Preparation and characterization of water soluble and conducting poly(sodium 4-styrenesulfonate) doped poly(3,4-ethylenedioxythiophene)/multi-walled carbon nanotubes core–shell nanocomposites by in situ polymerization

Water soluble and conducting poly(sodium 4-styrenesulfonate) (PSSNa) doped poly(3,4-ethylenedioxythiophene) (PEDOT)/multi-walled carbon nanotubes (MWNTs) nanocomposites were synthesized by PSSNa functionalized MWNTs and 3,4-ethylenedioxythiophene (EDOT) in situ oxidation polymerization. In the process, MWNTs were functionalized by PSSNa via physicochemical interaction, PSS groups on the surface of MWNTs absorbed EDOT monomers and acted as counter ions during in situ polymerization, macromolecules of PEDOT growth on the surface of MWNTs formed a homogeneous core (MWNTs)–shell (PEDOT) nanostructure. Owing to water soluble PEDOT–PSSNa coating on the surface of MWNTs and the association of PSSNa acting as inter-linking between PEDOT and MWNTs, the core–shell nanostructures were dissolved in water forming stable aqueous solution with good transparence. The composite was more stable in the temperature range up to 300 °C and exhibited improved thermal stability at the range of 300–500 °C compared with PEDOT–PSSNa. Because of π–π interactions between MWNTs and PEDOT coatings as well as homogenously dispersion of MWNTs in PEDOT, conductivity of the composites at room temperature was increased by two orders of magnitude over PEDOT–PSSNa.     

PEDOT:PSS nano-gels for highly electrically conductive silver/epoxy composite adhesives

In this work, we report a methanol-facilitated approach to directly use aqueous Poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonate) (PEDOT:PSS) in the silver/epoxy composites for preparation of highly electrically conductive adhesives (ECAs) and an investigation of the interaction between PEDOT:PSS nano-gels and silver microflakes. PEDOT:PSS nano-gel (18?<?d?<?30 nm) aqueous dispersion is immiscible with epoxy resin and difficult to incorporate into the conventional silver-filled ECAs. To overcome this challenge, we used methanol to facilitate the dispersion of PEDOT:PSS and silver microflake in epoxy resin. The synergetic interactions between PEDOT:PSS and silver and the effect of methanol were investigated using dynamic light scattering (DLS), atomic force microscopy, Kelvin probe force microscopy, and scanning electron microscope. When PEDOT:PSS was exposed to methanol, its morphology changed from coil to coil/linear structure; the contact potential difference between silver microflake and PEDOT:PSS increased from 9.47 to 22.56 mV, showing an increased conductivity between PEDOT:PSS and silver microflake. It was found that the introduction of a small amount of PEDOT:PSS (0.1 wt%) to the conventional ECA with 60 wt% silver microflake remarkably improved the electrical conductivity from 104 to 386 S/cm. A significantly high conductivity of 2526 S/cm was achieved by further increasing the PEDOT:PSS concentration to 1 wt%. The impact of PEDOT:PSS on the adhesive bonding strength towards copper substrate was also examined; the bonding strength slightly decreased when <?1 wt% PEDOT:PSS was used, but abruptly dropped when PEDOT:PSS content was further increased beyond 1 wt%. The incorporation of the optimal 1 wt% PEDOT:PSS into conventional ECAs with 60% silver microflake greatly increased the electrical conductivities by 25 times with limited impact on the shear strength. The results provide insights to the synergetic interplay of conductive polymer and metallic fillers, and might have profound technical implications on the development of advanced conductive composites.     

Improved thermoelectric performance of PEDOT:PSS films prepared by polar-solvent vapor annealing method

To improve thermoelectric performance, polar-solvent vapor annealing (PSVA) method was introduced into the preparation of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films. The solvent vapors included dimethyl sulfoxide, ethylene glycol, N,N-dimethylformamide, N-methyl-2-pyrrolidone, and deionized water (H₂O). The PSVA-treated PEDOT:PSS films exhibited significantly enhanced electrical conductivity and the maximum value was up to 496 S cm^?1. Especially, utilizing the PSVA method, H₂O could also remarkably enhance the electrical conductivity of pristine PEDOT:PSS film from 0.2 to 57 S cm^?1. There was no distinct change for the Seebeck coefficient of PSVA-treated films with the significantly enhanced electrical conductivity, thereby a maximum power factor of 9.47 μW m^?1 K^?2 at room temperature was obtained. The effects of PSVA method on thermoelectric performance of PEDOT:PSS films were also investigated systematically by analyzing the changes in morphology, carrier mobility and carrier concentration. The results confirmed that PSVA-treated PEDOT:PSS films could obtain smoother morphologies and realize the simultaneous increase of carrier mobility and carrier concentration, which results in the improvement of the thermoelectric performance.     

