Aqueous PEDOT Research Articles

PEDOT:PSS-based electronic “paper” with high surface-interface and mechanical strength and ultra-long wet-resistant capacity

Organic electrochromic conducting polymers (CPs) are at the forefront of flexible and ultra-thin display electronics. Solution processable poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) exhibits excellent electrical and electrochemical behavior in line with great processability, stability, and other promising properties. However, their uses are limited by the weak mechanical properties, wet instability, as well as inevitable conflicts among different functionalities and structural characteristics, etc. In this study, we designed and fabricated a high-mechanical-strength electronic “paper”, PEDOT:PSS/PEG-UPy film, employed a thermoplastic polyurethane poly(ethylene glycol)-2-amino-5-(2-hydroxyethyl)-6-methylpyrimidin-4-ol (PEG-UPy) using diverse processing (drop coating, spin coating, blade coating and 3D printing) of its “electric ink (E-ink)” from the mechanical mixture of its isopropanol (IPA) solution with aqueous PEDOT:PSS dispersion. Compared to PEDOT:PSS film, the incorporation of supramolecular chain-expanding unit 2-amino-4-hydroxy-6-methylpyrimidine (UPy) into the PEG-UPy molecular backbone resulted into optimized self-supporting (substrate-free) film of PEDOT:PSS/PEG-UPy(10 wt%) which showed great flexibility, enhanced mechanical strength (elongation at break 47.08 %, tensile strength of 19.16 MPa, toughness 7.973 MJ m−3), considerable electrical properties (0.509 S cm−1), desirable physical properties including resistance to abrasion and solvent-wiping, and excellent surface-interface properties (e.g., hardness of 3H, adhesion of level 0, glossiness of 91). Its electrochromic capabilities include an optical contrast (ΔT) value of 67 %, a fast redox reaction (4 s and 3 s, respectively), and a coloring efficiency (722.19 cm2 C−1). Similar to paper, they can be easily tailored or folded into a variety of forms, but have greater advances on dense morphology, flat surface, considerable optical transparency (79.5 %), as well as robust resistance to mechanical damage (in the case of bending, stretching, and folding, etc.), water (immersing > 150 days), and dirt. The combined effect of molecular design of PEG-UPy, abundant hydrogen-bonded cross-linking interaction and “good” solvent effect of IPA to PEDOT:PSS play important roles in this system. This is the first work on solution processable PEDOT:PSS-based electrochromic “paper” being able to meet much comprehensive performance requirements for the application in practical complex working environment.

Stretchable, stabilized‐conductive XNBR/PEDOT:PSS composites based on bottom‐deposited structure

AbstractConductive composites have attracted much attention due to its high conductivity, stretchability, and sensitivity. However, designing conductive composites with relatively stable conductivity under 100% deformation using simple methods remains a challenge. In this work, we employ a simple and straightforward approach to prepare a poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) solution. Based on the conductivity‐optimized PEDOT:PSS (5.95 S/cm), it was combined with carboxylated acrylonitrile‐butadiene rubber latex (XNBRL) to make a flexible conductive material with a unique bottom‐deposited structure. The incorporation of PEDOT:PSS establishes an interconnected conductive network within the XNBR, enhancing both the tensile strength (from 0.31 to 1.24 MPa) and conductivity of the composites. Remarkably, even at 100% strain, the resistance change (ΔR/R0) in the composite remains minimal (<2), demonstrating its exceptional flexibility and high electrical conductivity while maintaining relatively stable resistance during cyclic stretching at 50% deformation. Moreover, the conductive composite can maintain good relative resistance stability under different tensile rates and different strains. This conductive XNBR/PEDOT:PSS composite has promising application prospects in medical devices, which require relatively stable and high conductivity over a relatively large deformation.Highlights A simple method to increase the electrical conductivity of aqueous PEDOT:PSS. Flexible conductive composite with a small change in ΔR/R0. Enables rigid PEDOT to be used in stretchable electronic devices. Construction of 3D conductive network and bottom deposition structure.

