Electropolymerization of aniline in phosphonium‐based ionic liquids and their application as protective films against corrosion

Conductive polyaniline (PANI) films were deposited on mild steel by an electropolymerization technique in the presence of different types of phosphonium‐based ionic liquids, including tetrabutylphosphonium bromide, tetraoctylphosphonium bromide, and ethyltributylphosphonium diethylphosphate. The formation of the PANI films was followed by repetitive cyclic voltammetry scans and was confirmed with diffuse reflectance infrared Fourier transform spectroscopy. The morphology, surface roughness parameters, and grain sizes of these coatings were evaluated by atomic force microscopy. The corrosion behavior of the bare and PANI‐coated electrodes was investigated by potentiodynamic polarization, open‐circuit potential, and electrochemical impedance spectroscopy techniques in a simulated marine environment in 3.5 wt % aqueous NaCl solutions. The quantum chemical parameters of the PANI composite films were also calculated with parametric method 3, a semi‐empirical quantum mechanical method. The theoretical conclusions were found to be consistent with the reported experimental data. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43923.     

Electrical properties of nitric acid and DMSO treated PEDOT:PSS/n-Si hybrid heterostructures for optoelectronic applications

Organic/inorganic heterostructures are an emerging and interesting field of research for optoelectronics. In this work, an efficient organic/inorganic hybrid heterojunction between PEDOT:PSS and n-type Silicon has been fabricated for optoelectronic applications. Samples with varying thickness of PEDOT:PSS were prepared by spin coating technique and the electrical conductivity of organic layers was modified using DMSO as additive. Post fabrication, the hybrid heterostructures were treated with HNO₃ vapor so as to enhance the conductivity of the organic layer. Surface treatment with HNO₃ was found to lower the roughness of the organic layer and enhance the transparency of the layer. I–V characteristics reveal optimized behavior of HNO₃ treated PEDOT:PSS layer with a low Ideality factor (n~3.2) and a barrier height (Φ_B) of 0.8 eV. The findings of the study provide a promising efficient method to enhance the electrical and device properties of PEDOT:PSS/n-Si heterostructures for optoelectronic applications. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48952.     

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.     

Tricolor electrochromism of PEDOT film electrodeposited in mixed solution of boron trifluoride diethyl etherate and tetrahydrofuran: Hypsochromic effect

PEDOT [poly (3,4‐ethyldioxythiophene)] films have been electrochemically prepared in mixed solution of boron trifluoride diethyl etherate and tetrahydrofuran (BFEE‐THF). The film shows tricolor electrochromism which is claret red at ?0.8 V, light grey at 0.2 V, and sea blue at 1.0 V. The film retains 74% of the original electroactivity and unperturbed electrochromic behaviors after 3000 cycles indicating potential applications on EC devices. Spectroelectrochemistry indicates that the π‐π* transition absorption peak (λ_max) in the neutral state is located at 512 nm and the calculated energy gap (E_g) is 1.76 eV by the onset wavelength. Compared to the electropolymerization of PEDOT films in conventional solvent, tricolor electrochromism can be ascribed both to the low onset oxidation potential and polymerization rate in BFEE‐THF, which may result in a low conjugation length of PEDOT. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Variable‐emittance infrared electrochromic skins combining unique conducting polymers,ionic liquid electrolytes,microporous polymer membranes,and semiconductor/polymer coatings,for spacecraft thermal control

