Conductive PEDOT Research Articles

Lightweight, elastic and conductive pure PEDOT:PSS foam for dual-mode sensing

Pure PEDOT:PSS foam with a multi-scale porous structure and dual-mode sensing characteristics.

Electrodeposition of conductive polymer PEDOT on the surface of the LiNi0.8Co0.1Mn0.1O2 electrode for high-performance lithium-ion batteries

Electrochemical polymerization of PEDOT on the NCM811 cathode and aluminum foil enhances bonding strength and cycling stability by reducing side reactions with the electrolyte.

Fabrication and characterization of hybrid thermoelectric materials based on aligned nanowires.

This study introduces the synthesis of a hybrid thermoelectric material with enhanced conductivity and a high Seebeck coefficient, leveraging the properties of Te nanowires (NWs) and the conductive polymer PEDOT:PSS. Te NWs were synthesized using the galvanic displacement reaction. To further enhance conductivity, Ag-Te NWs were synthesized under optimized conditions via the Ag topotactic reaction, achieving desired results within 7min using ethylene glycol and AgNO3. This hybrid material exhibited an electrical conductivity of 463S/cm, a Seebeck coefficient of 69.5μV/K at 300K, and a power factor of 260μW/mK2. These metrics surpassed those of conventional Te/PEDOT:PSS hybrids by a factor of 3.6, highlighting the superior performance of our approach. This study represents a significant advancement in thermoelectric materials, improving both conductivity and efficiency.

Beyond acid treatment of PEDOT:PSS: decoding mechanisms of electrical conductivity enhancement

Coupling the acid post-treatment and hot-pressing processes can exponentially improve the electrical conductivity of PEDOT:PSS (3360 S cm−1) by providing a densely packed and well-ordered structure of PEDOT lamella along the edge-on direction.

A dendrite-free Zn anode enabled by PEDOT:PSS/MoS2 electrokinetic channels for aqueous Zn-ion batteries.

Notorious Zn dendrites and severe parasitic side reactions severely disrupt the anode-electrolyte interface during Zn plating/stripping, resulting in uncontrollable Zn deposition and limiting the application of aqueous zinc-ion batteries (AZIBs). Although the construction of an artificial interface is a highly desirable strategy, it is often limited by slow Zn2+ transport kinetics. To address these issues, we present a bifunctional polymer coating (PEPM) constructed from highly conductive PEDOT:PSS and monolayer MoS2, where the introduced PEDOT plays an important role in driving the fast Zn ion transfer kinetics as a zincophilic site and 2D MoS2 acts as a buffer layer to induce uniform Zn nucleation. With this corrosion inhibition and nucleation-oriented coating, the mobility of Zn2+ flux and the uniformity of Zn deposition were significantly improved, resulting in a stable plating/stripping performance at an ultra-low overpotential (<50 mV) of 2000 h and a high average coulombic efficiency (>99.4%) of 1000 cycles without significant dendrite formation. The proposed strategy provides a cost-efficient remedy and opens a new avenue for the development of dendrite-free zinc anodes.

A 3D printable gelatin methacryloyl/chitosan hydrogel assembled with conductive PEDOT for neural tissue engineering

In neural tissue engineering, biomaterial scaffolds that have high conductivity and customized structures are crucial in promoting nerve regeneration. Poly(3,4-ethylenedioxythiophene) (PEDOT) has emerged as a promising conductive polymer with excellent chemical stability and biocompatibility. However, traditional three-dimensional (3D) printing of PEDOT-based conductive scaffolds faces challenges in limited printing resolution, poor solubility, and brittleness of conductive materials. Herein, digital light processing (DLP) printing was used to fabricate complex hydrogel structures using gelatin methacryloyl (GelMA) and chitosan (CS) while incorporating PEDOT nanoparticles through interfacial polymerization to create conducting pathways within a hydrogel structure. The integration of PEDOT significantly enhanced the electrical conductivity and mechanical properties of the GelMA/CS hydrogel while preserving printed details. The GelMA/CS-PEDOT hydrogel promoted cell proliferation and facilitated axon outgrowth of PC12 cells and Schwann cells during in vitro culture. Moreover, in vitro direct current electrical stimulation promoted axon elongation of PC12 cells cultured on a conductive substrate. In vivo studies used a conductive nerve conduit to repair a 10-mm rat sciatic nerve defect, validating the efficacy of GelMA/CS-PEDOT scaffold in peripheral nerve injury repair. These findings highlight the significant potential of conductive GelMA/CS-PEDOT hydrogel in the field of neural tissue engineering.