Morphological characterization and analytical application of poly(3,4-ethylenedioxythiophene)-Prussian blue composite films electrodeposited in situ on platinum electrode chips

Electrochemical in situ preparation and morphological characterization of inorganic redox material-organic conducting polymer coatings as thin films on platinum electrodes are presented. Composite inorganic-organic coatings consist of Prussian blue (PB) and [poly(3,4-ethylenedioxythiophene)] (PEDOT), and PEDOT organic polymers doped with ferricyanide (PEDOT-FeCN). The PEDOT coating deposited from an aqueous solution containing the 3,4-ethylenedioxythiophene monomer and LiClO₄ as supporting electrolyte was used as a “reference” material (PEDOT-ClO₄). The composite coatings were prepared by electrochemical methods on platinum electrode chips, which consist of a 150 nm Pt layer deposited on 100-oriented standard 3″ silicon wafers. Electrochemical behavior of the composite inorganic-organic coatings is based mainly on inorganic component redox reactions. Different surface properties of the composite materials were studied. Thus, the roughness of the deposited films was measured by both atomic force microscopy (AFM) and profilometry, leading to roughness values ranging from 3 nm to 217 nm for PEDOT-ClO₄, and PEDOT-FeCN and PEDOT-PB coatings, respectively. AFM and Scanning Electron Microscopy pictures were also produced to characterize the film morphologies, and revealed a granular pattern of the deposited inorganic component inside the organic polymer matrix. Moreover, the adhesion properties of the composites were studied by AFM and proved to be very different from one material to the other depending on the film structure. The electrochemical responses of these composite coatings to H₂O₂ reduction were also investigated using chronoamperometry. A linear response over a concentration range from 1 × 10^− 4 to 1 × 10^− 5 M and a detection limit of 10 μM were obtained.     

Electrochemical preparation of composite coatings of 3,4-etylenodioxythiophene (EDOT) and 4-(pyrrole-1-yl) benzoic acid (PyBA) with heteropolyanions

The possibility of incorporating 4-(pyrrole-1-yl) benzoic acid, (PyBA), and heteropolyacids (SiMo₁₂) during the electrodeposition of poly (3,4-ethylenedioxythiophene), PEDOT, is demonstrated in the paper. The formed novel composite material was applied on the electrode surface as a moderately thin (ca. 0.9–1 μm thick) PEDOT/PyBA/SiMo₁₂ coating. The physicochemical identity of our composite coating was established with the use of electrochemical, spectroscopic, and microscopic techniques. The fact that carboxylate-containing PyBA units link with positively charged and PEDOT structures tend to improve the overall stability and adherence of composite coatings to glassy carbon and stainless steel. The PEDOT/PyBA composite serves as a stable host matrix for large negatively charged silicium heteropolymolybdates inorganic species. Consequently, due to the formation of denser polymeric structures and due to the existence of electrostatic repulsion effects, the large polyanion-containing composite coatings are capable of blocking the access of smaller pitting-causing anions (chlorides) to the surface of stainless steel.     

Fabrication of flexible conductive films derived from poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonic acid) (PEDOT:PSS) on the nonwoven fabrics substrate

In this research, conducting poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonic acid) (PEDOT:PSS) aqueous dispersion was synthesized at first via chemical oxidative polymerization and followed by mixing it with poly(styrene-r-butyl acrylate) P(St-BA) aqueous latex, creating a conductive material with outstanding stretchability. The elastic conductive composite were then film formed on the glass and poly(ethylene terephthalate) (PET) nonwoven fabric substrate by spin coating and dip coating, respectively. Composite films with various contents of PEDOT:PSS polymer (10–100 wt.%) had been prepared. From the conductivity measurements, the conductivity was still kept as high as 88 S cm⁻¹ even the PEDOT:PSS content was lowered to 10 wt.%. Furthermore, the elasticity of conductive films on the PET-nonwoven fabric substrate was evaluated by the 180° bending test repeating 100 times. With introducing soft P(St-BA) material in the PEDOT:PSS phase, the surface resistance increased merely 3–6 times after bending 100 times, while the surface resistance for pure PEDOT:PSS film could reach 18–20 times.     

