Abstract:Poly(3,4-ethylenedioxythiophene) chemically doped with poly(styrene sulfonic acid) (PEDOT:PSS) is a material system commonly used as a conductive and transparent coating in several important electronic applications. The material is also electrochemically active and exhibits electrochromic (EC) properties making it suitable as the active element in EC display applications.In this work uniformly coated PEDOT:PSS layers were used both as the pixel electrode and as the counter electrode in EC display components. The pixel and counter electrodes were separated by a whitish opaque and water-based polyelectrolyte and the thicknesses of the two EC layers were varied independently in order to optimize the color contrast of the display element. A color contrast (ΔE*, CIE L*a*b* color space) exceeding 40 was obtained with maintained relatively short switching time at an operational voltage less than 2 V.

Additional Supporting Information may be found in the online version of this article. ABSTRACTA flexible electrochromic active matrix addressed display, including 8×8 pixels, is demonstrated by using solution processing based on standard printing and coating manufacturing techniques.Each organic electrochromic display (OECD) pixel and its corresponding organic electrochemical transistor (OECT) are located on different sides of the flexible PET substrate. Electronic vias generated through the plastic substrate connects each OECD pixel with one addressing OECT.When comparing this display with actively addressed OECDs with all its components located on the same side, the present approach based on this electronic via-substrate provides an enhanced pixel resolution and a relatively more simplified manufacturing process.

Symmetric and fast (~ 5 ms) on-to-off and off-to-on drain current switching characteristics have been obtained in screen printed organic electrochemical transistors (OECT) including PEDOT:PSS (poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid)) as the active transistor channel material. Improvement of the drain current switching characteristics is made possible by including a carbon conductor layer on top of PEDOT:PSS at the drain electrode that is in direct contact with both the channel and the electrolyte of the OECT. This carbon conductor layer suppresses the effects from a reduction front that is generated in these PEDOT:PSS-based OECTs. In the off-state of these devices this reduction front slowly migrate laterally into the PEDOT:PSS drain electrode, which make off-to-on switching slow. The OECT including carbon electrodes was manufactured using only standard printing process steps and may pave the way for fully integrated organic electronic systems that operate at low voltages for applications such as logic circuits, sensors and active matrix addressed displays.

Flexible displays are attracting considerable attention as a visual interface for applications such as in electronic papers and paper electronics. Passive or active matrix addressing of individual pixels require display elements that include proper signal addressability, which is typically provided by non-linear device characteristics or by incorporating transistors into each pixel. Including such additional devices into each pixel element make manufacturing of flexible displays using adequate printing techniques very hard and complicated. Here, we report all-printed passive matrix addressed electrochromic displays (PMAD), built up from a very robust three-layer architecture, which can be manufactured using standard printing tools.Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) serves as -2 -the conducting and electrochromic pixel electrodes and carbon paste is used as the pixel counter electrodes. These electrodes sandwich self-assembled layers of a polyelectrolyte that are confined to desired pixel areas via surface energy patterning. The particular choice of materials results in a desired current vs. voltage threshold that enables addressability in electronic cross-point matrices. The resulting PMAD operates at less than 3 V, exhibits high colour switch contrast without cross-talk and promises for high-volume and low-cost production of flexible displays using reel-to-reel printing tools on paper or plastic foils.

Ferroelectric-coated counter electrodes control the electrochemistry of conducting polymers.

Abstract-A novel vertical architecture for all-printed organic electrochemical transistors, based on PEDOT:PSS, realized on flexible substrates is reported. The transistors are manufactured along both faces of paper or plastic substrates and via connections are realized using laser ablation and simple punch through using a pin. Successful modulation of the electric current that flows between the two sides of the substrate is achieved using electrolyte-gating and electrochemical modulation of the electronic charge transport of the bulk of the transistor channel. In addition to this, the transistors are exhibiting fast switching and high on/off current ratios. Introductionuring the last decade the research field of printed electronics (PE) has experienced a tremendous advancement in terms of the performance of single electronic devices, complexity of functional printed systems, and also regarding potential application areas [1][2][3][4][5]. One of the prime key criteria to success with the printed-on-paper and printed-on-plastic electronics revolution is that simple and robust device architectures are developed so that large area, high throughput and low cost manufacturing techniques can be used. Various qualities of flexible plastic foils and cellulose-based papers are explored as the carrying substrates for PE, of which paper nowadays attracts an increased attention in part thanks to its environmentally friendly characteristics [6]. Various sensors [7], thin film transistors (TFTs) [8], displays [9] and supercapacitors [10] have been realized on paper and plastic foils [8,11,12]. Moreover, different high volume sheet-based or roll-to-roll printing, coating and lamination tools have been successfully utilized to manufacture complete device systems. However, the device structure of many PE components typically mimics the architecture of devices developed for electronics manufactured using inorganic rigid substrates such as silicon, or thin film devices produced using various evaporation and sputtering methods. Improvements in performance obtained in inorganic-based technologies have in part been achieved by using multi-stack structures [13,14]. A similar strategy could be utilized also for organic electronic components by constructing device architectures in a vertical configuration; for instance by printing materials on top of each other and to connect devices defined on both sides, using electrical vias, of the carrying flexible substrate to improve integration density and operation performance [15,16]. Here, we report such an electrical via approach to achieve organic electrochemical transistors (OECT), based on poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrene sulfonate) (PSS), that exhibit improved drain current switch on/off-ratio and switch time characteristics. The vertical OECTs have been realized on both paper and plastic substrates with electrical vias based on carbon paste. The gate, source, electrolyte and PEDOT:PSS channel are all located on the same side of the substrate, whereas the ...

Damage-less full molecular-pore-stack SiOCH (MPS) / Cu interconnect is developed to reduce effective k-value (k eff ).MPS with high endurance against plasma processes is introduced into both via and trench dielectrics without hard mask (HM). Low friction slurry and chemical modification of MPS surface by He-plasma treatment suppress defect generation during direct CMP of the MPS surface. The full-MPS interconnect with low-k (k=3.1) cap demonstrates 10% lower inter-line capacitance and 34% lower inter-layer capacitance than the full-SiOCH (k=3.0) interconnect with SiCN-cap (k=4.9). The effective k-value k eff reduces to 2.67 for the damage-less full MPS structure which is applicable to 32nm LSIs and beyond.

wood. The resulting films, which carry ionic or electronic functionalities, are all-organic, disposable, light-weight, flexible, self-adhesive, elastic and self-supporting. The mechanical and self-adhesive properties of the films enable us to achieve simple and flexible electronic systems by assembling the films into various kinds of components using a "cut and stick" method. Additionally, the self-adhesive surfaces provide us with a new concept that not only allows for simplified system integration of printed electronic components, but also allows for a unique possibility to detach and reconfigure one or several subcomponents by a "peel and stick" method to create yet another device configuration. This is demonstrated by a stack of two films that first served as the electrolyte layer and the pixel electrode of an electrochromic 2 display, which then was detached from each other and transferred to another configuration, thus becoming the electrolyte and gate electrode of an electrochemical transistor. Further, smart pixels, consisting of the combination of one electrochromic pixel and one electrochemical transistor, have successfully been manufactured with the NFC-hybridized materials. The concept of system reconfiguration was further explored by that a pixel electrode charged to its colored state could be detached and then integrated on top of a transistor channel. This resulted in spontaneous discharging and associated current modulation of the transistor channel without applying any additional gate voltage. Our peel and stick approach promises for novel reconfigurable electronic devices, e.g. in sensor, label and security applications.