeraldine-base (PANI-EB), and poly(3, 4-ethylenedioxythiophene)-polystyrene sulfonate. The process for creating ceramic nanotubes involves three steps: creating polymer fiber nets using poly(methyl methacrylate), depositing ceramic films onto the nanofiber nets using magnetron deposition, and heating the nanotubes to 600 °C to burn off the polymer support completely. The technology for obtaining hybrid nanostructures from ceramic nanotubes and conducting polymers is drop-casting. AFM analysis emphasized a higher roughness, mainly in the case of PANI-EB, for both nanotube types, with a much larger grain size dimension of over 5 μm. The values of the parameter Rku were close or slightly above 3, indicating, in all cases, the formation of layers predominantly characterized by peaks and not by depressions, with a Gaussian distribution. An ink-jet printer was used to generate chemiresistors from ceramic nanotubes and PANI-EB structures, and the metallization was made with commercial copper ink for printed electronics. Calibration curves were experimentally generated for both sensing structures across a wider range of NH3 concentrations in air, reaching up to 5 ppm. A 0.5 ppm detection limit was established. The curve for the ZnO:PANI-EB structure presented high linearity and lower resistance values. The sensor could be used in medical diagnosis for the analysis of breath ammonia and biomarkers for predicting CKD in stages higher than 1. The threshold value of 1 ppm represents a feasible value for the presented sensor, which can be defined as a simple, low-value and robust device for individual use, beneficial at the patient level. [ABSTRACT FROM AUTHOR]

The growing interest in flexible conductive materials and printed electronic components has spawned a series of new commercial applications, including smart devices, functional clothing, and intelligent packaging. This review summarizes the main preparation techniques for conductive ink fillers, while considering the influence of the source materials (metals, carbon nanoparticles and polymers) that affect the performance of the conductive inks. The preparation methods and related research advances in electronic components (flexible electrodes and sensors) based on inkjet printing and screen‐printing technology are summarized. In addition, the literature review reveals that the current research content rarely considers the influence of printing conditions on the quality of the printed electronic devices, thus indicating that numerous specific engineering challenges need to be overcome for the commercial application of printed electronics. [ABSTRACT FROM AUTHOR]

[Display omitted] • MOF nanosheets reconfigured by electrostatic coupling and interfacial conditioning strategies. • PEDOT:PSS and MOF nanosheets with interoperable conductive network and excellent interfacial properties. • MOF nanosheets attenuate the entanglement of PEDOT:PSS. • Homogeneous ink prepared using solution engineering for flexible supercapacitor preparation. Two-dimensional metal – organic frameworks (2D MOFs) hold great promise as electrochemically active materials. However, their application in MOF nanocomposite electrodes in solution engineering is limited by structural self-stacking and imperfect conductive pathways. In this study, we used meso -tetra(4-carboxyphenyl) porphine (TCPP) with off-domain π-bonds to reconstitute Zn-TCPP (ZMOF) and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) through an interfacial modulation strategy involving electrostatic coupling and hydrogen bonding, creating a conductive composite with a nanosheet structure. The negatively charged PSS and ZMOF formed a three-dimensional interconnected conductive network with excellent interfaces. The positively charged PEDOT, fine tuned with the lamellar structure, established strong π-π stacking interactions between the porphyrin and thiophene rings. ZMOF also induced changes in the PEDOT chain structure, weakening PSS entanglement and enhancing charge-transport properties. The specific capacitance of the prepared supercapacitor was as high as 967.8 F g−1. Flexible supercapacitors produced on a large scale using dispensing printing technology exhibited an energy density of 1.85 μWh cm−2 and a power density of 7.08 μW cm−2. This interfacial modulation strategy also exhibited excellent wearable properties, with 96 % capacitance retention at a 180° bending angle and stable cycling performance. This study presented a significant advancement in the functionalization of 2D materials, highlighting their potential for device-grade capacitive architectures. [ABSTRACT FROM AUTHOR]

