Preparation and capacitive performances of PEDOT/indigo carmine composite hydrogel

In this article, indigo carmine (IC) was introduced into poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT‐PSS) hydrogel by in situ polymerization to prepare PEDOT/IC composite hydrogel. The structural characterization of PEDOT/IC composite hydrogel was analyzed by Fourier‐transform infrared spectroscopy (FTIR), UV–vis spectroscopy, X‐Ray diffraction (XRD), and Scanning electron microscopy (SEM). The results indicated that IC was successfully introduced into PEDOT‐PSS hydrogel. Electrochemical performances were investigated by cyclic voltammetry, galvostatic charge‐discharge, and electrochemical impedance technology. The specific capacitance of PEDOT‐PSS hydrogel was efficiently increased by the introduction of IC. The specific capacitance of PEDOT‐PSS hydrogel increased first and then decreased with the increase of the concentration of IC. The specific capacitance of PEDOT‐PSS hydrogel was increased from 38F/g to a maximum value of 123F/g (current density = 0.5 A/g) when the concentration of IC reached 5 mM. On the basis of cycle‐life tests, the capacitance retention of about 68% for the PEDOT/IC composite hydrogel after 5000 cycles suggested a high cycle stability of PEDOT/IC composite hydrogel and its potential as an electrode material for supercapacitor applications. POLYM. COMPOS., 34:989–996, 2013. © 2013 Society of Plastics Engineers     

New carbon nanotube–conducting polymer composite electrodes for drug delivery applications

A novel drug delivery system (DDS) based on a carbon nanotube (CNT)–poly(3,4‐ethylenedioxythiophene) (PEDOT) composite was constructed via a layering method. Single‐walled CNTs (SWNTs) were immobilized on a gold electrode using a layer‐by‐layer technique. In particular, cysteamine (Cys) was firstly bonded to the gold surface through the strong S? Au association and SWNTs were subsequently linked onto the Cys layer through condensation reaction of ? NH₂ and carboxyl groups by 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide/N‐hydroxysuccinimide coupling. X‐ray photoelectron spectroscopy and Raman spectroscopy demonstrate that this is a facile route for immobilizing CNTs on gold electrodes. Finally PEDOT was electropolymerized on the SWNT‐functionalized electrode to make a SWNT–PEDOT composite, and the modified electrode was applied as a DDS. Dexamethasone, as a model drug, was incorporated into PEDOT in the electropolymerization. Investigations of the electrochemical properties of SWNT–PEDOT demonstrate that SWNTs greatly improve the conductivity and increase the charge capacity of PEDOT. The composite exhibits a petal‐like surface structure, 20–30 nm thick and 100–200 nm wide. Compared to a DDS based on pure PEDOT synthesized under the same conditions, SWNT–PEDOT has the merits of higher drug release rate and larger release amount. The average mass release for every five voltammetry cycles increases from 1.4126 to 1.8864 mg cm^?2. Copyright © 2011 Society of Chemical Industry     

Effect of silver decorated graphene oxide on the PEDOT:PSS-matrix composite films

Silver decorated graphene oxide (GO) was added in poly(3,4-ethylenedioxythiopphene): poly(styrene sulfonate) (PEDOT:PSS) matrix to fabricate composite films, aiming for an improved electrical conductivity. Silver particles were deposited on GO surfaces by reaction with Tollens’ reagent. The composite films reinforced by silver decorated GO showed a sheet resistance of 744 Ω/sq. with 88.9% transparency, which outperformed PEDOT:PSS matrix and GO/PEDOT:PSS composite films. The deposited silver particles were consisted of elementary silver and positively charged silver. The GO surfaces were negatively charged. The distinction of positive domain and negative domain on silver decorated GO surfaces promoted the phase separation of conductive PEDOT molecules and insulting PSS molecules, which contributed to the increase of the electrical conductivity of the composite films. Moreover, the deposition of elementary silver introduced extra electron pathways in the composite films.     