Variable emittance (ε) is a property vital for the increasing needs in thermal control of future microspacecraft. This article describes fabrication, function, and performance of thin‐film, flexible, variable‐emittance (V‐E) electrochromic skins that use a conducting polymer/‐Au/‐microporous membrane (CP/Au/µP) base, and a new, unique ionic liquid electrolyte (IonEl). Poly(aniline‐co‐diphenyl amine) with a long‐chain polymeric dopant is used as the CP. A unique, patented device design yields no barrier between the active, electrochromic CP surface and the external environment, except for a thin, infrared‐transparent semiconductor/polymer film that lowers solar absorptance [α(s)] and protects from atomic‐O/far‐UV. Use of the IonEl requires special activation methods. Data presented show tailorable ε variations from 0.19 to 0.90, Δε values of >0.50 (which is the highest reported thus far for any functional V‐E material, to our knowledge), α(s) < 0.35, and nearly indefinite cyclability. Extended space durability testing, including calorimetric thermal vacuum and continuous light/dark cycling over >7 months under space conditions (<10^?5 Pa vacuum, far‐UV), show excellent durability. Other data show resistance to solar wind, atomic‐O, electrostatic discharge, and micrometeoroids. These lightweight, inexpensive, advanced polymeric materials represent the only technology that can work with micro‐ (<20 kg) and nano‐ (<2 kg) spacecraft, thus eventually allowing for much greater flexibility in their design and potentially “democratizing” the entire space industry, for example, allowing small firms to launch their own, dedicated satellites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40850.     

Preparation and electrochemical performance of modified Ti3C2Tx/polypyrrole composites

MXenes with a large surface area have been widely studied to improve the pseudocapacitance of electrode materials by combining conductive polymer materials. In this article, a superficial strategy to enhance the electrochemical properties by in situ polymerization of a pyrrole monomer between the Ti₃C₂T_x layers modified with 1,5-naphthalene disulfonic acid (NA) and cetyltrimethylammonium bromide (CTAB) was investigated. It is found that polypyrrole (PPy) and Ti₃C₂T_x can be combined through strong interactions between each other, and the specific capacitance of the modified Ti₃C₂T_x/PPy composite was increased to a maximum value of 437 F g⁻¹, which was more than thrice higher than that of pure PPy. The composite also exhibited good cycling performance (76% capacitance retention after 1000 cycles). Moreover, owing to the synergistic effect between the PPy and Ti₃C₂T_x layers, the composite provided better electron or ion transfer and surface redox processes than that of pure PPy, which indicated that this composite can be used as a promising electrode material for supercapacitors. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47003.     

Interfacial polymerization of poly(2,5‐dimethoxyaniline) and its enhanced capacitive performances

The poly(2,5‐dimethoxyaniline) (PDMA) were synthesized through interfacial polymerization method using three various organic solvent/water reaction systems. As comparison with conventional chemical polymerized PDMA, the interfacial polymerization can produce uniform nanoparticular PDMA, especially for using high density (higher than water) solvent as organic phase. The capacitive performances of interfacial polymerized PDMA can be benefited from its uniform morphologies and loose packing structure. The specific capacitance of interfacial polymerized PDMA using carbon tetrachloride is 194 Fg^?1 at current density of 50 mA cm^?2, which has 59% enhancement over 122 Fg^?1 of conventional PDMA at the same current density. The energy density of interfacial polymerized PDMA is 39 Wh kg^?1 at current density of 5 mA cm^?2 and the power density is 28,421 W kg^?1 at current density of 50 mA cm^?2. The energy density has improvement in different extent as comparison with that of conventional PDMA. The enhanced capacitive performances can be attributed to the increased ionic conductivity induced by the loose molecular packing structure and uniform morphology produced by the interfacial polymerization process. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40666.     

Multifunctional polyaniline–tin oxide (PANI–SnO2) nanocomposite: Synthesis,electrochemical, and field emission investigations