Mechanisms of methanol detection in graphene oxide and conductive polymer active layers for gas sensing devices

The admixture of PEDOT:PSS with Graphene Oxide (GO) in precise proportions achieves a substantial reduction in electrical resistivity, thereby augmenting its suitability as an electrode in organic devices. This study explores the electrical and morphological attributes of commercial PEDOT:PSS and chemically synthesized aqueous PEDOT ink when both are combined with GO. The investigation extends to the application of these conductive inks as active layers in flexible methanol sensing devices. Notably, a resistivity minimum is observed in the case of GO:PEDOT:PSS 78%, while the highest response to methanol is attained with GO:PEDOT:PSS 68%. To establish a theoretical underpinning for these findings, and to understand the interaction between gas/vapors with nanostructured materials, a model rooted in Kirchhoff’s Circuit approach is developed, with the aim of elucidating the factors behind the resistivity minimum and response maximum at distinct specific mass ratios between PEDOT and GO. Calculating the equivalent resistivity and response of the systems, the positions of minimum and maximum points are in agreement with the experimental data. Furthermore, the influence of PSS in the samples is examined, unveiling diverse interaction mechanisms between methanol molecules and the active layer, resulting in varying signals during the exposure to alcoholic vapor. The theoretical model is subsequently applied to these systems, demonstrating qualitative and quantitative agreement with the experimental results.

Design and construction of a flexible conductor based on a complex conductive polymer: PEDOT:PSS/polyaniline and its application as a pressure sensor

Cotton fibers are the most widely used fiber in the production of textiles and garments. Because of their flexibility and toughness, they are more durable and easier to incorporate into clothing than other inorganic materials. This paper presents flexible, conductive, and functional smart textiles based on a complex of PEDOT:PSS and polyaniline, without using dopants. The interaction between polyaniline and the aqueous PEDOT:PSS solution leads to the formation of a new complex polymer. The polymer exhibits high electrical conductivity because of the interaction between its components, and an increase in the conductivity of the intramolecular backbones of both polyaniline and PEDOT. The effect of complex concentration on the electrical conductivity of electronic textiles is studied using a small fixed amount of PEDOT:PSS and different concentrations of polyaniline. We proved that the sheet resistance of the conductive complex polymer fabric depends on the amount of polyaniline and reaches a minimum value of 0.714 kΩ/□ at a polyaniline concentration of 49.24 wt%. The conductive textiles based on the PEDOT:PSS/polyaniline complex show semiconducting metal behavior in the temperature range from room temperature to 160 °C. These treated textiles perform well as electrical sensors when pressure is applied, causing the electrical resistance to decrease. When the pressure is removed, the resistance returns to its original value.

Intrinsic thermal stability of inverted perovskite solar cells based on electrochemical deposited PEDOT

Thermal stability of perovskite materials is an issue impairing the long-term operation of inverted perovskite solar cells (PSCs). Herein, the thermal attenuation mechanism of the MAPbI3 films that deposited on two different hole transport layers (HTL), poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and poly(3,4-ethylenedioxythiophene) (PEDOT), is comprehensively studied by applying a heat treatment at 85 °C. The thermal stress causes the mutual ions migration of I, Pb and Ag through the device, which leads to the thermal decomposition of perovskite to form PbI2. Interestingly, we find that I ions tend to migrate more towards electron transport layer (ETL) during heating, which is different with the observation of I ions migration towards HTL when bias pressure is applied. Moreover, the use of electrochemical deposited PEDOT as HTL significantly decreases the defect density of MAPbI3 films as compared to PEDOT:PSS supported one. The electrochemical deposition PEDOT has good carrier mobility and low acidity, which avoids the drawbacks of aqueous PEDOT:PSS. Accordingly, the inverted PSCs based on PEDOT show superior durability than that with PEDOT:PSS. Our results reveal detailed degradation routes of a new kind of inverted PSCs which can contribute to the understanding of the failure of thermal-aged inverted PSCs.