Direct Ink writing of high conductive PEDOT:PSS dispersion with an engineered conformation and electronic structure for printed electronic circuits

PEDOT:PSS dispersions with engineered conformation and electronic structure are obtained by controlling polymerization parameters. Outstanding electrical conductivity makes them promising candidates for conductive inks in printed electronic circuits.

Effect of Film Morphology on Electrical Conductivity of PEDOT:PSS.

Commercially available formulations of the popular conductive polymer, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) are aqueous dispersions that require the addition of secondary dopants such as dimethyl sulphoxide (DMSO) or ethylene glycol (EG) for fabricated films to have the desired levels of conductivity. CleviosTM F HC Solar, a formulation of PEDOT:PSS produced by Heraeus, GmbH, achieves over 500 S/cm without these secondary dopants. This work studies whether secondary dopants such as DMSO have any additional effect on this type of PEDOT:PSS. The temperature dependencies of the conductivity of F HC Solar spin-coated thin films measured using a four-probe method seem to exhibit different charge transport properties compared with secondary doped PH1000. Observations made using atomic force microscopy (AFM) show that different concentrations of DMSO affect the orientation of the PEDOT domains in the thin film. These morphological changes cause room temperature conductivity to reduce from 640 S/cm in pristine films to as low as 555 S/cm after adding 7 wt% of DMSO along the film. Such tuning may prove useful in future applications of PEDOT:PSS, such as nanoprobes, transistors and hybrid solar cells.

(Invited) Transparent Conductive Films of PEDOT:PSS-Amino Acid Composite

Transparent conductive electrode is an important component of optoelectronic devices such as light emitting diodes, photodiodes, and photovoltaic cells as well touchscreen technology. Growing demand for these technologies, as well as need for functionalities such as cost-effectiveness and flexibility, has resulted in various research on developing organic polymer-based transparent electrodes as an alternative to indium tin oxide (ITO) which is the current industry standard. One of the organic conducting polymers most commonly studied for their potential to be used as ITO-free transparent electrodes is PEDOT:PSS due to its high transmittance as a thin film, solution processability, flexibility, environmental stability, and commercial availability. There have been various works carried out to improve the conductivity of the PEDOT:PSS-based thin films by introducing dopants to improve the charge transport. We present our results demonstrating that not only the conductivity but also the transmittance of PEDOT-PSS-based films can be significantly improved by the introduction of amino acids such as phenylalanine in the film. We have observed that this enhancement in conductivity and optical transmittance of PEDOT:PSS-phenylalanine composite film is retained even when the amount of amino acid in the composite films is larger than the amount of PEDOT:PSS. We will present our study on the charge transport mechanism on these films based on electrochemical impedance spectroscopy (EIS) measurements. We will also further present our studies based on Scanning Electron Microscopy (SEM) as well as Scanning Probe Microscopy techniques such as topography imaging and conducting probe atomic force microscopy (CP-AFM) to elucidate the relationship between film morphology and charge transport in these composite films. The use of bioderived materials such as amino acids to create transparent composite films could open up avenues for developing and integrating bio-based materials in future electronics, help improve the environmental footprint of the electronics, and potentially also allow for the development of materials with a higher degree of biocompatibility for their application in bioelectronics.

Oxidative Molecular Layer Deposition of Conductive PEDOT Coatings Onto Polymer Sponges to Form Compressible Porous Electrodes

The formation of compressible porous sponge electrodes is appealing to overcome liquid phase diffusion in electrochemical applications including energy storage, water desalination, and electrocatalysis. Previous work has employed wet chemical synthesis to deliver conductive materials into porous polymer sponge supports, but these approaches struggle to produce functional electrodes due to (1) poor electrical connectivity of the conductive network and (2) mechanical rigidity of the foam after coating. In this work we employ oxidative molecular layer deposition (oMLD) via sequential gas-phase exposures of 3,4 ethylenedioxythiophene (EDOT) and molybdenum pentachloride (MoCl5) oxidant to coat polyurethane sponges with electrically-conductive and redox-active poly(3,4 ethylenedioxythiophene) (PEDOT) coatings. We analyze the oMLD deposition on compressible polyurethane sponges and modify the reaction conditions to obtain mechanically compressible and electrically conductive sponges. We specifically identify the importance MoCl5 dose time to enhance the conductivity of the sponges and the importance of EDOT purge time to preserve the mechanical properties of the sponges. This approach produces an electrically conductive PEDOT network within the sponge support with minimal impact on the sponge’s mechanical properties, offering advantages over wet-chemical synthesis approaches. The compressible, conductive sponges we generate have the potential to be used as compressible electrodes for water desalination, energy storage, and electrocatalysis.