A transparent,solvent-free laminated top electrode for perovskite solar cells

A simple lamination process of the top electrode for perovskite solar cells is demonstrated. The laminate electrode consists of a transparent and conductive plastic/metal mesh substrate, coated with an adhesive mixture of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS, and sorbitol. The laminate electrode showed a high degree of transparency of 85%. Best cell performance was achieved for laminate electrodes prepared with a sorbitol concentration of ~30 wt% per milliliter PEDOT:PSS dispersion, and using a pre-annealing temperature of 120°C for 10 min before lamination. Thereby, perovskite solar cells with stabilized power conversion efficiencies of (7.6 ± 1.0)% were obtained which corresponds to 80% of the reference devices with reflective opaque gold electrodes.     

The thermoelectric performance of carbon black/poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) composite films

Carbon black/poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (CB/PEDOT:PSS) composite films have been prepared by a spin-coating method. The morphology of the composite films was investigated by field emission scanning electron microscopy and atomic force microscopy. The thermoelectric properties of CB/PEDOT:PSS composite films were measured at room temperature. As the content of CB increased from 0 to 11.16 wt%, the electrical conductivity of the composite films first increased sharply and then decreased, while the Seebeck coefficient increased slowly. A highest power factor of 0.96 μWm^?1 K^?2 was obtained.     

导电聚3,4-乙撑二氧噻吩的制备及性能

以水为溶剂,分别选用对甲苯磺酸钠、高氯酸锂、硫酸钠为支持电解质,用电化学法合成聚3,4-乙撑二氧噻吩(PEDOT)膜。采用线性扫描伏安法(LSV)确定了合适的聚合电位;采用循环伏安法(CV)、电化学交流阻抗谱(EIS)研究了PEDOT膜的电化学行为。结果表明,掺杂阴离子种类对膜的循环伏安特性、EIS曲线等有很大的影响;此外研究了掺杂不同阴离子的PEDOT膜对电极的粘接性能,发现粘接性能也与阴离子种类有关。     

Thermoelectric properties of graphite-PEDOT:PSS coated flexible polyester fabrics

Flexible thermoelectric (TE) fabrics were prepared by dip coating of a mixture solution of water base colloidal graphite and dimethyl sulfoxide doped poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) on polyester fabric. The phase composition and morphology of the TE fabrics were investigated by X-ray diffraction and field emission scanning electron microscopy. The TE properties of the graphite-PEDOT:PSS coated fabrics with different graphite loadings were measured in the temperature range from 298 to 398 K. As the content of graphite increased from 5 to 20 wt%, the electrical conductivity of the graphite-PEDOT:PSS coated polyester fabrics decreased, while the Seebeck coefficient increased in the measured temperature range from 298 to 398 K. A maximum power factor of ~0.025 μWm^?1K^?2 at 398 K was obtained for the graphite-PEDOT:PSS coated fabric with 15 wt% graphite loading.     

Application of poly(3,4-ethylenedioxythiophene):polystyrenesulfonate in polymer heterojunction solar cells

In this study, p-type semiconducting polymer of acid, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS), has been employed as a hole-transporting electrode to fabricate organic polymer heterojunction photovoltaic cells. The results showed that the resultant poly(3-hexylthiophene): C₆₀ derivatives [6]-phenyl-C₆₁-butyric acid methyl ester (P3HT:PCBM)/PEDOT:PSS can significantly expand the light absorption range which was expected to enhance the sunlight excitation. The influences of annealing conditions and barrier layer on the photoelectric performances were investigated in detail, giving an optimized synthesis conditions: annealed temperature was at 120 °C for 90 min, the thickness of PEDOT:PSS film was approximately 3–4 μm, and the ratio of PCBM and P3HT was 1:2. The blended heterojunction consisting of PCBM and P3HT was used as charge carrier-transferring medium to replace I₃ ^?/I^? redox electrolyte, showing a short-circuit current of 4.30 mA cm^?2, an open-circuit voltage of 0.83 V, and a light-to-electric energy conversion efficiency of 2.37 % under a simulated solar light irradiation of 100 mW cm^?2. In addition, a solid-state polymer heterojunction photovoltaic cells with a short-circuit current of 3.59 mA cm^?2, an open-circuit voltage of 0.80 V, and a light-to-electric energy conversion efficiency of 1.9 % was successfully fabricated by simplifying the process.     