Optimizing Conducting Polymer Top Electrodes for Nonfullerene Organic Solar Cells

AbstractPoly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is a promising solution‐processed electrode for printable organic solar cells (OSCs). PEDOT:PSS‐based top electrode has been used in fullerene OSCs, but hasn't been successfully used in nonfullerene OSCs. The PEDOT:PSS electrode suffers energy level mismatch with emerging nonfullerene active layers and poor wettability on the top of those active layers. In this work, two types of PEDOT (alcohol‐dispersed PEDOT:F and aqueous PEDOT:PSS PH1000) are combined to fabricate efficient top electrodes for nonfullerene OSCs. The alcohol‐dispersed PEDOT:F solves the issues of the energy level mismatch and poor wetting. PEDOT:PSS is transfer‐printed onto the PEDOT:F to obtain high electrical conductivity for hole collection. Nonfullerene OSCs with the PEDOT:F/PEDOT:PSS polymer top electrodes (vacuum‐free processing) show power conversion efficiency of 12.46% based on PM6:Y6:PC71BM active layer.

Laser-induced porous graphene from PEDOT:PSS films for dye-sensitized solar cells

• 3D porous graphene was firstly fabricated from PEDOT:PSS by a laser-scribing method. • Sheet resistance and morphology of LIG can be easily tuned by changing laser power. • LIG shows enhanced photovoltaic performance as a counter electrode for DSSCs. For the emerging laser-induced graphene (LIG) technologies, the exploration of laser irradiation interactions with various polymers and their new applications remains challenging. Herein, we report a novel strategy for the fabrication of 3D porous graphene electrodes from the aqueous PEDOT:PSS dispersion by a 445-nm diode laser in ambient air. By adjusting the laser power, LIG films exhibit a sheet resistance as low as 50 Ω/sq and their morphologies can change from a carbonized surface to a hierarchical porous structure. The dye-sensitized solar cell with a LIG70 counter electrode achieved a power conversion efficiency of 3.66%, which is over four times that of the pristine PEDOT:PSS electrode (0.80%). This work demonstrates the great potential for the application of PEDOT:PSS-based LIG films in photovoltaic devices.

Autonomous Chemistry Enabling Environment-Adaptive Electrochemical Energy Storage Devices

Autonomous Chemistry Enabling Environment-Adaptive Electrochemical Energy Storage Devices

Electrochemical performance of passivated antimonene nanosheets and of in-situ prepared antimonene oxide-PEDOT:PSS modified screen-printed graphite electrodes

Herein, we present the production of antimonene nanosheets and the in-situ preparation of antimonene oxide/PEDOT:PSS nanocomposite via tip sonication of bulk β-phase antimony in water and aqueous PEDOT:PSS, respectively. Nanomaterials were characterized via SEM, EDX, XRD, FT-IR, electrochemical impedance spectroscopy and cyclic voltammetry, while the resulting modified graphite screen-printed electrodes (Sbene/SPE and Sbene oxide/PEDOT:PSS/SPE, respectively) were evaluated in the cathodic determination of 4-nitrotoluene (4-NT), which was used as a model compound, in the presence of dissolved oxygen and in deoxygenated environments. Data document the electrochemical passivation of Sbene/SPE, which, on the one hand, demonstrate a beneficial poor activity towards the oxygen reduction reaction, and on the other hand, enhanced detection capabilities, thus allowing the determination of 4-NT at the micromolar concentration level at non-deoxygenated solutions. As a result, passivated Sbene/SPE show great promise in sensing applications outside of the laboratory where the deoxygenation of the samples is a big obstacle. Moreover, data demonstrate enhanced detection capabilities for Nafion membrane protected Sbene oxide/PEDOT:PSS/SPE, in deoxygenated solutions, which exhibit a detection range from 50 to 5000 nM 4-NT, while achieving an LOD of 16.7 nM (S/N 3). Nafion membrane is essential for the reusability of the electrodes. Sbene oxide/PEDOT:PSS/SPE was also used to the analysis of a spiked river water sample. Recovery was 97.9%.

Enabling water-free PEDOT as hole selective layer in lead-free tin perovskite solar cells.

Metal halide perovskites are set to revolutionise photovoltaic energy harvesting owing to an unmatched combination of high efficiency and low fabrication costs. However, to improve the sustainability of this technology, replacing lead with less toxic tin is highly desired. Tin halide perovskites are approaching 15% in power conversion efficiency (PCE), mainly employing PEDOT:PSS as a hole-selective layer. Unfortunately, PEDOT:PSS is processed from an aqueous solution, which is hardly compatible with the strict anoxic requirements for processing tin halide perovskites due to tin's instability to oxidation. Here, we present a water-free PEDOT formulation for developing tin-based lead-free perovskite solar cells. We show that the main difference between the PCE of devices made from aqueous and water-free PEDOT is due to the marked hydrophobicity of the latter, which complicates the perovskite deposition. By modifying the surface of water-free PEDOT with a thin Al2O3 interlayer, we could achieve good perovskite morphology that enabled perovskite solar cells with a PCE of 7.5%.

