Conductive PEDOT Research Articles

Restraint of Nonradiative Recombination via Modulation of n-Phase Distribution through Interfacial Lithium Salt Insertion for High-Performance Pure-Blue Perovskite LEDs.

Quasi-two-dimensional perovskite has been widely used in blue perovskite light-emitting diodes. However, the performance of these devices is still hampered by random phase distribution, nonradiative recombination, and imbalanced carrier transport. In this work, an effective strategy is proposed to mitigate these limitations by inserting lithium salts at the interfaces between the hole transport layer (HTL) and the perovskite layer. The perovskite film on the inserted Li2CO3 layer exhibits reasonable n-value redistribution, which leads to the repressive nonradiation recombination and enhanced carrier transport. Moreover, the inserted Li2CO3 layer also improves the electrical conductivity of PEDOT:PSS and hinders indium ion diffusion from the PEDOT:PSS layer to the perovskite film, which inhibits exciton quenching and nonradiative recombination loss at the HTL/perovskite interface. Taking advantage of these merits, we have successfully fabricated efficient pure-blue PeLEDs with an external quantum efficiency of 6.2% at 472 nm and a luminance of 726 cd cm-2. The restraint of nonradiative recombination at the interface offers a promising approach for efficient pure-blue PeLEDs.

Photography-Inspired Patterned Vapor Phase Polymerization of Conductive PEDOT on Rigid and Stretchable Substrates

Photography-Inspired Patterned Vapor Phase Polymerization of Conductive PEDOT on Rigid and Stretchable Substrates

P‐143: Enhanced Carrier Transportation towards High Luminescent Light‐Emitting Diodes with Multi‐cation Perovskite

In this work, more conductive and lower work function PEDOT:PSS 1000 was used as hole transporting layer to fabricate high luminescent perovskite light‐emitting diodes. Combined with potassium doping strategy, the according MAxCs1‐xPbBr3 (0 <x <1)perovskite light‐emitting diode reaches a high brightness of65 000 cd/m2.

Flexible Organic Electrochemical Transistor Based on Conjugated Conducting Polymers

In this work, we have fabricated a side-gated organic electrochemical transistor (OECT) where the source, drain, and gate terminals are screen-printed on a flexible polyethylene terephthalate substrate through a scalable screen-printing process. The semiconducting channel material is made of polyethylene dioxythiophene: polystyrene sulfonate (PEDOT: PSS), applied via spray coating. The OECT operates by volumetric gating of the channel through a gel electrolyte containing poly sodium 4-styrene sulfonate, transitioning highly conductive PEDOT+ to PEDOT0 through de-doping, biased by a positive gate voltage. Additionally, the OECT displayed a transconductance (gm) of 62.5 µA/V, mobility (µ) of 6.6×106 cm2 / Vs, and a threshold voltage (Vth) of -0.39 V, with the ON/OFF ratio being relatively low at 33.2. The repeatability was confirmed through the fabrication of three devices that exhibited nearly identical behavior. Future work emphasizes functionalizing the electrolyte to detect biomolecules such as glucose, pH, and ion species.

Solvent-doped PEDOT:PSS: Structural transformations towards enhanced electrical conductivity and transferable electromagnetic shields

The enhanced electrical conductivity of solvent-doped poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) is attributed to the screening effect between PSS and PEDOT chains. Yet, the precise manner in which this effect influences the crystalline structure and conformation of PEDOT:PSS remains unclear. In this study, we utilize Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Grazing-incidence wide-angle X-ray scattering (GIWAXS) to examine the conformational changes and two-dimensional (2D) crystalline structure of PEDOT:PSS when doped with a variety of solvents, including dimethyl sulfoxide (DMSO), ethylene glycol (EG), dimethylformamide (DMF), methanol (MeOH), ethanol (EtOH), tetrahydrofuran (THF), and acetone. Our observations unveil that solvent doping improves the electrical conductivity of PEDOT:PSS by modifying its crystalline structure. This alteration leads to reduced inter-lamellar (d200) and π-π stacking (d010) distances, facilitating the formation of densely packed and well-ordered PEDOT crystallites in both face-on and edge-on orientations. Moreover, this doping process enhances the transferability and mechanical properties of drop-casted films, resulting in a flexible and transferable electromagnetic interference (EMI) shield with exceptional total shielding effectiveness (SET) of 35.70 dB and specific shielding effectiveness (SSE/t) of 7105.34 dB cm2.g−1.

