Showing papers on "Conductive polymer published in 2020"

3D printing of conducting polymers.

Abstract: Conducting polymers are promising material candidates in diverse applications including energy storage, flexible electronics, and bioelectronics. However, the fabrication of conducting polymers has mostly relied on conventional approaches such as ink-jet printing, screen printing, and electron-beam lithography, whose limitations have hampered rapid innovations and broad applications of conducting polymers. Here we introduce a high-performance 3D printable conducting polymer ink based on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) for 3D printing of conducting polymers. The resultant superior printability enables facile fabrication of conducting polymers into high resolution and high aspect ratio microstructures, which can be integrated with other materials such as insulating elastomers via multi-material 3D printing. The 3D-printed conducting polymers can also be converted into highly conductive and soft hydrogel microstructures. We further demonstrate fast and streamlined fabrications of various conducting polymer devices, such as a soft neural probe capable of in vivo single-unit recording.

Progress in Conductive Polyaniline-Based Nanocomposites for Biomedical Applications: A Review.

Abstract: Inherently conducting polymers (ICPs) are a specific category of synthetic polymers with distinctive electro-optic properties, which involve conjugated chains with alternating single and double bonds. Polyaniline (PANI), as one of the most well-known ICPs, has outstanding potential applications in biomedicine because of its high electrical conductivity and biocompatibility caused by its hydrophilic nature, low-toxicity, good environmental stability, and nanostructured morphology. Some of the limitations in the use of PANI, such as its low processability and degradability, can be overcome by the preparation of its blends and nanocomposites with various (bio)polymers and nanomaterials, respectively. This review describes the state-of-the-art of biological activities and applications of conductive PANI-based nanocomposites in the biomedical fields, such as antimicrobial therapy, drug delivery, biosensors, nerve regeneration, and tissue engineering. The latest progresses in the biomedical applications of PANI-based nanocomposites are reviewed to provide a background for future research.

Novel Functionalized BN Nanosheets/Epoxy Composites with Advanced Thermal Conductivity and Mechanical Properties.

Abstract: The effective dissipation of heat is critical to the performance and longevity of high-power electronics, so it is important to prepare highly thermally conductive polymer-based packaging materials for efficient thermal management. Due to the excellent thermal conductivity of boron nitride nanosheets (BNNSs), the hexagonal boron nitride (hBN) powder was dissolved in a mixed solution of isopropanol and deionized water for ultrasonic exfoliation to obtain hydroxylated BN nanosheets. Then, the prepared BNNS was functionalized with (3-aminopropyl)triethoxysilane (APTES) to enhance its dispersibility and interfacial compatibility in the epoxy resin, which play an important role in the improvement of the thermal conductivity of the composites. Finally, APTES-BNNS was uniformly dispersed in the epoxy resin by solvent mixing, and the oriented APTES-BNNS/epoxy composites were prepared through spin-coating and hot-pressing methods. It was found that APTES-BNNS/epoxy composites prepared herein exhibited significant anisotropic thermal conductivity. The results show that the thermal conductivity of APTES-BNNS/epoxy composites reached 5.86 W/mK at a filler content of 40 wt % and these composites have favorable thermal stability and mechanical properties. The APTES-BNNS/epoxy composite prepared in this paper has excellent thermal management capability and can be applied to the packaging of high-power electronic devices.

Three-dimensional interconnected networks for thermally conductive polymer composites: Design, preparation, properties, and mechanisms

Abstract: With the development of science and technology, microelectronic components have evolved to become increasingly integrated and miniaturized. As a result, thermal management, which can seriously impact the function, reliability, and lifetime of such components, has become a critical issue. Recently, the use of polymer-based thermal interface materials (TIMs) in thermal management systems has attracted considerable attention in view of the superior comprehensive properties of the former. Compared with designing and fabricating a polymer with an intrinsically high thermal conductivity, a more effective and widely used strategy for improving the heat conductivity is to fill a polymer matrix with a thermally conductive filler. Specifically, three-dimensional (3D) interconnected heat-conductive networks can increase the thermal conductivity (k) of polymers more effectively than dispersed fillers can, owing to their intrinsic continuous structures. In this review, we first introduce the heat conduction mechanisms and the problems associated with polymer-based TIMs fabricated using engineering polymer chains and traditional filling methods. Next, we discuss the advantages and mechanisms of 3D interconnected heat-conductive networks for preparing thermally conductive polymer-based composites. In addition, we highlight new advancements in the design and fabrication of 3D thermally conductive networks as well as their application in improving the k of polymers. Our exhaustive review of 3D interconnected networks includes graphene, carbon nanotubes, boron nitride, metal and other 3D hybrid architectures. The key structural parameters and control methods for improving the thermal properties of polymer composites are outlined. Finally, we summarize some effective strategies and possible challenges for the development of polymer-based thermally conductive composites via integration with 3D interconnected networks.