Electrochemical immobilization of ascorbate oxidase in poly(3,4‐ethylenedioxythiophene)/multiwalled carbon nanotubes composite films

Immobilization of ascorbate oxidase (AO) in poly(3,4‐ethylenedioxythiophene) (PEDOT)/multiwalled carbon nanotubes (MWCNTs) composite films was achieved by one‐step electrochemical polymerization. The PEDOT/MWCNTs/AO modified electrode was fabricated by the entrapment of enzyme in conducting matrices during electrochemical polymerization. The PEDOT/MWCNTs modified electrodes were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The experimental results showed that the composite films exhibited better mechanical integrity, electrochemical activity, higher electronic and ionic conductivity, and larger redox capacitance compared with pure PEDOT films, which would be beneficial to the fabrication of PEDOT/MWCNTs/AO electrochemical biosensors. The scanning electron microscopy studies revealed that MWCNTs served as backbone for 3,4‐ethylenedioxythiophene (EDOT) electropolymerization. Furthermore, the resulting enzyme electrode could be used to determine L ‐ascorbic acid successfully, which demonstrated the good bioelectrochemical catalytic activity of the immobilized AO. The results indicated that the PEDOT/MWCNTs composite are a good candidate material for the immobilization of AO in the fabrication of enzyme‐based biosensor. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Capacitance properties of unipolar pulsed electro‐polymerized PEDOT films

Poly(3,4‐ethylenedioxythiophene) (PEDOT) film has been prepared on conductive carbon paper (CP) substrates by unipolar pulse electrochemical deposition. The effects of different polymerization parameters, including pulse potential and width, deposition frequency, and duty cycle on the capacitance of PEDOT films, were studied by cyclic voltammetry in 0.5 M sulfuric acid solution. The PEDOT‐coated CP electrode was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy to confirm the three‐dimensional porous structure and the presence of dopant ion conjugation during the electro‐polymerization. The results of cyclic voltammetry and galvanostatic charge‐discharge show that the PEDOT electrodes exhibit good specific capacitance of 151.31 F/g, rate performance and stability with a retention rate of 80.25% after 5000 cycles. The thin, lightweight electrode materials show considerable potential for low‐cost, high‐performance energy storage applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46729.     

Effect of microstructure on the dielectric properties of poly(vinyl alcohol)–poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonate) composite films

Poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT–PSS) was blended with poly(vinyl alcohol) (PVA) to form 0, 10, 20, 30, 40, and 50 vol % PEDOT–PSS/PVA solutions, and their freestanding films were prepared with a simple and cost‐effective solution casting technique at 27 °C in the absence of additives. Field emission scanning electron microscopy images revealed changes in the cocontinuous network to a rodlike morphology in the composite films from 10 to 50 vol % PEDOT–PSS/PVA. The alternating‐current conductivity was found to obey Jonscher's power law. The obtained values of the dielectric constant at 27 °C were relatively high, and a maximum value of 6.7 × 10⁴ at 100 Hz for 40 vol % PEDOT–PSS'/PVA was observed. The dielectric loss attained a maximum value of about 10⁶ at 100 Hz for 40 vol % PEDOT–PSS/PVA. However, a decrease in the dielectric parameters was observed at 50 vol % PEDOT–PSS/PVA because of locally induced strain in the microstructure. The variations in polarization with respect to the applied electric field (P–E) were determined for 50, 100, and 500 Hz at 500 V for the freestanding composite films of lower concentrations up to 20 vol % PEDOT–PSS/PVA. In summary, the dielectric and P–E measurements confirmed that the electrical characteristics changed in accordance to the contribution from both resistive and capacitive sites in the PEDOT–PSS/PVA composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45079.     

Electrically conductive poly(3,4‐ethylenedioxythiophene)–polystyrene sulfonic acid/polyacrylonitrile composite fibers prepared by wet spinning

Composite conductive fibers based on poly(3,4‐ethylenedioxythiophene) (PEDOT)–polystyrene sulfonic acid (PSS) blended with polyacrylonitrile (PAN) were prepared via a conventional wet‐spinning process. The influences of the PEDOT–PSS content on the electrical conductivity, thermal stability, and mechanical properties of the composite fibers were investigated. The fibers with 1.83 wt % PEDOT–PSS showed a conductivity of 5.0 S/cm. The breaking strength of the fibers was in the range 0.36–0.60 cN/dtex. The thermal stability of the PEDOT–PSS/PAN composite fibers was similar to but slightly lower than that of the pure PAN. The X‐ray diffraction results revealed that both the pure PAN and PEDOT–PSS/PAN composite fibers were amorphous in phase, and the crystallization of the latter was lower than that of the former. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of solvent on electrical conductivity and gas sensitivity of PEDOT: PSS polymer composite films