Synthesis of PANI–SnO₂ nanocomposite has been performed using a simple two step chemical oxidative polymerization route. The structural, morphological and chemical properties of the as‐synthesized PANI–SnO₂ nanocomposite have been revealed by various characterization techniques such as SEM, TEM, XRD, FTIR, and XPS. Interestingly the as‐synthesized PANI–SnO₂ nanocomposite exhibits supercapacitance value of 721 F g^?1 with energy density 64 Wh kg^?1, which is noticed to be higher than that of pristine SnO₂ and PANI nanostructures. Furthermore, the galvanostatic charge–discharge characteristics revealed pseudocapacitive nature of the PANI–SnO₂ nanocomposite. The estimated values of charge transfer resistance and series resistance estimated from the Nyquist plot are found to be lower. Along with the supercapacitive nature, PANI–SnO₂ nanocomposite showed promising field emission behavior. The threshold field, required to draw emission current density of 1 μA/cm², is observed to be 0.90 V/μm and emission current density of 1.2 mA/cm² has been drawn at applied field of ～2.6 V/μm. The emission current stability investigated at preset values of 0.02 and 0.1 mA/cm² is observed to be fairly stable over duration of more than 3 h. The enhanced supercapacitance values, as well as, the promising field emission characteristics are attributed to the synergic effect of SnO₂ nanoparticles and PANI nanotubes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41401.     

Flexible polymer thermoelectric device based on PEDOT:PSS and surface treated pyromellitic dianhydride-oxydianiline polyimide substrate

Flexible polymer thermoelectric devices based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and pyromellitic dianhydride-oxydianiline polyimide polyimide (PI) were fabricated and investigated in this work. PI was selected as a substrate for PEDOT:PSS to secure from repeated bending cycles of flexible device. To enhance the interfacial adhesion between PEDOT:PSS and PI, oxygen plasma treatment was used on the surface of PI substrate. The effect of the surface treatment with oxygen plasma on the synthesized PI substrate was significant. The polar component of surface free energy of PI was increased from 2.8 to 31.8 mJ/m². The power factor of PEDOT:PSS on the PI substrate was increased from 25.86 to 43.78 μW m⁻¹ K⁻². Also, as a result of 10 k times of bending test, the electrical performance consistency and the mechanical stability of the fabricated devices were confirmed. This verified fabricated flexible polymer thermoelectric devices based on PEDOT:PSS and PI are suitable for the various applications.     

Preparation and characterization of a class of self-doping aromatic polyoxadiazole electrochromic materials

This article describes the preparation and characterization of six novel organic-soluble aromatic polyoxadiazole sulfonates (PODs) containing different side groups through sulfation polycondensation, which can undergo reversible redox reactions and self-doping. In order to further characterize its properties, they are assembled into solution type electrochromic devices (ECDs), which turn orange-yellow, purple, pink, deep pink, blue-ray green, and reddish-purple, respectively, by applying a voltage. The assembled ECDs show extremely high color contrast, which has a range from 34 to 97.6% at the maximum absorption wavelength in coloring state. These POD materials are n-doped type, so they have the potential to work with other p-doped electrochromic polymers to produce colorful devices.     

Electrochemical formation of poly(thionine) thin films: The effect of amine group on the polymeric film formation of phenothiazine dyes

The electropolymerization of thionine in an aqueous solution has been carried out by using both cycling voltammetry and chronoamperometry experiments. Electropolymerization has been applied at various pHs by using different working electrodes. The characterization of poly(thionine) thin films is performed by using cyclic voltammetry, current–time transients, atomic force microscopy, scanning tunnelling microscopy, ATR‐FTIR, and UV–vis absorption spectroscopy techniques. It is deduced from current–time transients and morphological data that poly(thionine) film forms with random adsorption process and exhibits an irregular polymeric film. Poly(thionine) film formation was compared with that of previously published results of phenothiazine derivatives of poly(azure A) and poly(methylene blue). It has been concluded that type of amine functional group of phenothiazine dyes is very effective on the formation of polymeric film structure. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39686.     