Organic electroactive materials, particularly semiconducting polymers, are at the forefront of emerging organic electronics. Among the plethora of unique features, the possibility to formulate inks out of these materials is particularly promising for the large‐scale manufacturing of electronics at lower cost on a variety of soft substrates. While solution deposition of semiconducting materials is promising for developing printed electronics, the environmental footprint of the materials and related devices needs to be considered to achieve sustainable manufacturing. Towards the development of greener printed electronics, this work investigates the utilization of a non‐toxic, environmentally‐friendly solvent, namely branched polyethylene (BPE), to formulate semiconducting inks. Focusing on a diketopyrrolopyrrole‐based (DPP) semiconducting polymer, shellac as dielectric, and BPE as the solvent, solutions were prepared in different concentrations and their rheological properties were characterized. Then, printing on polyethylene terephthalate (PET) substrates using two different techniques was performed to fabricate organic field‐effect transistors (OFETs). Both printing techniques yielded OFETs with good performance and device characteristics, averaging approximately 10−2 and 10−4 cm2 V−1 s−1, respectively, for slot‐die coating and direct‐ink writing deposition. Notably, despite some difference in threshold voltages, OFETs produced via slot‐die coating and direct‐ink writing showed comparable charge mobilities to previously reported OFETs prepared from similar materials, particularly those prepared on silicon dioxide wafers. Overall, this work confirms the suitability of BPE to formulate semiconducting inks to develop printed electronics in a greener manner. The printing methodology developed in this work also open new avenues for the design of functional printed electronics and related technologies. [ABSTRACT FROM AUTHOR]

We have investigated the potential of three dielectric materials to meet the future demands of green dielectrics: Polycaprolactone (PCL) thermoplastic, polyvinyl alcohol (PVA)‐carrageenan (CAR) crosslinked biopolymer, and boron nitride nanotubes (BNNTs) as a nano additive in PVA. Metal–insulator–metal (MIM) capacitors and organic thin film transistors (OTFT) were built with bilayer dielectric stacks of PVA‐CAR, PVA‐PCL, and PVA‐BNNT materials to examine their electrical properties. The PVA‐CAR layer uses a cyclic freeze thaw process to crosslink PVA and CAR for superior mechanical and electrical properties to either material alone. The PVA‐CAR MIM capacitors showed a dielectric constant of 23, which was found to be consistent with the extracted OTFT gate dielectric characteristics. Of the OTFT devices tested, PVA‐CAR OTFT showed highest device currents at low applied biases and produced an ON/OFF ratio of 104–105, both values were highest amongst the tested gate dielectrics. This material is therefore extremely promising for green electronics. The PVA‐PCL OTFT had very low leakage current and beneficial hydrophilic properties with comparable electrical properties to the commonly used organic material polytetrafluoroethylene. PVA‐BNNT MIM capacitors showed a low dielectric constant of 0.7, and the high resistivity makes this a promising material for shielding or substrates in high frequency applications. All three materials have the potential to fulfil different niches in a sustainable electronics future. [ABSTRACT FROM AUTHOR]

The doping levels of conjugated polymers significantly influence their conductivity, energetics, and optical properties. Recently, a highly conductive n‐doped polymer called poly (3,7‐dihydrobenzo[1,2‐b:4,5‐b′]difuran‐2,6‐dione) (poly(benzodifurandione), n‐PBDF) is discovered, opening new possibilities for n‐type conducting polymers in printed electronics and other fields. Controlling the doping level of n‐PBDF is of great interest due to its wide range of potential applications. Here controlled dedoping and redoping of n‐PBDF is reported and a mechanistic understating of such a process is provided. Dedoping occurs through electron transfer and proton capture, wherein the ionic dopants, tris(4‐bromophenyl)ammoniumyl hexachloroantimonate (Magic Blue), exhibit efficient proton capture ability and stronger interaction with n‐PBDF, resulting in high dedoping efficiency. Moreover, chemically dedoped PBDF can be redoped using various proton‐coupled electron transfer agents. By manipulating the doping levels of n‐PBDF thin films, ranging from highly doped to dedoped states, the system demonstrates controllable conductivity in five orders of magnitude, adjustable optical properties, and energetics. As a result, these characteristics demonstrate the potential applications of n‐PBDF in organic electrochemical transistors and thermoelectrics. [ABSTRACT FROM AUTHOR]