Conductive ink based on PEDOT nanoparticles dispersed in water without organic solvents, passivant agents or metallic residues

Poly(3,4-ethyledioxythiophene), or PEDOT, is a well-known polymer used in organic electronics due to its high electrical conductivity, flexibility and optical transparency. This study proposes a simple and fast method to obtain a conductive ink based on PEDOT aqueous dispersion, stable for months without surfactants, polymers, or additives, formed by polymer nanoparticles with low metallic content. PEDOT was obtained by oxidative polymerization of the monomer with anhydrous iron(III) chloride in acetonitrile. The obtained solid was washed and the residue content is decreased to lower than 0.5%. Fresh polymerized and wet PEDOT was sonicated in water and resulted in aqueous ink with concentration up to 1.145 g L−1, stabilized by electrostatic repulsion. This conductive ink was deposited via air-brush technique on glass substrates and has formed conductive and transparent thin films with sheet resistances of 1 and 20 kΩ sq−1 and transmittances at 550 nm of 50% and 80% respectively. Those electrodes have PEDOT distributed over macroscopic distances and recovering the entire substrates, which shows the great potential of the aqueous PEDOT ink as well as the deposition technique to be used in organic electronic devices.

Planar Organic‐Si Hybrid Solar Cell with MoOx Mixed PEDOT:PSS as Hole Injection Layer Profits from Mo5+ and Mo6+ Synergistic Effects

AbstractPoly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole injection layer plays an important role in planar Si/PEDOT:PSS heterojunction solar cells (HSCs). Herein, a MoOx mixed aqueous PEDOT:PSS cosolvent is developed and is applied into a Si/PEDOT:PSS solar cell preparation via a time‐saving one‐step spin‐coating method. With an optimal concentration of MoOx dopants, the power conversion efficiency of the device exhibits from 10.26% up to 13.82% with all inherent photovoltaic parameters enhanced. The detailed characterization and analytical results indicate that an advanced electronic property is produced by MoOx dopants and interface optimization caused by synergistic effects from Mo5+ and Mo6+ species with PEDOT:PSS, which enhances its interface work function and promotes hole transportation capacity. The result paves a path for exploring efficient Si/PEDOT:PSS HSCs with suitable functional material and a simple solution‐processable method.

Design of Potassium-Selective Mixed Ion/Electron Conducting Polymers.

An approach providing cation-selective poly-(3,4-ethylenedioxythiophene)(PEDOT):polyelectrolyte-mixed conductors is presented in this communication based on the structural modification of this ambivalent (ionic and electronic conductive) polymer complex. First, an 18-crown-6 moiety is integrated into the styrene sulfonate monomer structure as a specific metal cation scavenger particularly targeting K+ versus Na+ detection. This newly functionalized monomer is characterized by 1 H NMR titration to evaluate the ion selectivity. Aqueous PEDOT dispersion inks containing the polymeric ion-selective moieties are designed and their electrical and electrochemical properties analyzed. These biocompatible inks are the first proof-of-concept step towards ion selectivity in view of their interfacing with biological cells and microorgans of interest in the field of biosensors and physiology.

Human sweat monitoring using polymer-based fiber

Lightweight nano/microscale wearable devices that are directly attached to or worn on the human body require enhanced flexibility so that they can facilitate body movement and overall improved wearability. In the present study, a flexible poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) fiber-based sensor is proposed, which can accurately measure the amount of salt (i.e., sodium chloride) ions in sweat released from the human body or in specific solutions. This can be performed using one single strand of hair-like conducting polymer fiber. The fabrication process involves the introduction of an aqueous PEDOT:PSS solution into a sulfuric acid coagulation bath. This is a repeatable and inexpensive process for producing monolithic fibers, with a simple geometry and tunable electrical characteristics, easily woven into clothing fabrics or wristbands. The conductivity of the PEDOT:PSS fiber increases in pure water, whereas it decreases in sweat. In particular, the conductivity of a PEDOT:PSS fiber changes linearly according to the concentration of sodium chloride in liquid. The results of our study suggest the possibility of PEDOT:PSS fiber-based wearable sensors serving as the foundation of future research and development in skin-attachable next-generation healthcare devices, which can reproducibly determine the physiological condition of a human subject by measuring the sodium chloride concentration in sweat.