Electrochemical supercapacitor properties of polyaniline thin films in organic salt added electrolytes

We demonstrate optimized supercapacitive characteristics of electrodeposited polyaniline by adding organic salt into electrolyte. The optimum amount of the organic salt is found to be 2 wt % which provides better ionic conductivity of the electrolyte, leading to the improved specific capacitance of 259 Fg^?1. This capacitance remains at up to 208 Fg^?1 (80% capacity retention) after 1000 charge–discharge cycles. The optimized organic salt added electrolyte causes better rate performance and higher cyclability. Significantly reduced electrochemical charge transfer resistance at the electrode/electrolyte interface results in the increased ionic conductivity, which can be useful in electrochemically preferred power devices for better applicability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40306.     

Tunable morphology and resistivity of ternary polymer composites of carbon black/low density polyethylene/ethylene-vinyl acetate with carbon blacks having different surface properties

Medium to extra-high voltage electrical cables typically comprise a semiconductive polymer composite layer to homogenize the electromagnetic field through the cables. The semiconductive layers usually contain a high content of carbon black (CB) for reduced electrical resistivity. In this study, we found that both the morphology and resistivity of a ternary polymer composite of CB/low density polyethylene (LDPE)/ethylene-vinyl acetate (EVA) depend on CBs used and the order of addition. Three types of CB were investigated. CB-A, which has the lowest surface energy and the most uniform surface energy profile, exhibits a strong affinity to LDPE and always segregates in the LDPE phase whether it is first added in the LDPE phase or the EVA phase. CB-B and CB-C, which have higher and less homogeneous surface energies, distribute differently with different orders of addition. We observe a significant reduction in the percolation threshold of CB-A in the CB/LDPE/EVA composite, but not with CB-B or CB-C. Adding CB-A in the LDPE phase first results in substantially lower resistivity than adding it in the EVA phase first, whereas adding CB-B or CB-C in the LDPE phase first results in higher resistivity than adding them in the EVA phase first.     

Facile fabrication of superhydrophobic polyaniline structures and their anticorrosive properties

We report a simple approach for the preparation of superhydrophobic polyaniline (PANI) and its application for the corrosion protection coatings. First, PANI was synthesized conventionally by oxidative polymerization with APS. Subsequently, PANI with different wettability was obtained by modification with different surfactants. The surface modification of PANI with three different surfactants (sodium dodecylbenzenesulfonate, polyethylene glycol, and cetyltrimethylammonium bromide) provided excellent surface superhydrophobicity (water contact angle >150°). The structure and morphology of as‐prepared PANI were characterized with Fourier transform infrared, Energy dispersive X‐ray spectroscopy, and Scanning electron microscopy. Corrosion protection performance of PANI with different wettability was evaluated in 3.5% NaCl electrolyte using Tafel polarization curves and electrochemical impedance spectroscopy. The results indicated that various superhydrophobic PANI coatings have better anticorrosion performance as compared to the hydrophilic PANI. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44248.     

Synthesis and chemical properties of electrochromic π‐conjugated polyphenylenes with pendant viologen‐TCNQ salts

Polyphenylene (PP) with NH₂ side groups, namely, PFluNH ₂ , was synthesized by the Pd‐catalyzed reaction of 2,5‐dibromoaniline with 9,9‐dihexylfluorene‐2,7‐diboronic acid bis(1,3‐propanediol) ester. The reaction of PFluNH ₂ with 1‐hexyl‐1′‐(2,4‐dinitrophenyl)‐4,4′‐bipyridinium diiodide ( SaltBPy(I^?) ) eliminated 2,4‐dinitroaniline to yield PPs with viologen (1,1′‐disubstituted 4,4′‐bipyridinium dications), PFluBPy(I^?) . The reaction of PFluBPy(I^?) with Li⁺TCNQ ^? resulted in anion exchange between Cl ^? and TCNQ ^? , and yielded PFluBPy(TCNQ^?) . The reaction of PFluBPy(TCNQ^?) with the neutral TCNQ⁰ resulted in an interaction between TCNQ ^? and TCNQ⁰, and yielded PFluBPy(TCNQ^?‐TCNQ⁰) . Cyclic voltammetry measurements suggested that an electrochemical reduction of the viologen moiety and oxidation of the polymer backbone within PFluBPy(TCNQ^?) and PFluBPy(TCNQ^?‐TCNQ⁰) . Furthermore, this reaction was accompanied by electrochromism. The electric conductivities (σ) of the pellets molded from PFluBPy(TCNQ^?) to PFluBPy(TCNQ^?‐TCNQ⁰) were 2.7 × 10 ^{? 4} and 4.2 × 10 ^{? 4} Scm ^{? 1}, respectively; these σ values were higher than that observed for PFluNH ₂ (σ < 10 ^{? 8} Scm ^{? 1}) due to the self‐doping in the polymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of a conducting polyaniline/TiO2−SiO2 composites