Electrochemiluminescence (ECL) has attracted significant attention as a promising light‐emitting technology owing to its simple configuration and solution processability. ECL has wide applications in biological and chemical sensors, lighting, and displays. ECL lighting devices are fabricated as sandwiched structures with a transparent electrode on top, which limits their widespread adoption. Intricate structures with high precision and customizable designs can be directly fabricated using 3D printing. However, 3D printing of ECL devices is challenging because of poor printability and structural integrity of ECL luminophore inks. Here, all‐printed electrically driven lighting is demonstrated using the direct ink writing method. The ECL reactive layer and electrodes are directly printed using a side‐by‐side electrode configuration. A 3D printable ECL ink is developed by incorporating silica nanoparticles as rheological modifiers to realize well‐defined patterns with high structural integrity. Graphene is introduced on Ag multilayer electrodes to embrace both the electrical conductivity and electrochemical stability for efficient ECL operation. This all‐printing approach allows the fabrication of ECL devices with complex designs, such as combs and spirals. Moreover, it facilitates seamless printing on various substrate materials, making this technology an asset in the fields of biology, chemistry, and electronics. [ABSTRACT FROM AUTHOR]

Nowadays, additive manufacturing technologies have impacted different engineering sectors. Three- and four-dimensional printing techniques are increasingly used in soft and flexible electronics thanks to the possibility of working contemporarily with several materials on various substrates. The materials portfolio is wide, as well as printing processes. Shape memory polymers, together with composites, have gained great success in the electronic field and are becoming increasingly popular for fabricating pH, temperature, humidity, and stress sensors that are integrated into wearable, stretchable, and flexible devices, as well as for the fabrication of communication devices, such as antennas. Here, we report an overview of the state of the art about the application of 4D printing technologies and smart materials in electronics. [ABSTRACT FROM AUTHOR]

In battery systems, there are several established form factors targeting mass market applications, like D, C, AA, AAA series, lithium round cells, and coin cells. Besides these standardized batteries, in printed electronics, there are several approaches to realize flat batteries of different material systems fabricating primary and secondary battery types. For a dedicated application in agriculture, a sensor system requires a degradable primary battery. In this paper, the development of a dedicated zinc–carbon battery is described, supplying the sensor application with 4.5 Vnom. The battery has a 170 mm length and a 23 mm outer diameter. while the inner core is open for the antenna system of the application. The active area is up to 161 cm2. The design and manufacturing aspects are described. The rolled-up battery system is fully charged after manufacturing and ready to operate. It may remain inside the degradable sensor system after use in the field. [ABSTRACT FROM AUTHOR]

Over the past several years, atomically thin two‐dimensional carbides, nitrides, and carbonitrides, otherwise known as MXenes, have been expanded into over fifty material candidates that are experimentally produced, and over one hundred fifty more candidates that have been theoretically predicted. They have demonstrated transformative properties such as metallic‐type electrical conductivities, optical properties such as plasmonics and optical nonlinearity, and key surface properties such as hydrophilicity, and unique surface chemistry. In terms of their applications, they are poised to transform technological areas such as energy storage, electromagnetic shielding, electronics, photonics, optoelectronics, sensing, and bioelectronics. One of the most promising aspects of MXene's future application in all the above areas of interest, we believe, is reliably developing their flexible and bendable electronics and optoelectronics by printing methods (henceforth, termed as printed flexible MXetronics). Designing and manipulating MXene conductive inks according to the application requirements will therefore be a transformative goal for future printed flexible MXetronics. MXene's combined property of high electrical conductivity and water‐friendly nature to easily disperse its micro/nano‐flakes in an aqueous medium without any binder paves the way for designing additive‐free highly conductive MXene ink. However, the chemical and/or structural and hence functional stability of water based MXene inks over time is not reliable, opening research avenues for further development of stable and conductive MXene inks. Such priorities will enable applications requiring high‐resolution and highly reliable printed MXene electronics using state‐of‐the art printing methods. Engineering MXene structural and surface functional properties while tuning MXene ink rheology in benign solvents of choice will be a key for ink developments. This review article summarizes the present status and prospects of MXene inks and their use in inkjet‐printed (IJP) technology for future flexible and bendable MXetronics. [ABSTRACT FROM AUTHOR]