Poly(3,4‐ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS) was blended with polyethylene oxide (PEO) and polyvinyl alcohol (PVA) and composite film was cast. Additional solvents of dimethyl sulfoxide (DMSO) and ethylene glycol (EG) were mixed and their effects on electrical conductivity and structural changes were investigated. The electrical conductivity increased in response to the additional solvent, leading to an increase in the PEDOT ratio relative to the control. PEDOT:PSS/PEO composite film had a much higher electrical conductivity than PEDOT:PSS/PVA. When blended with PEO, the quinoid structure revealed by Raman spectroscopy increased relative to the PVA‐blended case, indicating higher electrical conductivity. The current–voltage response and gas sensitivity showed much better performance in PEDOT:PSS/PEO/DMSO composite film. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42628.     

Using water‐soluble nickel acetate as hole collection layer for stable polymer solar cells

We report polymer solar cells (PSCs) based on poly(3‐hexylthiophene (P3HT) and [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PCBM) using water‐soluble nickel acetate (Ni(CH₃COO)₂, NiAc) instead of acidic poly(3,4‐ethylenedioxythiophene) : poly(styrenesulfonate) (PEDOT : PSS) as hole collection layer (HCL) between the indium tin oxide (ITO) electrode and photoactive layer. The NiAc layer can effectively decrease R_s and increase R_p and shows effective hole collection property. Under the illumination of AM1.5G, 100 mW/cm², the short‐circuit current density (J_sc) of the NiAc based device (ITO/NiAc/P3HT : PCBM/Ca/Al) reach 11.36 mA/cm², which is increased by 11% in comparison with that (10.19 mA/cm²) of PEDOT : PSS based device (ITO/PEDOT : PSS/P3HT : PCBM/Ca/Al). The power conversion efficiency of the NiAc based devices reach 3.76%, which is comparable to that (3.77%) of the device with PEDOT : PSS HCL under the same experimental conditions. Moreover, NiAc based PSCs show superior long‐term stability than PEDOT : PSS based PSCs. Our work gives a new option for HCL selection in designing more stable PSCs. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A novel hierarchical Pt- and FTO-free counter electrode for dye-sensitized solar cell

A novel hierarchical Pt- and FTO-free counter electrode (CE) for the dye-sensitized solar cell (DSSC) was prepared by spin coating the mixture of TiO₂ nanoparticles and poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) solution onto the glass substrate. Compared with traditional Pt/FTO CE, the cost of the new CE is dramatically reduced by the application of bilayer TiO₂-PEDOT:PSS/PEDOT:PSS film and the glass substrate. The sheet resistance of this composite film is 35 Ω sq⁻¹ and is low enough to be used as an electrode. The surface morphologies of TiO₂-PEDOT:PSS layer and modified PEDOT:PSS layer were characterized by scanning electron microscope, which shows that the former had larger surface areas than the latter. Electrochemical impedance spectra and Tafel polarization curves prove that the catalytic activity of TiO₂-PEDOT:PSS/PEDOT:PSS/glass CE is higher than that of PEDOT:PSS/FTO CE and is similar to Pt/FTO CE''s. This new fabricated device with TiO₂-PEDOT:PSS/PEDOT:PSS/glass CE achieves a high power conversion efficiency (PCE) of 4.67%, reaching 91.39% of DSSC with Pt/FTO CE (5.11%).     

Electrochemical and spectroelectrochemical monitoring of supercapacitance and electrochromic properties of hydrous ruthenium oxide embedded poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) composite

A new composite film was prepared by depositing hydrous ruthenium oxide (RuO₂) particles into a polymer matrix comprising of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(styrene sulfonic acid) (PSS). The composite, PEDOT-PSS-RuO₂, showed an enhanced capacitance and optical properties due to the presence of RuO₂ particles in the composite. Specific capacitance of the PEDOT-PSS-RuO₂ composite was found to be 1409 F/g. After anodic polarization, the PEDOT-PSS-RuO₂ composite film exhibited enhanced visible-light coloration in comparison with PEDOT/PSS and simple RuO₂ films. Differential voltabsorptometric curves (dA/dt versus potential (derivative cyclic voltabsorptogram, DCVA)) were deduced for few selected wavelengths to characterize the optical properties. The changes in the electrochromic characteristics (in the visible region) of the composite is attributed mainly to transition of Ru(III) to Ru(IV). SEM images revealed the presence of smaller sized particles of hydrous ruthenium oxide in the composite film. The existence of smaller size RuO₂ particles having more active surface area is the reason for the enhanced capacitance and optical properties.     