Incorporation of PEDOT:PSS to Reduce Iridium Loading at Anode Catalyst Layer for Proton Exchange Membrane Water Electrolysis

Proton exchange membrane water electrolysis (PEMWE) is one of the most promising technologies to produce green hydrogen with high efficiency. However, its commercialization is hindered by the large usage of expensive iridium as anode electrocatalyst [1-3] . Incorporation of cheap conductive materials into the catalyst ink, e.g., titanium powder [4], is a straightforward and efficient method to reduce noble metal loading of membrane electrode assembly (MEA). In this study, we aimed to use a conductive polymer PEDOT:PSS to build the low Ir loading catalyst layer for PEMWE.The MEAs at 0.3 mgIr cm-2 loading were fabricated with different PEDOT:PSS contents. In practice, the dispersion of IrO2 particles is difficult in catalyst ink, leading to the formation of big IrO2 agglomerates. We found that the zeta potential of the anode catalyst ink gained obvious enhancement after the addition of PEDOT:PSS. This indicated that PEDOT:PSS as dispersant could increase the stability of the catalyst ink. The morphology of anode catalyst layers was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The surface and cross-sectional images of morphology exhibited small IrO2 particles and porous structure in the catalyst layer with the addition of PEDOT:PSS, which would contribute to the water/gas movement in triple-phase boundaries. Electrochemical measurements such as polarization curves, electrochemical impedance spectroscopy (EIS), cyclic voltammogram (CV) and durability tests were conducted in a PEMWE single cell. The MEA using PEDOT:PSS as binder displayed better electrochemical performance (3.4 A cm-2@2.0 V) than other references with Nafion only (2.4 A cm-2@2.0 V). Moreover, the addition of PEDOT:PSS improved the high-frequency resistance due to its excellent electronic conductivity. In consideration of the conductive binder and dispersant effect of PEDOT:PSS, future research will focus on reducing Ir loading below 0.1 mg cm-2 through designing novel structure of anode catalyst layer with PEDOT:PSS. Keywords:PEM water electrolysis, low iridium loading, PEDOT:PSS

Effects of Doped Hole-Transporting Layers on Perovskite Solar Cell Performances

The influences of doped hole-transporting layers (HTLs) on the performances of perovskite solar cells were studied. The influences of electrostatic and surface roughness effects using solvent additive doping were compared. The electrostatic effect of solvent additive doping was compared through the addition of 1,8-diiodooctane and 1,8-dichlorooctane to the HTL. The surface roughness effect of solvent additive doping was examined using atomic force microscopy. The perovskite crystallinity of doped HTLs was studied using X-ray diffraction. The conductivity of HTLs was measured using four probe methods and was higher for doped devices. The enhanced conductivity of PEDOT: PSS film was also proved using fluorescence emission quenching. The long-term stability of the device was enhanced through doping HTLs. The device with the solvent additive exhibited much greater enhanced stability retained over 80% of the initial PCE for 400 h, while PCE of the device without the solvent additive decreased to less than 80% after 200 h. A very weak power microwave treatment was used for the post-annealing of the fully fabricated devices. Post-annealing enhanced the lifetime of the device. Comparing different sizes of cells, the device lifetime was decreased as the cell area increased and as the size of the cell increased; the extent of lifetime enhancement through doping was increased.

Rationally designed conductive wood with mechanoresponsive electrical resistance

Porous cellular foams, combining lightweight, high strength, and compressibility, hold great promise in a wide range of advanced applications. Here, the native structure of pine wood was modified by in-situ lignin sulfonation and unidirectional freezing, resulting in an alveolate structure inside the wood cell wall with arrays of sub-100 nm channels. The obtained wood foam exhibited highly enhanced permeability while retaining the native cellular arrangement and high lignin and hemicellulose content. Such engineered cellular foam contributed to superior mechanical performance with compressive strength of 9 MPa and Young’s modulus of 344 MPa in the longitudinal direction. The high porosity allowed homogeneous infiltration of conductive polymer PEDOT:PSS inside the wood cell wall. The resulting composite exhibited high conductivity, sponge-like compressibility and the ability to modulate electrical resistance in a reversible manner in the radial direction. This rationally designed conductive wood demonstrated potential in durable and ultrasensitive pressure-responsive devices and strain sensors.

Enhancing the Conductivity of PEDOT:PSS Films by the Confinement of Ice Crystals.

