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Due to their complex formulation, conductive nanoparticle inks for inkjet printing are limited in terms of the types of metals and substrates that can be utilized. A new and simplified class of inks called metal salt decomposition (MSD) inks has the potential to introduce a multitude of metals, which can be printed directly onto a wide range of substrates. Here, the use of atmospheric oxygen plasma to develop polycrystalline Au and Pt films at processing temperatures near room temperature (≈33 °C) with excellent conductivities up to 105 S m−1 is demonstrated. The conformal nature of the ink allows metal films to be printed onto a broad range of temperature-sensitive substrates including polymers, papers, and fabric. The Au ink is then used to build a simple light-emitting diode circuit showing its flexibility, durability, and long-term stability as deposited thin metal films. Additionally, such inks cost less than one-third the price of similar nanoparticle inks highlighting their overall affordability and good stability., This project was made possible by MCIU/AEI/FEDER Funding agency (RTI2018-102070-B-C21) under the name ECOTRONIC, and MICINN-Spain (RTC2019-007226-7). C.M-D acknowledges her Juan de la Cierva grant (ref. FJC2019-042161-I) from Ministerio de Ciencia e Innovación. All authors would like to thank Prof. Fabiola Vilaseca Morera at the University of Girona (UdG) and her students for graciously providing various CNF paper substrates derived from cellulose pulp, eucalyptus, and abaca. Additionally, the authors would like to extend gratitude to David Batet for providing Teslin + CNF samples., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

Organic Electronics provides multiple technological advantages such as low cost, flexibility, solution processability and waste reduction through the use of new materials and alternative fabrication techniques in the microelectronic world. The use of additive and printed fabrication processes allows the development of instantly fabricated, fully additive, low temperature processing together with lightweight, bendable, scalable and sustainable systems. Different models have been presented in the field but none of them with an industrial implementation. Complete simulation models are very useful for circuit production and commercialization since the organic electronics market is expected to grow in the near future and the need for industrial solutions for designers will increase. For this reason and for the first time, we present a compact model of DC and AC behaviour combined with different ambient conditions and parameter variability for full organic electronic system simulations., This work was supported by MICIU-Spain (RTI2018-102070-B-C21), MICIU-Spain (RTC2019-007226-7), Marie Skłodowska-Curie No 801342 (Tecniospring INDUSTRY), NeuDrive Ltd. (UK) for providing the devices and circuits manufactured., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

The implementation of organic semiconductor (OSC) materials in X-ray detectors provides exciting new opportunities for developing a new generation of biocompatible devices with high potential for the fabrication of sensitive and low-cost X-ray imaging systems. Here, the fabrication of high performance organic field-effect transistors (OFETs) based on blends of 1,4,8,11-tetramethyl-6,13-triethylsilylethynyl pentacene (TMTES) with polystyrene is reported. The films are printed employing a low cost and high-throughput deposition technique. The devices exhibit excellent electrical characteristics with a high mobility and low density of hole traps, which is ascribed to the favorable herringbone packing (different from most pentacene derivatives) and the vertical phase separation in the blend films. As a consequence, an exceptional high sensitivity of (4.10 ± 0.05) × 1010 µCGy–1cm–3 for X-ray detection is achieved, which is the highest reported so far for a direct X-ray detector based on a tissue equivalent full organic active layer, and is higher than most perovskite film-based X-ray detectors. As a proof of concept to demonstrate the high potential of these devices, an X-ray image with sub-millimeter pixel size is recorded employing a 4-pixel array. This work highlights the potential exploitation of high performance OFETs for future innovative large-area and highly sensitive X-ray detectors for medical dosimetry and diagnostic applications., This work was funded by the Spanish Government within: research projects GENESIS PID2019-111682RB-I00 and RTI2018-095460-B-I00, the “Severo Ochoa” Programme for Centers of Excellence in R&D (FUNFUTURE CEX2019-000917-S) and the “María de Maeztu” program for Spanish Structures of Excellence (MDM-2017-0767). Funding was also provided by the Generalitat de Catalunya (2017-SGR-918, 2017-SGR13). A.T. acknowledges his FPU fellowship and is enrolled in the UAB Materials Science PhD program. C.M-D. acknowledges her Juan de la Cierva grant (ref. FJC2019-042161-I) from Ministerio de Ciencia e Innovación. I.F., A.C., B.F. and L.B. acknowledge funding from INFN through the CSN5 FIRE project. All the authors acknowledge Giuliana Tromba and Diego Dreossi at ELETTRA synchrotron in Trieste for hardware and software technical support during the experiments, in particular for the acquisition of X-ray image. R.S. acknowledges funding from MINECO under grant agreement CTQ2017-87773-P/AEI/FEDER., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