The Mechanism of Dedoping PEDOT:PSS by Aliphatic Polyamines.

Poly(3,4-ethylenedioxythiophene) blended with polystyrenesulfonate and poly(styrenesulfonic acid), PEDOT:PSS, has found widespread use in organic electronics. Although PEDOT:PSS is commonly used in its doped electrically conducting state, the ability to efficiently convert PEDOT:PSS to its undoped nonconducting state is of interest for a wide variety of applications ranging from biosensors to organic neuromorphic devices. Exposure to aliphatic monoamines, acting as an electron donor and Brønsted–Lowry base, has been reported to be partly successful, but monoamines are unable to fully dedope PEDOT:PSS. Remarkably, some—but not all—polyamines can dedope PEDOT:PSS very efficiently to very low conductivity levels, but the exact chemical mechanism involved is not understood. Here, we study the dedoping efficacy of 21 different aliphatic amines. We identify the presence of two or more primary amines, which can participate in an intramolecular reaction, as the key structural motif that endows polyamines with high PEDOT:PSS dedoping strength. A multistep reaction mechanism, involving sequential electron transfer and deprotonation steps, is proposed that consistently explains the experimental results. Finally, we provide a simple method to convert the commonly used aqueous PEDOT:PSS dispersion into a precursor formulation that forms fully dedoped PEDOT:PSS films after spin coating and subsequent thermal annealing.

Analysis of impact dynamics and deposition of single and multiple PEDOT:PSS solution droplets

In line with recent efforts and developments in emerging printed electronics, using solution-processed coatings, we studied the impact dynamics and deposition of single and multiple polymeric aqueous and isopropanol (IPA)-diluted PEDOT:PSS solution droplets, across seven orders of magnitude timescale. The solution properties and release height of droplets from a needle were varied to generate Weber numbers in the range of 94–510, with two Ohnesorge numbers of 0.0108 and 0.0195, for aqueous and IPA-diluted PEDOT:PSS solution droplets, respectively. The former droplet on FTO glass substrate is partially wetting, whereas the latter is fully wetting, generating different phenomena in the prolonged wetting and drying time. The solutions showed shear-thinning behavior at high shear rates, but viscosity immediately reached a saturated limit at higher shear rates and, therefore, the fluids behaved as Newtonian fluids during impact. Among the results, the addition of IPA resulted in improved spreading of PEDOT:PSS in the wetting phase, with wetting trend following the Tanner’s law. We then assessed the prediction power of existing models to predict maximum spreading, taking into account the role of measured static and dynamic contact angles during spreading. Multiple droplets (2, 5, and 15) were impacted nearly simultaneously and formed lines and films. We examined the bridge formation, spreading length growth, and shape evolution of multiple coalescing droplets. We also correlated the formed surface area with the number of coalescing droplets and discussed the ideality of the shape of the formed film. The results of this study will help to pave the way for large-scale manufacturing of organic coatings using droplet-based methods.

Printing of µm structures with nano inks using a novel combination of high‐resolution plasma printing and subsequent rotogravure printing

In this paper, we investigated reel‐to‐reel area‐selective microplasma treatment of polymer films using the plasma printing technique in combination with subsequent rotogravure printing. The aim was to explore whether and how the plasma printing pretreatment could contribute to increase print resolution with conductive nano inks on flexible polymer substrates. Substrate materials tested included films of biaxially oriented polyester and polypropylene. As the plasma process gas, a nonflammable mixture of 97% N2 and 3% H 2 was used. Novel microplasma sources developed during the course of this work achieved satisfactory plasma modification effects for the control of ink‐wetting patterns at process speeds of up to 3 m/min. In the case of biaxially oriented polypropylene (BOPP) film, this value was six times higher than the process speeds using previous microplasma sources. The reproduction accuracy achieved with these process parameters was typically better than 1.5% for structures with widths as low as 10 µm. Organic solvent and water‐based ink systems with silver and PEDOT:PSS as conductive components were tested in the rotogravure process following the area‐selective plasma pretreatment. In the combined plasma printing and gravure printing process, a resolution as good as 50 µm, was achieved using an aqueous PEDOT:PSS‐based ink. Conductive tracks produced on BOPP with this ink also passed the tape test for adhesion.