Porous highly conductive PEDOT film for high-performance supercapacitors

Thick and highly conductive poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate films with ideal porous structure are fulfilling as electrodes for supercapacitors. However, the homogeneous micro-structure without the aid of templates or composite presents a significant obstacle, due to the intrinsic softness of the dominant PSS component. In this study, we have successfully developed a porous configuration by employing a solvothermal approach with ethylene glycol (EG) as the solvent. The synergistic action of elevated pressure and temperature was crucial in prompting EG to tailor the microstructure of the PEDOT:PSS films by removing non-conductive PSS chains and improving PEDOT crystallinity, and the formation of a porous network. The resulting porous PEDOT:PSS films exhibited a high conductivity of 1644 ​S ​cm−1 and achieved a volumetric capacitance record of 270 ​F ​cm−3, markedly exceeding previous records. The flexible all-solid-state supercapacitor assembled by the films had an outstanding volumetric capacitance of 97.8 ​F ​cm−3 and an energy density of 8.7 ​mWh cm−3, which is best one for pure PEDOT:PSS-based supercapacitors. Grazing-incidence wide-angle X-ray scattering, X-ray photo-electron spectroscopy, and other characterizations were carried out to characterize the structure evolution. This work offers an effective novel method for conducting polymer morphology control and promotes PEDOT:PSS applications in energy storage field.

A reusable, healable, and biocompatible PEDOT:PSS hydrogel-based electrical bioadhesive interface for high-resolution electromyography monitoring and time–frequency analysis

As the most ideal interface between bioelectronic devices and biological tissues, the electrical bioadhesive interface (EBI) holds significant potential for various applications, including soft bioelectronics, wearable devices, and electrophysiological signal monitoring. However, most current EBIs are disposable products that lack repeatable adhesion and self-healing properties, thus hindering practical applications. Herein, we develop a reusable EBI by incorporating a dynamic non-covalent interaction enhancer polydopamine (PDA) and conductive PEDOT:PSS into an adhesive hydrogel matrix polyacrylamide (PAM). The EBI exhibits intriguing overall electrical and mechanical properties, including high conductivity (5.57 S m−1), tissue-like Young’s modulus (2.7 kPa), low interfacial impedance (1 kΩ), and excellent adhesion strength (46.45 ± 1.75 kPa on porcine skin) with excellent retention (87 %) after 200 adhering/detaching cycles, high self-healing efficiency of 94.11 %, and outstanding biocompatibility in HDF-a and HaCaT cell models. Benefiting from these superior properties, we further demonstrate the fabrication and application of an EBI-based reusable electromyography monitoring patch (EMP). The reusable EMP enables high-resolution electromyography signal monitoring capability with a higher signal-to-noise ratio (SNR) of 30.05 dB than commercial electrodes (12.06 dB). Remarkably, such reusable EMP maintains very stable SNR of 21.82 dB after 200 adhering/detaching cycles (3.8 times higher than commercial electrodes, 5.74 dB after 30 cycles), and showcases typical time and frequency-domain characteristics. These findings demonstrate a promising reusable EMP to enhance the accuracy and convenience of electromyography monitoring.

Highly Conductive PEDOT:PSS: Ag Nanowire-Based Nanofibers for Transparent Flexible Electronics.