The fabrication of diodes by inkjet printing has been hampered by difficulties in printing low work function metals required to establish Schottky barriers with organic semiconductors. This limitation has been a major roadblock in the use of inkjet printing technology for the development of organic rectifying diodes. This paper presents the fabrication and characterization of a novel inkjet-printed metal- organic insulator- organic semiconductor diode on flexible plastic substrates. The structure consists of a polymeric insulator/semiconductor interface sandwiched between two silver electrodes. It is proposed that the rectification properties are due to a voltage controlled leakage current across the insulator/semiconductor interface. The current across the insulator is caused by the formation of a semiconductor brush-like morphology into the underneath porous insulator layer. The carrier injection into the insulator follows a thermionic emission model. Temperature dependent measurements reveal an interfacial barrier height between 0.97 eV and 0.36 eV depending on the morphology and type of insulator layer used. Metal- organic insulator- organic semiconductor based diodes show rectification ratios up to 150 at |10V| and a current density up to approximately 1 μAcm−2. The simple fabrication process of the diodes also makes it advantageous for scaling up to roll-to-roll production.

Altres ajuts: Agència per a la Competitivitat de l'Empresa de la Generalitat de Catalunya by FEDER funds, Institució Catalana de Recerca i Estudis Avançats, and ERDF funds In this paper, an organic, fully recyclable and eco-friendly 20-bit inkjet-printed chipless RFID tag is presented. The tag operates in the near field and is implemented by means of chains of resonant elements. The characterization and manufacturing process of the tag, printed with a few layers of a commercial organic ink on conventional paper substrate (DIN A4), are presented, and tag functionality is demonstrated by reading it by means of a custom-designed reader. The tags are read by proximity (through the near field), by displacing them over a resonator-loaded transmission line, and each resonant element (bit) of the tag is interrogated by a harmonic signal tuned to the resonance frequency. The coupling between the reader line and the resonant elements of the tag produce and amplitude modulated (AM) signal containing the identification (ID) code of the tag.

In the last years there has been a growing interest in the realization of low-cost, flexible and large area electronic systems such as item-level RFID tags, flexible displays or smart labels, among others. Specifically, inkjet printing technology has been increasingly applied as advanced deposition technology in the field of printed electronics due to the high flexibility in terms of patterns (mask-less) and materials, and its low cost approach as only a small amount of materials is required in comparison to other solution-based deposition techniques. Our work focuses on the development of Organic Thin Film Transistors (OTFTs) by using organic, inorganic inks and low-cost all-inkjet purely printing process, thus centring the effort in the design, manufacturing and characterization point of view in order to fabricate all-inkjet printed organic integrated circuits. Electrical and morphological characterizations were performed in order to obtain device statistics to investigate the origins of the failures responsible for the low yields. Most of research works are based on laboratory inkjet equipment for manufacturing using single nozzle systems to fabricate small numbers of devices. The variability and mismatch of the printed devices are underrepresented in literature and are key factors towards commercialization of printed electronics.

© The Author(s)., It is well known that organic thin film transistor (OTFT) parameters can be shifted depending on the geometry of the device. In this work, we present two different transistor geometries, interdigitated and Corbino, which provide differences in the key parameters of devices such as threshold voltage (VT), although they share the same materials and fabrication procedure. Furthermore, it is proven that Corbino geometries are good candidates for saturation-mode current driven devices, as they provide higher ION/IOFF ratios. By taking advantage of these differences, circuit design can be improved and the proposed geometries are, therefore, particularly suited for the implementation of logic gates. The results demonstrate a high gain and low hysteresis organic monotype inverter circuit with full swing voltage at the output, This research was funded by MICIU-Spain, grant number RTI2018–102070-B-C21.