Phenazine-Based Covalent Organic Framework Cathode Materials with High Energy and Power Densities.

Abstract: Redox-active covalent organic frameworks (COFs) are promising materials for energy storage devices because of their high density of redox sites, permanent and controlled porosity, high surface areas, and tunable structures. However, the low electrochemical accessibility of their redox-active sites has limited COF-based devices either to thin films (<250 nm) grown on conductive substrates or to thicker films (1 μm) when a conductive polymer is introduced into the COF pores. Electrical energy storage devices constructed from bulk microcrystalline COF powders, eliminating the need for both thin-film formation and conductive polymer guests, would offer both improved capacity and potentially scalable fabrication processes. Here we report on the synthesis and electrochemical evaluation of a new phenazine-based 2D COF (DAPH-TFP COF), as well as its composite with poly(3,4-ethylenedioxythiophene) (PEDOT). Both the COF and its PEDOT composite were evaluated as powders that were solution-cast onto bulk electrodes serving as current collectors. The unmodified DAPH-TFP COF exhibited excellent electrical access to its redox sites, even without PEDOT functionalization, and outperformed the PEDOT composite of our previously reported anthraquinone-based system. Devices containing DAPH-TFP COF were able to deliver both high-energy and high-power densities, validating the promise of unmodified redox-active COFs that are easily incorporated into electrical energy storage devices.

Design Strategies for High-Performance Aqueous Zn/Organic Batteries.

Abstract: Organic electroactive compounds are attractive to serve as the cathode materials of aqueous zinc-ion batteries (ZIBs) because of their resource renewability, environmentally friendliness and structural diversity. Up to now, various organic electrode materials have been developed and different redox mechanisms are observed in aqueous Zn/organic battery systems. In this Minireview, we present the recent developments in the energy storage mechanisms and design of the organic electrode materials of aqueous ZIBs, including carbonyl compounds, imine compounds, conductive polymers, nitronyl nitroxides, organosulfur polymers and triphenylamine derivatives. Furthermore, we highlight the design strategies to improve their electrochemical performance in the aspects of specific capacity, output voltage, cycle life and rate capability. Finally, we discuss the challenges and future perspectives of aqueous Zn/organic batteries.

Cryopolymerization enables anisotropic polyaniline hybrid hydrogels with superelasticity and highly deformation-tolerant electrochemical energy storage.

Abstract: The development of energy storage devices that can endure large and complex deformations is central to emerging wearable electronics. Hydrogels made from conducting polymers give rise to a promising integration of high conductivity and versatility in processing. However, the emergence of conducting polymer hydrogels with a desirable network structure cannot be readily achieved using conventional polymerization methods. Here we present a cryopolymerization strategy for preparing an intrinsically stretchable, compressible and bendable anisotropic polyvinyl alcohol/polyaniline hydrogel with a complete recovery of 100% stretching strain, 50% compressing strain and fully bending. Due to its high mechanical strength, superelastic properties and bi-continuous phase structure, the as-obtained anisotropic polyvinyl alcohol/polyaniline hydrogel can work as a stretching/compressing/bending electrode, maintaining its stable output under complex deformations for an all-solid-state supercapacitor. In particular, it achieves an extremely high energy density of 27.5 W h kg−1, which is among that of state-of-the-art stretchable supercapacitors.

