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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]

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]

All inkjet‐printed thermal sensors are manufactured based on a metal–insulator–metal (MIM) interface or capacitor architecture, for the adapted device size ranging from 16 to 36 mm2 active area. Two different material inks, namely a nanoparticle conductive silver ink and an inorganic‐polymer‐based hybrid insulator ink, are applied layer by layer on a thin flexible polyimide substrate, for developing the printed MIM devices. To ensure the desired electronic conductivity and insulation from the layers, the manufacturing process steps and parameters are tuned, accordingly. The results show that the inkjet‐printed MIM devices could constitute up to 15 μm thickness and demonstrate average detection of a change in electrical capacitance ranging from 20 to 100 pF, when the temperature is varied between 100 and 300 °C. The investigations also summarize that the change in the electrical response is enough to detect an increment of 50 °C. The printed sensors also display high operational stability and repeatability, when subjected to thermal cycling. [ABSTRACT FROM AUTHOR]

Herein, it is intended to show the effect of embedding an inkjet printed poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) track in an insulator polymer, impacting its electronic transition behavior, as a consequence of temperature variation. A transition from semiconductor‐to‐metal‐like behavior is observed, when the temperature is seen to exceed a certain value, which is of a nonchemical origin. Both the presented experimental and simulation results show how this transition really occurs. The proposed physical mechanism for explaining such a behavior is verified with good repeatability. The main conclusion indicates consideration of special precautions, while enclosing inkjet‐printed PEDOT:PSS‐based tracks or sensors operating under ambient conditions, along with fluctuations. This conclusion can potentially be applied to any other inkjet printed conductive organic polymer film embedded in an insulator that fulfills the conditions encountered in the experiments. The impact of this effect may be reduced and mitigated by using inkjet printing, in combination with other additive manufacturing technique. The results presented here are considered very important, as they lay the foundation for the correct compensation of the thermal drift of organic electronics‐based circuits. [ABSTRACT FROM AUTHOR]

Robot-guided inkjet printing technology offers a new way for the digital and additive deposition of low-viscous inks to be made directly onto arbitrary surfaces and, thus, enables the production of individualized printed electronics on large-scale objects. When compared to conventional flatbed printing, the distance between the nozzle plate and the object's surface varies and needs to be considered in order to match the accuracy requirements needed for the positioning of single drops. Knowledge about applicable distance limits and the influence of tunable print parameters is crucial for improving the print process and results. This study discusses the sources of errors in the inkjet printing process onto 3D objects and presents extensive results about position accuracy in relation to jetting distance for different parameter sets of functional inks, drop volumes, and piezo voltages. Additionally, an efficient novel method was applied to determine the drop position accuracy of inkjet droplets in relation to the jetting distance. The method relies on cylinder geometry for the object and an inkjet head that is guided by a six-axis robot manipulator along the cylinder's axis. For the determination of drop placement accuracy, the position of single dots on the surface was compared to a model which considered the cylinder radii, drop velocity, and the movement speed of the guided inkjet printhead. The method and the extensive research results can be utilized for the prediction of achievable drop placement accuracy and the prior definition of distance limits. [ABSTRACT FROM AUTHOR]

Herein, the reliability and potential of inkjet‐printed flexible heaters are demonstrated by a set of resilience tests, showing never before performed high‐temperature application. The flexible heaters can operate up to 400 °C and failures are not caused by the printed conductor, but due to the temperature sensitivity of the base substrate only. Furthermore, these heaters show an accurate repetition rate with fluctuations <3% (2 °C within ten up–down cycles between 20 and 150 °C) and great long‐lasting capability (200 h on‐time operation at 150–180 °C). The bending strength has been proven by 10 000 cycles with resistance change less than 5%. Additionally, the adaptability and adjustability of defined temperature zones with the help of design rules for the layout definition are illustrated. These inkjet‐printed heaters demonstrate a high potential of usage in high‐temperature and flexible applications with the prerequisite of high stability and reliability. [ABSTRACT FROM AUTHOR]