Preparation of a working electrode with a conducting PEDOT:PSS film and its applications in a dye-sensitized solar cell

This study investigates the applicability of a working electrode with a poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) film on a dye-sensitized solar cell (DSSC). This working electrode was designed and fabricated by inserting a PEDOT:PSS film between a fluorine-doped tin oxide (FTO) glass substrate and a layer of nanocrystalline TiO₂ particles (P-25). This study also examines the effects of annealing temperature and duration on the transmittance and microstructure of a PEDOT:PSS film as well as the power conversion efficiency of DSSC with this film. The power conversion efficiency of a DSSC with a PEDOT:PSS film (6.37%) substantially exceeds that of a conventional DSSC (4.24%). This result is attributed to the fact that this transparent and conductive PEDOT:PSS film deposited on the FTO glass substrate using a simple spin coating method substantially improves the short-circuit photocurrent per unit area and the fill factor of DSSC.     

Composite supercapacitor electrodes made of activated carbon/PEDOT:PSS and activated carbon/doped PEDOT

In this paper, we report on the high electrical storage capacity of composite electrodes made from nanoscale activated carbon combined with either poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) or PEDOT doped with multiple dopants such as ammonium persulfate (APS) and dimethyl sulfoxide (DMSO). The composites were fabricated by electropolymerization of the conducting polymers (PEDOT:PSS, doped PEDOT) onto the nanoscale activated carbon backbone, wherein the nanoscale activated carbon was produced by ball-milling followed by chemical and thermal treatments. Activated carbon/PEDOT:PSS yielded capacitance values of 640 F g^?1 and 26 mF cm^?2, while activated carbon/doped PEDOT yielded capacitances of 1183 F g^?1 and 42 mF cm^?2 at 10 mV s^?1. This is more than five times the storage capacity previously reported for activated carbon–PEDOT composites. Further, use of multiple dopants in PEDOT improved the storage performance of the composite electrode well over that of PEDOT:PSS. The composite electrodes were characterized for their electrochemical behaviour, structural and morphological details and electronic conductivity and showed promise as high-performance energy storage systems.     

Efficiency enhancement of polymer solar cells with Ag nanoparticles incorporated into PEDOT:PSS layer

In this study, large-sized silver nanoparticles (Ag NPs) (average size: 80 nm) have been introduced into the anodic buffer poly-(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer (thickness: about 55 nm) of poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester bulk heterojunction polymer solar cells. The results showed that the short-circuit current density can increase from 8.73 to 11.36 mA/cm², and power conversion efficiency increases from 2.28 to 2.65 % when 0.1 wt% Ag NPs was incorporated in PEDOT:PSS layer, corresponding to an efficiency improvement of 16.2 %. Absorption spectrums of the active layers indicate that large-sized Ag NPs have no clear contribution to optical absorption improvement. By measuring the conductivity of PEDOT:PSS films without and with Ag NPs and analyzing device structure of this polymer solar cell, it was founded that the improvements in power conversion efficiency was originated from higher conductivity of PEDOT:PSS layer incorporated with Ag NPs and the shorter routes for holes to travel to the anode.     

On the mechanism of conductivity enhancement in plasma treated poly(3,4-ethylenedioxythiophene) films

The conductive poly(3,4-ethylenedioxythiophene): p-toluene sulfonate (PEDOT : PTS) films were prepared by gas-phase polymerization using CVD technique. PEDOT : PTS films with better electrical performance were produced by the additional doping with O₂ plasma after vapor phase polymerization. The mechanism for this conductivity enhancement is studied through surface structural analyses using Raman and X-ray photoelectron spectroscopy (XPS). The increase in conductivity is likely to be due to the generation of new functional groups such as carboxyl and hydroxyl groups that are acted as a dopant and the removal of the impurities on PEDOT: PTS surface with plasma treatment.     