Electrochemical performances of poly(3,4-ethylenedioxythiophene)-NiFe2O4 nanocomposite as electrode for supercapacitor

Poly 3,4-ethylenedioxythiophene (PEDOT)-based NiFe₂O₄ conducting nanocomposites were synthesized and their electrochemical properties were studied in order to find out their suitability as electrode materials for supercapacitor. Nanocrystalline nickel ferrites (5-20 nm) have been synthesized by sol-gel method. Reverse microemulsion polymerization in n-hexane medium for PEDOT nanotube and aqueous miceller dispersion polymerization for bulk PEDOT formation using different surfactants have been adopted. Structural morphology and characterization were studied using XRD, SEM, TEM and IR spectroscopy. Electrochemical performances of these electrode materials were carried out using cyclic voltammetry at different scan rates (2-20 mV/s) and galvanostatic charge-discharge at different constant current densities (0.5-10 mA/cm²) in acetonitrile solvent containing 1 M LiClO₄ electrolyte. Nanocomposite electrode material shows high specific capacitance (251 F/g) in comparison to its constituents viz NiFe₂O₄ (127 F/g) and PEDOT (156 F/g) where morphology of the pore structure plays a significant role over the total surface area. Contribution of pseudocapacitance (C_FS) arising from the redox reactions over the electrical double layer capacitance (C_DL) in the composite materials have also been investigated through the measurement of AC impedance in the frequency range 10 kHz-10 mHz with a potential amplitude of 5 mV. The small attenuation (∼16%) in capacitance of PEDOT-NiFe₂O₄ composite over 500 continuous charging/discharging cycles suggests its excellent electrochemical stability.     

High cycling stability and well printability poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate)/multi‐walled carbon nanotube nanocomposites via in situ polymerization applied on electrochromic display

A high cycling stability material and an additive manufacturing method are reported for the fabrication of solid electrochromic devices. The poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate)/multi‐walled carbon nanotube (PEDOT:PSS/MWCNT) nanocomposites were synthesized via in situ polymerization. A carboxymethyl cellulose gel was used as the ink vehicle for screen printing. The electrochromic (EC) performance of films patterned by screen printing was also examined. The results of characterization indicate that strong interfacial interactions occurred between PEDOT:PSS and the MWCNTs and the MWCNTs formed a network in these conducting polymers film, so the composite was more conductive than pure PEDOT:PSS. Devices containing PEDOT:PSS/MWCNTs were more stable after 1000 cycles, exhibited higher rate of ion exchange and faster increases in current. The composite containing 0.3 wt % MWCNTs also had a 23% higher color contrast (ΔE*) than pure PEDOT:PSS at 2.5 V applied voltages. The EC inks with well printability not only can be used to print large area films, but also can print fine lines and pixel‐type dots in displays. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45943.     

Morphological and electronic consequences of modifications to the polymer anode ‘PEDOT:PSS’

We present a microscopic and electronic investigation of the polymeric anode poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) used as an electrode in photovoltaic and single carrier diodes. PEDOT:PSS is processed from aqueous solution as a colloidal dispersion with excess PSS present. We modify the PEDOT:PSS solution by the addition of a high boiling point alcohol, glycerol, which is known to increase the conductivity of the spin-coated film. Atomic force microscopy indicates swelling and greater aggregation of the PEDOT-rich colloidal particles found in this system. Current-voltage characteristics of ‘hole-transporting’ diodes, formed with gold contacts, suggest less surface enrichment of PSS in the glycerol modified electrode. Through Kelvin probe microscopy, we find the surface potential of glycerol modified PEDOT:PSS decreases by approximately 0.12 eV, which we assign to a reduction in surface enrichment by PSS. Photovoltaic diodes, using a PFB:F8BT polymer blend as the photo-active layer, and glycerol modified PEDOT:PSS anodes are significantly improved as compared to those with unmodified PEDOT:PSS anodes. This is likely to be due to improved hole-injection from the active polymer film into the PEDOT:PSS anode. This emphasises the electronic consequences of the morphological reorientation of the PEDOT and PSS.     

