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Printed electronic paper identifies its interest in flexible organic electronics and sustainable and clean energy applications because of its straightforward production method, cost‐effectiveness, and positive environmental impact. However, current limitations include restricted material thickness and the use of supporting substrate for printing. Here, 2D and 3D electronic patterned paper are fabricated from direct ink writing (DIW) nanocellulose and PEDOT:PSS‐based materials using syringe deposition and 3D printing. The conductor patterns are integrated in the bulk of the paper, while non‐conductive sections are used as support to form free‐standing paper. The strong interface between the patterns of electronic patterned paper gives mechanical stability for practical handling. The conductive paper‐based electrode has 202 S cm−1 and is capable of handling electric current up to 0.7 A, which can be used for high‐power devices. Printed supercapacitor papers show high specific energy of 4.05 Wh kg−1, specific power of 4615 W kg−1 at 0.06 A g−1, and capacitance retention above 95% after 2000 cycles. The new design structure of electronic patterned papers presents a solution for additive manufacturing of paper‐based composites for supercapacitors, wearable electronics, or sensors for smart packaging. [ABSTRACT FROM AUTHOR]

The quest for eco‐friendly materials with anticipated positive impact for sustainability is crucial to achieve the UN sustainable development goals. Classical strategies of composite materials can be applied on novel nanomaterials and green materials. Besides the actual technology and applications also processing and manufacturing methods should be further advanced to make entire technology concepts sustainable. Here, they show an efficient way to combine two low‐cost materials, cellulose and zinc oxide (ZnO), to achieve novel functional and "green" materials via paper‐making processes. While cellulose is the most abundant and cost‐effective organic material extractable from nature. ZnO is cheap and known of its photocatalytic, antibacterial, and UV absorption properties. ZnO nanowires are grown directly onto cellulose fibers in water solutions and then dewatered in a process mimicking existing steps of large‐scale papermaking technology. The ZnO NW paper exhibits excellent photo‐conducting properties under simulated sunlight with good ON/OFF switching and long‐term stability (90 minutes). It also acts as an efficient photocatalyst for hydrogen peroxide (H2O2) generation (5.7 × 10−9 m s−1) with an envision the possibility of using it in buildings to enable large surfaces to spontaneously produce H2O2 at its outer surface. Such technology promise for fast degradation of microorganisms to suppress the spreading of diseases. [ABSTRACT FROM AUTHOR]

To address the rising need of sustainable solutions in electronic devices, the development of electronically conductive composites based on lightweight but mechanically strong wood structures is highly desirable. Here, a facile approach for the fabrication of highly conductive wood/polypyrrole composites through top‐down modification of native lignin followed by polymerization of pyrrole in wood cell wall. By sodium sulfite treatment under neutral condition, sulfonated wood veneers with increased porosity but well‐preserved cell wall structure containing native lignin and lignosulfonates are obtained. The wood structure has a content of sulfonic groups up to 343 µmol g−1 owing to in situ sulfonated lignin which facilitates subsequent oxidative polymerization of pyrrole, achieving a weight gain of polypyrrole as high as 35 wt%. The lignosulfonates in the wood structure act as dopant and stabilizer for the synthesized polypyrrole. The composite reaches a high conductivity of 186 S m−1 and a specific pseudocapacitance of 1.71 F cm−2 at the current density of 8.0 mA cm−2. These results indicate that tailoring the wood/polymer interface in the cell wall and activating the redox activity of native lignin by sulfonation are important strategies for the fabrication of porous and lightweight wood/conductive polymer composites with potential for sustainable energy applications. [ABSTRACT FROM AUTHOR]

Low weight, small footprint, and high performances are essential requisites for the implementation of energy storage devices within consumer electronics. One way to achieve these goals is to increase the thickness of the active material layer. In this work, carbonized and graphitized rayon felt, a cellulose‐derived material, is used as a three‐dimensional current collector scaffold to enable the incorporation of large amount of active energy storage materials and ionic liquid‐based gel electrolyte in the supercapacitor devices. PEDOT:PSS, alone or in combination with active carbon, has been used as the active material. Three‐dimensional supercapacitors with high per unit area capacitance (more than 1.1 F/cm2) have been achieved owing to the loading of large amount of active material in the felt matrix. Areal energy density of more than 101 μWh/cm2 and areal power density of more than 5.9 mW/cm2 have been achieved for 0.8 V operating voltage at a current density of 1 mA/cm2. A nanographite material was found to be beneficial in reducing the internal serial resistance of the supercapacitor to lower than 1.7 Ω. Furthermore, it was shown that even after 2000 times cycling test, the devices could still retain its performance with at least 88% coulombic efficiency for all the devices. All the materials are readily available commercially, environmentally sustainable and the process can potentially be upscaled with industrial process. [ABSTRACT FROM AUTHOR]

Organic electronic circuits based on organic electrochemical transistors (OECTs) are attracting great attention due to their printability, flexibility, and low voltage operation. Inverters are the building blocks of digital logic circuits (e.g., NAND gates) and analog circuits (e.g., amplifiers). However, utilizing OECTs in electronic logic circuits is challenging due to the resulting low voltage gain and low output voltage levels. Hence, inverters capable of operating at relatively low supply voltages, yet offering high voltage gain and larger output voltage windows than the respective input voltage window are desired. Herein, inverters realized from poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate‐based OECTs are designed and explored, resulting in logic inverters exhibiting high voltage gains, enlarged output voltage windows, and tunable switching points. The inverter designs are based on multiple screen‐printed OECTs and a resistor ladder, where one OECT is the driving transistor while one or two additional OECTs are used as variable resistors in the resistor ladder. The inverters' performances are investigated in terms of voltage gain, output voltage levels, and switching point. Inverters, operating at +/−2.5 V supply voltage and an input voltage window of 1 V, that can achieve an output voltage window with ∼110% increment and a voltage gain up to 42 are demonstrated. [ABSTRACT FROM AUTHOR]