Copper-based conductive ink has received attention to fabricate thin, flexible, and lightweight devices through printing techniques. In particular, the copper formate based conductive inks, called metal organic decomposition (MOD) inks, which are fabricated by using amine ligand coordinated copper formate have been well studied because of higher oxidative resistant against air than that of metallic copper before thermal annealing. The copper formate moiety of amine ligand coordinated copper formate complexes varies by changing the coordinated amine species, however, for the thermal decomposition temperature of such ink is not well understand. Here, we analyzed the influence of the amine ligand on the thermal decomposition temperature drop of copper formate moiety. Amine-copper formate complexes bearing several amine ligands containing primary amine, pyridine, and imidazole groups were fabricated. The relationship between the evaluated decomposition temperature and the differences between the wavenumbers of symmetric and antisymmetric vibration mode peaks in Fourier transform infrared (FTIR) spectra was found to be nearly linear. This finding demonstrates that the thermal decomposition temperature is governed by the structural modification of formate ions by the coordination of amine groups. Based on this finding, the order of thermal decomposition temperature of the copper moiety is predictable by using FTIR measurement. [ABSTRACT FROM AUTHOR]

The state-of-the-art technology of fabricating printed copper electronics is focussed largely on thermal sintering restricting transition towards heat sensitive flexible substrates. Herein we report a pioneering technology which eliminates the need for conventional sintering. Biopolymer-stabilised copper particles are prepared such that they can be compressed at room temperature to generate air-stable films with very low resistivities (2.05 – 2.33 × 10−8 Ω m at 20 °C). A linear positive correlation of resistivity with temperature verifies excellent metallic character and electron microscopy confirms the formation of films with low porosity (< 4.6%). An aqueous ink formulation is used to fabricate conductive patterns on filter paper, first using a fountain/dip pen and then printing to deposit more defined patterns (R < 2 Ω). The remarkable conductivity and stability of the films, coupled with the sustainability of the approach could precipitate a paradigm-shift in the use of copper inks for printable electronics. [ABSTRACT FROM AUTHOR]

There is an increasing interest in printed electronics driven principally by flexible and wearable applications. The interest stems from the ability to fabricate electronic devices, such as Field Effect Transistors (FET), more efficiently in terms of materials use and cost‐effectively than traditional lithographic techniques. Challenges persist in achieving high resolution and accuracy in defining device geometry. In the study, a high‐resolution materials printer able to achieve resolutions in the micron range, surpassing the capabilities of commercially available printers is successfully designed and fabricated. The printer incorporates an all‐in‐one printing system, comprising Inkjet and a Dip Pen Nanolithography (DPN) technique, enabling both additive and subtractive manufacturing at the microscale. The experiments demonstrate the successful fabrication of FETs based on 2D materials (2DMs), with micrometric channel lengths exhibiting a high degree of controllability and repeatability, even when contacting limited channel regions as micrometer‐sized molybdenum disulfide (MoS2) flakes. Electrical characterizations of the fabricated devices underscore the significant technological advancements achieved by the prototypes. [ABSTRACT FROM AUTHOR]

The printed electronics (PEs) market has witnessed substantial growth, reaching a valuation of USD 10.47 billion in the previous year. Driven by its extensive use in a multitude of applications, this growth trend is expected to continue with a projected compound annual growth rate of 22.3% from 2022 to 2032. Compared to screen printing, the adoption of inkjet printing (IJP) technology to manufacture PEs has been limited to laboratory‐scale research only. The fact that IJP's inability to maintain consistent high‐resolution quality over large printing areas has made transitioning IJP for commercial production arduous. Most of the previous literatures have focused on holistic discussion on material design for IJP, but this review provides insight into key aspects in material processing up to printing optimization to realize high‐resolution PEs. This review also highlights the challenges in controlling the functional ink properties and their interaction with the substrate as well as printing parameters to deliver the desired quality of the droplets and final prints. Imminent application of IJP in PEs and future perspectives are also included in this review. [ABSTRACT FROM AUTHOR]