Influence of ethylene glycol vapor annealing on structure and property of wet-spun PVA/PEDOT:PSS blend fiber

In this study, blend fibers composed of poly(vinyl alcohol) and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) were prepared via wet-spinning technology. Ethylene glycol (EG) vapor annealing was employed to improve the electrical conductivity and tensile properties of blend fibers. The effects of EG vapor annealing on structures and properties of blend fibers were investigated in detail by analyzing the changes in chemical constituent and structure, molecular structure, surface morphology, surface chemical composition, electrical conductivity, and tensile properties. FTIR spectroscopy indicates that EG vapor annealing does not change the chemical constituent and structure of blend fibers. Raman spectroscopy shows that vapor annealing leads to conformational changes of PEDOT chains from benzoid structure to quinoid structure. AFM and SEM images show that surface morphology of blend fibers become smoother after vapor annealing. XPS measurement shows that EG vapor annealing induces significant phase separation between PEDOT and PSS, forming an enriched PSS layer on the surface of blend fibers, thus leading to a thinner insulating PSS layer between PEDOT grains. This conformational change is beneficial to improve the electrical conductivity of blend fibers. The resultant blend fiber reached conductivity up to 20.4 S cm^?1. The mechanical properties of blend fibers were also improved by EG vapor annealing, with the Young’s modulus and tensile strength increasing from 3.6 GPa and 112 MPa to 4.4 GPa and 132.7 MPa, respectively.     

乙腈对环己烷单体溶液中沉降聚合聚3,4-乙撑二氧噻吩涂层结构与光电性能的影响EI北大核心CSCD

为利用溶剂化效应来优化液相沉降聚合聚3,4-乙撑二氧噻吩(PEDOT)的结构和光电性能,将吸附Fe(OTs)3的聚对苯二甲酸乙二醇酯(PET)膜悬于含乙腈的EDOT环己烷溶液中,于60℃原位合成PEDOT涂层。以紫外-可见吸收光谱、X射线光电子能谱分析所合成PEDOT的共轭链结构和掺杂度,以四探针测量表面电阻,研究乙腈含量对合成PEDOT结构与性能的影响。当乙腈体积分数为0.05%时,添加的乙腈能抑制短共轭链的生成,提高掺杂度,在降低表面电阻的同时,改善透光率。乙腈体积分数在0.24%以内时,PEDOT的导电性随乙腈体积分数的上升而增加。当乙腈体积分数超过0.7%时,PEDOT中短共轭链数目增加,光电性能下降。当乙腈体积分数为8%时,由于吸附的Fe(OTs)_3溶解太快,无法在PET表面合成导电PEDOT膜。乙腈体积分数为0.24%时,获得的PEDOT膜的表面电阻可达174Ω,透光率80%,粘附力为5B级。     

Experimental study of culture for mouse fibroblast used conductive polymer films

The purpose of this study is to develop electrodes for electrical stimulation of the nervous system using conductive polymers, polypyrrole (PPy) and/or poly(3,4-ethylenedioxythiophene), PEDOT. We evaluated biocompatibility in fibroblast and/or myoblast of mouse. Cultured cells on PPy and/or PEDOT extended their neuritis and survived over a week. These experiments have demonstrated that conductive polymers such as PPy, PEDOT, etc. have high biocompatibility, and PPy and/or PEDOT are applicable to nerve stimulation electrodes.     

PEDOT:PSS as back contact for CdTe solar cells and the effect of PEDOT:PSS conductivity on device performance

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was studied as the back contact of Cadmium telluride (CdTe) solar cells and was compared with conventional Cu-based back contact. A series of PEDOT:PSS aqueous solutions with different conductivities were spin coated onto the glass/SnO2:F/SnO2/CdS/CdTe structures as back contact, and the PEDOT:PSS conductivity dependence of device performance was studied. It was found that PEDOT:PSS back contact with higher conductivity produces devices with lower series resistance and higher shunt resistance, leading to higher fill factor and higher device efficiencies. As the conductivity of PEDOT:PSS increased from 0.03 to 0.24 S/cm, the efficiency of the solar cell increased from 2.7 to 5.1 %. Methanol cleaning also played an important role in increasing the device performance. The efficiency of our best device with PEDOT:PSS back contact has reached 9.1 %, approaching those with conventional Cu/Au back contact (12.5 %).     

Polymeric anodes from poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) for 3.5% efficient organic solar cells

We present highly efficient indium tin oxide free polymer solar cells based on poly-(3-hexylthiophene-2,5-diyl) and C₆₁-bis-butric-acid-methyl-ester (P3HT:bisPCBM) comprising a polymeric anode from highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) formulations. The film conductivity was optimized by various additives. We found conductivities of almost 600 S/cm upon the addition of dimethylsulfoxide. The wetting properties of different PEDOT:PSS formulations were investigated by contact angle measurements. The optimized high conductivity in combination with the good film forming properties allow for the fabrication of highly efficient organic solar cells with an external power conversion efficiency of 3.5% with PEDOT:PSS as polymeric anode.