Highly conductive, transparent, and easily available materials are needed in a wide range of devices, such as sensors, solar cells, and touch screens, as alternatives to expensive and unsustainable materials such as indium tin oxide. Herein, electrospinning was employed to develop fibers of PEDOT:PSS/silver nanowire (AgNW) composites on various substrates, including poly(caprolactone) (PCL), cotton fabric, and Kapton. The influence of AgNWs, as well as the applied voltage of electrospinning on the conductivity of fibers, was thoroughly investigated. The developed fibers showed a sheet resistance of 7 Ω/sq, a conductivity of 354 S/cm, and a transmittance value of 77%, providing excellent optoelectrical properties. Further, the effect of bending on the fibers' electrical properties was analyzed. The sheet resistance of fibers on the PCL substrate increased slightly from 7 to 8 Ω/sq, after 1000 bending cycles. Subsequently, as a proof of concept, the nanofibers were evaluated as electrode material in a triboelectric nanogenerator (TENG)-based energy harvester, and they were observed to enhance the performance of the TENG device (78.83 V and 7 μA output voltage and current, respectively), as compared to the same device using copper electrodes. These experiments highlight the untapped potential of conductive electrospun fibers for flexible and transparent electronics.

Investigations on Impact of YSZ Nanoparticles on Morphology & Electrical conductivity of PEDOT: PSS

Conductive polymer nanocomposites, which combine the flexibility and conductivity of polymers with the unique properties of nanofillers, have generated interest in various fields such as energy storage, sensors, coatings, and corrosion protection. This study discusses the effect of Yttria-stabilized zirconium nanoparticles (YSZ NPs) on the morphology and electrical conductivity of poly(3,4-ethylenedioxythiophene): poly(4-styrenesulfonate) (PEDOT: PSS). Thin films of PEDOT: PSS and PEDOT: PSS: YSZ were fabricated using spin coating technique. FTIR and XRD characterizations confirmed the interaction between YSZ nanoparticles and the PEDOT: PSS matrix, leading to changes in chemical morphology and film crystallinity. The investigation of the current-voltage (I-V) relationship showed improved electrical conductivity in PEDOT: PSS films with the addition of YSZ nanoparticles, with respective conductivities of 0.028×10−6 S cm−1 and 0.0885×10−4 S cm−1 for pristine and YSZ-containing films. Additionally, the sensing properties of the PEDOT: PSS: YSZ film in detecting organic vapours were studied. These findings suggest that these conducting polymer nanocomposite thin films could potentially be used as electrolyte components in battery cells, supercapacitors, and fuel cells, as well as serve as sensors for certain organic vapours.

Stimuli-responsive thin film composites of conducting polymers and cellulose nanocrystals for tissue engineering

Thin composite films comprising two primary representatives of conducting polymers, poly(3, 4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy), with eco-friendly cellulose nanocrystals (CNC) were prepared through electrochemical polymerization. The combination of CNC and PEDOT (or PPy) results in the formation of films with highly different surface topography and thickness. Intriguingly, different surface conductivity of PEDOT and PPy was revealed by atomic force microscopy albeit that the electrochemical properties were rather similar. The biological properties of the composites in contact with prospective human induced pluripotent stem cells (hiPSC) and cardiomyocytes derived from hiPSC demonstrated good cytocompatibility of both composites and their potential in engineering of electro-sensitive tissues. The as-prepared conducting, eco-friendly and cytocompatible composites are thus promising candidates for biomedical applications where stimuli-responsivity is a crucial cell-instructive property.

Improving the Performance of Si/PEDOT:PSS Hybrid Solar Cells with More Economical and Environmentally Friendly Alcohol Ether Solvents.