High‐performing dye‐sensitized solar cells based on reduced graphene oxide/PEDOT‐PSS counter electrodes with sulfuric acid post‐treatment

Four kinds of counter electrodes are prepared with polystyrene‐sulfonate doped poly(3,4‐ethylenedioxythiophene) (PEDOT‐PSS) as basic material, reduced graphene oxide (rGO) sheets as additives and H₂SO₄ as treating agent. The cyclic voltammetry and Tafel polarization are measured to evaluate catalytic activity of these counter electrodes for /I^? redox couple. It is found that H₂SO₄ treated rGO and PEDOT‐PSS hybrid counter electrode (S/rGO/PEDOT‐PSS counter electrode) has the highest catalytic activity among these counter electrodes. Power conversion efficiency of the dye‐sensitized solar cell with S/rGO/PEDOT‐PSS counter electrode can attain to 7.065%, distinctly higher than that of the cells with the other three ones, owing to the great enhanced fill factor and short‐circuit current density. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42648.     

Preparation and performance of a transparent poly(3,4‐ethylene dioxythiophene)–poly(p‐styrene sulfonate‐co‐acrylic acid sodium) film with a high stability and water resistance

Poly(p‐styrene sulfonate‐co‐acrylic acid sodium) (PSA) from the copolymerization of acrylic acid sodium and p‐styrene sulfonate monomers were used to dope poly(3,4‐ethylene dioxythiophene) (PEDOT) to generate PEDOT–PSA antistatic dispersions. Compared to those of the PEDOT–poly(p‐styrene sulfonate sodium) (PSS), the physical and electrical properties of the PEDOT–PSA conductive liquids were much better. The PEDOT–PSA films possessed a better water resistance without a decrease in the conductivity. The sheet resistance of the PEDOT–PSA–poly(ethylene terephthalate) (PET) films was about 1.5 × 10⁴ Ω/sq with a 100 nm thickness, the same as the PEDOT–PSS–PET films. The transmittance of the PEDOT–PSA–PET films exceeded 88%. Furthermore, the environmental dispersity of the PEDOT–PSA antistatic dispersion was apparently improved by the dopant PSA so that the stability was extraordinarily promoted. Meanwhile, the water resistances of the PEDOT–PSA–PET and PEDOT–PSA films were also enhanced. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45163.     

Binder‐free porous PEDOT electrodes for flexible supercapacitors

Conducting polymers are attractive for potential applications in flexible electronic industries because of their unique advantages. To simplify the process of electrode preparation, porous poly(3,4‐ethylenedioxythiophene) (PEDOT) film electrodes without binder and conductive additive were synthesized facilely for flexible supercapacitors via an in situ solution micro polymerization at the surface of a soft etched tunnel aluminum (ETA) template at room temperature. The template was directly used as the current collector of electrodes. The morphologies of the samples and the template were compared using scanning electron microscopy (SEM), and the polymer molecular structure and composition were analyzed with Fourier‐transform infrared (FTIR) spectroscopy. Symmetric supercapacitors were assembled with the PEDOT electrodes, Celgard 2300 separator, and 1.0 M LiPF₆/EC+DMC+EMC (1 : 1 : 1 in volume) electrolyte. The electrochemical performance was evaluated using different techniques like galvanostatic charging/discharging tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The results from different current densities and scanning rates show the supercapacitors have good rate performance. The specific capacitance, energy density, and coulombic efficiency of the PEDOT supercapacitor can reach 69.0 F g^?1 (or 103.0 F m^?2), 24.0 Wh kg^?1, and ～95% at a current density of 0.2 A g^?1, respectively. Furthermore, the PEDOT electrodes exhibit relatively good cycle performance, and the capacitance retention ratio is ～72% after 1500 cycles. The electrode process was discussed. The results are comparable to that of the reported PEDOT, which indicates the applicability of the novel simple method of solution microreaction at the surface of a soft metal template to directly prepare binder‐free flexible electrodes. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42549.     