In recent years, the fast construction, expansion and repowering of wind parks have been a major source of concern for the weather radar community and meteorological services. Among others because wind turbines are extremely tall, reflective, and moving objects, which make them a source of interference that is hard to distinguish from meteorological echoes and therefore difficult to filter and even more difficult to correct. Polarimetric C-Band Doppler weather radar measurements enable us to analyse and understand the impact of wind turbine interference on meteorological weather radar echoes and to build up knowledge. The main idea is to analyse the raw IQ-data in order to quantify the behaviour of wind turbine interference with meteorological scattering. As a first step in this direction, this paper will focus on the derivation and analysis of radar moments such as Reflectivity (Z), Differential Reflectivity (ZDR), Differential Propagation Phase (PHIDP), Mean Doppler Velocity (V), and Correlation Coefficient (RHOHV). We will consider two cases: (i) events with precipitation, and (ii) events without precipitation, in order to understand and model the impact of wind turbine interference (WTI). For this purpose, weather radar measurements from Deutscher Wetterdienst (DWD), recorded under the aegis of the project RIWER (Removing the Influence of Wind Park Echoes in Weather Radar Measurements), are presented, analysed and discussed in detail. [ABSTRACT FROM AUTHOR]

This article reports on developments in the manufacturing of heating elements by means of digital inkjet printing technology. The area coverage of the meander lines ranges from 34 lpi (lines per inch) to 51 and 102 lpi, which mainly influences the temperature distribution and homogeneity. Furthermore, the line width of the meander lines is varied between 250, 500, and 1000 μm. All heating elements are deposited by single‐pass printing of a nanoparticle silver ink with subsequent thermal sintering on a standard flexible polymer film, to demonstrate that inkjet printing allows the manufacturing of printed thin devices also on low‐cost material. The implementation of various designs allows the control of the temperature distribution and heat development. The printed structures are evaluated regarding their optical and electrical characteristics and their thermal performance is assessed using an infrared camera. This research has succeeded in developing bendable printed heaters, which reach homogeneous average temperature of 100 °C over an area of approximately 15 cm2 at a power supply of 12 V. The feasibility of the inkjet printed heaters is demonstrated by a long‐term test over several days with negligible fluctuations in the area temperature and highest stability in the resistance. [ABSTRACT FROM AUTHOR]

Herein, the inkjet printing of bioresorbable materials tuned to function as electrode, dielectric, and semiconductor layers is reported, thereby developing multilayered microelectronic devices such as capacitors and thin‐film transistors, potentially applicable to address specific medical needs. Polymers and natural materials, e.g., poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate), shellac, and β‐carotene, indigo inks are implemented using jettable formulations, that are either commercially procured or self‐formulated, designed explicitly to deposit fundamental layers for capacitors and transistors. Several parameters are evaluated and adjusted to precisely define a layer's thickness, topology, and geometry, matching with the properties of a fully biodegradable Ormocere substrate, explicitly developed for the specific biological applications. Furthermore, these parameters support in acquiring the intended electrical properties of layers, i.e., conductivity, insulation, semiconductivity, capacitance, and current versus voltage characteristics. The entire manufacturing process of devices is accomplished on the Ormocere substrate under ambient conditions and below 60 °C. The results exhibit that the electrical characteristics of the printed functional layers and devices show direct influence to the physical geometry of the printed features. A fully printed capacitor demonstrates capacitance of 1 nF cm−2, whereas transistors show p‐type and n‐type characteristics with current 0.18–5 μA and mobility 6 × 10−4–7 × 10−2 cm2 V−1 s−1. [ABSTRACT FROM AUTHOR]

The technological advancement in the field of printed electronics over roll-to-roll (R2R) platform has become very attractive, because of the several advantages such as mass production, large area application, cost-saving and high-speed capabilities. The inkjet technology, on the other hand, among other printing technologies promotes individualization and contact-less deposition process qualities. In this article, the authors demonstrate the state of the art R2R setup for printing silver (Ag) conductive patterns on PEN substrate using inkjet and infra-red technologies. The deposition of the conductive patterns was accomplished using a nanoparticle-based Ag ink and industrial printheads from Fujifilm Dimatix. The novelty of the research work is realization of a print setup, consisting of an industry relevant flexible printhead assembly and drop evaluation station, which are mounted over a R2R printing system. The entire setup allows the user to first evaluate the ejection of the droplets and then stabilize the print parameters without involving the web substrate, followed by re-positioning of the inkjet assembly back to the R2R printing system. The capability of the print setup is exhibited by varying the printing resolution for the defined digital patterns. In addition, the post-treatment of the conductive patterns was tailored with the implementation of an infra-red based sintering module from Heraeus Noblelight GmbH. The power density of the filaments from the sintering module was varied to achieve the maximum conductivity and to ensure no physical damage to the patterns and substrate. The results indicate that such a print setup is very flexible and can offer several benefits to the printing process of conductive patterns, e.g., obtaining line width below 80 µm and sheet resistance of about 0.5 =, with the advantage of sintering the patterns within 20 s. c 2018 Society for Imaging Science and Technology. [ABSTRACT FROM AUTHOR]