Ultrathin devices are rapidly developing for skin‐compatible medical applications and wearable electronics. Powering skin‐interfaced electronics requires thin and lightweight energy storage devices, where solution‐processing enables scalable fabrication. To attain such devices, a sequential deposition is employed to achieve all spray‐coated symmetric microsupercapacitors (μSCs) on ultrathin parylene C substrates, where both electrode and gel electrolyte are based on the cheap and abundant biopolymer, cellulose. The optimized spraying procedure allows an overall device thickness of ≈11 µm to be obtained with a 40% active material volume fraction and a resulting volumetric capacitance of 7 F cm−3. Long‐term operation capability (90% of capacitance retention after 104 cycles) and mechanical robustness are achieved (1000 cycles, capacitance retention of 98%) under extreme bending (rolling) conditions. Finite element analysis is utilized to simulate stresses and strains in real‐sized μSCs under different bending conditions. Moreover, an organic electrochromic display is printed and powered with two serially connected μ‐SCs as an example of a wearable, skin‐integrated, fully organic electronic application. [ABSTRACT FROM AUTHOR]

Low‐voltage operating organic electronic circuits with long‐term stability characteristics are receiving increasing attention because of the growing demands for power efficient electronics in Internet of Things applications. To realize such circuits, inverters, the fundamental constituents of many circuits, with stable transfer characteristics should be designed to provide low‐power consumption. Here, a rational inverter design, based on fully screen printed p‐type organic electrochemical transistors with a channel size of 150 × 80 µm2, is explored for driving conditions with input voltage levels that differs of about 1 V. Further, three different inverter circuits are explored, including resistor ladders with resistor values ranging from tens of kΩ to a few MΩ. The performance of single inverters, 3‐stage cascaded inverters and 3‐stage ring oscillators are characterized with respect to output voltage levels, propagation delay, static power consumption, voltage gain, and operational frequency window. Depending on the application, the key performance parameters of the inverter can be optimized by the specific combination of the input voltage levels and the resistor ladder values. A few of the inverters are in fact fully functional up to 30 Hz, even when using input voltage levels as low as (0 V, 1 V). [ABSTRACT FROM AUTHOR]

Abstract: State‐of‐the‐art solar energy harvesting systems based on photovoltaic technology require constant illumination for optimal operation. However, weather conditions and solar illumination tend to fluctuate. Here, a device is presented that extracts electrical energy from such light fluctuations. The concept combines light‐induced heating of gold nanodisks (acting as plasmonic optical nanoantennas), and an organic pyroelectric copolymer film (poly(vinylidenefluoride‐co‐trifluoroethylene)), that converts temperature changes into electrical signals. This hybrid device can repeatedly generate current pulses, not only upon the onset of illumination, but also when illumination is blocked. Detailed characterization highlights the key role of the polarization state of the copolymer, while the copolymer thickness has minor influence on performance. The results are fully consistent with plasmon‐assisted pyroelectric effects, as corroborated by combined optical and thermal simulations that match the experimental results. Owing to the tunability of plasmonic resonances, the presented concept is compatible with harvesting near infrared light while concurrently maintaining visible transparency. [ABSTRACT FROM AUTHOR]

A novel patterning technique of conductive polymers produced by vapor phase polymerization is demonstrated. The method involves exposing an oxidant film to UV light which changes the local chemical environment of the oxidant and subsequently the polymerization kinetics. This procedure is used to control the conductivity in the conjugated polymer poly(3,4-ethylenedioxythiophene):tosylate by more than six orders of magnitude in addition to producing high-resolution patterns and optical gradients. The mechanism behind the modulation in the polymerization kinetics by UV light irradiation as well as the properties of the resulting polymer are investigated. [ABSTRACT FROM AUTHOR]

In article number 1900050, Jesper Edberg and co-workers use the redox-active dye molecule alizarin to enhance the energy storage capacity of all-organic paper-supercapacitors. The electrochemical performance and secondary doping effect of the dye on the conductive polymer PEDOT:PSS is investigated, and symmetric redox-enhanced supercapacitor devices are demonstrated. [Extracted from the article]

A supercapacitor made from organic and nature‐based materials, such as conductive polymers (PEDOT:PSS), nanocellulose, and an the organic dye molecule (alizarin), is demonstrated. The dye molecule, which historically was extracted from the roots of the plant rubia tinctorum, is here responsible for the improvement in energy storage capacity, while the conductive polymer provides bulk charge transport within the composite electrode. The forest‐based nanocellulose component provides a mechanically strong and nonporous network onto which the conductive polymer self‐organizes. The electrical and electrochemical properties of the material composition are investigated and prototype redox‐enhanced supercapacitor devices with excellent specific capacitance exceeding 400 F g−1 and an operational stability over >1000 cycles are demonstrated. This new class of supercapacitors, which in part are based on organic materials from plants, represents an important step toward a green and sustainable energy technology. [ABSTRACT FROM AUTHOR]