Review—Conducting Polymers as Chemiresistive Gas Sensing Materials: A Review

Abstract: Detection of harmful gases is important to ensure human and environmental health. Industrial waste gases such as CO, NO2, H2S, and NH3 are of typical focus among researchers over the years. Chemiresistive sensors are suitable for detecting these harmful gases. One suitable candidate material for this sensor is the conducting polymer, which offers the advantage of room-temperature operation. This review focuses on the overall development of conducting polymer as chemiresistive sensing materials. Effects of different parameters influencing sensor performance such as response, gas concentration, response time, and recovery time of conducting polymers are explored. Different conducting polymers are compared and their affinities to specific gases are determined. An understanding of pure conducting polymers assists further exploration of these polymers in composite form. A comprehensive understanding based on an overview of literature will facilitate researchers in selecting appropriate conducting polymers for different gas sensing applications and is expected to encourage further progress in this area. © The Author(s) 2019. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. [DOI: 10.1149/2.0032003JES]

Design and fabrication of conductive polymer hydrogels and their applications in flexible supercapacitors

Abstract: In recent years, as an energy storage device with a fast charge and discharge speed, long cycle life, and good stability, flexible supercapacitors (SCs) have been extensively used in flexible electronic devices such as smart textiles, flexible display screens, and micro-robots. Combining the advantages of conductive materials and hydrogels, conductive polymer hydrogels have good flexibility, biocompatibility, and adjustable mechanical and electrochemical properties, which enable them to be used as electrolyte or electrode materials for flexible SCs, endowing flexible SCs with various excellent properties and meeting their various working requirements. This paper comprehensively reviews the flexible SCs based on conductive polymer hydrogels, from the design, synthesis and application aspects of conductive polymer hydrogels, the various superior functions (e.g., self-healing, high stretchability and compressibility, high toughness, electrochromic and shape memory) of flexible SCs based on conductive polymer hydrogels to different structures of flexible SCs, including fiber-shaped structures, all-in-one sandwich structures, and in-plane interdigital microstructures. Finally, we summarize the challenges faced by flexible SCs based on conductive polymer hydrogels, which provides new research directions and prospects for future development in this field.

Designing High Performance Organic Batteries.

Abstract: ConspectusRedox active organic and polymeric materials have witnessed the rapid development and commercialization of lithium-ion batteries (LIBs) over the last century and the increasing interest in developing various alternatives to LIBs in the past 30 years. As a kind of potential alternative, organic and polymeric materials have the advantages of flexibility, tunable performance through molecular design, potentially high specific capacity, vast natural resources, and recyclability. However, until now, only a handful inorganic materials have been adopted as electrodes in commercialized LIBs. Although the development of carbonyl-based materials revived organic batteries and stimulated plentiful organic materials for batteries in the past 10 years due to their high theoretical capacities and long-term cycleabilities compared with their pioneers (e.g., conducting polymers), organic batteries are still facing many challenges. For example, it is still essential to enhance the theoretical and experimental capacities of organic materials. Moreover, typically, organic materials suffer relatively low conductivity, which limits their rate capability. In addition, many organic materials, especially small molecules, show poor cycling stability because of their dissolution in organic electrolytes. Other requirements, such as high voltage output and low cost, are also crucial for organic batteries. Therefore, insights into fundamentals (e.g., intramolecular and intermolecular interactions) for a deep understanding of organic batteries and constructive strategies ranging from material design to manipulation of other components (e.g., conductive additives, binders, electrolytes, and separators through controlling the intramolecular and intermolecular interactions and manipulating the ionic transport) are of great significance to boost the performance of organic batteries.In this Account, we give an overview of our efforts to develop high performance organic batteries with various strategies from the aspects of molecular design and the manipulation of other components. Inspired by the experience in organic electronics, we proposed that the extension of the π-conjugated system is helpful for stabilizing the +1/-1 charge/discharge states, improving the charge transport, and facilitating the layered packing (good for ionic diffusion) and hence would benefit the rate capability and cyclability. The π-d conjugation can effectively improve the electrical conductivity and provide stable and fast ionic storage, which enriches the materials for high-performance batteries and further deepens the understanding of conjugated coordination polymers (CCPs). Different from inorganic materials, organic materials are composed of molecules (either small molecules, macromolecules, or polymeric molecules) with weak intermolecular interactions. Therefore, the manipulation of active molecules or additives (conductive additives, binders, and other special additives) through control of intermolecular interactions is crucial for enhancing the electrochemical performance of organic batteries. Regarding the possible dissolution of active materials, the modification of separators through addition of selectively permeable membranes as ionic sieves is the most efficient and universal strategy to mitigate the shuttling of dissolved molecules but allow smaller sized cations to pass and hence is able to enhance the cyclability. On the basis of these findings, the challenges and several future trends for organic batteries are discussed. This Account provides a summary of our recent progress, understanding of the fundamentals for high performance organic batteries, insight into the intramolecular and intermolecular interactions, and prospects for future development of organic materials for next-generation rechargeable batteries.