In this study, the application of printing technologies for the manufacturing of passive microwave components such as antennas is highlighted, and a detailed example is given. Common printing technologies such as inkjet, screen, and gravure printing become adjusted to print conductive inks for the manufacturing of printed antennas on flat substrates or even on threedimensional (3D) surfaces. Especially, printing technologies such as pad printing, micro-jetting, dispensing, and aerosol jetting are candidates for the manufacturing of microwave components onto challenging 3D surfaces, which may facilitate new designs. Depending on the substrate, one technical challenge is to choose a proper metal ink in combination with a suitable thermal treatment to reach critical requirements such as electrical conductivity above 106 S/m or proper adhesion of the printed pattern for an antenna application. This study gives an overview and comparison of the state-of-the-art materials, inks, printing processes, and options of subsequent thermal treatment. The challenges and possibilities for printed-passive microwave components are discussed with regard to microwave applications. The development of a printed radio-frequency identification antenna on a 3D surface is demonstrated, and the performance of the manufactured antenna is discussed in detail. [ABSTRACT FROM AUTHOR]

This paper demonstrates the manufacturing of inductor coils, capacitors, and rectifying diodes solely using the inkjet printing technology. Industrially relevant printheads from Fujifilm Dimatix were employed to prove the process scalability of the inkjet printing technology by manufacturing hundreds of devices. Organic and inorganic conductors and different organic dielectrics were applied for the manufacturing of electrical devices as well as a p-type organic semiconductor. The manufacturing yield effects of varying printing parameters, such as print resolution (drop spacing) and the size of the printed area on the layer morphology and electrical characteristics, were investigated. [ABSTRACT FROM AUTHOR]

Microelectronic devices have great potential to be integrated into the Internet of Things, bringing benefits to the environment, society, and economy. Especially, microscaled chemical sensors for environmental monitoring are of great interest since they can be manufactured by cost, time, and resource efficient inkjet printing technology. The aim of the present literature review is a reflection of state-of-the-art inkjet-printed chemiresistive sensors. It examines current material approaches used to realize printed chemiresistors, especially the challenges in the realisation of accurate electrode patterns as well as the deposition of various sensing materials by inkjet printing technology. The review will be completed by an overview of current research activities dealing with the integration of chemiresistive sensors into wireless applications. The result of this review confirms that during the last decades, the number of publications covering inkjet-printed chemical, especially chemiresistive, sensors and their introduction into the Internet of Things is growing. Furthermore, it reveals the need for further research regarding material science and printing technology compatibility to achieve reliable and reproducible chemiresistive sensors. [ABSTRACT FROM AUTHOR]

Vehicle tracking systems based on ultra high frequency (UHF) radio frequency identification (RFID) technology are already introduced to control the access to car parks and corporate premises. For this field of application so-called Windshield RFID transponder labels are used, which are applied to the inside of the windshield. State of the art for manufacturing these transponder antennas is the traditional lithography/etching approach. Furthermore the performance of these transponders is limited to a reading distance of approximately 5 m which results in car speed limit of 5 km/h for identification. However, to achieve improved performance compared to existing all-purpose transponders and a dramatic cost reduction, an optimized antenna design is needed which takes into account the special dielectric and in particular metallic car environment of the tag and an roll-to-roll (R2R) printing manufacturing process. In this paper we focus on the development of a customized UHF RFID transponder antenna design, which is adopted for vehicle geometry as well as R2R screen printing manufacturing processes. [ABSTRACT FROM AUTHOR]