We report on the development of inkjet-printed thin-film resistors using both organic and inorganic ink formulations. The passive devices were manufactured on flexible polymer substrates in ambient condition without the need for a cleanroom environment or inert atmosphere and at a maximum temperature of 150 °C. By using the same manufacturing process, the rapid electrical sintering (RES) method is demonstrated as effective for the fabrication of inkjet-printed, programmable Write-Once-Read-Many (WORM) memories. Several hundred fully inkjet-printed resistors with different parameters were fabricated and subsequently morphologically and electrically characterized with the aim of obtaining statistically significant data. From a manufacturing process viewpoint, the procedures based on inkjet printing herein described are highly attractive: they do not require high temperatures, low pressures, special atmospheric conditions, and any masks, therefore providing a versatile low-cost approach to fabricate passive electrical components and simple circuits useful for the electronic industry. Printing can be carried out at a sufficiently low temperature to avoid damage to the fabric substrate and these devices can be used in a range of applications requiring flexible and conformal devices from embedded passive filters in PCBs to wearable electronics.

Altres ajuts: CERCA Programme/Generalitat de Catalunya. Biosensors based on Organic Field-Effect Transistors (OFETs) have attracted increasing attention due to the possibility of rapid, label-free, and inexpensive detection. Among all the different possibilities, inkjet-printed top-gate organic Field Effect Transistors-Based Biosensors (BioFETs) using a polymeric gate insulator have been seldom reported. In this work, a systematic investigation in terms of topographical and electrical characterization was carried out in order to find the optimal fabrication process for obtaining a reliable polymer insulator. Previous studies have demonstrated that the best electrical performance arises from the use of the perfluoropolymer Cytop™[12,13,14]. Consequently, a simple immobilization protocol was used to ensure the proper attachment of a model biomolecule onto the Cytop's hydrophobic surface whilst keeping its remarkable insulating properties with gate current in the range of dozens of pico-amperes. The top-gate inkjet-printed BioFETs presented in this study operate at threshold voltages in the range of 1-2 V and show durability even when exposed to oxygen plasma, wet amine functionalization treatments, and aqueous media. As a preliminary application, the inkjet-printed top-gate BioFETs is used for monitoring an immunoreaction by measuring changes in the drain current, paving the way for further use of this device in the immunosensing field.

The rise of internet of things (IoTs) applications has led to the development of a new generation of light-weight, flexible, and cost-effective electronics. These devices and sensors have to be sim ...

A process design kit (PDK) or Technology Design kit (TDK) is a set of files which describes manufacturing parameters that are relevant for the designers (fabrication layers, electrical parameters and design rules) for a certain technology of a given foundry. PDKs customize CAD/EDA tools used by designers, providing enough abstraction of technological details to facilitate the design of (organic electronics) circuits. Design rules are a set of geometric restrictions imposed to the different layers fabricated by the foundry that designers have to respect. By taking the geometric design rules into account, the design engineers address physical layout to develop devices and circuits without the need of a deep knowledge of process and materials. These rules guarantee their manufacturability and enable working circuits with an optimal balance of yield versus integration density. Design rules for inkjet printing are similar to general design rules for photolithographic processes but also need to cope with the failures related to additive printing of inks and related curing. In this paper, parameterizable cells (PCells) have been used to automate the generation of a complete set of structures to formalize and arrive at technology-independent design rules. A set of test vehicles has been designed, printed and characterized demonstrating the methodology to comprehensively capture the design criteria for inkjet printing technology. For improving design rules and scaling down device dimensions, we present a design approach that combines pre-patterned, high-resolution substrates with digital inkjet fabrication as a demonstration of the capabilities of combining inkjet with other fabrication technologies.

The operational stability of all-inkjet printed transistors is reported. At room temperature the threshold voltage shifts following a stretched exponential with a relaxation time τ=1x103 s. Two distinct trap sites active in different temperature ranges, one at 200-250 K and other above 310 K cause the electrical instability. Both types of traps capture holes and can be fast neutralized by photogenerated electrons. Optically induced detrapping currents confirm the differences in trap signature. It is proposed, that the traps have a common physical origin related to water.