Strong adhesion of wet conducting polymers on diverse substrates.

Abstract: Conducting polymers such as poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), polypyrrole (PPy), and polyaniline (PAni) have attracted great attention as promising electrodes that interface with biological organisms. However, weak and unstable adhesion of conducting polymers to substrates and devices in wet physiological environment has greatly limited their utility and reliability. Here, we report a general yet simple method to achieve strong adhesion of various conducting polymers on diverse insulating and conductive substrates in wet physiological environment. The method is based on introducing a hydrophilic polymer adhesive layer with a thickness of a few nanometers, which forms strong adhesion with the substrate and an interpenetrating polymer network with the conducting polymer. The method is compatible with various fabrication approaches for conducting polymers without compromising their electrical or mechanical properties. We further demonstrate adhesion of wet conducting polymers on representative bioelectronic devices with high adhesion strength, conductivity, and mechanical and electrochemical stability.

Semiconductor Gas Sensors: Materials, Technology, Design, and Application

Abstract: This paper presents an overview of semiconductor materials used in gas sensors, their technology, design, and application. Semiconductor materials include metal oxides, conducting polymers, carbon nanotubes, and 2D materials. Metal oxides are most often the first choice due to their ease of fabrication, low cost, high sensitivity, and stability. Some of their disadvantages are low selectivity and high operating temperature. Conducting polymers have the advantage of a low operating temperature and can detect many organic vapors. They are flexible but affected by humidity. Carbon nanotubes are chemically and mechanically stable and are sensitive towards NO and NH3, but need dopants or modifications to sense other gases. Graphene, transition metal chalcogenides, boron nitride, transition metal carbides/nitrides, metal organic frameworks, and metal oxide nanosheets as 2D materials represent gas-sensing materials of the future, especially in medical devices, such as breath sensing. This overview covers the most used semiconducting materials in gas sensing, their synthesis methods and morphology, especially oxide nanostructures, heterostructures, and 2D materials, as well as sensor technology and design, application in advance electronic circuits and systems, and research challenges from the perspective of emerging technologies.

Redox polymers for rechargeable metal-ion batteries

Abstract: Redox polymers have the advantages of potentially low-cost, flexibility, sustainability, high redox activity, good electrochemical reversibility and high energy density, which have been widely reported in energy storage devices. Their electrochemical properties can be easily tailored by molecular engineering. Herein, the polymers including conducting polymers, organosulfur polymers, radical polymers, carbonyl polymers, polymers of arylamines, polymers based on unsaturated C-N and C-C bonds are overviewed and their applications in various metal-ion (Li+, Na+, K+, Zn2+, Mg2+, Ca2+, Al3+) batteries are comprehensively summarized. By virtue of the advantage of molecular design, conjugated porous polymers are specifically highlighted due to the further enhancement of ionic diffusion and accommodation of inserted ions, which combine the merits of flexibility of organic/polymeric materials and the advantages of porous structures. In the last section, strategies for improving electrochemical properties of metal-ion batteries are discussed, followed by the prospects of key challenges and future trends of redox polymers as electrode materials for advanced electrochemical energy storage devices.

Interaction of conducting polymers, polyaniline and polypyrrole, with organic dyes: polymer morphology control, dye adsorption and photocatalytic decomposition

Abstract: Conducting polymers, such as polyaniline and polypyrrole, have frequently been discussed in the literature due to ease of preparation and high application potential. These polymers have been observed to interact with organic dyes because of the similarity in the conjugated molecular structure of both moieties. The interaction manifests itself in three fundamental directions that have been so far treated separately. The first is represented by the conductivity enhancement and morphology control when using organic dyes as templates in polypyrrole preparation. The adsorption of dyes on conducting polymers is the second field oriented at the water pollution treatment. Finally, the photocatalytic decomposition of organic dyes aims at the similar environmental target. The last two applications do not require the presence of conductivity which, on the other hand, is a key parameter of conducting polymers. The future design of advanced adsorbents, however, has to exploit both the conductivity and electroactivity in the control of pollutant adsorption or degradation. For this reason, all these interactions and their practical impact are considered in the present review.