Aerosol jet printing offers high resolution, broad materials compatibility, and digital patterning for flexible, conformal, and hybrid electronics. However, limited throughput, instability, and complex optimization requirements inhibit translation to industrial applications. An in‐line heater integrated on a custom printer is demonstrated to modulate droplet evaporation in the aerosol phase, thereby decoupling the deposition rate of functional solids and liquid ink to enable taller, narrower features with aspect ratios reaching 0.29 for a single line. Heating the printhead from room temperature to 80 °C reduced the sensitivity of resolution to deposition rate by ≈90%, improving reliability. With this strategy, increasing the linear deposition rate by 10x results in a modest increase of 27% in line width, compared to a four‐fold increase without heating, permitting higher throughput without sacrificing print quality. Providing a control for in‐line drying independent of ink formulation enables rapid, straightforward design of new materials and processes. This ability to engineer drying of droplets prior to impingement provides a versatile tool to meet complex fabrication challenges, as demonstrated here for both high aspect ratio printing and conformal patterning on rough and three‐dimensional surfaces. [ABSTRACT FROM AUTHOR]

This study reports on the first all‐printed vertically stacked organic electrochemical transistors (OECTs) operating in accumulation mode; the devices, relying on poly([4,4′‐bis(2‐(2‐(2‐methoxyethoxy)ethoxy)ethoxy)‐2,2′‐bithiophen‐5,5′‐diyl]‐alt‐[thieno[3,2‐b]thiophene‐2,5‐diyl]) (pgBTTT) as the active channel material, are fabricated via a combination of screen and inkjet printing technologies. The resulting OECTs (W/L ≈5) demonstrate good switching performance; gm, norm ≈13 mS cm−1, µC* ≈21 F cm−1 V−1 s−1, ON–OFF ratio > 104 and good cycling stability upon continuous operation for 2 h. The inkjet printing process of pgBTTT is established by first solubilizing the polymer in dihydrolevoglucosenone (Cyrene), a non‐toxic, cellulose‐derived, and biodegradable solvent. The resulting ink formulations exhibit good jettability, thereby providing reproducible and stable p‐type accumulation mode all‐printed OECTs with high performance. Besides the environmental and safety benefits of this solvent, this study also demonstrates the assessment of how the solvent affects the performance of spin‐coated OECTs, which justifies the choice of Cyrene as an alternative to commonly used harmful solvents such as chloroform, also from a device perspective. Hence, this approach shows a new possibility of obtaining more sustainable printed electronic devices, which will eventually result in all‐printed OECT‐based logic circuits operating in complementary mode. [ABSTRACT FROM AUTHOR]

Conductive ink is an important component to fabricate printed electronics, such as flexible, stretchable, and wearable electronics. Solvents are essential for fabrication of conductive inks, but most of the organic solvents are expensive, toxic, and not environmentally friendly. In this review, stability, wettability, and electrical conductivity of different types of solvent- and water-based metal and carbon-based conductive inks are discussed. Further, the utilization of surfactants to facilitate aqueous homogeneous dispersion and stability of metal and carbon nanomaterial-based conductive material is discussed. Particularly, the solvent- and water-based surfactant-assisted conductive inks on the stability and electrical properties of metal- and carbon-based conductive materials are highlighted. In addition, the different characterization methods for assessing the dispersion and stability of conductive inks, such as zeta potential, UV–Visible, long-term stability, and wettability properties, were discussed in this review. [ABSTRACT FROM AUTHOR]

Mechanically flexible and stretchable inductive coils are critical for enabling communication, sensing, and wireless power transfer capabilities in wearable electronics that conform to the body for healthcare and Internet of Things (IoT) applications. Leading stretchable conductors such as liquid metals (LMs) offer conformability but sacrifice electromagnetic performance compared with Cu wires, leading to lossy radio‐frequency (RF) characteristics. Here, a strategy leveraging multistranded 3D woven 'litz' transmission lines is presented to amplify the resonant RF performance of LM inductors. Through comprehensive simulations and experiments, it is discovered that interwoven LM litz wires boost the Quality Factor (Q) by 80% compared to standard liquid metal wires. A fabrication methodology is also demonstrated for stretchable coils that retain high Q (>30), outperforming the previously reported LM coils and maintaining 98% of their wireless transmission efficiency under up to 30% biaxial strain. Moreover, the versatility of this approach is showcased by 3D printing four‐terminal 'choke' inductors optimized for RF filtering and inductance tunability, overcoming the fabrication limitations of traditional planar printed electronics. These results offer valuable insights into the design and implementation of 3D‐printed inductors for a diverse suite of electromagnetic device applications. [ABSTRACT FROM AUTHOR]