Non-covalent modification of graphene sheets in PEDOT composite materials by ionic liquids

An ionic liquid (IL) supported composite of poly(3,4-ethylene dioxythiophene) (PEDOT) and graphene oxide (GO) is presented. GO was dispersed in ILs and electropolymerization carried out after loading of EDOT to the dried dispersion. The content of GO was optimized to obtain high electrical conductivity of the composite material. The IL acts as the dispersant for GO and as dopant in the synthesis of PEDOT leading to films with a highly porous structure indicated from the scanning electron microscopy (SEM) images. Subsequently, GO was reduced electrochemically by cyclic voltammetry to obtain PEDOT/rGO composite films. The successful formation of composite materials was confirmed using Raman and X-ray photoelectron spectroscopy (XPS) techniques. XPS was also used to verify removal of oxygen-containing functional groups upon electrochemical reduction of the composite films. The electrochemical properties of PEDOT, PEDOT/GO and PEDOT/rGO were studied using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The results show that electrochemical reduction clearly increases the capacitance of the composite and furthermore the cycling stability. Such an increase could be obtained if >20 cycles, extending to highly negative potentials (−2.0 V), was used during the electroreduction of incorporated GO. Owing to the high porosity, favorable electrochemical properties and cycling stability these hybrid materials shows great potential towards supercapacitor applications.     

Dulse‐derived porous carbon–polyaniline nanocomposite electrode for high‐performance supercapacitors

Dulse‐derived porous carbon (DDPC)–polyaniline (PANI) nanocomposites were fabricated by a method based on the in situ chemical oxidation polymerization of aniline on DDPC. The characterization of the material showed that the nano‐PANI was grown on the surface of DDPC in the form of nanosticks or nanoparticles. The DDPC–PANI nanocomposites were further used as electrode materials for energy‐storage applications. Meanwhile, the effect of the amount of aniline on the electrochemical performance of DDPC–PANI was also investigated. The results show that a maximum specific capacitance of 458 F/g was achieved for the DDPC–PANI nanocomposites; this was higher than that of the DDPC electrode (218 F/g), and the PANI electrode (318 F/g). The specific capacitance of DDPC–PANI remained 66.0% of the initial value after 5000 cycles; this was higher than that of PANI (50.5%). Finally, a device of DDPC–PANI–activated carbon (AC) was assembled with DDPC–PANI as a positive electrode, which exhibited a high energy density of 9.02 W h/kg, which was higher than that of PANI–AC device. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45776.     

Synthesis of oxadiazole‐based polymers containing a carbazole–vinylene or fluorene–vinylene group and their hole‐injection/transport behavior in light‐emitting diodes

A series of conjugated (poly{N‐(2‐ethylhexyl)‐3,6‐carbazole–vinylene‐alt‐[(2,5‐bisphenyl)‐1,3,4‐oxadiazole]}) and nonconjugated (poly{N‐(2‐ethylhexyl)‐3,6‐carbazole–vinylene‐alt‐[(2,5‐bisphenol)‐1,3,4‐oxadiazole]}) and poly{9,9‐dihexyl‐2,7‐fluorene–vinylene‐alt‐[(2,5‐bisphenol)‐1,3,4‐oxadiazole]}) polymers containing oxadiazole and carbazole or fluorene moieties in the polymer backbone were synthesized with a multiple‐step procedure. The properties of the polymers, including the photophysical and electrochemical characteristics, could be fine‐tuned by adjustment of the components or structures in the polymer chains. The polymers were used to examine the hole‐injection/transport behavior as hole‐injection/hole‐transport layers in double‐layer indium tin oxide (ITO)/polymer/aluminum tris(8‐hydroxyquinoline)/LiF/Al devices by the determination of their energy levels. The effects of the polymers in these devices on the charge‐transport behavior were compared with a control device fabricated with poly(ethylenedioxythiophene) (PEDOT)–poly(styrene sulfonate) (PSS). Devices containing the synthesized polymers showed comparable adhesion to the ITO anode and good hole‐injection/transport performance. In addition, they exhibited higher electroluminescence over an identical range of current densities than the control device. This was attributed to the prevention of radiative exciton quenching caused by the PEDOT–PSS interfaces and the improvement of electron/exciton blocking due to the higher electron affinity of the synthesized polymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011