Polyaniline/TiO₂?SiO₂ composites were prepared by an in situ chemical oxidation polymerization approach in the presence of hybrid TiO₂?SiO₂ fillers. The obtained polyaniline/TiO₂?SiO₂ composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FTIR), X‐ray diffraction (XRD), thermogravimetry (TG), and current?voltage (I?V) measurements. SEM picture shows a variation in morphology of polyaniline (PANI) from fiber shape to relatively regular particle shape with increasing TiO₂?SiO₂ contents in the composites. The floccule‐like structures were observed by high resolution TEM, which may help improve the efficiency of conductive network. SEM, XRD, TG, and FTIR spectra all reveal that a relatively strong interaction exist between TiO₂?SiO₂ and PANI. The I?V characteristics in such composites indicate that the charge transport is mainly governed by the space charge effects, which occurs at the interface between the conducting PANI and TiO₂?SiO₂. Meanwhile, PANI/TiO₂?SiO₂ composites exhibit significant increase in conductivity than PANI/TiO₂ or PANI/SiO₂. The reasons about high conductivity of PANI/TiO₂?SiO₂ have also been discussed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2288–2295, 2013     

In situ thermal polymerization of an ionic liquid monomer for quasi‐solid‐state dye‐sensitized solar cells

In situ thermal polymerization of a model ionic liquid monomer and ionic liquids mixture to form gel electrolytes is developed for quasi‐solid‐state dye‐sensitized solar cells (Q‐DSSCs). The chemical structures and thermal property of the monomers and polymer are investigated in detail. The effect of iodine concentration on the conductivity and triiodide diffusion of the gel electrolytes is also investigated in detail. The conductivity and triiodide diffusion of the gel electrolytes increase with the increasing I₂ concentration, while excessive I₂ contents will decrease the electrical performances. Based on the in situ thermal polymeric gel electrolytes for Q‐DSSCs, highest power conversion efficiency of 5.01% has been obtained. The superior long‐term stability of fabricated DSSCs indicates that the cells based on in situ thermal polymeric gel electrolytes can overcome the drawbacks of the volatile liquid electrolyte. These results offer us a feasible method to explore new gel electrolytes for high‐performance Q‐DSSCs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42802.     

Synthesis and spectroelectrochemistry of dithieno(3,2‐b:2′,3′‐d)pyrrole derivatives

New π‐conjugated polymers containing dithieno(3,2‐b:2′,3′‐d)pyrrole (DTP) were successfully synthesized via electropolymerization. The effect of structural differences on the electrochemical and optoelectronic properties of the 4‐[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl]aniline (DTP–aryl–NH₂), 10‐[4H‐dithiyeno(3,2‐b:2′,3′‐d)pirol‐4‐il]dekan‐1‐amine (DTP–alkyl–NH₂), and 1,10‐bis[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl] decane (DTP–alkyl–DTP) were investigated. The corresponding polymers were characterized by cyclic voltammetry, NMR (¹H‐NMR and ¹³C‐NMR), and ultraviolet–visible spectroscopy. Changes in the electronic nature of the functional groups led to variations in the electrochemical properties of the π‐conjugated systems. The electroactive polymer films revealed redox couples and exhibited electrochromic behavior. The replacement of the DTP–alkyl–DTP unit with DTP–aryl–NH₂ and DTP–alkyl–NH₂ resulted in a lower oxidation potential. Both the poly(10‐(4H‐Dithiyeno[3,2‐b:2′,3′‐d]pirol‐4‐il)dekan‐1‐amin) (poly(DTP–alkyl–NH₂)) and poly(1,10‐bis(4H‐dithieno[3,2‐b:2′,3′‐d]pyrrol‐4‐yl) decane) (poly(DTP–alkyl–DTP)) films showed multicolor electrochromism and also fast switching times (<1 s) in the visible and near infrared regions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40701.     