Hydrosilanes are highly attractive compounds, which can be processed as liquids with printing technology to amorphous silicon films on nearly any solid substrate. The silicon layers can be processed for electronic devices like transistors or thin‐film solar cells. The endothermic character of hydrosilanes with their positive enthalpies of formation results in favorable properties for processing. The larger the molecules, the lower their decomposition temperature and the higher their photoactivity. Cyclic hydrosilanes such as cyclopentasilane and cyclohexasilane can be easily deposited. The branched neopentasilane is more difficult to deposit but yields better‐quality films after processing. The key challenge is the complex synthesis of the precursors and the hydrosilanes. The available preparative methods are presented in this review and their advantages and disadvantages are evaluated. The following synthesis methods are presented and discussed in this article: Wurtz coupling and other reductive coupling processes, dehydrogenative coupling of silanes, plasma synthesis of chlorinated polysilanes, amine‐ or chloride‐induced disproportionations, and transformation of monosilane to higher silanes. Plasma synthesis is already carried out today as a continuous industrial process. The most effective synthesis methods in the laboratory are currently amine‐ and chloride‐induced disproportionations. There is a great need to further optimize the syntheses of hydrosilanes and to develop new simple synthesis variants. [ABSTRACT FROM AUTHOR]

Temperature sensors are critical components in many industrial and research applications, particularly in harsh environments where high temperatures, corrosion and mechanical stress are prevalent. In this paper, we investigate the use of plasma spray technique as a versatile and simple method to print multipoint thermocouples and resistance temperature detectors (RTDs) based on NiCr-NiAl coatings on steel and ceramic substrates using stencil masking and laser scribing. The thickness of alumina the dielectric layer was optimized using metal-insulator-metal test. The thermoelectric properties of the printed thermocouples were investigated up to 1000 °C. The thermal independency of printed thermocouples and the capability of multilocation measurement at the surface on the same substrate was demonstrated. The thermoelectric properties of the printed RTD were investigated up to 850 °C. The electrical resistance of the RTD sensor is linear with the temperature variation from room temperature to 500 °C. The oxidation effect of the printed sensor metallic layers at high temperature was investigated and discussed. [ABSTRACT FROM AUTHOR]

In this study, Silicon Carbide (SiC) nanoparticle-based serigraphic printing inks were formulated to fabricate highly sensitive and wide temperature range printed thermistors. Inter-digitated electrodes (IDEs) were screen printed onto Kapton® substrate using commercially avaiable silver ink. Thermistor inks with different weight ratios of SiC nanoparticles were printed atop the IDE structures to form fully printed thermistors. The thermistors were tested over a wide temperature range form 25 °C to 170 °C, exhibiting excellent repeatability and stability over 15 h of continuous operation. Optimal device performance was achieved with 30 wt.% SiC-polyimide ink. We report highly sensitive devices with a TCR of −0.556%/°C, a thermal coefficient of 502 K (β -index) and an activation energy of 0.08 eV. Further, the thermistor demonstrates an accuracy of ±1.35 °C, which is well within the range offered by commercially available high sensitivity thermistors. SiC thermistors exhibit a small 6.5% drift due to changes in relative humidity between 10 and 90%RH and a 4.2% drift in baseline resistance after 100 cycles of aggressive bend testing at a 40° angle. The use of commercially available low-cost materials, simplicity of design and fabrication techniques coupled with the chemical inertness of the Kapton® substrate and SiC nanoparticles paves the way to use all-printed SiC thermistors towards a wide range of applications where temperature monitoring is vital for optimal system performance. [ABSTRACT FROM AUTHOR]