Rapid developments in organic electronics demand highly conductive and freestanding (PEDOT:PSS) films. However, the synthesis of highly conductive PEDOT:PSS films requires toxic reagents, such as high-concentration acids and bases. Herein, an eco-friendly and cost-effective strategy is reported for improving the conductivity of PEDOT:PSS films through the confinement of ice crystals. The crystallization of water swelled by the film facilitated the phase separation of PEDOT and PSS, and the excess PSS in the skin layer is effectively removed. Moreover, under the confinement effect, the carrier mobility of the film is enhanced through the formation of a well-crystallized PEDOT molecular morphology. A detailed elucidation of aggregate structure evolution in PEDOT:PSS films during annealing, solvent post-treatment, and subsequent confined crystallization is presented herein. After multiple water crystallization cycles, the conductivity of the PEDOT:PSS film increased by over 85%, achieving a maximum of 2564±142Scm-1. Finally, compared to post-treatment with dimethyl sulfoxide (DMSO), the current strategy can improve the Seebeck coefficient by 5.6% and the power factor by 139%.

An Electrically Resistive Switching Nonvolatile Memory System Based on PEDOT:PSS

The current density–voltage (J–V) curves of poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) are examined at room temperature, which reveal nonlinear behavior and hysteresis loop‐like patterns. Herein, the potential of the material for nonvolatile applications requiring resistive random access memory (ReRAM) is demonstrated. The resistive switching effect is explained using a Schottky barrier and the space‐charge‐limited conduction model. Additionally, dielectric and electrical characteristics are analyzed in the frequency range from 20 Hz to 10 MHz. The impedance, electric modulus, dielectric loss tangent, and AC conductivity are explored through On‐ and Off‐states of resistive switching. A modified Debye function and Jonscher's power law are used for data fitting. The resistive switching memory behavior of PEDOT:PSS are studied using J–V and chemical impedance spectroscopy (CIS) measurements. The Cu/PEDOT:PSS/Cu sandwich‐type devices show bipolar switching behavior, and an equivalent circuit model based on the impedance spectra is proposed to describe the CIS response in both states. The switching process is attributed to the electrical‐field‐induced effect of dipolar reorientation on the electrical conductivity of PEDOT:PSS at grain boundaries.

In-situ growth of hydrogen-bonded organic framework on conductive PEDOT:PSS polymer to realize conductivity-enhanced electrochemiluminescence for fabricating ultrasensitive biosensor

Hydrogen-bonded organic frameworks (HOFs) have gradually received research interest in the electrochemiluminescence (ECL) realm for their high porosity, large surface area, low toxicity, and remarkable biocompatibility, whereas the poor electrical conductivity of HOFs limits electrochemical excitation of ECL luminophores to cause low utilization ratio of ECL luminophores. To circumvent the problem, we prepared a conductive HOF composite (H3TATB-HOF/PEDOT:PSS) by in-situ growth of H3TATB-HOF (H3TATB = 2,4,6-tris(4-carboxyphenyl)− 1,3,5-triazine) on highly conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) polymer. Satisfactorily, the ECL intensity of H3TATB-HOF/PEDOT:PSS presented a respective 14.94-time, 4.71-time, and 2.82-time improvement than those of H3TATB monomers, H3TATB aggregates, and H3TATB-HOF, which was mainly attributed to the high-conductivity PEDOT:PSS that facilitated charge transport throughout the H3TATB-HOF/PEDOT:PSS framework, enabling more H3TATB to be excited electrochemically. Considering the H3TATB-HOF/PEDOT:PSS featuring superior ECL properties, an ultrasensitive ECL biosensor for microRNA-21 assay was designed by combining H3TATB-HOF/PEDOT:PSS as an ECL beacon with a 3D DNA walker amplification strategy, exhibiting broad linear range (100 aM to 1 nM) with a low detection limit (45.7 aM). Overall, this work demonstrates that the ECL performance of HOF-based ECL materials can be significantly improved by enhancing electrical conductivity, thus providing a new idea to explore high-efficiency ECL emitters for building high-sensitivity ECL biosensors.