The photoelectric characteristics of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) films significantly affect the power conversion efficiency and stability of Si/PEDOT:PSS hybrid solar cells. In this paper, we investigated PEDOT:PSS modification with alcohol ether solvents (dipropylene glycol methyl ether (DPM) and propylene glycol phenyl ether (PPH)). The reduction of PSS content and the transformation of the PEDOT chain from benzene to a quinone structure in PEDOT:PSS induced by doping with DPM or PPH are the reasons for the improved conductivity of PEDOT:PSS films. DPM and PPH doping improves the quality of silicon with the PEDOT:PSS heterojunction and silicon surface passivation, thereby reducing the surface recombination of charge carriers, which improves the photovoltaic performance of Si/PEDOT:PSS solar cells. Comparing the power conversion performance (PCE) and air stability of Si/PEDOT:PSS solar cells with DPM (13.24%), DPH (13.51%), ethylene glycol (EG, 13.07%), and dimethyl sulfoxide (DMSO, 12.62%), it is suggested that doping with DPM and DPH can replace DMSO and EG to enhance the performance of Si/PEDOT:PSS solar cells. The EG and DMSO solvents not only have a certain toxicity to the human body but also are not environmentally friendly. In comparison to DMSO and EG, DPM and DPH are more economical and environmentally friendly, helping to reduce the manufacturing cost of Si/PEDOT:PSS solar cells and making them more conducive to their commercial applications.

Highly Conductive PEDOT:PSS Aerogels

AbstractPoly(3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate) (PEDOT:PSS) aerogel has attracted much attention in bioelectronics, electromagnetic shielding, and energy‐related systems due to its biocompatibility, intrinsic electronic conductivity, and favorable processability. However, fabrication of highly conductive and low‐density PEDOT:PSS aerogels is still challenging. In this work, highly conductive PEDOT:PSS aerogels are produced via ice‐templated pre‐assembly followed by a specially designed thawing process in H2SO4 solution. Upon optimization of heat and mass transfer during the thawing process, along with the unique ice template effect, the microstructure and thin walls of PEDOT:PSS frozen samples are well preserved. Importantly, the porous structure and thin walls facilitate diffusion of H2SO4 into polymer matrix, inducing phase separation of PEDOT:PSS, thus increasing PEDOT crystallinity and partially removing of PSS component. As a result, the as‐prepared pristine PEDOT:PSS aerogels exhibit a high electrical conductivity of 1200 ± 231 S m−1 along the freezing direction at a low density of 15.3 ± 1.5 mg cm−3, enhanced mechanical properties, and a competitive electromagnetic interference shielding efficiency of 25 115 dB cm2 g−1. Moreover, the compressed aerogels show good performances as active materials in symmetrical supercapacitors with thickness‐independent capacitance (maximum 2.1 F cm−2 at 1.0 mA cm−2) and in current collector‐free micro‐supercapacitors processed by laser carving.

Direct printing of conductive hydrogels using two-photon polymerization

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) based conductive hydrogels have been extensively used for bioelectronics and tissue engineering applications owing to their high electrical conductivity and ability to interface with soft biological tissues. However, the fabrication of PEDOT:PSS-based hydrogels has mostly relied on conventional fabrication techniques such as casting and transfer printing, which limits the feature size to micro- or mesoscale. To address these limitations, this study offers a novel PEDOT:PSS-based hydrogel material that can be printed directly to nano/microscale structures using the Two-Photon Polymerization (TPP) technique. The TPP-printability of the newly developed hydrogel was analyzed, and its printing window was characterized. The prepared hydrogel exhibits enhanced radial swelling, electrical properties, and biocompatibility compared to the pristine PEDOT:PSS. To validate the micro-manufacturing feasibility of hydrogel, several microstructures were fabricated using the TPP process. The fabricated microstructures demonstrate many properties, including electrical conductivity, biocompatibility, high resolution, and structural stability. The direct printing of highly conductive PEDOT:PSS hydrogel micro-devices overcomes the limitations of traditional conductive hydrogel manufacturing methods. It opens up new possibilities for applications in micro-energy storage devices, flexible micro/nanoelectromechanical systems (MEMS), and flexible biomedical micro-devices. The combination of high-resolution direct printing and unique hydrogel properties offers promising opportunities in these fields.