Silver nanoparticles are widely utilized in printed electronics for forming conductive lines due to their exceptional electrical conductivity, resistance to oxidation, and mechanical reliability. Molecular dynamics simulations are employed to monitor real-time sintering behavior at the atomic scale. This feat is challenging to achieve through experimental means. Thermal properties, including melting points and sintering behaviors, are theoretically characterized across a range of particle sizes (from 3 nm to 20 nm). This study analyzes the melting behavior of multi-sized silver nanoparticles and simulates the structural evolution and morphology changes during the sintering process. The simulations reveal noteworthy phenomena, such as variations in melting points, gyration radii, and mean square displacements based on different particle sizes. Additionally, an optimal sintering temperature is determined through shrinkage coefficient calculations. These simulation outcomes shed light on phenomena at the atomic level, presenting a theoretical foundation for optimizing conductive ink formulation and refining sintering conditions. [ABSTRACT FROM AUTHOR]

Patterning metal halide perovskite thin films is a necessary pathway to expand their optoelectronic applications. However, developing a suitable patterning technique is challenging as conventional lithographic processes are either detrimental to the perovskite layer or lack compatibility with scalable fabrication processes used in the manufacturing of printed electronics. In this work, a complete bottom‐up patterning method is proposed based on de‐wetting from a hydrophobic molecular template, which constrains the perovskite ink to directly crystallize in selected hydrophilic regions. Octadecylphosphonic acid molecules are used as the hydrophobic template and are effectively transferred onto metal‐oxide substrates via micro‐contact printing. This allows for a low‐cost, rapid, and scalable micron‐scale patterning of perovskite thin films. Facile control over light transmittance is demonstrated by adjusting the amount of exposed area and the corresponding spectral shape changes shift the film's appearance toward being color‐neutral. Finally, the method's scalability and versatility are shown by fabricating 25 cm2 patterned films over rigid and flexible substrates. [ABSTRACT FROM AUTHOR]

The technology to jet print metal lines with precise shape fidelity on diverse substrates is gaining higher interest across multiple research fields. It finds applications in additively manufactured flexible electronics, environmentally friendly and sustainable electronics, sensor devices for medical applications, and fabricating electrodes for solar cells. This paper provides an experimental investigation to deepen insights into the non-contact printing of solder lines using StarJet technology, eliminating the need for surface activation, substrate heating, curing, or post-processing. Moreover, it employs bulk metal instead of conventional inks or pastes, leading to cost-effective production and enhanced conductivity. The effect of molten metal temperature, substrate temperature, standoff distance, and printing velocity was investigated on polymer foils (i.e., PET sheets). Robust printing parameters were derived to print uniform, bulge-free, bulk metal lines suitable for additive manufacturing applications. The applicability of the derived parameters was extended to 3D-printed PLA, TPU, PA-GF, and PETG substrates having a much higher surface roughness. Additionally, a high aspect ratio of approx. 16:1 wall structure has been demonstrated by printing multiple metal lines on top of each other. While challenges persist, this study contributes to advancing additively manufactured electronic devices, highlighting the capabilities of StarJet metal jet-printing technology. [ABSTRACT FROM AUTHOR]

Conductive ink is the key to the development of flexible printed electronics. However, at present, the sintering temperature of conductive ink is still high, which restricts its use in some flexible substrates. This paper reported a kind of non-granular silver conductive ink which can be sintered at low temperature. The particle-free silver conductive ink was prepared from silver acetate using ammonia as the complexing agent, ethanol as an auxiliary agent and formic acid as a reducing agent. The obtained conductive ink droplets were coated on PET substrate and then sintered into film in an oven. The conductive ink and film were characterized by means of X-ray diffractometer (XRD), scanning electron microscope (SEM), Fourier infrared spectrometer (FTIR) and other methods. The effects of formic acid and ethanol on the properties of the conductive ink and film were systematically investigated. The results show that the conductive ink has good stability. After sintered at 90 °C for 60 min, its resistivity is 11.83 µΩ cm. By adjusting the ink formula, the roughness and uniformity of silver film can be improved significantly and the film will exhibit good bending performance. [ABSTRACT FROM AUTHOR]

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