Recent developments in conducting polymers: applications for electrochemistry

Abstract: Scientists have categorized conductive polymers as materials having strongly reversible redox behavior and uncommon combined features of plastics and metal. Because of their multifunctional characteristics, e.g., simplistic synthesis, acceptable environmental stability, beneficial optical, electronic, and mechanical features, researchers have largely considered them for diverse applications. Therefore, their capability of catalyzing several electrode reactions has been introduced as one of their significant features. A thin layer of the conducting polymer deposited on the substrate electrode surface can augment the electrode process kinetics of several solution species. Such electrocatalytic procedures with modified conducting polymer electrodes can create beneficial utilization in diverse fields of applied electrochemistry. This review article explores typical recent applications of conductive polymers (2016–2020) as active electrode materials for energy storage applications, electrochemical sensing, and conversion fields such as electrochemical supercapacitors, lithium-ion batteries, fuel cells, and solar cells.

Conducting Polymers for Optoelectronic Devices and Organic Solar Cells: A Review

Abstract: In this review paper, we present a comprehensive summary of the different organic solar cell (OSC) families. Pure and doped conjugated polymers are described. The band structure, electronic properties, and charge separation process in conjugated polymers are briefly described. Various techniques for the preparation of conjugated polymers are presented in detail. The applications of conductive polymers for organic light emitting diodes (OLEDs), organic field effect transistors (OFETs), and organic photovoltaics (OPVs) are explained thoroughly. The architecture of organic polymer solar cells including single layer, bilayer planar heterojunction, and bulk heterojunction (BHJ) are described. Moreover, designing conjugated polymers for photovoltaic applications and optimizations of highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy levels are discussed. Principles of bulk heterojunction polymer solar cells are addressed. Finally, strategies for band gap tuning and characteristics of solar cell are presented. In this article, several processing parameters such as the choice of solvent(s) for spin casting film, thermal and solvent annealing, solvent additive, and blend composition that affect the nano-morphology of the photoactive layer are reviewed.

A 2D Titanium Carbide MXene Flexible Electrode for High-Efficiency Light-Emitting Diodes.

Abstract: Although several transparent conducting materials such as carbon nanotubes, graphene, and conducting polymers have been intensively explored as flexible electrodes in optoelectronic devices, their insufficient electrical conductivity, low work function, and complicated electrode fabrication processes have limited their practical use. Herein, a 2D titanium carbide (Ti3 C2 ) MXene film with transparent conducting electrode (TCE) properties, including high electrical conductivity (≈11 670 S cm-1 ) and high work function (≈5.1 eV), which are achieved by combining a simple solution processing with modulation of surface composition, is described. A chemical neutralization strategy of a conducting-polymer hole-injection layer is used to prevent detrimental surface oxidation and resulting degradation of the electrode film. Use of the MXene electrode in an organic light-emitting diode leads to a current efficiency of ≈102.0 cd A-1 and an external quantum efficiency of ≈28.5% ph/el, which agree well with the theoretical maximum values from optical simulations. The results demonstrate the strong potential of MXene as a solution-processable electrode in optoelectronic devices and provide a guideline for use of MXenes as TCEs in low-cost flexible optoelectronic devices.

Mussel-Inspired Redox-Active and Hydrophilic Conductive Polymer Nanoparticles for Adhesive Hydrogel Bioelectronics

Abstract: Conductive polymers (CPs) are generally insoluble, and developing hydrophilic CPs is significant to broaden the applications of CPs. In this work, a mussel-inspired strategy was proposed to construct hydrophilic CP nanoparticles (CP NPs), while endowing the CP NPs with redox activity and biocompatibility. This is a universal strategy applicable for a series of CPs, including polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene). The catechol/quinone contained sulfonated lignin (LS) was doped into various CPs to form CP/LS NPs with hydrophilicity, conductivity, and redox activity. These CP/LS NPs were used as versatile nanofillers to prepare the conductive hydrogels with long-term adhesiveness. The CP/LS NPs-incorporated hydrogels have a good conductivity because of the uniform distribution of the hydrophilic NPs in the hydrogel network, forming a well-connected electric path. The hydrogel exhibits long-term adhesiveness, which is attributed to the mussel-inspired dynamic redox balance of catechol/quinone groups on the CP/LS NPs. This conductive and adhesive hydrogel shows good electroactivity and biocompatibility and therefore has broad applications in electrostimulation of tissue regeneration and implantable bioelectronics.