The mechanism of enhancing the conductivity of PEDOT: PSS films through molecular weight optimization of PSS

Poly(3,4-ethylenedioxythiophene) (PEDOT): poly (styrene sulfonic acid) (PSS) is a promising intrinsically conductive polymer. Researchers have been modifying PSS to enhance the conductivity of PEDOT: PSS films, however, the relationship between PSS molecular weight and PEDOT: PSS conductivity remains unclear. Herein, the conductivity mechanism is discussed in detail, and it is observed that, as the molecular weight of PSS increases, the conductivity initially increases but then decreases after reaching a peak. This behavior can be attributed to the different aggregation state structures, the degree of oxidation, and the molecular conformation of PEDOT. Specifically, the optimal PSS molecular weight leads to an increase in PEDOT crystallinity and the appearance of a continuous nanoproto-fiber morphology. Additionally, the highest degree of PEDOT oxidation and the largest molecular weight of PEDOT polymerized after reduction treatment, along with the transition from coiled-coil conformation to linear or swollen coils, synergistically increase the carrier mobility and carrier concentration, resulting in a significant improvement in electrical conductivity. However, further increase in PSS molecular weight leads to decreased crystallinity, reduced continuous crystal domains, lower PEDOT oxidation levels, and molecular weights, preventing the generation of effective charge pathways. The electrical conductivity mechanism reported here provides theoretical models and specific strategies for improving the electrical conductivity of thermoelectric, electromagnetic shielding, and bioelectronic materials.

Efficient Tin-Based Perovskite Solar Cell with a Cesium Acetate Pre-buried PEDOT:PSS Hole Transport Layer.

The strong Lewis acid tin halide leads to an excessively fast crystallization rate, resulting in more defects in the film and degraded device performance. In this work, a cesium acetate (CsAc) pre-buried poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transport layer acts as nucleation points during the crystallization of tin-based perovskite, which can induce preferential orientation growth of crystals and increase the grain size to improve the quality of crystallization. The addition of CsAc not only can increase the conductivity of PEDOT:PSS but also can improve the wettability of the perovskite precursor solution to enhance the interface contact between the hole transport layer and perovskite layer. Because of the incorporation of CsAc in PEDOT:PSS, the average short-circuit current density increases from 23.80 to 27.60 mA cm-2. Furthermore, a power conversion efficiency of 10.99% is achieved for a tin-based perovskite solar cell with CsAc-doped PEDOT:PSS as the hole transport layer.

A Novel and Green Method for Preparing Highly Conductive PEDOT:PSS Films for Thermoelectric Energy Harvesting.

As a π-conjugated conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is recognized as a promising environmentally friendly thermoelectric material. However, its low conductivity has limited applications in the thermoelectric field. Although thermoelectric efficiency can be significantly enhanced through post-treatment doping, these processes often involve environmentally harmful organic solvents or reagents. In this study, a novel and environmentally benign method using purified water (including room temperature water and subsequent warm water) to treat PEDOT:PSS film has been developed, resulting in improved thermoelectric performance. The morphology data, chemical composition, molecular structure, and thermoelectric performance of the films before and after treatment were characterized and analyzed using a scanning electron microscope (SEM), Raman spectrum, XRD pattern, X-ray photoelectron spectroscopy (XPS), and a thin film thermoelectric measurement system. The results demonstrate that the water treatment effectively removes nonconductive PSS from PEDOT:PSS composites, significantly enhancing their conductivity. Treated films exhibit improved thermoelectric properties, particularly those treated only 15 times with room temperature water, achieving a high electrical conductivity of 62.91 S/cm, a Seebeck coefficient of 14.53 μV K-1, and an optimal power factor of 1.3282 µW·m-1·K-2. In addition, the subsequent warm water treatment can further enhance the thermoelectric properties of the film sample. The underlying mechanism of these improvements is also discussed.

Boosting the Performance of PEDOT:PSS Based Electronics Via Ionic Liquids.

The conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) offers superior advantages in electronics due to its remarkable combination of high electrical conductivity, excellent biocompatibility, and mechanical flexibility, making it an ideal material among electronic skin, health monitoring, and energy harvesting and storage. Nevertheless, pristine PEDOT:PSS films exhibit limitations in terms of both low conductivity and stretchability; while, conventional processing techniques cannot enhance these properties simultaneously, facing the dilemma that highly conductive interconnected PEDOT:PSS domains are susceptible to tensile strain. Via modifying PEDOT:PSS with ionic liquids (ILs), not only a synergistic enhancement of the electrical and mechanical properties can be achieved but also the requirements for the printable bioelectronic are satisfied. In this comprehensive review, the task of providing a thorough examination of the mechanisms and applications of ILs as modifiers for PEDOT:PSS is undertaken. First, the theoretical mechanisms governing the interactions between ILs and PEDOT:PSS are discussed in detail. Then, the enhanced properties and the elucidation of the underlying mechanisms achieved through the incorporation of ILs are reviewed. Next, specific applications of ILs-modified PEDOT:PSS relevant to bioelectronic devices are presented. Last, there is a concise summary and a discussion regarding the opportunities and challenges in this exciting field.

Multifunctional Poly(3,4-ethylenedioxythiophene)/Crystalline Nanofibrous Cellulose Composites for Eco-Friendly and Sustainable Electronics.

Nanocellulose constitutes promising resources for next-generation electronics, particularly when incorporated with conductive polymers due to their abundance, renewability, processability, biodegradability, flexibility, and mechanical performance. In this study, electrically conducting cellulose nanofibers were fabricated through in situ chemical polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT) on the surface of sulfuric acid-treated cellulose nanofibers (SACN). The utilization of highly crystalline SACN extracted from tunicate yielded synergistic effects in PEDOT polymerization for achieving a highly conductive and molecularly uniform coating. Polymerization parameters, such as monomer concentration, molar ratio with oxidants, and temperature, were systematically investigated. High electrical conductivity of up to 57.8 S cm-1 was obtained without utilizing the classical polystyrenesulfonate dopant. The resulting nanocomposite demonstrates the unique advantages of both electrically conductive PEDOT and mechanically robust high-crystalline cellulose nanofibers. As a proof-of-applicational concept, an electrical circuit was drawn with SACN-PEDOT as the conductive ink on flexible paper using a simple commercial extrusion-based printer. Furthermore, the flame-retardant property of SACN-PEDOT was demonstrated owing to the high crystallinity of SACN, effective char formation, and high conductivity of PEDOT. The multifunctional SACN-PEDOT developed in this study shows great promise to be employed in versatile applications as a low-cost, ecofriendly, flexible, and sustainable electrically conductive material.

Lightweight, flexible, and conductive PEDOT:PSS coated polyimide nanofibrous aerogels for piezoresistive pressure sensor application

Conductive PEDOT:PSS-coated polyimide nanofibrous aerogels as piezoresistive pressure sensors.

Engineering of graphene-based composites with hexagonal boron nitride and PEDOT:PSS for sensing applications.

A unique nanomaterial has been developed for sweat analysis, including glucose level monitoring. Simple resusable low-cost sensors from composite materials based on graphene, hexagonal boron nitride, and conductive PEDOT:PSS (poly(3,4-ethylenedioxythiophene)polystyrene sulfonate) polymer have been developed and fabricated via 2D printing on flexible substrates. The sensors were tested as biosensors using different water-based solutions. A strong increase in the current response (several orders of magnitude) was observed for aqua vapors or glucose solution vapors. This property is associated with the sorption capacity of graphene synthesized in a volume of plasma jets and thus having many active centers on the surface. The structure and properties of graphene synthesized in a plasma are different from those of graphene created by other methods. As a result, the current response for a wearable sensor is 3-5 orders of magnitude higher for the reference blood glucose concentration range of 4-14 mM. It has been found that the most promising sensor with the highest response was fabricated based on the graphene:PEDOT:PSS composite. The graphene:h-BN:PEDOT:PSS (h-BN is hexagonal boron nitride) sensors demonstrated a longer response and the highest response after the functionalization of the sensors with a glucose oxidase enzyme. The reusable wearable graphene:PEDOT:PSS glucose sensors on a paper substrate demonstrated a current response of 10-10 to 10-5 A for an operating voltage of 0.5 V and glucose range of 4-10 mM.