Matched‐dual‐polymer electrochromic lenses,using new cathodically coloring conducting polymers,with exceptional performance and incorporated into automated sunglasses

Reported are syntheses of several new monomer precursors of cathodically coloring conducting polymers (CPs), based on a propylene dioxythiophene skeleton. These are shown to yield CPs—both as homopolymers and as copolymers—that are nearly “perfectly” matched electrochemically and electrochromically with a set of anodically coloring poly(aromatic amines), for use in dual‐polymer electrochromic lenses. Resulting dual‐polymer electrochromic lenses display very high light/dark contrast (typically up to 70/7% or 50/0.5% Transmission (integrated over visible spectrum, vs. air reference), Haze < 2%, very high cyclability (> 10 K cycles), multiyear shelf life, appealing transparent to dark‐blue‐black transition, and excellent optical memory. Dramatic lowering of switching time, from 8 to < 1 s, is demonstrated using unique applied‐potential algorithm resident on inexpensive Microcontroller chip. Working, practical dual‐polymer electrochromic spectacles are demonstrated with electrochromic lenses retrofitted to spectacles meeting ANSI Z87.1, GL‐PD 10–12 (U.S. military) specifications. These incorporate photosensor, rechargeable Li battery, Microcontroller, allow for automated operation. Ab‐initio‐design spectacles, also conforming to above specifications, are also demonstrated, with components seamlessly hidden within frame. To the best of our knowledge, the electrochromic lenses and sunglasses reported herein represent the best visible‐region electrochromic performance for dual‐polymer CP electrochromic systems to date and the first practical implementation in working sunglasses. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41043.     

Effect of CuBr2 salt treatment on the performance of nanocolloidal PPy:PSS multilayer thin film counter electrodes of dye‐sensitized solar cells

A thin Pt layer on fluorine‐doped tin oxide (FTO) glass is commonly used as the counter electrode (CE) for dye‐sensitized solar cells (DSCs). We have investigated thin layers on FTO glass made from spherical polypyrrole (PPy)–poly(styrene sulfonate) (PSS) nanocolloidal particles with and without treatment of CuBr₂ and used them as CEs. The colloidal polymer composite (PPy:PSS) was spin‐coated at 4000 rpm, and PPy:PSS multilayer (one, three, five) films were employed as the CEs. Aqueous solutions of CuBr₂ (0.5 M and 1 M) were coated onto the multilayer CEs, which increased the efficiency of DSCs. When compared with the untreated PPy:PSS counter electrodes, the CuBr₂‐treated PPy:PSS films showed lower charge‐transfer resistance, higher surface roughness, and improved catalytic performance for the reduction of . The enhanced catalytic performance is attributed to the interaction of the superior electrocatalytic activity of PPy:PSS and CuBr₂ salt. Under standard AM 1.5 sunlight illumination, the counter electrodes based on a single‐layer PPy:PSS composite with 0.5 M and 1 M CuBr₂ salt treatment demonstrated power conversion efficiencies (PCE) of 5.8% and 5.6%, respectively. These values are significantly higher than that of the untreated PPy:PSS CE and are comparable with that of a Pt CE. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43772.