We report on the detailed electrical investigation of all-inkjet-printed thin-film transistor (TFT) arrays focusing on TFT failures and their origins. The TFT arrays were manufactured on flexible polymer substrates in ambient condition without the need for cleanroom environment or inert atmosphere and at a maximum temperature of 150 degrees C. Alternative manufacturing processes for electronic devices such as inkjet printing suffer from lower accuracy compared to traditional microelectronic manufacturing methods. Furthermore, usually printing methods do not allow the manufacturing of electronic devices with high yield (high number of functional devices). In general, the manufacturing yield is much lower compared to the established conventional manufacturing methods based on lithography. Thus, the focus of this contribution is set on a comprehensive analysis of defective TFTs printed by inkjet technology. Based on root cause analysis, we present the defects by developing failure categories and discuss the reasons for the defects. This procedure identifies failure origins and allows the optimization of the manufacturing resulting finally to a yield improvement.

Multiple successive breakdown events are reported for HfO"2/Al"2O"3 nanolaminate dielectrics grown by atomic-layer deposition. The first breakdown distribution is not a Weibull distribution and shows a long TBD tail at high failure percentiles. Analysis of the correlation between time-to-breakdown and initial current leakage allows identifying this tail with extrinsic breakdown. Screening of the data to eliminate the extrinsic tail demonstrates that the successive breakdown events are completely uncorrelated and perfectly match the successive breakdown theory. The statistical correlation between initial current and extrinsic breakdown distribution is explained in terms of variations of the unintentional interfacial SiO"x layer at the silicon substrate/dielectric interface.

Inkjet Technology is often mis-believed to be a deposition/patterning technology which is not meant for high fabrication throughput in the field of printed and flexible electronics. In this work, we report on the 1) printing, 2) fabrication yield and 3) characterization of exemplary simple devices e.g. capacitors, organic transistors etc. which are the basic building blocks for logical circuits. For this purpose, printing is performed first with a Proof of concept Inkjet printing system Dimatix Material Printer 2831 (DMP 2831) using 10 pL small print-heads and then with Dimatix Material Printer 3000 (DMP 3000) using 35 pL industrial print-heads (from Fujifilm Dimatix). Printing at DMP 3000 using industrial print-heads (in Sheet-to-sheet) paves the path towards industrialization which can be defined by printing in Roll-to-Roll format using industrial print-heads. This pavement can be termed as "Bridging Platform". This transfer to "Bridging Platform" from 10 pL small print-heads to 35 pL industrial print-heads help the inkjet-printed devices to evolve on the basis of functionality and also in form of up-scaled quantities. The high printed quantities and yield of inkjet-printed devices justify the deposition reliability and potential to print circuits. This reliability is very much desired when it comes to printing of circuits e.g. inverters, ring oscillator and any other planned complex logical circuits which require devices e.g. organic transistors which needs to get connected in different staged levels. Also, the up-scaled inkjet-printed devices are characterized and they reflect a domain under which they can work to their optimal status. This status is much wanted for predicting the real device functionality and integration of them into a planned circuit.

We report about the use of a printed pentafluorothiophenol layer on top of the dielectric surface as a passivation coating to improve the operational stability of all-ink-jet printed transistors. Transistors with bottom-gate structure were fabricated using cross-linked poly-4-vinylphenol (c-PVP) as dielectric layer and an ink formulation of an amorphous triarylamine polymer as semiconductor. The resulting TFTs had low turn-on voltage (Vth < |5 V|) and a mobility ≈0.1 cm2/(V s). A comparison of identically fabricated transistors shows that devices with coated dielectric have a higher operational stability than those using bare c-PVP. This conclusion is supported by a quantitative study of the threshold voltage shift with time under continuous operation. Long exposure to the ambient atmosphere causes an increase in the threshold voltage strongly dependent on the used semiconducting ink formulation. © 2015 Elsevier Ltd.