Promoting homogeneous lithiation of silicon anodes via the application of bifunctional PEDOT:PSS/PEG composite binders

Polymeric conducting binders have increasingly become a subject of significant research interest due to their dual roles as both a binder and a conducting agent. This dual functionality not only increases the proportion of active materials in the electrode but also elevates the volumetric energy density of current Li-ion batteries. In this study, we explore the potential of a composite of PEDOT:PSS and polyethylene glycol (PEG) as a high-performing binder for silicon anodes. This highly conductive PEDOT:PSS, enhanced by the addition of PEG polymer, displays exceptional electrochemical characteristics, including superior C-rate, Li-ion diffusivity performance, and extended cycle endurance. Of particular interest are the enhanced mechanical properties bestowed by the plasticizing effect of the PEG polymer. This improvement aids the Si anode in resisting pulverization during successive discharge and charge cycles. As a result, this enables extended cyclability without the creation of anode cracking. Additionally, the use of operando optical microscopy allows for the direct observation of lithiation kinetics within the PEDOT:PSS/PEG binder. This revealed a uniform color change with restrained volume expansion, demonstrating the successful operation of the binder. Consequently, the bifunctional PEDOT:PSS/PEG binder shows promise as a robust strategy for the next generation of high-performance lithium-ion battery binders.

Research progress on the modification of organic highly conductive polymer PEDOT: PSS

PEDOT: PSS (poly(3,4-ethylenedioxythiophene): poly(4-styrenesulfonic acid)) is a high-profile organic conductive polymer, which is widely used because of its excellent conductivity and stability. The application of PEDOT: PSS is of great significance in the fields of energy, electronics, medical treatment and the environment. It offers an efficient, transparent, flexible, and environmentally friendly material option that drives various innovations and advancements. However, the traditional PEDOT: PSS can no longer meet the high requirements of today's electronic devices. Therefore, changing the conductivity, ductility and other properties of PEDOT: PSS through various physical and chemical methods has become an important topic. This paper reviews the progress of effectively improving the conductivity of PEDOT: PSS by reviewing PSS doping optimization, solvent doping modification (inorganic acid, organic reagent), and nanomaterial modification (CNTs, Graphene), so as to provide researchers with directions. Overall, PEDOT: PSS, as a material with excellent performance and wide application potential, has broad prospects for its application. With the continuous demand for flexible electronics, renewable energy, smart optoelectronic devices and biomedical applications, PEDOT: PSS will play an important role in these fields and promote the further development and innovation of related technologies.

Self-adhesive and conductive hydrogels and their applications in bioelectronics

At present, the market pressure strain sensors mainly include intrinsic conductivity, composite conductivity, and flexible metal conductivity. Most of the strain sensors can met various basic requirements such as strain sensitivity and mechanical properties. However, biocompatibility and the ease of use are still areas to be explored and improved. This paper proposes a novel strategy to fabricate a kind of self-adhesive and conductive hydrogel using natural biomacromolecule gelatin, tannic acid (TA) and conductive polymer PEDOT: PSS. The sensor is biocompatible, nontoxic, and can be directly attached to the skin without the use of adhesive tape, and sufficiently large electrical signal response can be collected under stress. The presence of tannic acid forms a cross-linking network with the gelatin in the organic hydrogel, which can effectively increase the toughness (which can reach 203.62 kPa/m3). PEDOT: PSS provides the conductivity for the hydrogel, and hydrogel with 0.3wt% PEDOT: PSS content have a conductivity of about 2.1ms/cm. Therefore, this study found the possibility of making a flexible electronic element by using a composite of PEDOT: PSS, gelatin, and TA.

Structural optimization of slot-die heads with T-shaped cavity for fabrication of large-area OLEDs

With an attempt to achieve highly uniform large-area organic thin films for potential applications in solution-processable organic light-emitting diodes (OLEDs), we have optimized the structure of slot-die heads with T-shaped cavity (manifold) by computational fluid dynamics (CFD) simulation. Depending on the viscosity of coating solutions, the pressure distribution inside the cavity and the velocity distribution at the outlet are analyzed by varying the structure parameters such as the shim thickness, cavity volume (cavity depth, cavity height, cavity width), and land length. From CFD simulation results, we have derived the maximum shim thickness at which the pressure non-uniformity becomes less than 5 %, which can provide a simple and intuitive design guideline. It is addressed that the maximum shim thickness is most affected by the cavity width, followed by the cross-sectional area of the cavity and then the land length. Using the structurally optimized slot-die head, we have carried out slot-die coating of low-viscosity (80 cPs) poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and high-viscosity (4,800 cPs) polydimethylsiloxane (PDMS) and achieved thin films with the thickness non-uniformity less than 10 %. Furthermore, we have successfully fabricated 120 mm × 20 mm OLED devices with the slot-coated conductive PEDOT:PSS layer, exhibiting the luminance of 801 cd/m2 at 6 V.