A Review of Conductive Hydrogel Used in Flexible Strain Sensor.

Abstract: Hydrogels, as classic soft materials, are important materials for tissue engineering and biosensing with unique properties, such as good biocompatibility, high stretchability, strong adhesion, excellent self-healing, and self-recovery. Conductive hydrogels possess the additional property of conductivity, which endows them with advanced applications in actuating devices, biomedicine, and sensing. In this review, we provide an overview of the recent development of conductive hydrogels in the field of strain sensors, with particular focus on the types of conductive fillers, including ionic conductors, conducting nanomaterials, and conductive polymers. The synthetic methods of such conductive hydrogel materials and their physical and chemical properties are highlighted. At last, challenges and future perspectives of conductive hydrogels applied in flexible strain sensors are discussed.

PEDOT:PSS-Based Conductive Textiles and Their Applications.

Abstract: The conductive polymer complex poly (3,4-ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS) is the most explored conductive polymer for conductive textiles applications. Since PEDOT:PSS is readily available in water dispersion form, it is convenient for roll-to-roll processing which is compatible with the current textile processing applications. In this work, we have made a comprehensive review on the PEDOT:PSS-based conductive textiles, methods of application onto textiles and their applications. The conductivity of PEDOT:PSS can be enhanced by several orders of magnitude using processing agents. However, neat PEDOT:PSS lacks flexibility and strechability for wearable electronics applications. One way to improve the mechanical flexibility of conductive polymers is making a composite with commodity polymers such as polyurethane which have high flexibility and stretchability. The conductive polymer composites also increase attachment of the conductive polymer to the textile, thereby increasing durability to washing and mechanical actions. Pure PEDOT:PSS conductive fibers have been produced by solution spinning or electrospinning methods. Application of PEDOT:PSS can be carried out by polymerization of the monomer on the fabric, coating/dyeing and printing methods. PEDOT:PSS-based conductive textiles have been used for the development of sensors, actuators, antenna, interconnections, energy harvesting, and storage devices. In this review, the application methods of PEDOT:SS-based conductive polymers in/on to a textile substrate structure and their application thereof are discussed.

Synthesis of an MXene/polyaniline composite with excellent electrochemical properties

Abstract: As a family member of MXenes, Ti3C2Tx has received worldwide interest due to its excellent electrochemical energy storage properties. However, freestanding Ti3C2Tx films synthesized by direct assembly of two-dimensional (2D) sheets have relatively low specific capacitance and rate capability due to the low ion transport efficiency between Ti3C2Tx (MXene) sheets. Here, we demonstrate an effective method to improve the electrochemical performance of MXene-based electrodes by incorporating MXene sheets with conducting polymers. A Ti3C2Tx/polyaniline (MXene/PANI) composite was fabricated by chemical oxidative polymerization of aniline monomers on the surface of Ti3C2Tx sheets. Benefiting from the highly conductive open structure, efficient ion and electron transport and high electrochemical activity of Ti3C2Tx and PANI, the MXene/PANI electrode presents a maximum specific capacitance of 556.2 F g−1 at a current density of 0.5 A g−1, an impressive rate capability (high capacitance retention of 78.7% at 5 A g−1) and excellent cycling stability with a high capacitance retention of 91.6% after 5000 cycles at 5 A g−1. Therefore, this paper provides a facile and effective method to achieve high performance MXene-based electrode materials for supercapacitors.

A water-based and metal-free dye solar cell exceeding 7% efficiency using a cationic poly(3,4-ethylenedioxythiophene) derivative.

Abstract: A green, efficient and stable solar cell based only on water and safe and cheap elements of the periodic table is proposed in this work, finally consolidating (also from a sustainability viewpoint) the concept of “artificial photosynthesis” studied for decades by the scientific community. The concept of dye-sensitized solar cells is re-proposed here with a metal-free organic dye, an iodine-based electrolyte in a 100% aqueous environment and a new cathode (cationic PEDOT) synthesized for the first time with the aim of inhibiting the repulsion between the anions of redox couples and the PEDOT:PSS matrix commonly used as the counter-electrode. This elegant setup leads to a record efficiency of 7.02%, the highest value ever obtained for a water-based solar cell and, in general, for a photovoltaic device free of both organic solvents and expensive/heavy metals.