Over the past decade, inkjet technology has been well recognized for the manufacturing of products that include “printing beyond colors.” This micrometer-scale precise technology provides a straightforward approach toward judicious deposition of electronically functional material inks on various substrates over relatively large areas, for printed/flexible electronics. The technology promotes upscalability and has become a renowned process tool for fabricating electronic devices in the field of printed/flexible electronics. Here, the fabrication of printed thin-film transistors (TFT) on cheap coated paper substrate using inkjet technology is reported. For developing the TFT layer stack conductive nanoparticle inks, a polymeric dielectric ink and a p-type organic semiconductor ink are employed. The coating on the paper provides several advantages for fabrication process of TFTs; for example, control over ink spreading. This control of ink spreading can directly influence the fabrication of interdigitated source/drain (S/D) electrodes for TFTs, when a top gate bottom contact architecture is considered. This results in better manufacturing yields and promising electrical performance, which are also the focus of this research. The all inkjet-printed TFTs on paper exhibit electrical performance with maximum S/D current ranging to 170 nA, charge carrier mobility of 0.087 cm2 V−1 s−1, and current on/off ratio of 330.

All inkjet printed rectifying diodes based on a metal-insulator-semiconductor (MIS) layer stack are presented. The rectifying properties were optimized by careful selection of the insulator interlayer thickness and the layout structure. The different diode architectures based on the following materials are investigated: (1) silver/ poly (methylmethacrylate-methacrylic acid)/ polytriarylamine/ silver, (2) silver/ polytriarylamine/ poly (methylmethacrylate-methacrylic acid)/ silver, and (3) silver/ poly (methylmethacrylate-methacrylic acid)/ poly-triarylamine/ poly(3,4-ethylenedioxythiophene) poly (styrenesulfonate). The MIS diodes show an averaged rectification ratio of 200 and reasonable forward current density reaching 40 mA cm -2. They are suitable for a number of applications in flexible printed organic electronics. EU [287682]

Inkjet printing is a well-accepted deposition technology for functional materials in the area of printed electronics. It allows the precise deposition of patterned functional layers on both, rigid and flexible substrates. Furthermore, inkjet printing is considered as up-scalable technology towards industrial applications. Many electronic devices manufactured with inkjet printing have been reported in the recent years. Some of the evident examples are capacitors, resistors, organic thin film transistors and rectifying Schottky diodes. [1, 2, 3] In this paper we report on the manufacturing of an inkjet-printed metal-insulator-semiconductor (MIS) diode on flexible plastic substrate. The structure is comprised of an insulating and a polymeric semiconducting layer sandwiched between two silver electrodes. The current vs. voltage characteristics are rectifying with rectification ratio up to 100 at |4 V|. Furthermore, they can carry high current densities (up to mA/cm2) and have a low capacitance which makes them attractive for high frequency rectifying circuits. They are also an ideal candidate to replace conventional Schottky diodes for which the fabrication remains a challenge. This is because inkjet printing of Schottky diodes require additional processing steps such as intense pulsed light sintering (IPL sintering) [4] or post-treatments at high temperatures. The deposition of two different metal layers using inkjet printing e.g. Cu or Al with Ag is possible. However, the mentioned post treatment technologies might be incompatible with the already existing layer stack– e.g. it could degrade the organic semiconductor or can damage insulator which in this case is present in the MIS diode architecture.

One of the greatest challenges in the field of printed electronics is the performance stability of the devices fabricated by the different printing technologies e.g. inkjet or gravure printing technology. The performance instability can be defined in terms of the device breakdown or by other effects like the emergence of leakage current under the constant high voltage inputs (especially the dielectric within the transistor architecture). The reasons behind this phenomenon can be various, but the most prominent indication can be detected from the materials used and the deposition methodology. For this purpose the herein work is presented, targeting on the all inkjet-printed organic thin film transistor (OTFT), but keeping the focus on the basic building block for fabricating inkjet-printed OTFTs. In this case it is the metal-insulator-metal (MIM) layer structure. Herein, the MIM structures are inkjet-printed, and then characterized optically and electrically. The dielectric layers for the MIM structures are printed using three different dielectric ink materials either individually 1) Single component system; or in combination with each other as in form of bi-layer stack 2) Multiple component system. The thickness of the printed dielectric layers is varied for these MIM structures. The electrical characterization is performed with respect to current vs. applied voltage and is done for a large number of iterations. The leakage current is of interest and shows a negative and positive trend towards the single component system and multiple component system for the dielectric layers in the MIM characterization structures respectively.