Pure PEDOT:PSS hydrogels

Hydrogels of conducting polymers, particularly poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), provide a promising electrical interface with biological tissues for sensing and stimulation, owing to their favorable electrical and mechanical properties. While existing methods mostly blend PEDOT:PSS with other compositions such as non-conductive polymers, the blending can compromise resultant hydrogels’ mechanical and/or electrical properties. Here, we show that designing interconnected networks of PEDOT:PSS nanofibrils via a simple method can yield high-performance pure PEDOT:PSS hydrogels. The method involves mixing volatile additive dimethyl sulfoxide (DMSO) into aqueous PEDOT:PSS solutions followed by controlled dry-annealing and rehydration. The resultant hydrogels exhibit a set of properties highly desirable for bioelectronic applications, including high electrical conductivity (~20 S cm−1 in PBS, ~40 S cm−1 in deionized water), high stretchability (> 35% strain), low Young’s modulus (~2 MPa), superior mechanical, electrical and electrochemical stability, and tunable isotropic/anisotropic swelling in wet physiological environments.

Selective Coating of SnS on the Bio‐Inspired Moth‐Eye Patterned PEDOT:PSS Polymer Films

AbstractA new strategy for the selective coating of tin sulfide (SnS) on the surface of moth‐eye patterned (MEP) conducting polymer film is studied by considering the optical properties of the antireflective moth‐eye pattern and flexibility of polymer films. The semiconductor SnS is selectively coated on the surface of MEP microdomes of poly(3,4‐ethylenedioxythiophene) poly(styrene‐sulfonate) (PEDOT:PSS) film. The SnS coated MEP film is obtained by using pore selectively SnS thin layer functionalized polystyrene honeycomb‐patterned porous (HCP) film as a template. Aqueous PEDOT:PSS solution is poured on the SnS functionalized HCP films and detached for the fabrication of SnS coated MEP films. The films show a satisfactory photo‐responsive property under solar stimulated light illumination due to the antireflective MEP structure of PEDOT film and homogenous SnS coating on the surface of the conducting polymer.

Roll-to-Roll Fabrication of PEDOT:PSS Stripes Using Slot-Die Head With <inline-formula> <tex-math notation="LaTeX">$\mu$ </tex-math> </inline-formula>-Tips for AMOLEDs

Stripe coating offers an approach to remove the pixel bank structure used to confine ink droplets. For potential application in solution-processable active-matrix organic light-emitting diode displays, we fabricate fine and dense stripes of poly(3,4-ethylenedioxythiophene): poly(4-styrenesulfonate)(PEDOT:PSS) using a slot-die head with the dual plate (shim plate with slit channels and meniscus-guiding plate with μ-tips as narrow as pixels). We analyze the flow distribution of the aqueous PEDOT:PSS solution near the μ-tip by varying the dual-plate configuration (μ-tip width, μ-tip length, and shim plate thickness) together with the process variable (i.e., coating speed) and offer design guidelines for the roll-to-roll fabrication of a fine stripe pattern. It can be achieved by reducing the μ-tip length as well as the shim plate thickness and increasing the coating speed until the flow breaks up. This scheme also enables us to raise the stripe density without defects. It is found that the μ-tip length is crucial for coatings of dense stripes. If μ-tip is long, it is not feasible to fabricate dense stripes regardless of the shim plate thickness due to an increase in resistance to flow. It is also found that the wettability of the solution serves as one of the critical parameters that determine the stripe profiles. We have fabricated 100 stripes with the average width of 227 μm and interstripe width nonuniformity as low as 9.2%. Finally, we have fabricated organic light-emitting diodes (OLEDs) atop the conductive PEDOT:PSS stripes and successfully obtained light emission from OLED stripes.